From d60fa9e565a2811436b6e788dc602fa4a513f855 Mon Sep 17 00:00:00 2001
From: Face o' Cat <face@modcrafters.net>
Date: Sat, 7 Nov 2026 11:38:36 +0200
Subject: [PATCH 1/9] Harden machine inventories and add inherited screens with
 processor controls

---
 gradle.properties                             |   1 +
 scripts/companion.gradle                      |   8 +-
 scripts/generate_gui_sprites.py               |  31 +-
 .../moddev/mc/companion/CompanionMod.java     |  21 +-
 .../mc/companion/CreativePowerEntity.java     |   8 +-
 .../moddev/mc/companion/ProcessorEntity.java  | 130 +++---
 .../mc/companion/RecoveryCapsuleItem.java     |  14 +-
 .../mmdlib/screen/base_powered_machine.xml    |  16 +
 .../resources/mmdlib/screen/crusher.xml       |   5 +-
 .../resources/mmdlib/screen/dual_crusher.xml  |  56 ++-
 .../resources/mmdlib/screen/transmuter.xml    |  28 +-
 .../companion/test/CompanionClientSmoke.java  |  14 +-
 .../mc/companion/test/CompanionGameTests.java | 139 ++++++
 .../test/InventoryLifecycleTests.java         | 144 +++++++
 .../test/ProcessorButtonClientSmoke.java      | 192 +++++++++
 .../test/ReservationClientSmoke.java          |   8 +
 .../mc/companion/test/StatsClientSmoke.java   |  34 +-
 .../api/automation/AutomationInventory.java   |  15 +-
 .../mc/lib/api/capabilities/FluidStorage.java | 129 +++++-
 .../mc/lib/api/capabilities/ItemStorage.java  | 134 +++++-
 .../lib/api/capabilities/StorageRecovery.java |  29 ++
 .../mc/lib/gui/client/MachineScreen.java      |  36 +-
 .../mc/lib/gui/client/RedstoneDrawer.java     |  16 +-
 .../moddev/mc/lib/gui/load/ScreenBinder.java  |  16 +-
 .../moddev/mc/lib/gui/load/ScreenLoader.java  |  63 ++-
 .../moddev/mc/lib/gui/load/ScreenReader.java  | 176 ++++++--
 .../mc/lib/gui/load/ScreenTemplates.java      | 129 ++++++
 .../zone/moddev/mc/lib/gui/model/Element.java |  15 +-
 .../lib/gui/model/ProcessorButtonState.java   |  24 ++
 .../zone/moddev/mc/lib/gui/model/Screen.java  |  23 +-
 .../mc/lib/gui/runtime/AutomationMenu.java    |   4 +-
 .../mc/lib/gui/runtime/MachineMenu.java       |  30 ++
 .../mc/lib/gui/runtime/RedstoneMenu.java      |  18 +
 .../moddev/mc/lib/gui/runtime/ScreenHost.java |   5 +
 .../runtime/ScreenInventoryValidation.java    |  55 +++
 .../mc/lib/gui/runtime/ScreenSnapshots.java   |  13 +
 .../mc/lib/machine/feature/FeatureHost.java   |  36 +-
 .../lib/machine/feature/MachineFeature.java   |   3 +
 .../lib/machine/feature/RecipeProcessor.java  |  18 +
 .../neoforge/MachineInventoryLifecycle.java   | 145 +++++++
 .../machine/neoforge/MachineResources.java    | 201 +++++++++
 .../machine/neoforge/RecipeInputFilters.java  |  79 ++++
 .../lib/machine/neoforge/StorageGroups.java   |   8 +-
 .../resources/assets/mmdlib/lang/en_us.json   |   9 +
 .../gui/sprites/icon_processor_conflict.png   | Bin 0 -> 83 bytes
 .../gui/sprites/icon_processor_pause.png      | Bin 0 -> 97 bytes
 .../gui/sprites/icon_processor_play.png       | Bin 0 -> 108 bytes
 .../gui/sprites/icon_processor_stop.png       | Bin 0 -> 91 bytes
 .../gui/sprites/icon_redstone_paused.png      | Bin 0 -> 96 bytes
 .../gui/sprites/icon_redstone_running.png     | Bin 0 -> 96 bytes
 .../mmdlib/textures/gui/sprites/icon_stop.png | Bin 0 -> 96 bytes
 src/main/resources/mmdlib/schema/screen.xsd   |  68 ++-
 .../lib/smoke/InventoryArchitectureSmoke.java | 400 ++++++++++++++++++
 .../moddev/mc/lib/smoke/MMDLibGameTests.java  |  34 +-
 .../mc/lib/gui/ProcessorButtonTest.java       | 100 +++++
 .../mc/lib/gui/ScreenInheritanceTest.java     | 258 +++++++++++
 .../moddev/mc/lib/gui/ScreenLoaderTest.java   | 114 +++--
 57 files changed, 2940 insertions(+), 312 deletions(-)
 create mode 100644 src/companion/resources/mmdlib/screen/base_powered_machine.xml
 create mode 100644 src/companionTest/java/zone/moddev/mc/companion/test/InventoryLifecycleTests.java
 create mode 100644 src/companionTest/java/zone/moddev/mc/companion/test/ProcessorButtonClientSmoke.java
 create mode 100644 src/main/java/zone/moddev/mc/lib/api/capabilities/StorageRecovery.java
 create mode 100644 src/main/java/zone/moddev/mc/lib/gui/load/ScreenTemplates.java
 create mode 100644 src/main/java/zone/moddev/mc/lib/gui/model/ProcessorButtonState.java
 create mode 100644 src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenInventoryValidation.java
 create mode 100644 src/main/java/zone/moddev/mc/lib/machine/neoforge/MachineInventoryLifecycle.java
 create mode 100644 src/main/java/zone/moddev/mc/lib/machine/neoforge/MachineResources.java
 create mode 100644 src/main/java/zone/moddev/mc/lib/machine/neoforge/RecipeInputFilters.java
 create mode 100644 src/main/resources/assets/mmdlib/textures/gui/sprites/icon_processor_conflict.png
 create mode 100644 src/main/resources/assets/mmdlib/textures/gui/sprites/icon_processor_pause.png
 create mode 100644 src/main/resources/assets/mmdlib/textures/gui/sprites/icon_processor_play.png
 create mode 100644 src/main/resources/assets/mmdlib/textures/gui/sprites/icon_processor_stop.png
 create mode 100644 src/main/resources/assets/mmdlib/textures/gui/sprites/icon_redstone_paused.png
 create mode 100644 src/main/resources/assets/mmdlib/textures/gui/sprites/icon_redstone_running.png
 create mode 100644 src/main/resources/assets/mmdlib/textures/gui/sprites/icon_stop.png
 create mode 100644 src/runtimeTest/java/zone/moddev/mc/lib/smoke/InventoryArchitectureSmoke.java
 create mode 100644 src/test/java/zone/moddev/mc/lib/gui/ProcessorButtonTest.java
 create mode 100644 src/test/java/zone/moddev/mc/lib/gui/ScreenInheritanceTest.java

diff --git a/gradle.properties b/gradle.properties
index 37d916dd..bee48734 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -36,6 +36,7 @@ curios_version = 9.5.1+1.21.1
 curios_version_range = [9.5.1,10)
 sophisticated_backpacks_version = 1.21.1-3.26.20.2244
 sophisticated_core_version = 1.21.1-1.5.28.2458
+jade_version = 15.10.6+neoforge
 
 # Gradle
 org.gradle.jvmargs = -Xmx3G
diff --git a/scripts/companion.gradle b/scripts/companion.gradle
index 161c0953..bcd58c75 100644
--- a/scripts/companion.gradle
+++ b/scripts/companion.gradle
@@ -7,7 +7,7 @@ sourceSets {
         compileClasspath += sourceSets.companion.output + sourceSets.companion.compileClasspath
         runtimeClasspath += sourceSets.companion.output + sourceSets.companion.runtimeClasspath
     }
-    // Mock GameTest connections cannot negotiate Curios' login-sync payloads.
+    // Mock GameTest connections cannot negotiate Curios/Jade login-sync payloads.
     // Reuse the compiled fixtures, but keep optional mods for real client/server smoke runs.
     companionServerTest {
         runtimeClasspath += sourceSets.companionTest.output + sourceSets.companion.output + sourceSets.main.output + sourceSets.main.runtimeClasspath
@@ -18,6 +18,12 @@ neoForge.addModdingDependenciesTo(sourceSets.companion)
 neoForge.addModdingDependenciesTo(sourceSets.companionTest)
 neoForge.addModdingDependenciesTo(sourceSets.companionServerTest)
 
+// Jade is present in playable companion and real-client smoke runs, including their integrated server.
+// Keep mock GameTest connections isolated, as with Curios below; publish neither runtime fixture.
+dependencies {
+    companionRuntimeOnly "maven.modrinth:jade:${jade_version}"
+}
+
 // Development fixtures only: do not add backpack APIs or required mod metadata to either jar.
 // -PwithoutBackpacks retains a companion run without Curios or backpack mods.
 if (!providers.gradleProperty('withoutBackpacks').isPresent()) {
diff --git a/scripts/generate_gui_sprites.py b/scripts/generate_gui_sprites.py
index 55e930b7..6382ba63 100644
--- a/scripts/generate_gui_sprites.py
+++ b/scripts/generate_gui_sprites.py
@@ -275,17 +275,44 @@ def glyph(img, rows, x, y, ink):
                 if bit != ".": img[y + dy][x + dx] = ink
 
     pause = ["##...##"] * 9
+    stop = ["#######"] * 7
     play = ["#......", "###....", "#####..", "#######", "#######", "#####..", "###....", "#......"]
     letters = {"a": [".#.", "#.#", "###", "#.#", "#.#"],
                "b": ["##.", "#.#", "##.", "#.#", "##."]}
-    for name, rows, ink in (("pause", pause, (240, 198, 70, 255)),
+    for name, rows, ink in (("stop", stop, (232, 86, 72, 255)),
+                            ("pause", pause, (240, 198, 70, 255)),
                             ("resume", play, (100, 216, 112, 255))):
-        for lane in ("", "a", "b"):
+        for lane in (("",) if name == "stop" else ("", "a", "b")):
             img = canvas(16, 16)
             glyph(img, rows, 3 if lane else 4, 2 if lane else 3, ink)
             if lane: glyph(img, letters[lane], 11, 9, grey(245))
             write_png("icon_" + name + ("_" + lane if lane else ""), img)
 
+    # Native 12px sprites for the compact processor controls: no 16-to-12 scaling.
+    # All three glyphs, including their shadow, occupy the same centered 8x8 box.
+    for name, rows, ink in (
+        ("pause", ["##...##"] * 7, (240, 198, 70, 255)),
+        ("stop", ["#######"] * 7, (232, 86, 72, 255)),
+        ("play", ["#......", "###....", "#####..", "#######", "#####..", "###....", "#......"], (100, 216, 112, 255)),
+    ):
+        img = canvas(12, 12)
+        glyph(img, rows, 2, 2, ink)
+        write_png("icon_processor_" + name, img)
+
+    for name, rows, ink in (
+        ("running", ["#....", "###..", "#####", "###..", "#...."], (100, 216, 112, 255)),
+        ("paused", ["##.##"] * 5, (240, 198, 70, 255)),
+    ):
+        img = canvas(7, 7)
+        glyph(img, rows, 0, 0, ink)
+        write_png("icon_redstone_" + name, img)
+
+    img = canvas(5, 5)
+    for y, row in enumerate([".###.", "#####", "#####", "#####", ".###."]):
+        for x, bit in enumerate(row):
+            if bit == "#": img[y][x] = (244, 55, 55, 255)
+    write_png("icon_processor_conflict", img)
+
     torch = [".###.", "#####", "#####", ".###.", "..#..", "..#..", "..#..", "..#..", "..#.."]
     badges = {"ignore": ["#.#", ".#.", "#.#"],
               "high": [".#.", "###", ".#."], "low": ["...", "###", "..."]}
diff --git a/src/companion/java/zone/moddev/mc/companion/CompanionMod.java b/src/companion/java/zone/moddev/mc/companion/CompanionMod.java
index 187adaeb..218889ef 100644
--- a/src/companion/java/zone/moddev/mc/companion/CompanionMod.java
+++ b/src/companion/java/zone/moddev/mc/companion/CompanionMod.java
@@ -92,18 +92,15 @@ public CompanionMod(IEventBus bus) {
             id("tank_container"),
             MaterialEventTypes.GUI_CLICK,
             CompanionMod::transferTankContainer);
-    for (int lane = 0; lane < 2; lane++) {
-      int index = lane;
-      MaterialExtensions.GLOBAL
-          .events()
-          .registerCallback(
-              id("toggle_" + lane),
-              MaterialEventTypes.GUI_CLICK,
-              click -> {
-                if (click.menu().blockEntity instanceof ProcessorEntity machine)
-                  machine.toggle(index);
-              });
-    }
+    // The custom progress dial remains clickable; processor buttons have a library-owned action.
+    MaterialExtensions.GLOBAL
+        .events()
+        .registerCallback(
+            id("toggle_0"),
+            MaterialEventTypes.GUI_CLICK,
+            click -> {
+              if (click.menu().blockEntity instanceof ProcessorEntity machine) machine.toggle(0);
+            });
   }
 
   private static void transferTankContainer(ScreenClick click) {
diff --git a/src/companion/java/zone/moddev/mc/companion/CreativePowerEntity.java b/src/companion/java/zone/moddev/mc/companion/CreativePowerEntity.java
index c2b68d86..faa9d4c8 100644
--- a/src/companion/java/zone/moddev/mc/companion/CreativePowerEntity.java
+++ b/src/companion/java/zone/moddev/mc/companion/CreativePowerEntity.java
@@ -41,8 +41,12 @@ public CreativePowerEntity(BlockEntityType<?> type, BlockPos pos, BlockState sta
             java.util.List.of(0),
             java.util.List.of("energy"),
             new SideConfig(IoMode.OUTPUT));
-    group.bind(this::facing, side -> energy.view(() -> group.mode(side)));
-    automation = new AutomationInventory(this, java.util.List.of(group));
+    automation =
+        new zone.moddev.mc.lib.machine.neoforge.MachineResources(this, this::facing)
+            .energy(group, energy)
+            .build()
+            .automation();
+    zone.moddev.mc.lib.gui.runtime.ScreenInventoryValidation.validate(this);
   }
 
   @Override
diff --git a/src/companion/java/zone/moddev/mc/companion/ProcessorEntity.java b/src/companion/java/zone/moddev/mc/companion/ProcessorEntity.java
index d80cce9b..d65c7741 100644
--- a/src/companion/java/zone/moddev/mc/companion/ProcessorEntity.java
+++ b/src/companion/java/zone/moddev/mc/companion/ProcessorEntity.java
@@ -6,14 +6,12 @@
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.HolderLookup;
 import net.minecraft.nbt.CompoundTag;
-import net.minecraft.nbt.NbtOps;
 import net.minecraft.network.chat.Component;
 import net.minecraft.network.protocol.Packet;
 import net.minecraft.network.protocol.game.ClientGamePacketListener;
 import net.minecraft.network.protocol.game.ClientboundBlockEntityDataPacket;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.world.Clearable;
-import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.level.Level;
 import net.minecraft.world.level.block.entity.BlockEntityType;
 import net.minecraft.world.level.block.state.BlockState;
@@ -32,10 +30,9 @@
 import zone.moddev.mc.lib.gui.runtime.ScreenHost;
 import zone.moddev.mc.lib.machine.feature.FeatureHost;
 import zone.moddev.mc.lib.machine.feature.RecipeProcessor;
-import zone.moddev.mc.lib.machine.inventory.MachineInventory;
-import zone.moddev.mc.lib.machine.inventory.SlotPlan;
 import zone.moddev.mc.lib.machine.neoforge.FeatureSync;
-import zone.moddev.mc.lib.machine.neoforge.StorageGroups;
+import zone.moddev.mc.lib.machine.neoforge.MachineInventoryLifecycle;
+import zone.moddev.mc.lib.machine.neoforge.MachineResources;
 
 /** The dual crusher deliberately runs two lanes over the same input and output groups. */
 public final class ProcessorEntity extends DemoEntity
@@ -49,6 +46,8 @@ public enum Kind {
 
   public final ItemStorage items;
   public final AutomationInventory automation;
+  public final MachineResources resources;
+  public final MachineInventoryLifecycle inventoryLifecycle;
   public final FluidStorage fluids = new FluidStorage().onChange(this::setChanged);
   public final List<RecipeProcessor> lanes;
   public final FeatureHost features =
@@ -92,45 +91,30 @@ public ProcessorEntity(BlockEntityType<?> type, BlockPos pos, BlockState state,
     if (kind == Kind.LOGISTICS)
       for (int i = 0; i < 4; i++) fluids.addTank(4000, i < 2 ? Role.INPUT : Role.OUTPUT);
     int[] outputSlots = kind == Kind.CRUSHER ? new int[] {1, 2} : new int[] {1};
-    var inventory = MachineInventory.builder().group("energy", StorageGroups.energy(energy));
+    resources = new MachineResources(this, this::facing);
     if (kind == Kind.TRANSMUTER) {
       // One key, and one item: the recipe consumes the whole slot before inserting gold.
       items = new ItemStorage(1).limit(1, 0).onChange(this::setChanged);
-      inventory.group("slot", StorageGroups.items(items, 0));
     } else {
       items =
           new ItemStorage(1 + outputSlots.length)
               .role(Role.INPUT, 0)
               .role(kind == Kind.CRUSHER ? Role.STORAGE : Role.OUTPUT, outputSlots)
               .onChange(this::setChanged);
-      inventory
-          .group("input", StorageGroups.items(items, 0))
-          .group("output", StorageGroups.items(items, outputSlots));
     }
-    var shared = inventory.build();
     var recipeType = kind == Kind.TRANSMUTER ? CompanionMod.TRANSMUTING : CompanionMod.CRUSHING;
-    var processors = new ArrayList<RecipeProcessor>();
-    for (int i = 0; i < (kind == Kind.DUAL ? 2 : 1); i++) {
-      var processor =
-          new RecipeProcessor(
-              "lane_" + i,
-              recipeType,
-              shared,
-              Component.translatable("screen.mmdlib_companion.processor", i + 1));
-      processors.add(processor);
-      features.add(processor);
-    }
-    lanes = List.copyOf(processors);
-    var groups = new ArrayList<ResourceGroup<?>>();
-    groups.add(
-        itemGroup("input", 0x568bd8, kind == Kind.TRANSMUTER ? IoMode.BOTH : IoMode.INPUT, 0));
+    resources.items(
+        itemGroup("input", 0x568bd8, kind == Kind.TRANSMUTER ? IoMode.BOTH : IoMode.INPUT, 0),
+        items);
     if (kind != Kind.TRANSMUTER)
-      groups.add(
+      resources.items(
           itemGroup(
-              "output", 0xe48f45, kind == Kind.CRUSHER ? IoMode.BOTH : IoMode.OUTPUT, outputSlots));
+              "output", 0xe48f45, kind == Kind.CRUSHER ? IoMode.BOTH : IoMode.OUTPUT, outputSlots),
+          items);
+    items.slotId(0, "input");
+    for (int i = 1; i < items.getSlots(); i++) items.slotId(i, "output_" + i);
     int[] colours = {0x64bfc1, 0xa678cb, 0xe0c55d, 0xce668e};
     for (int i = 0; i < fluids.getTanks(); i++) {
-      final int tank = i;
       var group =
           new ResourceGroup<>(
               "tank_" + i,
@@ -142,10 +126,8 @@ public ProcessorEntity(BlockEntityType<?> type, BlockPos pos, BlockState state,
               List.of(i == 0 ? "tank" : "tank_" + i),
               new SideConfig(
                   kind == Kind.CRUSHER ? IoMode.BOTH : (i < 2 ? IoMode.INPUT : IoMode.OUTPUT)));
-      group.bind(
-          this::facing,
-          side -> fluids.view(index -> index == tank ? group.mode(side) : IoMode.DISABLED));
-      groups.add(group);
+      resources.fluids(group, fluids);
+      fluids.tankId(i, group.id());
     }
     var energyGroup =
         new ResourceGroup<>(
@@ -158,11 +140,31 @@ public ProcessorEntity(BlockEntityType<?> type, BlockPos pos, BlockState state,
             List.of("energy"),
             new SideConfig(kind == Kind.LOGISTICS ? IoMode.BOTH : IoMode.INPUT));
     if (kind == Kind.LOGISTICS) energy.setRates(1000, 1000);
-    energyGroup.bind(this::facing, side -> energy.view(() -> energyGroup.mode(side)));
-    groups.add(energyGroup);
-    automation = new AutomationInventory(this, groups);
+    resources.energy(energyGroup, energy);
+    if (kind == Kind.TRANSMUTER) resources.recipeGroup("slot", "input");
+    if (kind != Kind.LOGISTICS)
+      resources.recipeInputs(recipeType, kind == Kind.TRANSMUTER ? "slot" : "input");
+    resources.build();
+    automation = resources.automation();
+    var processors = new ArrayList<RecipeProcessor>();
+    for (int i = 0; i < (kind == Kind.DUAL ? 2 : 1); i++) {
+      var processor =
+          new RecipeProcessor(
+              "lane_" + i,
+              recipeType,
+              resources.recipes(),
+              Component.translatable("screen.mmdlib_companion.processor", i + 1));
+      processors.add(processor);
+      features.add(processor);
+    }
+    lanes = List.copyOf(processors);
+    inventoryLifecycle =
+        new MachineInventoryLifecycle(this, features, automation, energy)
+            .items("items", items)
+            .fluids("fluids", fluids)
+            .energy("energy", energy);
     var outputParts = new ArrayList<Object>();
-    for (var group : groups)
+    for (var group : automation.groups())
       outputParts.add(
           RedstoneOutput.resource(
               group,
@@ -190,6 +192,7 @@ public ProcessorEntity(BlockEntityType<?> type, BlockPos pos, BlockState state,
               }));
     if (kind != Kind.LOGISTICS) outputParts.add(features);
     redstone = new RedstoneControl(this, outputParts);
+    zone.moddev.mc.lib.gui.runtime.ScreenInventoryValidation.validate(this);
   }
 
   private ResourceGroup<net.neoforged.neoforge.items.IItemHandler> itemGroup(
@@ -206,9 +209,7 @@ private ResourceGroup<net.neoforged.neoforge.items.IItemHandler> itemGroup(
                 .mapToObj(i -> i == 0 ? id : id + "_" + (i + 1))
                 .toList(),
             new SideConfig(mode));
-    return group.bind(
-        this::facing,
-        side -> items.view(index -> group.contains(index) ? group.mode(side) : IoMode.DISABLED));
+    return group;
   }
 
   @Override
@@ -216,6 +217,11 @@ public RedstoneControl screenRedstone() {
     return redstone;
   }
 
+  @Override
+  public FeatureHost screenFeatures() {
+    return features;
+  }
+
   public AutomationInventory screenAutomation() {
     return automation;
   }
@@ -223,12 +229,10 @@ public AutomationInventory screenAutomation() {
   @Override
   public void serverTick() {
     redstone.readInputs();
-    features.tick(
-        level,
-        kind != Kind.LOGISTICS
-            && redstoneAllowsRun()
-            && energy.stored() >= energy.capacity() * reservePercent / 100);
-    AutomationTransfers.tick(automation, energy);
+    inventoryLifecycle.tick(
+        kind != Kind.LOGISTICS && energy.stored() >= energy.capacity() * reservePercent / 100,
+        !redstoneAllowsRun(),
+        MachineInventoryLifecycle.PausePolicy.PROCESSING_ONLY);
     redstone.updateOutputs();
   }
 
@@ -251,11 +255,7 @@ private boolean redstoneAllowsRun() {
   public void toggle(int index) {
     if (index < 0 || index >= lanes.size()) return;
     var processor = lanes.get(index);
-    if (processor.paused()) processor.resume();
-    else processor.interrupt();
-    // Redstone can hold the feature tick, so persist and sync a manual toggle immediately.
-    setChanged();
-    FeatureSync.send(this);
+    features.setProcessorPaused(processor.key(), !processor.paused());
   }
 
   public int getProgress() {
@@ -300,10 +300,6 @@ public boolean getPaused() {
     return lanes.getFirst().paused();
   }
 
-  public boolean getSecondPaused() {
-    return lanes.size() == 2 && lanes.get(1).paused();
-  }
-
   public List<Component> getWarnings() {
     var warnings = new ArrayList<Component>();
     if (energy.stored() < energy.capacity() * reservePercent / 100)
@@ -338,8 +334,7 @@ public int[] screenRecipeSlots(ResourceLocation category) {
 
   @Override
   public void dropContents(Level level, BlockPos pos) {
-    items.dropAll(level, pos);
-    automation.dropAll(
+    inventoryLifecycle.dropContents(
         payload ->
             net.minecraft.world.Containers.dropItemStack(
                 level,
@@ -351,28 +346,17 @@ public void dropContents(Level level, BlockPos pos) {
 
   @Override
   public void clearContent() {
-    automation.clear();
-    lanes.forEach(RecipeProcessor::reset);
-    for (int slot = 0; slot < items.getSlots(); slot++) {
-      items.setPlan(slot, SlotPlan.NONE);
-      items.setStackInSlot(slot, ItemStack.EMPTY);
-    }
-    energy.setStored(0);
-    for (int i = 0; i < fluids.getTanks(); i++) fluids.tank(i).setFluid(FluidStack.EMPTY);
-    setChanged();
+    inventoryLifecycle.clear();
     FeatureSync.send(this);
   }
 
   @Override
   protected void saveAdditional(CompoundTag tag, HolderLookup.Provider registries) {
     super.saveAdditional(tag, registries);
-    tag.put("items", items.serializeNBT(registries));
-    tag.put("automation", automation.save(registries));
+    inventoryLifecycle.save(tag, registries);
     tag.put("redstone_control", redstone.save(registries));
     tag.putString("machine_name", machineName);
     tag.putInt("reserve_percent", reservePercent);
-    if (hasTank()) tag.put("fluids", fluids.serializeNBT(registries));
-    tag.put("features", features.save(registries.createSerializationContext(NbtOps.INSTANCE)));
   }
 
   @Override
@@ -392,11 +376,7 @@ protected void loadAdditional(CompoundTag tag, HolderLookup.Provider registries)
             ? savedName.strip()
             : "Crusher";
     reservePercent = Math.clamp(tag.getInt("reserve_percent"), 0, 100);
-    items.deserializeNBT(registries, tag.getCompound("items"));
-    automation.load(tag.getCompound("automation"), registries);
-    if (hasTank() && tag.contains("fluids"))
-      fluids.deserializeNBT(registries, tag.getCompound("fluids"));
-    features.load(registries.createSerializationContext(NbtOps.INSTANCE), tag.get("features"));
+    inventoryLifecycle.load(tag, registries);
   }
 
   @Override
diff --git a/src/companion/java/zone/moddev/mc/companion/RecoveryCapsuleItem.java b/src/companion/java/zone/moddev/mc/companion/RecoveryCapsuleItem.java
index 333e043e..5397a585 100644
--- a/src/companion/java/zone/moddev/mc/companion/RecoveryCapsuleItem.java
+++ b/src/companion/java/zone/moddev/mc/companion/RecoveryCapsuleItem.java
@@ -52,7 +52,19 @@ public static boolean restore(ItemStack stack, ProcessorEntity target) {
       var entry = resources.getCompound(i);
       var data = entry.getCompound("data");
       String type = entry.getString("type");
-      if (type.equals(ResourceType.FLUIDS.id().toString())) {
+      if (type.equals(ResourceType.ITEMS.id().toString())) {
+        var item =
+            ItemStack.parseOptional(target.getLevel().registryAccess(), data.getCompound("item"));
+        if (!item.isEmpty()) {
+          var remaining =
+              zone.moddev.mc.lib.api.capabilities.Transfer.insert(target.items, item, false);
+          if (remaining.getCount() < item.getCount()) {
+            changed = true;
+            if (remaining.isEmpty()) data.remove("item");
+            else data.put("item", remaining.save(target.getLevel().registryAccess()));
+          }
+        }
+      } else if (type.equals(ResourceType.FLUIDS.id().toString())) {
         var fluid =
             FluidStack.parseOptional(target.getLevel().registryAccess(), data.getCompound("fluid"));
         int moved = target.fluids.fill(fluid, IFluidHandler.FluidAction.EXECUTE);
diff --git a/src/companion/resources/mmdlib/screen/base_powered_machine.xml b/src/companion/resources/mmdlib/screen/base_powered_machine.xml
new file mode 100644
index 00000000..2a1333a5
--- /dev/null
+++ b/src/companion/resources/mmdlib/screen/base_powered_machine.xml
@@ -0,0 +1,16 @@
+<screen xmlns="https://moddev.zone/mmdlib/screen" abstract="true">
+  <vbox padding="7" spacing="4">
+    <placeholder name="heading"/>
+    <hbox spacing="6" align="center">
+      <placeholder name="machine" required="true"/>
+      <spacer/>
+      <energy-gauge id="energy" length="3s"/>
+    </hbox>
+  </vbox>
+  <placeholder name="inventory_controls">
+    <inventory-controls id="inventory_controls">
+      <processor-button id="toggle_0" processor-key="lane_0"/>
+    </inventory-controls>
+  </placeholder>
+  <placeholder name="info"/>
+</screen>
diff --git a/src/companion/resources/mmdlib/screen/crusher.xml b/src/companion/resources/mmdlib/screen/crusher.xml
index 22748392..dc15f28d 100644
--- a/src/companion/resources/mmdlib/screen/crusher.xml
+++ b/src/companion/resources/mmdlib/screen/crusher.xml
@@ -47,10 +47,7 @@
     </context>
   </vbox>
   <inventory-controls id="inventory_controls">
-    <button flat="true" id="toggle_0" value="#getPaused" on-click="mmdlib_companion:toggle_0"
-            icons="mmdlib:icon_pause mmdlib:icon_resume"
-            value-labels="screen.mmdlib_companion.pause.off screen.mmdlib_companion.pause.on"
-            tooltip="screen.mmdlib_companion.pause.tip"/>
+    <processor-button id="toggle_0" processor-key="lane_0"/>
   </inventory-controls>
   <popout id="info" kind="info" edge="left" text="screen.mmdlib_companion.info.crusher" value="#getWarnings"/>
 </screen>
diff --git a/src/companion/resources/mmdlib/screen/dual_crusher.xml b/src/companion/resources/mmdlib/screen/dual_crusher.xml
index ff802f40..875c27c6 100644
--- a/src/companion/resources/mmdlib/screen/dual_crusher.xml
+++ b/src/companion/resources/mmdlib/screen/dual_crusher.xml
@@ -1,35 +1,29 @@
 <screen xmlns="https://moddev.zone/mmdlib/screen" title="block.mmdlib_companion.dual_crusher" title-fallback="Dual Crusher"
-        block-entity="zone.moddev.mc.companion.ProcessorEntity">
-  <vbox padding="7" spacing="4">
-    <hbox spacing="6" align="center">
+        block-entity="zone.moddev.mc.companion.ProcessorEntity" extends="mmdlib_companion:base_powered_machine">
+  <fill name="machine">
+    <spacer/>
+    <slot id="input" index="0"/>
+    <vbox spacing="4">
       <spacer/>
-      <slot id="input" index="0"/>
-      <vbox spacing="4">
-        <spacer/>
-        <hbox spacing="4" align="center">
-          <label text="screen.mmdlib_companion.lane_a" text-fallback="Lane A"/>
-          <progress id="progress" value="#getProgress" max="#getTime" jei-recipes="mmdlib_companion:crushing"/>
-        </hbox>
-        <hbox spacing="4" align="center">
-          <label text="screen.mmdlib_companion.lane_b" text-fallback="Lane B"/>
-          <progress id="second_progress" value="#getSecondProgress" max="#getSecondTime"/>
-        </hbox>
-        <spacer/>
-      </vbox>
-      <slot id="output" index="1"/>
+      <hbox spacing="4" align="center">
+        <label text="screen.mmdlib_companion.lane_a" text-fallback="Lane A"/>
+        <progress id="progress" value="#getProgress" max="#getTime" jei-recipes="mmdlib_companion:crushing"/>
+      </hbox>
+      <hbox spacing="4" align="center">
+        <label text="screen.mmdlib_companion.lane_b" text-fallback="Lane B"/>
+        <progress id="second_progress" value="#getSecondProgress" max="#getSecondTime"/>
+      </hbox>
       <spacer/>
-      <energy-gauge id="energy" length="3s"/>
-    </hbox>
-  </vbox>
-  <inventory-controls id="inventory_controls">
-    <button flat="true" id="toggle_0" value="#getPaused" on-click="mmdlib_companion:toggle_0"
-            icons="mmdlib:icon_pause_a mmdlib:icon_resume_a"
-            value-labels="screen.mmdlib_companion.pause.off screen.mmdlib_companion.pause.on"
-            tooltip="screen.mmdlib_companion.pause.a.tip"/>
-    <button flat="true" id="toggle_1" value="#getSecondPaused" on-click="mmdlib_companion:toggle_1"
-            icons="mmdlib:icon_pause_b mmdlib:icon_resume_b"
-            value-labels="screen.mmdlib_companion.pause.off screen.mmdlib_companion.pause.on"
-            tooltip="screen.mmdlib_companion.pause.b.tip"/>
-  </inventory-controls>
-  <popout id="info" kind="info" edge="left" text="screen.mmdlib_companion.info.dual_crusher" value="#getWarnings"/>
+    </vbox>
+    <slot id="output" index="1"/>
+  </fill>
+  <fill name="inventory_controls">
+    <inventory-controls id="inventory_controls">
+      <processor-button id="toggle_0" processor-key="lane_0"/>
+      <processor-button id="toggle_1" processor-key="lane_1"/>
+    </inventory-controls>
+  </fill>
+  <fill name="info">
+    <popout id="info" kind="info" edge="left" text="screen.mmdlib_companion.info.dual_crusher" value="#getWarnings"/>
+  </fill>
 </screen>
diff --git a/src/companion/resources/mmdlib/screen/transmuter.xml b/src/companion/resources/mmdlib/screen/transmuter.xml
index febcc901..60cadb8b 100644
--- a/src/companion/resources/mmdlib/screen/transmuter.xml
+++ b/src/companion/resources/mmdlib/screen/transmuter.xml
@@ -1,20 +1,14 @@
 <screen xmlns="https://moddev.zone/mmdlib/screen" title="block.mmdlib_companion.transmuter" title-fallback="Iron-to-Gold Converter"
-        block-entity="zone.moddev.mc.companion.ProcessorEntity">
-  <vbox padding="7" spacing="4">
+        block-entity="zone.moddev.mc.companion.ProcessorEntity" extends="mmdlib_companion:base_powered_machine">
+  <fill name="heading">
     <label text="screen.mmdlib_companion.single" text-fallback="One iron in, one gold out"/>
-    <hbox spacing="6" align="center">
-      <spacer/>
-      <slot id="input" index="0"/>
-      <progress id="progress" value="#getProgress" max="#getTime" jei-recipes="mmdlib_companion:transmuting"/>
-      <spacer/>
-      <energy-gauge id="energy" length="3s"/>
-    </hbox>
-  </vbox>
-  <inventory-controls id="inventory_controls">
-    <button flat="true" id="toggle_0" value="#getPaused" on-click="mmdlib_companion:toggle_0"
-            icons="mmdlib:icon_pause mmdlib:icon_resume"
-            value-labels="screen.mmdlib_companion.pause.off screen.mmdlib_companion.pause.on"
-            tooltip="screen.mmdlib_companion.pause.tip"/>
-  </inventory-controls>
-  <popout id="info" kind="info" edge="left" text="screen.mmdlib_companion.info.transmuter" value="#getWarnings"/>
+  </fill>
+  <fill name="machine">
+    <spacer/>
+    <slot id="input" index="0"/>
+    <progress id="progress" value="#getProgress" max="#getTime" jei-recipes="mmdlib_companion:transmuting"/>
+  </fill>
+  <fill name="info">
+    <popout id="info" kind="info" edge="left" text="screen.mmdlib_companion.info.transmuter" value="#getWarnings"/>
+  </fill>
 </screen>
diff --git a/src/companionTest/java/zone/moddev/mc/companion/test/CompanionClientSmoke.java b/src/companionTest/java/zone/moddev/mc/companion/test/CompanionClientSmoke.java
index c65a95bd..a4f2ab84 100644
--- a/src/companionTest/java/zone/moddev/mc/companion/test/CompanionClientSmoke.java
+++ b/src/companionTest/java/zone/moddev/mc/companion/test/CompanionClientSmoke.java
@@ -61,6 +61,9 @@ public static void tick(ClientTickEvent.Post event) {
       if (System.currentTimeMillis() > DEADLINE)
         throw new AssertionError("Timed out on " + mc.screen);
       if (!started && mc.screen instanceof TitleScreen) {
+        if (!net.neoforged.fml.ModList.get().isLoaded("jade"))
+          throw new AssertionError("Jade must be installed in companion runs");
+        MMDLib.LOGGER.info("JADE_COMPANION_PRESENT");
         started = true;
         var settings =
             new LevelSettings(
@@ -286,6 +289,11 @@ public static void frame(RenderFrameEvent.Post event) {
         waitingTicks = 0;
         return;
       }
+      if (stage == 0 && !ProcessorButtonClientSmoke.run(screen)) {
+        frames = 0;
+        waitingTicks = 0;
+        return;
+      }
       if ((stage == 0 || stage == 2) && !StatsClientSmoke.run(screen)) {
         frames = 0;
         waitingTicks = 0;
@@ -299,7 +307,11 @@ public static void frame(RenderFrameEvent.Post event) {
       if (stage == 0 && controlStage < 3) {
         var dial = menu.bound.screen().find("progress").orElseThrow();
         var pause = menu.bound.screen().find("toggle_0").orElseThrow();
-        if (!(menu.value(pause, false) instanceof Boolean paused)) return;
+        var state =
+            zone.moddev.mc.lib.gui.model.ProcessorButtonState.fromWire(menu.value(pause, false));
+        if (state.isEmpty()) return;
+        boolean paused =
+            state.orElseThrow() == zone.moddev.mc.lib.gui.model.ProcessorButtonState.PAUSED;
         if (controlStage == 0 && !paused || controlStage == 1 && paused) {
           var bounds = screen.bounds(dial);
           screen.mouseClicked(bounds.x() + 10, bounds.y() + 10, 0);
diff --git a/src/companionTest/java/zone/moddev/mc/companion/test/CompanionGameTests.java b/src/companionTest/java/zone/moddev/mc/companion/test/CompanionGameTests.java
index 611d66d0..55db4d34 100644
--- a/src/companionTest/java/zone/moddev/mc/companion/test/CompanionGameTests.java
+++ b/src/companionTest/java/zone/moddev/mc/companion/test/CompanionGameTests.java
@@ -38,6 +38,145 @@
 public final class CompanionGameTests {
   private static final BlockPos CENTER = new BlockPos(2, 2, 2);
 
+  @GameTest(template = "empty")
+  public static void processorActivityTracksWorkAndHostGates(GameTestHelper helper) {
+    var machine = place(helper, CompanionMod.CRUSHER);
+    var processor = machine.lanes.getFirst();
+    require(!processor.paused() && !processor.processing(), "New processors are unpaused and idle");
+    machine.items.setStackInSlot(0, new ItemStack(Items.COPPER_ORE, 16));
+    machine.energy.setStored(100000);
+    tick(machine, 2);
+    require(processor.processing(), "Available work and energy start processing");
+    machine.energy.setStored(0);
+    machine.serverTick();
+    require(
+        !processor.processing() && !processor.paused(),
+        "An energy stall is idle, not manually paused");
+    machine.energy.setStored(100000);
+    machine.serverTick();
+    machine.setReservePercent(100);
+    machine.serverTick();
+    require(
+        !processor.processing() && !processor.paused(),
+        "An energy-reserve hold is not active processing");
+    machine.setReservePercent(0);
+    machine.serverTick();
+    machine.redstone.mode(0, zone.moddev.mc.lib.api.redstone.RedstoneControl.Mode.READ);
+    machine.redstone.range(0, 0, 15);
+    machine.serverTick();
+    require(
+        !processor.processing() && !processor.paused() && machine.items.hasPlan(0),
+        "Redstone holds work without manually pausing or releasing its reservation");
+    processor.pause();
+    require(processor.paused() && !processor.processing(), "Manual pause has its own state");
+    processor.resume();
+    machine.redstone.mode(0, zone.moddev.mc.lib.api.redstone.RedstoneControl.Mode.IGNORE);
+    machine.serverTick();
+    for (int ticks = 0; ticks < 200 && processor.progress() < processor.time() - 1; ticks++)
+      machine.serverTick();
+    require(processor.progress() == processor.time() - 1, "Resumed work reaches its final tick");
+    machine.serverTick();
+    require(
+        processor.completedCycles().signum() > 0 && processor.processing(),
+        "The completion tick remains processing so the icon does not flicker between cycles");
+    helper.succeed();
+  }
+
+  @GameTest(template = "empty")
+  public static void genericProcessorButtonsRespectRedstoneAndLaneKeys(GameTestHelper helper) {
+    var machine = place(helper, CompanionMod.DUAL_CRUSHER);
+    var player = helper.makeMockServerPlayerInLevel();
+    var pos = machine.getBlockPos();
+    player.setPos(pos.getX() + .5, pos.getY(), pos.getZ() + .5);
+    var menu = new MachineMenu(42, player.getInventory(), machine);
+    player.containerMenu = menu;
+    var button =
+        (zone.moddev.mc.lib.gui.model.Element.Button)
+            menu.bound.screen().find("toggle_1").orElseThrow();
+    require(
+        button.processorKey().orElseThrow().equals("lane_1") && !button.common().clicks().any(),
+        "The generic control targets a stable key without callbacks");
+    int index = menu.index(button);
+    menu.action(player, new ScreenNetwork.Action(42, index, 0, 1, 0, 0));
+    require(!machine.lanes.get(1).paused(), "Right click cannot toggle the processor");
+    menu.action(player, new ScreenNetwork.Action(42, index, 0, 0, 0, 1));
+    require(!machine.lanes.get(1).paused(), "Invalid options cannot toggle the processor");
+    var action = new ScreenNetwork.Action(42, index, 0, 0, 0, 0);
+    menu.action(player, action);
+    require(
+        machine.lanes.get(1).paused() && !machine.lanes.getFirst().paused(),
+        "Only the keyed lane pauses");
+    require(
+        !menu.redstone.watching() && !menu.redstone.conflicts(true),
+        "No input watching means no conflict indicator");
+    machine.redstone.mode(0, zone.moddev.mc.lib.api.redstone.RedstoneControl.Mode.EMIT);
+    require(!menu.redstone.watching(), "Output-only redstone does not watch inputs");
+    machine.redstone.mode(0, zone.moddev.mc.lib.api.redstone.RedstoneControl.Mode.READ);
+    machine.redstone.range(0, 0, 15);
+    machine.redstone.readInputs();
+    require(
+        menu.redstone.watching()
+            && menu.redstone.paused()
+            && !menu.redstone.conflicts(true)
+            && menu.redstone.conflicts(false),
+        "A redstone hold conflicts only with an enabled manual state");
+    menu.action(player, action);
+    require(
+        !machine.lanes.get(1).paused() && menu.redstone.paused(),
+        "Resume changes the manual state while redstone still holds processing");
+    machine.redstone.outside(0, true);
+    machine.redstone.readInputs();
+    require(
+        !menu.redstone.paused() && menu.redstone.conflicts(true) && !menu.redstone.conflicts(false),
+        "Redstone allowing work conflicts with manual pause");
+
+    int[] changes = {0}, syncs = {0};
+    var host =
+        new zone.moddev.mc.lib.machine.feature.FeatureHost(() -> changes[0]++, () -> syncs[0]++)
+            .add(machine.lanes.get(1));
+    require(
+        host.setProcessorPaused("lane_1", true) && changes[0] == 1 && syncs[0] == 1,
+        "Manual changes persist and sync without a processing tick");
+    require(
+        !host.setProcessorPaused("lane_1", true)
+            && !host.setProcessorPaused("missing", true)
+            && changes[0] == 1
+            && syncs[0] == 1,
+        "Repeated states and unknown keys are inert");
+    machine.lanes.get(1).pause();
+    machine.lanes.get(1).setPaused(false);
+    require(!machine.lanes.get(1).paused(), "The public pause setter resumes too");
+    var invalid =
+        new zone.moddev.mc.lib.gui.model.Element.Button(
+            button.common(),
+            button.text(),
+            button.icon(),
+            button.shows(),
+            button.icons(),
+            button.valueLabels(),
+            button.flat(),
+            java.util.Optional.of("missing"));
+    var original = menu.bound.screen();
+    var invalidScreen =
+        new zone.moddev.mc.lib.gui.model.Screen(
+            original.id(),
+            original.source(),
+            original.title(),
+            original.blockEntity(),
+            original.playerInventory(),
+            java.util.List.of(invalid),
+            java.util.List.of());
+    try {
+      zone.moddev.mc.lib.gui.runtime.ScreenInventoryValidation.validate(invalidScreen, machine);
+      throw new AssertionError("Unknown processor key accepted");
+    } catch (zone.moddev.mc.lib.gui.load.ScreenException expected) {
+      require(
+          expected.getMessage().contains("Unknown processor-key: missing"),
+          "An invalid control identifies its missing key");
+    }
+    helper.succeed();
+  }
+
   @GameTest(template = "empty")
   public static void statisticsProvidersDescribeCurrentRecipes(GameTestHelper helper) {
     var machine = place(helper, CompanionMod.DUAL_CRUSHER);
diff --git a/src/companionTest/java/zone/moddev/mc/companion/test/InventoryLifecycleTests.java b/src/companionTest/java/zone/moddev/mc/companion/test/InventoryLifecycleTests.java
new file mode 100644
index 00000000..87cd2722
--- /dev/null
+++ b/src/companionTest/java/zone/moddev/mc/companion/test/InventoryLifecycleTests.java
@@ -0,0 +1,144 @@
+package zone.moddev.mc.companion.test;
+
+import java.util.ArrayList;
+
+import net.minecraft.core.BlockPos;
+import net.minecraft.gametest.framework.*;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.world.item.*;
+
+import net.neoforged.neoforge.gametest.*;
+
+import zone.moddev.mc.companion.*;
+import zone.moddev.mc.lib.api.capabilities.*;
+import zone.moddev.mc.lib.machine.feature.*;
+import zone.moddev.mc.lib.machine.neoforge.MachineInventoryLifecycle.PausePolicy;
+
+@GameTestHolder(CompanionMod.ID)
+@PrefixGameTestTemplate(false)
+public final class InventoryLifecycleTests {
+  private static ProcessorEntity place(GameTestHelper h, boolean logistics) {
+    var pos = h.absolutePos(new BlockPos(2, 2, 2));
+    h.getLevel()
+        .setBlock(
+            pos,
+            (logistics ? CompanionMod.LOGISTICS : CompanionMod.CRUSHER)
+                .block
+                .get()
+                .defaultBlockState(),
+            3);
+    return (ProcessorEntity) h.getLevel().getBlockEntity(pos);
+  }
+
+  private static void require(boolean condition, String message) {
+    if (!condition) throw new AssertionError(message);
+  }
+
+  @GameTest(template = "empty")
+  public static void pausePolicySeparatesProcessingTransfersAndRefunds(GameTestHelper h) {
+    var machine = place(h, true);
+    int[] ticks = {0};
+    machine.features.add(
+        new MachineFeature<Integer>() {
+          public String key() {
+            return "policy_probe";
+          }
+
+          public com.mojang.serialization.Codec<Integer> codec() {
+            return com.mojang.serialization.Codec.INT;
+          }
+
+          public Integer state() {
+            return ticks[0];
+          }
+
+          public void restore(Integer value) {
+            ticks[0] = value;
+          }
+
+          public void tick(FeatureHost host) {
+            ticks[0]++;
+          }
+        });
+    var state = machine.automation.transferState("input", 0);
+    state.putBoolean("input", true);
+    state.putInt("batch", 8);
+    state.putLong("cost", 0);
+    state.put("item", new ItemStack(Items.DIAMOND, 3).save(h.getLevel().registryAccess()));
+    machine.energy.setStored(machine.energy.capacity());
+    machine.automation.refund(machine.energy, 5);
+    machine.energy.setStored(machine.energy.capacity() - 5);
+    machine.inventoryLifecycle.tick(true, true, PausePolicy.BOTH);
+    require(
+        ticks[0] == 0 && machine.items.getStackInSlot(0).isEmpty(),
+        "Both policy suspends processing and transfers");
+    require(
+        machine.automation.pendingRefund() == 0
+            && machine.energy.stored() == machine.energy.capacity(),
+        "pause still returns already owed energy");
+    machine.inventoryLifecycle.tick(true, true, PausePolicy.TRANSFERS_ONLY);
+    require(
+        ticks[0] == 1 && machine.items.getStackInSlot(0).isEmpty(),
+        "Transfer-only policy leaves processing enabled");
+    machine.inventoryLifecycle.tick(true, true, PausePolicy.PROCESSING_ONLY);
+    require(
+        ticks[0] == 1 && machine.items.getStackInSlot(0).getCount() == 3,
+        "Processing-only policy still delivers owned escrow");
+    machine.inventoryLifecycle.tick(true, true, PausePolicy.NEITHER);
+    require(ticks[0] == 2, "Neither policy ignores pause");
+    machine.inventoryLifecycle.tick(false, false, PausePolicy.NEITHER);
+    require(ticks[0] == 2, "Independent processing gate always applies");
+    h.succeed();
+  }
+
+  @GameTest(template = "empty")
+  public static void lifecycleLoadsStorageBeforeRestoringReservations(GameTestHelper h) {
+    var machine = place(h, false);
+    machine.items.insertItem(0, new ItemStack(Items.COPPER_ORE, 3), false);
+    machine.energy.setStored(100000);
+    machine.serverTick();
+    require(machine.items.hasPlan(0), "recipe started and reserved input");
+    var saved = new CompoundTag();
+    machine.inventoryLifecycle.save(saved, h.getLevel().registryAccess());
+    for (int i = 0; i < 3; i++) {
+      machine.items.restoreStack(0, ItemStack.EMPTY);
+      machine.inventoryLifecycle.load(saved, h.getLevel().registryAccess());
+      require(
+          machine.items.getStackInSlot(0).getCount() == 3 && machine.items.plan(0).take() == 1,
+          "load restores contents before plan and never accumulates reservations");
+    }
+    machine.inventoryLifecycle.load(new CompoundTag(), h.getLevel().registryAccess());
+    require(
+        !machine.items.hasPlan(0)
+            && machine.lanes.getFirst().status() == RecipeProcessor.Status.IDLE,
+        "missing feature save does not retain previous running cycle");
+    h.succeed();
+  }
+
+  @GameTest(template = "empty")
+  public static void displacedItemsSurviveBreakAndCapsuleRestoration(GameTestHelper h) {
+    var machine = place(h, true);
+    var old = new ItemStorage(3).slotId(0, "input").slotId(1, "output_1").slotId(2, "removed");
+    old.restoreStack(2, new ItemStack(Items.DIAMOND, 9));
+    machine.items.deserializeNBT(
+        h.getLevel().registryAccess(), old.serializeNBT(h.getLevel().registryAccess()));
+    var payloads = new ArrayList<CompoundTag>();
+    machine.inventoryLifecycle.dropContents(payloads::add);
+    machine.inventoryLifecycle.dropContents(payloads::add);
+    require(payloads.size() == 1, "removed slot transfers to host once on destruction");
+    var capsule = RecoveryCapsuleItem.create(payloads.getFirst());
+    require(
+        RecoveryCapsuleItem.restore(capsule, machine),
+        "recovery capsule now restores displaced item resources");
+    require(
+        capsule.isEmpty() && machine.items.getStackInSlot(0).getCount() == 9,
+        "recovery conserves every item and consumes capsule");
+    machine.items.deserializeNBT(
+        h.getLevel().registryAccess(), old.serializeNBT(h.getLevel().registryAccess()));
+    machine.clearContent();
+    require(
+        machine.items.recoveryContents().isEmpty(),
+        "explicit clear also removes displaced contents");
+    h.succeed();
+  }
+}
diff --git a/src/companionTest/java/zone/moddev/mc/companion/test/ProcessorButtonClientSmoke.java b/src/companionTest/java/zone/moddev/mc/companion/test/ProcessorButtonClientSmoke.java
new file mode 100644
index 00000000..ccbde13b
--- /dev/null
+++ b/src/companionTest/java/zone/moddev/mc/companion/test/ProcessorButtonClientSmoke.java
@@ -0,0 +1,192 @@
+package zone.moddev.mc.companion.test;
+
+import java.util.function.Consumer;
+
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.Screenshot;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.Items;
+
+import zone.moddev.mc.companion.ProcessorEntity;
+import zone.moddev.mc.lib.api.redstone.RedstoneControl;
+import zone.moddev.mc.lib.gui.client.MachineScreen;
+import zone.moddev.mc.lib.gui.model.Element;
+import zone.moddev.mc.lib.gui.model.ProcessorButtonState;
+import zone.moddev.mc.lib.gui.runtime.MachineMenu;
+
+/** Real clicks and server snapshots for both directions of manual/redstone disagreement. */
+final class ProcessorButtonClientSmoke {
+  private static int step, attempts;
+  private static volatile boolean ready;
+  private static CompoundTag savedRedstone;
+  private static boolean savedPause;
+  private static int savedReserve;
+  private static long savedEnergy;
+
+  static boolean run(MachineScreen screen) {
+    if (step > 7) return true;
+    if (++attempts > 120)
+      throw new AssertionError("Processor button smoke stalled at step " + step);
+    if (step > 0 && !ready) return false;
+    var menu = screen.getMenu();
+    var button = (Element.Button) menu.bound.screen().find("toggle_0").orElseThrow();
+    if (button.processorKey().isEmpty())
+      throw new AssertionError("Companion must use the generic control");
+    var wireState = menu.value(button, false);
+    var state = ProcessorButtonState.fromWire(wireState).orElse(null);
+    switch (step) {
+      case 0 ->
+          server(
+              machine -> {
+                savedPause = machine.lanes.getFirst().paused();
+                savedReserve = machine.getReservePercent();
+                savedEnergy = machine.energy.stored();
+                savedRedstone = machine.redstone.save(machine.getLevel().registryAccess());
+                machine.lanes.forEach(lane -> lane.reset());
+                machine.items.setStackInSlot(0, new ItemStack(Items.COPPER_ORE, 16));
+                machine.items.setStackInSlot(1, ItemStack.EMPTY);
+                machine.items.setStackInSlot(2, ItemStack.EMPTY);
+                machine.setReservePercent(0);
+                machine.energy.setStored(100000);
+                for (int face = 0; face < 6; face++)
+                  machine.redstone.mode(face, RedstoneControl.Mode.IGNORE);
+                machine.features.setProcessorPaused("lane_0", false);
+              });
+      case 1 -> {
+        if (state != ProcessorButtonState.PROCESSING || menu.redstone.watching()) return false;
+        require(!menu.processorConflict(button), "No monitoring means no red dot");
+        tooltip(screen, button, "Working", "Click to stop and clear reservations");
+        require(
+            button.iconFor(wireState).orElseThrow().getPath().equals("icon_processor_stop"),
+            "An actively processing machine shows Stop");
+        capture("processor-enabled-no-watch.png");
+        server(
+            machine -> {
+              machine.redstone.mode(0, RedstoneControl.Mode.READ);
+              machine.redstone.range(0, 0, 15);
+              machine.redstone.outside(0, false);
+            });
+      }
+      case 2 -> {
+        if (!menu.redstone.watching()
+            || !menu.redstone.paused()
+            || state != ProcessorButtonState.IDLE) return false;
+        require(
+            button.iconFor(wireState).orElseThrow().getPath().equals("icon_processor_play"),
+            "A redstone-held processor is not processing and shows Play");
+        require(menu.processorConflict(button), "Enabled processor conflicts with redstone hold");
+        tooltip(
+            screen,
+            button,
+            "Idle",
+            "Click to pause",
+            "Redstone settings conflict:",
+            "Paused by redstone.");
+        capture("processor-redstone-hold.png");
+        click(screen, button);
+      }
+      case 3 -> {
+        if (state != ProcessorButtonState.PAUSED) return false;
+        require(
+            menu.redstone.paused() && !menu.processorConflict(button), "Both pause controls agree");
+        tooltip(screen, button, "Paused", "Click to unpause");
+        require(
+            button.iconFor(wireState).orElseThrow().getPath().equals("icon_processor_pause"),
+            "A manually paused processor shows Pause");
+        capture("processor-paused-redstone-hold.png");
+        server(machine -> machine.redstone.outside(0, true));
+      }
+      case 4 -> {
+        if (menu.redstone.paused()) return false;
+        require(
+            state == ProcessorButtonState.PAUSED && menu.processorConflict(button),
+            "Clearing redstone preserves manual pause and shows the conflict");
+        tooltip(
+            screen,
+            button,
+            "Paused",
+            "Click to unpause",
+            "Redstone settings conflict:",
+            "Manual pause takes priority.");
+        capture("processor-manual-hold.png");
+        click(screen, button);
+      }
+      case 5 -> {
+        if (state != ProcessorButtonState.PROCESSING) return false;
+        require(
+            menu.redstone.watching() && !menu.processorConflict(button),
+            "Both allow controls agree");
+        capture("processor-redstone-run.png");
+        server(machine -> machine.energy.setStored(0));
+      }
+      case 6 -> {
+        if (state != ProcessorButtonState.IDLE) return false;
+        require(
+            !menu.processorConflict(button), "Lack of power is not a manual/redstone disagreement");
+        tooltip(screen, button, "Idle", "Click to pause");
+        require(
+            button.iconFor(wireState).orElseThrow().getPath().equals("icon_processor_play"),
+            "An unpaused processor without power shows Play");
+        capture("processor-idle-no-power.png");
+        server(
+            machine -> {
+              machine.energy.setStored(savedEnergy);
+              machine.setReservePercent(savedReserve);
+              machine.redstone.load(savedRedstone, machine.getLevel().registryAccess());
+              machine.features.setProcessorPaused("lane_0", savedPause);
+            });
+      }
+      case 7 -> {
+        if (state == null || (state == ProcessorButtonState.PAUSED) != savedPause) return false;
+      }
+    }
+    attempts = 0;
+    step++;
+    return false;
+  }
+
+  private static void tooltip(MachineScreen screen, Element.Button button, String... expected) {
+    var bounds = screen.bounds(button);
+    var actual =
+        screen.tooltipLines(button, bounds.x(), bounds.y()).stream()
+            .map(net.minecraft.network.chat.Component::getString)
+            .toList();
+    require(actual.equals(java.util.List.of(expected)), "Unexpected processor tooltip: " + actual);
+  }
+
+  private static void click(MachineScreen screen, Element.Button button) {
+    var bounds = screen.bounds(button);
+    double x = bounds.x() + bounds.width() / 2., y = bounds.y() + bounds.height() / 2.;
+    require(screen.mouseClicked(x, y, 0), "Generic button accepts the real click");
+    screen.mouseReleased(x, y, 0);
+  }
+
+  private static void server(Consumer<ProcessorEntity> action) {
+    ready = false;
+    var server = Minecraft.getInstance().getSingleplayerServer();
+    server.execute(
+        () -> {
+          try {
+            var player = server.getPlayerList().getPlayers().getFirst();
+            var menu = (MachineMenu) player.containerMenu;
+            var machine = (ProcessorEntity) menu.blockEntity;
+            action.accept(machine);
+            machine.redstone.readInputs();
+            menu.broadcastChanges();
+            ready = true;
+          } catch (Throwable error) {
+            CompanionClientSmoke.fail(error);
+          }
+        });
+  }
+
+  private static void capture(String name) {
+    var mc = Minecraft.getInstance();
+    Screenshot.grab(mc.gameDirectory, name, mc.getMainRenderTarget(), message -> {});
+  }
+
+  private static void require(boolean value, String message) {
+    if (!value) throw new AssertionError(message);
+  }
+}
diff --git a/src/companionTest/java/zone/moddev/mc/companion/test/ReservationClientSmoke.java b/src/companionTest/java/zone/moddev/mc/companion/test/ReservationClientSmoke.java
index dbc85d9a..d39dd426 100644
--- a/src/companionTest/java/zone/moddev/mc/companion/test/ReservationClientSmoke.java
+++ b/src/companionTest/java/zone/moddev/mc/companion/test/ReservationClientSmoke.java
@@ -1,11 +1,13 @@
 package zone.moddev.mc.companion.test;
 
 import java.util.function.Consumer;
+
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.Screenshot;
 import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.item.Items;
+
 import zone.moddev.mc.companion.ProcessorEntity;
 import zone.moddev.mc.lib.gui.client.MachineScreen;
 import zone.moddev.mc.lib.gui.runtime.MachineMenu;
@@ -72,6 +74,12 @@ static boolean run(MachineScreen screen) {
       }
       case 4 -> {
         if (!menu.reservationPlan(0).isNone() || !menu.reservationPlan(1).isNone()) return false;
+        require(
+            menu.getSlot(0).mayPlace(new ItemStack(Items.COPPER_ORE)),
+            "Client recipe sync admits a valid ingredient before a recipe starts");
+        require(
+            !menu.getSlot(0).mayPlace(new ItemStack(Items.DIAMOND)),
+            "Client prediction rejects unrelated items without relying on reservations");
         capture("reservations-cleared.png");
         server(
             player ->
diff --git a/src/companionTest/java/zone/moddev/mc/companion/test/StatsClientSmoke.java b/src/companionTest/java/zone/moddev/mc/companion/test/StatsClientSmoke.java
index 49c298f1..7823daef 100644
--- a/src/companionTest/java/zone/moddev/mc/companion/test/StatsClientSmoke.java
+++ b/src/companionTest/java/zone/moddev/mc/companion/test/StatsClientSmoke.java
@@ -25,7 +25,6 @@ static boolean run(MachineScreen screen) {
             info.bottom() + 2,
             AutomationLayout.RAIL,
             AutomationLayout.TAB_HEIGHT);
-    int x = tab.x() - Math.min(160, tab.x() - 4), top = panel.y() + AutomationLayout.TOP;
     String name = menu.bound.screen().id().getPath();
     var mc = Minecraft.getInstance();
     switch (step) {
@@ -67,23 +66,23 @@ static boolean run(MachineScreen screen) {
             mc.gameDirectory, name + "-stats-tick.png", mc.getMainRenderTarget(), m -> {});
       }
       case 3 -> {
-        click(screen, tab.x() - 35, top + 10, 0);
+        clickUnit(screen, 0);
         requireUnit(screen, 1);
       }
       case 4 ->
           Screenshot.grab(
               mc.gameDirectory, name + "-stats-second.png", mc.getMainRenderTarget(), m -> {});
       case 5 -> {
-        click(screen, tab.x() - 35, top + 10, 0);
+        clickUnit(screen, 0);
         requireUnit(screen, 2);
       }
       case 6 ->
           Screenshot.grab(
               mc.gameDirectory, name + "-stats-minute.png", mc.getMainRenderTarget(), m -> {});
       case 7 -> {
-        click(screen, tab.x() - 35, top + 10, 0);
+        clickUnit(screen, 0);
         requireUnit(screen, 0);
-        click(screen, tab.x() - 35, top + 10, 1);
+        clickUnit(screen, 1);
         requireUnit(screen, 2);
       }
       case 8 ->
@@ -106,6 +105,23 @@ static boolean run(MachineScreen screen) {
     return false;
   }
 
+  private static void clickUnit(MachineScreen screen, int button) {
+    try {
+      var field = MachineScreen.class.getDeclaredField("stats");
+      field.setAccessible(true);
+      var drawer = field.get(screen);
+      var layout = drawer.getClass().getDeclaredMethod("layout");
+      layout.setAccessible(true);
+      layout.invoke(drawer);
+      var bounds = drawer.getClass().getDeclaredMethod("unitBounds");
+      bounds.setAccessible(true);
+      var rect = (Rect) bounds.invoke(drawer);
+      click(screen, rect.x() + rect.width() / 2, rect.y() + rect.height() / 2, button);
+    } catch (ReflectiveOperationException error) {
+      throw new AssertionError(error);
+    }
+  }
+
   private static void requireUnit(MachineScreen screen, int expected) {
     try {
       var field = MachineScreen.class.getDeclaredField("stats");
@@ -114,7 +130,13 @@ private static void requireUnit(MachineScreen screen, int expected) {
       var unit = drawer.getClass().getDeclaredField("unit");
       unit.setAccessible(true);
       if (unit.getInt(drawer) != expected)
-        throw new AssertionError("Timescale did not cycle to " + expected);
+        throw new AssertionError(
+            "Timescale did not cycle to "
+                + expected
+                + "; actual="
+                + unit.getInt(drawer)
+                + "; screen="
+                + screen.getMenu().bound.screen().id());
     } catch (ReflectiveOperationException error) {
       throw new AssertionError(error);
     }
diff --git a/src/main/java/zone/moddev/mc/lib/api/automation/AutomationInventory.java b/src/main/java/zone/moddev/mc/lib/api/automation/AutomationInventory.java
index 946e6d8a..1de104a0 100644
--- a/src/main/java/zone/moddev/mc/lib/api/automation/AutomationInventory.java
+++ b/src/main/java/zone/moddev/mc/lib/api/automation/AutomationInventory.java
@@ -3,10 +3,8 @@
 import java.util.*;
 import java.util.function.Consumer;
 
-import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
-
-import net.minecraft.core.HolderLookup;
 import net.minecraft.core.Direction;
+import net.minecraft.core.HolderLookup;
 import net.minecraft.nbt.*;
 import net.minecraft.server.level.ServerLevel;
 import net.minecraft.world.Containers;
@@ -14,10 +12,12 @@
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.level.block.entity.BlockEntity;
 
-import net.neoforged.neoforge.items.IItemHandler;
-import net.neoforged.neoforge.items.ItemStackHandler;
 import net.neoforged.neoforge.capabilities.BlockCapability;
 import net.neoforged.neoforge.capabilities.BlockCapabilityCache;
+import net.neoforged.neoforge.items.IItemHandler;
+import net.neoforged.neoforge.items.ItemStackHandler;
+
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 
 import zone.moddev.mc.lib.api.capabilities.*;
 
@@ -131,6 +131,11 @@ public ItemStackHandler slots() {
     return slots;
   }
 
+  /** The installed addon/filter items, separate from the machine's resource contents. */
+  public ItemStackHandler addonSlots() {
+    return slots;
+  }
+
   private void viewChanged() {
     viewRevision++;
     owner.setChanged();
diff --git a/src/main/java/zone/moddev/mc/lib/api/capabilities/FluidStorage.java b/src/main/java/zone/moddev/mc/lib/api/capabilities/FluidStorage.java
index b120622c..f53ad9b1 100644
--- a/src/main/java/zone/moddev/mc/lib/api/capabilities/FluidStorage.java
+++ b/src/main/java/zone/moddev/mc/lib/api/capabilities/FluidStorage.java
@@ -2,6 +2,7 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.function.Consumer;
 import java.util.function.IntFunction;
 import java.util.function.IntPredicate;
 import java.util.function.Predicate;
@@ -39,6 +40,9 @@ public zone.moddev.mc.lib.api.stats.Statistics statistics() {
 
   private final List<FluidTank> tanks = new ArrayList<>();
   private final List<Role> roles = new ArrayList<>();
+  private final List<String> tankIds = new ArrayList<>();
+  private final List<Predicate<FluidStack>> insertionRules = new ArrayList<>();
+  private final ListTag recovery = new ListTag();
   private final ReservationPlans<TankPlan> plans =
       new ReservationPlans<>(
           0,
@@ -115,6 +119,8 @@ public FluidStack drain(int maxDrain, FluidAction action) {
           }
         });
     roles.add(role);
+    tankIds.add(null);
+    insertionRules.add(fluid -> true);
     plans.add();
     revision++;
     return tanks.size() - 1;
@@ -133,6 +139,55 @@ public FluidTank tank(int index) {
     return tanks.get(index);
   }
 
+  /** Stable save identity; saves without identities continue to load by index. */
+  public FluidStorage tankId(int tank, String id) {
+    if (!inRange(tank) || id == null || id.isBlank())
+      throw new IllegalArgumentException("Invalid tank ID: " + id);
+    for (int i = 0; i < tankIds.size(); i++)
+      if (i != tank && id.equals(tankIds.get(i)))
+        throw new IllegalArgumentException("Duplicate tank ID: " + id);
+    tankIds.set(tank, id);
+    return this;
+  }
+
+  /** Additional external insertion rule; machine products use fillResult and bypass this rule. */
+  public FluidStorage restrict(Predicate<FluidStack> rule, int... indexes) {
+    for (int tank : indexes) insertionRules.set(tank, insertionRules.get(tank).and(rule));
+    revision++;
+    return this;
+  }
+
+  /** Machine product insertion, retaining the tank's structural filter and reservation. */
+  public int fillResult(int tank, FluidStack fluid, FluidAction action) {
+    return tank(tank).fill(fluid, action);
+  }
+
+  /** Unchecked restoration for save loading and transaction rollback. */
+  public void restoreFluid(int tank, FluidStack fluid) {
+    tank(tank).setFluid(fluid.copy());
+  }
+
+  public ListTag recoveryContents() {
+    return recovery.copy();
+  }
+
+  /** Explicitly discards contents, displaced fluids and plans. Stop owning processors first. */
+  public void clear() {
+    recovery.clear();
+    for (int tank = 0; tank < getTanks(); tank++) {
+      setPlan(tank, TankPlan.NONE);
+      restoreFluid(tank, FluidStack.EMPTY);
+    }
+    revision++;
+    onChange.run();
+  }
+
+  public void recover(Consumer<CompoundTag> receiver) {
+    StorageRecovery.handoff(recovery, "mmdlib:fluids", "fluid", receiver);
+    revision++;
+    onChange.run();
+  }
+
   /** Shared plan table, including transaction tracking for groups over this storage. */
   public ReservationPlans<TankPlan> reservationPlans() {
     return plans;
@@ -183,7 +238,10 @@ public int getTankCapacity(int tank) {
 
   @Override
   public boolean isFluidValid(int tank, FluidStack stack) {
-    return inRange(tank) && roles.get(tank) != Role.OUTPUT && tanks.get(tank).isFluidValid(stack);
+    return inRange(tank)
+        && roles.get(tank) != Role.OUTPUT
+        && insertionRules.get(tank).test(stack)
+        && tanks.get(tank).isFluidValid(stack);
   }
 
   @Override
@@ -270,10 +328,12 @@ private int fill(FluidStack resource, FluidAction action, IntPredicate allowed)
     int target = -1;
     for (int i = 0; i < tanks.size() && target < 0; i++)
       if (allowed.test(i)
+          && insertionRules.get(i).test(resource)
           && FluidStack.isSameFluidSameComponents(tanks.get(i).getFluid(), resource)
           && tanks.get(i).fill(resource, FluidAction.SIMULATE) > 0) target = i;
     for (int i = 0; i < tanks.size() && target < 0; i++)
       if (allowed.test(i)
+          && insertionRules.get(i).test(resource)
           && tanks.get(i).isEmpty()
           && tanks.get(i).fill(resource, FluidAction.SIMULATE) > 0) target = i;
     return target < 0 ? 0 : tanks.get(target).fill(resource, action);
@@ -303,19 +363,74 @@ private boolean inRange(int tank) {
   @Override
   public CompoundTag serializeNBT(HolderLookup.Provider provider) {
     ListTag list = new ListTag();
-    for (FluidTank tank : tanks) list.add(tank.writeToNBT(provider, new CompoundTag()));
+    for (int i = 0; i < tanks.size(); i++) {
+      var entry = tanks.get(i).writeToNBT(provider, new CompoundTag());
+      if (tankIds.get(i) != null) entry.putString("TankId", tankIds.get(i));
+      list.add(entry);
+    }
     CompoundTag tag = new CompoundTag();
     tag.put("Tanks", list);
+    tag.put("Recovery", recovery.copy());
     return tag;
   }
 
-  /** Loads tank contents by index; tanks missing from the save are emptied, extra ones ignored. */
+  /** Loads by stable identity or legacy index, preserving removed tanks and capacity overflow. */
   @Override
   public void deserializeNBT(HolderLookup.Provider provider, CompoundTag tag) {
-    ListTag list = tag.getList("Tanks", Tag.TAG_COMPOUND);
-    for (int i = 0; i < tanks.size(); i++) {
-      if (i < list.size()) tanks.get(i).readFromNBT(provider, list.getCompound(i));
-      else tanks.get(i).setFluid(FluidStack.EMPTY);
+    deserializeNBT(provider, tag, java.util.function.IntUnaryOperator.identity());
+  }
+
+  /** Explicit index migration for pre-identity saves. The host selects this by its save version. */
+  public void deserializeNBT(
+      HolderLookup.Provider provider,
+      CompoundTag tag,
+      java.util.function.IntUnaryOperator legacyTanks) {
+    var saved = tag.getList("Tanks", Tag.TAG_COMPOUND);
+    var list = new ListTag();
+    for (int i = 0; i < saved.size(); i++) {
+      var tank = saved.getCompound(i);
+      var entry = tank.getCompound("Fluid").copy();
+      if (entry.isEmpty()) continue;
+      entry.putInt("Tank", i);
+      if (tank.contains("TankId")) entry.putString("TankId", tank.getString("TankId"));
+      list.add(entry);
     }
+    list.addAll(tag.getList("Recovery", Tag.TAG_COMPOUND).copy());
+    recovery.clear();
+    for (var tank : tanks) tank.setFluid(FluidStack.EMPTY);
+    for (var value : list) {
+      var entry = (CompoundTag) value;
+      int index =
+          entry.contains("TankId")
+              ? tankIds.indexOf(entry.getString("TankId"))
+              : legacyTanks.applyAsInt(entry.getInt("Tank"));
+      if (!entry.contains("TankId")) {
+        entry.putInt("Tank", index);
+        if (inRange(index) && tankIds.get(index) != null)
+          entry.putString("TankId", tankIds.get(index));
+      }
+      var fluid = FluidStack.parseOptional(provider, entry);
+      if (fluid.isEmpty()) {
+        if (entry.contains("id")) recovery.add(entry.copy());
+        continue;
+      }
+      if (!inRange(index)
+          || (!tanks.get(index).isEmpty()
+              && !FluidStack.isSameFluidSameComponents(tanks.get(index).getFluid(), fluid))) {
+        recovery.add(entry.copy());
+        continue;
+      }
+      int held = tanks.get(index).getFluidAmount();
+      int accepted =
+          Math.min(fluid.getAmount(), Math.max(0, tanks.get(index).getCapacity() - held));
+      restoreFluid(index, fluid.copyWithAmount(held + accepted));
+      if (accepted < fluid.getAmount()) {
+        var extra = entry.copy();
+        extra.putInt("amount", fluid.getAmount() - accepted);
+        recovery.add(extra);
+      }
+    }
+    revision++;
+    onChange.run();
   }
 }
diff --git a/src/main/java/zone/moddev/mc/lib/api/capabilities/ItemStorage.java b/src/main/java/zone/moddev/mc/lib/api/capabilities/ItemStorage.java
index 853c39d3..eda8699f 100644
--- a/src/main/java/zone/moddev/mc/lib/api/capabilities/ItemStorage.java
+++ b/src/main/java/zone/moddev/mc/lib/api/capabilities/ItemStorage.java
@@ -1,11 +1,16 @@
 package zone.moddev.mc.lib.api.capabilities;
 
 import java.util.Arrays;
+import java.util.function.Consumer;
 import java.util.function.IntFunction;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 
 import net.minecraft.core.BlockPos;
+import net.minecraft.core.HolderLookup;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.nbt.ListTag;
+import net.minecraft.nbt.Tag;
 import net.minecraft.world.Containers;
 import net.minecraft.world.item.Item;
 import net.minecraft.world.item.ItemStack;
@@ -37,9 +42,121 @@ public zone.moddev.mc.lib.api.stats.Statistics statistics() {
   @SuppressWarnings("unchecked")
   private final Predicate<ItemStack>[] filters;
 
+  private final Predicate<ItemStack>[] insertionRules;
+
   private Runnable onChange = () -> {};
   private boolean bypass;
   private long revision;
+  private final String[] slotIds;
+  private final ListTag recovery = new ListTag();
+
+  /** Optional stable identity for save migration; legacy saves still load by index. */
+  public ItemStorage slotId(int slot, String id) {
+    checked(slot);
+    if (id == null || id.isBlank()) throw new IllegalArgumentException("Empty slot ID");
+    for (int i = 0; i < slotIds.length; i++)
+      if (i != slot && id.equals(slotIds[i]))
+        throw new IllegalArgumentException("Duplicate slot ID: " + id);
+    slotIds[slot] = id;
+    return this;
+  }
+
+  /** Adds an acceptance rule without replacing the machine's existing filter. */
+  public ItemStorage restrict(Predicate<ItemStack> filter, int... slots) {
+    for (int slot : slots) insertionRules[checked(slot)] = insertionRules[slot].and(filter);
+    revision++;
+    return this;
+  }
+
+  /** Unchecked restoration, explicitly bypassing placement rules and reservations. */
+  public void restoreStack(int slot, ItemStack stack) {
+    setStackInSlot(slot, stack.copy());
+  }
+
+  /** Displaced or undecodable stacks, retained verbatim until recovered or loadable again. */
+  public ListTag recoveryContents() {
+    return recovery.copy();
+  }
+
+  public void recover(Consumer<CompoundTag> receiver) {
+    StorageRecovery.handoff(recovery, "mmdlib:items", "item", receiver);
+    markChanged();
+  }
+
+  /** Explicitly discards contents, displaced items and plans. Stop owning processors first. */
+  public void clear() {
+    recovery.clear();
+    for (int slot = 0; slot < getSlots(); slot++) {
+      setPlan(slot, zone.moddev.mc.lib.machine.inventory.SlotPlan.NONE);
+      stacks.set(slot, ItemStack.EMPTY);
+    }
+    markChanged();
+  }
+
+  @Override
+  public CompoundTag serializeNBT(HolderLookup.Provider provider) {
+    var tag = super.serializeNBT(provider);
+    for (var value : tag.getList("Items", Tag.TAG_COMPOUND)) {
+      var entry = (CompoundTag) value;
+      int slot = entry.getInt("Slot");
+      if (inRange(slot) && slotIds[slot] != null) entry.putString("SlotId", slotIds[slot]);
+    }
+    tag.put("Recovery", recovery.copy());
+    return tag;
+  }
+
+  @Override
+  public void deserializeNBT(HolderLookup.Provider provider, CompoundTag tag) {
+    deserializeNBT(provider, tag, java.util.function.IntUnaryOperator.identity());
+  }
+
+  /** Explicit index migration for pre-identity saves. The host selects this by its save version. */
+  public void deserializeNBT(
+      HolderLookup.Provider provider,
+      CompoundTag tag,
+      java.util.function.IntUnaryOperator legacySlots) {
+    var entries = tag.getList("Items", Tag.TAG_COMPOUND).copy();
+    entries.addAll(tag.getList("Recovery", Tag.TAG_COMPOUND).copy());
+    recovery.clear();
+    for (int i = 0; i < getSlots(); i++) stacks.set(i, ItemStack.EMPTY);
+    for (var value : entries) {
+      var entry = (CompoundTag) value;
+      int slot = entry.getInt("Slot");
+      if (entry.contains("SlotId")) {
+        slot = -1;
+        for (int i = 0; i < slotIds.length; i++)
+          if (entry.getString("SlotId").equals(slotIds[i])) {
+            slot = i;
+            break;
+          }
+      } else {
+        slot = legacySlots.applyAsInt(slot);
+        entry.putInt("Slot", slot);
+        if (inRange(slot) && slotIds[slot] != null) entry.putString("SlotId", slotIds[slot]);
+      }
+      var stack = ItemStack.parseOptional(provider, entry);
+      if (stack.isEmpty()
+          || !inRange(slot)
+          || (!stacks.get(slot).isEmpty()
+              && !ItemStack.isSameItemSameComponents(stacks.get(slot), stack))) {
+        if (!entry.isEmpty()) recovery.add(entry.copy());
+        continue;
+      }
+      int held = stacks.get(slot).getCount();
+      int accepted =
+          Math.min(
+              stack.getCount(),
+              Math.max(0, Math.min(getSlotLimit(slot), stack.getMaxStackSize()) - held));
+      stacks.set(slot, stack.copyWithCount(held + accepted));
+      if (accepted < stack.getCount()) {
+        var extra = entry.copy();
+        extra.putInt("count", stack.getCount() - accepted);
+        recovery.add(extra);
+      }
+    }
+    onLoad();
+    markChanged();
+  }
 
   /** Change counter for recipe search invalidation. */
   public long revision() {
@@ -62,9 +179,12 @@ public ItemStorage(int size) {
     roles = new Role[size];
     limits = new int[size];
     filters = new Predicate[size];
+    insertionRules = new Predicate[size];
+    slotIds = new String[size];
     Arrays.fill(roles, Role.STORAGE);
     Arrays.fill(limits, Item.ABSOLUTE_MAX_STACK_SIZE);
     Arrays.fill(filters, (Predicate<ItemStack>) stack -> true);
+    Arrays.fill(insertionRules, (Predicate<ItemStack>) stack -> true);
   }
 
   /** Runs after every change, typically the block entity's {@code setChanged}. */
@@ -123,7 +243,7 @@ public boolean fits(int slot, ItemStack stack) {
 
   /**
    * Keeps the size given to the constructor, so loading a save written with a different slot count
-   * cannot desynchronize the per-slot settings; stacks in slots that no longer exist are dropped.
+   * cannot desynchronize the per-slot settings; displaced stacks are retained in recovery.
    */
   @Override
   public void setSize(int size) {
@@ -132,7 +252,11 @@ public void setSize(int size) {
 
   @Override
   public boolean isItemValid(int slot, ItemStack stack) {
-    boolean allowed = bypass || (roles[slot] != Role.OUTPUT && filters[slot].test(stack));
+    boolean allowed =
+        bypass
+            || (roles[slot] != Role.OUTPUT
+                && filters[slot].test(stack)
+                && insertionRules[slot].test(stack));
     return allowed && super.isItemValid(slot, stack);
   }
 
@@ -155,6 +279,12 @@ public void dropAll(Level level, BlockPos pos) {
     markChanged();
   }
 
+  /** Hands displaced contents to the host before dropping the ordinary slots. */
+  public void dropAll(Level level, BlockPos pos, Consumer<CompoundTag> recoverResources) {
+    recover(recoverResources);
+    dropAll(level, pos);
+  }
+
   /** An automation view with a fixed mode, e.g. {@link IoMode#BOTH} for unsided access. */
   public IItemHandler view(IoMode mode) {
     return view(() -> mode);
diff --git a/src/main/java/zone/moddev/mc/lib/api/capabilities/StorageRecovery.java b/src/main/java/zone/moddev/mc/lib/api/capabilities/StorageRecovery.java
new file mode 100644
index 00000000..f478ba5f
--- /dev/null
+++ b/src/main/java/zone/moddev/mc/lib/api/capabilities/StorageRecovery.java
@@ -0,0 +1,29 @@
+package zone.moddev.mc.lib.api.capabilities;
+
+import java.util.function.Consumer;
+
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.nbt.ListTag;
+
+/** Raw displaced contents survive missing registrations and can be handed to a recovery item. */
+public final class StorageRecovery {
+  private StorageRecovery() {}
+
+  public static void handoff(
+      ListTag entries, String type, String key, Consumer<CompoundTag> receiver) {
+    if (entries.isEmpty()) return;
+    var resources = new ListTag();
+    for (var entry : entries) {
+      var data = new CompoundTag();
+      data.put(key, entry.copy());
+      var resource = new CompoundTag();
+      resource.putString("type", type);
+      resource.put("data", data);
+      resources.add(resource);
+    }
+    var payload = new CompoundTag();
+    payload.put("resources", resources);
+    receiver.accept(payload);
+    entries.clear();
+  }
+}
diff --git a/src/main/java/zone/moddev/mc/lib/gui/client/MachineScreen.java b/src/main/java/zone/moddev/mc/lib/gui/client/MachineScreen.java
index ba607b55..ea4f5b9d 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/client/MachineScreen.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/client/MachineScreen.java
@@ -426,6 +426,13 @@ private void draw(GuiGraphics g, Element e, Rect r, int mx, int my, float partia
                         r.y() + (r.height() - iconSize) / 2,
                         iconSize,
                         iconSize));
+        if (menu.processorConflict(b))
+          g.blitSprite(
+              ResourceLocation.parse("mmdlib:icon_processor_conflict"),
+              r.right() - 6,
+              r.bottom() - 6,
+              5,
+              5);
       }
       case Element.Checkbox c -> {
         sprite(
@@ -755,10 +762,33 @@ public List<Component> tooltipLines(Element e, int mx, int my) {
                               .orElseGet(() -> ScreenText.number(menu.value(e, false), shift))
                           : ScreenText.number(menu.value(e, false), shift))
                   .replace("{max}", ScreenText.number(menu.value(e, true), shift));
-          lines.add(Component.literal(translated));
+          if (e instanceof Element.Button button && button.processorKey().isPresent()) {
+            var action =
+                ProcessorButtonState.fromWire(menu.value(button, false))
+                    .map(
+                        state ->
+                            switch (state) {
+                              case PAUSED -> "screen.mmdlib.processor.action.unpause";
+                              case PROCESSING -> "screen.mmdlib.processor.action.stop";
+                              case IDLE -> "screen.mmdlib.processor.action.pause";
+                            })
+                    .map(key -> Component.translatable(key).getString())
+                    .orElse("");
+            translated = translated.replace("{action}", action);
+          }
+          translated.lines().map(Component::literal).forEach(lines::add);
         });
     if (c.tooltipShift().isPresent() && !shift)
       lines.add(Component.translatable("screen.mmdlib.shift_for_more"));
+    if (e instanceof Element.Button button && menu.processorConflict(button))
+      Component.translatable(
+              menu.redstone.paused()
+                  ? "screen.mmdlib.processor.conflict.redstone"
+                  : "screen.mmdlib.processor.conflict.manual")
+          .getString()
+          .lines()
+          .map(Component::literal)
+          .forEach(lines::add);
     if (e instanceof Element.Slot slot) {
       var plan = menu.reservationPlan(slot.index());
       if (plan.take() > 0)
@@ -864,6 +894,10 @@ public boolean mouseClicked(double mx, double my, int button) {
                 button == 1 ? ItemStack.EMPTY : menu.getCarried().copyWithCount(1)));
         return true;
       }
+      if (e instanceof Element.Button b && b.processorKey().isPresent()) {
+        if (button == 0) send(e, 0, button, 0);
+        return true;
+      }
       if (e instanceof Element.Button b && b.shows().isPresent()) {
         send(e, 1, button, 0);
         var ref = b.shows().get();
diff --git a/src/main/java/zone/moddev/mc/lib/gui/client/RedstoneDrawer.java b/src/main/java/zone/moddev/mc/lib/gui/client/RedstoneDrawer.java
index 720977c4..519ff17d 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/client/RedstoneDrawer.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/client/RedstoneDrawer.java
@@ -31,7 +31,9 @@ final class RedstoneDrawer {
       BETWEEN = ResourceLocation.parse("mmdlib:icon_redstone_between"),
       OUTSIDE = ResourceLocation.parse("mmdlib:icon_redstone_outside"),
       REVERT = ResourceLocation.parse("mmdlib:icon_redstone_revert"),
-      REVERT_ON = ResourceLocation.parse("mmdlib:icon_redstone_revert_on");
+      REVERT_ON = ResourceLocation.parse("mmdlib:icon_redstone_revert_on"),
+      RUNNING = ResourceLocation.parse("mmdlib:icon_redstone_running"),
+      PAUSED = ResourceLocation.parse("mmdlib:icon_redstone_paused");
   private Language textLanguage;
   private Font textFont;
   private long infoRevision = -1;
@@ -102,7 +104,7 @@ void render(GuiGraphics g, int mx, int my) {
     tooltip = List.of();
     if (model.open()) SideDrawerRenderer.open(g, tab, body, Element.Edge.RIGHT, 0xc78181);
     else SideDrawerRenderer.tab(g, tab, 0xc78181);
-    g.renderItem(tabIcon, tab.x() + 3, tab.y() + 4);
+    renderTabIcon(g);
     if (tab.contains(mx, my)) tooltip = List.of(text("title"));
     if (!model.open()) return;
     g.enableScissor(body.x(), body.y(), body.right(), body.bottom());
@@ -392,7 +394,17 @@ void tooltip(GuiGraphics g, int x, int y) {
   void renderTab(GuiGraphics g) {
     layout();
     SideDrawerRenderer.tab(g, tab, 0xc78181);
+    renderTabIcon(g);
+  }
+
+  private void renderTabIcon(GuiGraphics g) {
     g.renderItem(tabIcon, tab.x() + 3, tab.y() + 4);
+    if (model.watching()) {
+      g.pose().pushPose();
+      g.pose().translate(0, 0, 200);
+      g.blitSprite(model.paused() ? PAUSED : RUNNING, tab.right() - 9, tab.bottom() - 9, 7, 7);
+      g.pose().popPose();
+    }
   }
 
   List<Rect> exclusions() {
diff --git a/src/main/java/zone/moddev/mc/lib/gui/load/ScreenBinder.java b/src/main/java/zone/moddev/mc/lib/gui/load/ScreenBinder.java
index 35af7187..1f866e4f 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/load/ScreenBinder.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/load/ScreenBinder.java
@@ -71,13 +71,25 @@ public static Bound bind(Screen screen, ClassLoader loader, WidgetTypes widgets)
     var maxima = new IdentityHashMap<Element, BoundValue>();
     for (var element : screen.elements()) {
       var c = element.common();
+      var elementSource = screen.source(c);
+      if (element instanceof Button button
+          && button.processorKey().isPresent()
+          && !zone.moddev.mc.lib.gui.runtime.ScreenHost.class.isAssignableFrom(owner))
+        throw new ScreenException(
+            elementSource, c.line(), "<processor-button> requires a ScreenHost");
       if (c.value().isPresent())
         values.put(
             element,
             resolve(
-                c.value().get(), owner, loader, source, c.line(), valueKinds(element, widgets)));
+                c.value().get(),
+                owner,
+                loader,
+                elementSource,
+                c.line(),
+                valueKinds(element, widgets)));
       if (c.max().isPresent())
-        maxima.put(element, resolve(c.max().get(), owner, loader, source, c.line(), NUMBERS));
+        maxima.put(
+            element, resolve(c.max().get(), owner, loader, elementSource, c.line(), NUMBERS));
     }
     return new Bound(screen, owner, values, maxima);
   }
diff --git a/src/main/java/zone/moddev/mc/lib/gui/load/ScreenLoader.java b/src/main/java/zone/moddev/mc/lib/gui/load/ScreenLoader.java
index f4a23e98..f9bd8ccf 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/load/ScreenLoader.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/load/ScreenLoader.java
@@ -11,8 +11,10 @@
 import net.minecraft.resources.ResourceLocation;
 
 import zone.moddev.mc.lib.common.loading.DefinitionLoader.SourceRoot;
+import zone.moddev.mc.lib.gui.WidgetTypes;
 import zone.moddev.mc.lib.gui.layout.ScreenLayout;
 import zone.moddev.mc.lib.gui.layout.TextMeasure;
+import zone.moddev.mc.lib.gui.model.Screen;
 
 /**
  * Finds and loads every screen file: {@code mmdlib/screen/<path>.xml} in each mod, whose ID is
@@ -33,8 +35,25 @@ private ScreenLoader() {}
    * @throws IllegalArgumentException if two files have the same ID
    */
   public static Map<ResourceLocation, ScreenBinder.Bound> load(List<SourceRoot> sources) {
-    zone.moddev.mc.lib.gui.WidgetTypes.GLOBAL.freeze();
+    WidgetTypes.GLOBAL.freeze();
+    var discovered = discover(sources);
     var screens = new TreeMap<ResourceLocation, ScreenBinder.Bound>();
+    read(discovered.nodes(), WidgetTypes.GLOBAL)
+        .forEach((id, screen) -> screens.put(id, bind(screen, discovered.loaders().get(id))));
+    return screens;
+  }
+
+  /** Reads and composes concrete screens without loading host classes, for layout tools. */
+  public static Map<ResourceLocation, Screen> read(List<SourceRoot> sources, WidgetTypes widgets) {
+    return read(discover(sources).nodes(), widgets);
+  }
+
+  private record Definitions(
+      Map<ResourceLocation, ScreenReader.Node> nodes, Map<ResourceLocation, ClassLoader> loaders) {}
+
+  private static Definitions discover(List<SourceRoot> sources) {
+    var definitions = new TreeMap<ResourceLocation, ScreenReader.Node>();
+    var loaders = new TreeMap<ResourceLocation, ClassLoader>();
     for (var source : sources) {
       var folder = source.root().resolve(SECTION);
       if (!Files.isDirectory(folder)) continue;
@@ -42,19 +61,35 @@ public static Map<ResourceLocation, ScreenBinder.Bound> load(List<SourceRoot> so
         for (var file :
             files.filter(Files::isRegularFile).filter(ScreenLoader::isXml).sorted().toList()) {
           var id = id(source.namespace(), folder, file);
-          var bound = loadFile(id, file, source.classLoader());
-          if (screens.putIfAbsent(id, bound) != null)
-            throw new IllegalArgumentException("Duplicate screen " + id + ": " + file);
+          try (var input = Files.newInputStream(file)) {
+            var definition = ScreenReader.parse(file.toString(), input);
+            if (definitions.putIfAbsent(id, definition) != null)
+              throw new IllegalArgumentException("Duplicate screen " + id + ": " + file);
+            loaders.put(id, source.classLoader());
+          }
         }
       } catch (IOException ex) {
         throw new UncheckedIOException("Cannot read screens in " + folder, ex);
       }
     }
+    return new Definitions(definitions, loaders);
+  }
+
+  private static Map<ResourceLocation, Screen> read(
+      Map<ResourceLocation, ScreenReader.Node> definitions, WidgetTypes widgets) {
+    var screens = new TreeMap<ResourceLocation, Screen>();
+    var templates = new ScreenTemplates(definitions);
+    // Discover all definitions first: bases may be in later files or another mod.
+    for (var id : definitions.keySet()) templates.resolve(id);
+    for (var id : definitions.keySet()) {
+      if (ScreenTemplates.flag(definitions.get(id), "abstract")) continue;
+      screens.put(id, ScreenReader.build(id, templates.expand(id), widgets));
+    }
     return screens;
   }
 
   /**
-   * Reads and binds one screen file.
+   * Reads and binds one standalone screen file. Use {@link #load} to resolve bases across files.
    *
    * @throws ScreenException if it is invalid
    * @throws IOException if it cannot be read
@@ -63,14 +98,18 @@ public static ScreenBinder.Bound loadFile(ResourceLocation id, Path file, ClassL
       throws IOException {
     try (var input = Files.newInputStream(file)) {
       var screen = ScreenReader.read(id, file.toString(), input);
-      try {
-        // Heights never depend on text, so whether the tabs fit can be checked without a font.
-        ScreenLayout.of(screen, TextMeasure.NONE);
-      } catch (IllegalArgumentException ex) {
-        throw new ScreenException(file.toString(), 0, ex.getMessage(), ex);
-      }
-      return ScreenBinder.bind(screen, loader);
+      return bind(screen, loader);
+    }
+  }
+
+  private static ScreenBinder.Bound bind(Screen screen, ClassLoader loader) {
+    try {
+      // Heights never depend on text, so whether the tabs fit can be checked without a font.
+      ScreenLayout.of(screen, TextMeasure.NONE);
+    } catch (IllegalArgumentException ex) {
+      throw new ScreenException(screen.source(), 0, ex.getMessage(), ex);
     }
+    return ScreenBinder.bind(screen, loader);
   }
 
   private static boolean isXml(Path file) {
diff --git a/src/main/java/zone/moddev/mc/lib/gui/load/ScreenReader.java b/src/main/java/zone/moddev/mc/lib/gui/load/ScreenReader.java
index 9fd7df3f..dbb08580 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/load/ScreenReader.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/load/ScreenReader.java
@@ -70,6 +70,12 @@ public static Screen read(
       ResourceLocation id, String source, InputStream input, WidgetTypes widgets)
       throws IOException {
     Node root = parse(source, input);
+    return build(id, new ScreenTemplates(Map.of(id, root)).expand(id), widgets);
+  }
+
+  static Screen build(ResourceLocation id, Node root, WidgetTypes widgets) {
+    validateExpanded(root);
+    String source = root.source();
     var screen = new Builder(source, widgets).screen(id, root);
     check(screen);
     return screen;
@@ -78,9 +84,14 @@ public static Screen read(
   // Parsing
 
   /** One parsed element, with its attributes as written (schema defaults filled in). */
-  private record Node(String name, Map<String, String> attributes, List<Node> children, int line) {}
+  record Node(
+      String name, Map<String, String> attributes, List<Node> children, String source, int line) {
+    Node withChildren(List<Node> children) {
+      return new Node(name, attributes, children, source, line);
+    }
+  }
 
-  private static Node parse(String source, InputStream input) throws IOException {
+  static Node parse(String source, InputStream input) throws IOException {
     try {
       var factory = SAXParserFactory.newInstance();
       factory.setNamespaceAware(true);
@@ -104,6 +115,50 @@ private static Node parse(String source, InputStream input) throws IOException {
     }
   }
 
+  /** Check placement again after fills are spliced into their destination containers. */
+  private static void validateExpanded(Node root) {
+    var validator = SCHEMA.newValidatorHandler();
+    var locator = new org.xml.sax.helpers.LocatorImpl();
+    validator.setDocumentLocator(locator);
+    validator.setErrorHandler(
+        new DefaultHandler() {
+          @Override
+          public void error(SAXParseException ex) throws SAXException {
+            throw ex;
+          }
+
+          @Override
+          public void fatalError(SAXParseException ex) throws SAXException {
+            throw ex;
+          }
+        });
+    try {
+      validator.startDocument();
+      validateNode(root, validator, locator);
+      validator.endDocument();
+    } catch (SAXException ex) {
+      throw new ScreenException(
+          locator.getSystemId(), locator.getLineNumber(), ex.getMessage(), ex);
+    }
+  }
+
+  private static void validateNode(
+      Node node,
+      javax.xml.validation.ValidatorHandler validator,
+      org.xml.sax.helpers.LocatorImpl locator)
+      throws SAXException {
+    locator.setSystemId(node.source());
+    locator.setLineNumber(node.line());
+    var attributes = new org.xml.sax.helpers.AttributesImpl();
+    node.attributes()
+        .forEach((name, value) -> attributes.addAttribute("", name, name, "CDATA", value));
+    validator.startElement(NAMESPACE, node.name(), node.name(), attributes);
+    for (var child : node.children()) validateNode(child, validator, locator);
+    locator.setSystemId(node.source());
+    locator.setLineNumber(node.line());
+    validator.endElement(NAMESPACE, node.name(), node.name());
+  }
+
   private static Schema loadSchema() {
     try (var stream = ScreenReader.class.getResourceAsStream("/mmdlib/schema/screen.xsd")) {
       if (stream == null) throw new IllegalStateException("Missing mmdlib/schema/screen.xsd");
@@ -144,7 +199,7 @@ public void startElement(String uri, String local, String qName, Attributes attr
         if (attributes.getURI(i).isEmpty())
           values.put(attributes.getLocalName(i), attributes.getValue(i));
       var children = new ArrayList<Node>();
-      var node = new Node(local, values, children, locator.getLineNumber());
+      var node = new Node(local, values, children, source, locator.getLineNumber());
       if (stack.isEmpty()) root = node;
       else open.getLast().add(node);
       stack.add(node);
@@ -173,6 +228,7 @@ public void fatalError(SAXParseException ex) throws SAXException {
   private static final class Builder {
     private final String source;
     private final WidgetTypes widgets;
+    private final Map<Common, String> origins = new java.util.IdentityHashMap<>();
 
     Builder(String source, WidgetTypes widgets) {
       this.source = source;
@@ -187,6 +243,8 @@ Screen screen(ResourceLocation id, Node root) {
         if (element instanceof SideTab || element instanceof Popout) tabs.add(element);
         else body.add(element);
       }
+      if (body.isEmpty() || body.getFirst() instanceof InventoryControls)
+        throw error(root, "A screen requires at least one body element");
       return new Screen(
           id,
           source,
@@ -194,7 +252,8 @@ Screen screen(ResourceLocation id, Node root) {
           root.attributes().get("block-entity"),
           !"none".equals(root.attributes().get("inventory")),
           body,
-          tabs);
+          tabs,
+          origins);
     }
 
     private List<Element> children(Node node) {
@@ -203,6 +262,7 @@ private List<Element> children(Node node) {
 
     private Element element(Node node) {
       if (node.name().equals("energy-gauge")) node = energyDefaults(node);
+      if (node.name().equals("processor-button")) node = processorDefaults(node);
       var c = common(node);
       return switch (node.name()) {
         case "vbox", "hbox" ->
@@ -256,7 +316,7 @@ private Element element(Node node) {
         case "progress" ->
             new Progress(c, id(node, "icon"), enumValue(Direction.class, node, "direction"));
         case "label" -> new Label(c, text(node, "text").orElseThrow());
-        case "button" ->
+        case "button", "processor-button" ->
             new Button(
                 c,
                 text(node, "text"),
@@ -267,7 +327,8 @@ private Element element(Node node) {
                     .map(key -> new Text(key, Optional.empty()))
                     .toList(),
                 java.util.Set.of("true", "1")
-                    .contains(node.attributes().getOrDefault("flat", "false")));
+                    .contains(node.attributes().getOrDefault("flat", "false")),
+                Optional.ofNullable(node.attributes().get("processor-key")));
         case "checkbox" -> new Checkbox(c, text(node, "text").orElseThrow());
         case "radio-group" ->
             new RadioGroup(
@@ -313,7 +374,8 @@ private Custom custom(Node node, Common common) {
           throw new IllegalArgumentException("This widget does not accept a value binding");
         type.validator().accept(element);
       } catch (RuntimeException ex) {
-        throw new ScreenException(source, node.line(), element.type() + ": " + ex.getMessage(), ex);
+        throw new ScreenException(
+            node.source(), node.line(), element.type() + ": " + ex.getMessage(), ex);
       }
       return element;
     }
@@ -327,33 +389,52 @@ private Node energyDefaults(Node node) {
         attributes.put("tooltip", "screen.mmdlib.energy");
         attributes.putIfAbsent("tooltip-fallback", "{value} / {max} FE");
       }
-      return new Node(node.name(), attributes, node.children(), node.line());
+      return new Node(node.name(), attributes, node.children(), node.source(), node.line());
+    }
+
+    private Node processorDefaults(Node node) {
+      if (node.attributes().get("processor-key").isBlank())
+        throw error(node, "processor-key must not be blank");
+      var attributes = new LinkedHashMap<>(node.attributes());
+      attributes.put(
+          "icons",
+          "mmdlib:icon_processor_pause mmdlib:icon_processor_stop mmdlib:icon_processor_play");
+      attributes.put(
+          "value-labels",
+          "screen.mmdlib.processor.paused screen.mmdlib.processor.processing"
+              + " screen.mmdlib.processor.idle");
+      if (!attributes.containsKey("tooltip"))
+        attributes.put("tooltip", "screen.mmdlib.processor.toggle");
+      return new Node(node.name(), attributes, node.children(), node.source(), node.line());
     }
 
     private Common common(Node node) {
       var a = node.attributes();
       var recipes = a.get("jei-recipes");
-      return new Common(
-          Optional.ofNullable(a.get("id")),
-          value(node, "value"),
-          value(node, "max"),
-          text(node, "tooltip"),
-          text(node, "tooltip-shift"),
-          new Common.Clicks(
-              id(node, "on-click"),
-              id(node, "on-right-click"),
-              id(node, "on-shift-click"),
-              id(node, "on-shift-right-click")),
-          id(node, "on-hover"),
-          Optional.ofNullable(a.get("hover-shows")),
-          recipes == null || recipes.isBlank()
-              ? List.of()
-              : java.util.Arrays.stream(recipes.trim().split("\\s+"))
-                  .map(ResourceLocation::parse)
-                  .toList(),
-          a.containsKey("offset-x") ? offset(node, "offset-x") : 0,
-          a.containsKey("offset-y") ? offset(node, "offset-y") : 0,
-          node.line());
+      var common =
+          new Common(
+              Optional.ofNullable(a.get("id")),
+              value(node, "value"),
+              value(node, "max"),
+              text(node, "tooltip"),
+              text(node, "tooltip-shift"),
+              new Common.Clicks(
+                  id(node, "on-click"),
+                  id(node, "on-right-click"),
+                  id(node, "on-shift-click"),
+                  id(node, "on-shift-right-click")),
+              id(node, "on-hover"),
+              Optional.ofNullable(a.get("hover-shows")),
+              recipes == null || recipes.isBlank()
+                  ? List.of()
+                  : java.util.Arrays.stream(recipes.trim().split("\\s+"))
+                      .map(ResourceLocation::parse)
+                      .toList(),
+              a.containsKey("offset-x") ? offset(node, "offset-x") : 0,
+              a.containsKey("offset-y") ? offset(node, "offset-y") : 0,
+              node.line());
+      origins.put(common, node.source());
+      return common;
     }
 
     private Optional<Text> text(Node node, String name) {
@@ -439,20 +520,20 @@ private <E extends Enum<E>> E enumValue(Class<E> type, Node node, String name) {
     }
 
     private ScreenException error(Node node, String message) {
-      return new ScreenException(source, node.line(), message);
+      return new ScreenException(node.source(), node.line(), message);
     }
   }
 
   // Checks a schema cannot express
 
   private static void check(Screen screen) {
-    var source = screen.source();
     var ids = new HashMap<String, Element>();
     var slots = new HashMap<Integer, Element>();
     var contexts = new HashMap<String, Set<String>>();
     Element inventory = null;
     for (var element : screen.elements()) {
       var c = element.common();
+      var source = screen.source(c);
       if (c.id().isPresent() && ids.putIfAbsent(c.id().get(), element) != null)
         throw new ScreenException(source, c.line(), "Duplicate id: " + c.id().get());
       if (element instanceof Slot slot && slots.putIfAbsent(slot.index(), element) != null)
@@ -465,7 +546,9 @@ private static void check(Screen screen) {
         for (var view : context.views())
           if (view.common().id().isEmpty())
             throw new ScreenException(
-                source, view.common().line(), "<view> needs an id for buttons to name");
+                screen.source(view.common()),
+                view.common().line(),
+                "<view> needs an id for buttons to name");
           else views.add(view.common().id().get());
         contexts.put(c.id().get(), views);
       }
@@ -477,11 +560,12 @@ private static void check(Screen screen) {
     }
     if (inventory != null && !screen.playerInventory())
       throw new ScreenException(
-          source,
+          screen.source(inventory.common()),
           inventory.common().line(),
           "<player-inventory> cannot be placed on a screen with inventory=\"none\"");
     for (var element : screen.elements()) {
       var c = element.common();
+      var source = screen.source(c);
       int line = c.line();
       if (c.hoverShows().isPresent() && !ids.containsKey(c.hoverShows().get()))
         throw new ScreenException(
@@ -490,6 +574,16 @@ private static void check(Screen screen) {
         throw new ScreenException(source, line, "max needs value");
       switch (element) {
         case Button button -> {
+          if (button.processorKey().isPresent()
+              && (c.value().isPresent()
+                  || c.max().isPresent()
+                  || c.clicks().any()
+                  || !c.jeiRecipes().isEmpty()))
+            throw new ScreenException(
+                source,
+                line,
+                "<processor-button> owns its state and click action; value, max, click handlers and"
+                    + " jei-recipes are not allowed");
           if (button.flat() && button.text().isPresent())
             throw new ScreenException(
                 source, line, "A flat button uses an icon, not a text caption");
@@ -497,7 +591,8 @@ private static void check(Screen screen) {
             throw new ScreenException(source, line, "<button> needs a tooltip saying what it does");
           if (button.text().isEmpty() && button.icon().isEmpty() && button.icons().isEmpty())
             throw new ScreenException(source, line, "<button> needs text or icon");
-          if (!button.icons().isEmpty() || !button.valueLabels().isEmpty())
+          if (button.processorKey().isEmpty()
+              && (!button.icons().isEmpty() || !button.valueLabels().isEmpty()))
             requireValue(source, element, "a stateful <button>", false);
           if (!button.icons().isEmpty()
               && !button.valueLabels().isEmpty()
@@ -545,8 +640,8 @@ private static void check(Screen screen) {
       }
     }
     checkSpacers(screen);
-    for (var element : screen.body()) checkFill(screen.source(), element, true);
-    for (var element : screen.tabs()) checkFill(screen.source(), element, true);
+    for (var element : screen.body()) checkFill(screen, element, true);
+    for (var element : screen.tabs()) checkFill(screen, element, true);
   }
 
   /**
@@ -556,7 +651,8 @@ private static void check(Screen screen) {
    *
    * @param verticalParent whether the element's parent stacks its children vertically
    */
-  private static void checkFill(String source, Element element, boolean verticalParent) {
+  private static void checkFill(Screen screen, Element element, boolean verticalParent) {
+    var source = screen.source(element.common());
     Orientation orientation = null;
     if (element instanceof Gauge gauge && gauge.fills()) orientation = gauge.orientation();
     if (element instanceof EnergyGauge gauge && gauge.fills()) orientation = gauge.orientation();
@@ -574,7 +670,7 @@ private static void checkFill(String source, Element element, boolean verticalPa
           "A horizontal length=\"fill\" matches the width of its column, so it belongs directly"
               + " in a <vbox>, <group>, <view> or <side-tab>");
     boolean vertical = !(element instanceof Box box && !box.vertical());
-    for (var child : element.children()) checkFill(source, child, vertical);
+    for (var child : element.children()) checkFill(screen, child, vertical);
   }
 
   private static void requireValue(String source, Element element, String what, boolean needsMax) {
@@ -592,13 +688,13 @@ private static void checkSpacers(Screen screen) {
         for (var child : element.children())
           if (child instanceof Spacer)
             throw new ScreenException(
-                screen.source(),
+                screen.source(child.common()),
                 child.common().line(),
                 "<spacer> belongs directly inside a vbox or hbox");
     for (var element : screen.body())
       if (element instanceof Spacer)
         throw new ScreenException(
-            screen.source(),
+            screen.source(element.common()),
             element.common().line(),
             "<spacer> belongs directly inside a vbox or hbox");
   }
diff --git a/src/main/java/zone/moddev/mc/lib/gui/load/ScreenTemplates.java b/src/main/java/zone/moddev/mc/lib/gui/load/ScreenTemplates.java
new file mode 100644
index 00000000..71e35cf7
--- /dev/null
+++ b/src/main/java/zone/moddev/mc/lib/gui/load/ScreenTemplates.java
@@ -0,0 +1,129 @@
+package zone.moddev.mc.lib.gui.load;
+
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Map;
+
+import net.minecraft.resources.ResourceLocation;
+
+import zone.moddev.mc.lib.gui.load.ScreenReader.Node;
+
+/** Resolves named screen templates before model validation, layout and getter binding. */
+final class ScreenTemplates {
+  private final Map<ResourceLocation, Node> definitions;
+  private final Map<ResourceLocation, Node> resolved = new LinkedHashMap<>();
+  private final LinkedHashSet<ResourceLocation> visiting = new LinkedHashSet<>();
+
+  ScreenTemplates(Map<ResourceLocation, Node> definitions) {
+    this.definitions = Map.copyOf(definitions);
+  }
+
+  static boolean flag(Node node, String attribute) {
+    return "true".equals(node.attributes().get(attribute))
+        || "1".equals(node.attributes().get(attribute));
+  }
+
+  Node resolve(ResourceLocation id) {
+    var cached = resolved.get(id);
+    if (cached != null) return cached;
+    var root = definitions.get(id);
+    if (!visiting.add(id)) throw error(root, "Screen inheritance cycle: " + visiting + " -> " + id);
+    if (!root.name().equals("screen")) throw error(root, "Expected a <screen> root");
+    var parent = root.attributes().get("extends");
+    Node result = root;
+    if (parent != null) {
+      var parentId = ResourceLocation.parse(parent);
+      if (!definitions.containsKey(parentId)) throw error(root, "Unknown base screen: " + parent);
+      var base = resolve(parentId);
+      var placeholders = placeholders(base);
+      var fills = new LinkedHashMap<String, Node>();
+      for (var child : root.children()) {
+        if (!child.name().equals("fill"))
+          throw error(child, "An extending screen supplies content through <fill> only");
+        var name = child.attributes().get("name");
+        if (fills.putIfAbsent(name, child) != null) throw error(child, "Duplicate fill: " + name);
+        if (!placeholders.containsKey(name)) throw error(child, "Unknown placeholder: " + name);
+      }
+      // Replacing an outer placeholder also replaces its nested extension points.
+      var used = new LinkedHashSet<String>();
+      var children = apply(base.children(), fills, used);
+      for (var entry : fills.entrySet())
+        if (!used.contains(entry.getKey()))
+          throw error(entry.getValue(), "Fill targets a replaced placeholder: " + entry.getKey());
+      var attributes = new LinkedHashMap<>(root.attributes());
+      if (!attributes.containsKey("inventory") && base.attributes().containsKey("inventory"))
+        attributes.put("inventory", base.attributes().get("inventory"));
+      result = new Node(root.name(), attributes, children, root.source(), root.line());
+    } else {
+      for (var child : root.children())
+        if (child.name().equals("fill")) throw error(child, "<fill> requires extends on <screen>");
+    }
+    placeholders(result); // Reject ambiguous names, including newly introduced extension points.
+    if (!flag(root, "abstract")) {
+      for (var attribute : List.of("title", "block-entity"))
+        if (!root.attributes().containsKey(attribute))
+          throw error(root, "A concrete screen requires its own " + attribute);
+    }
+    visiting.remove(id);
+    resolved.put(id, result);
+    return result;
+  }
+
+  Node expand(ResourceLocation id) {
+    var root = resolve(id);
+    if (flag(root, "abstract")) throw error(root, "An abstract screen cannot be opened or bound");
+    return root.withChildren(expand(root.children()));
+  }
+
+  private static Map<String, Node> placeholders(Node root) {
+    var found = new LinkedHashMap<String, Node>();
+    collect(root, found);
+    return found;
+  }
+
+  private static void collect(Node node, Map<String, Node> found) {
+    if (node.name().equals("placeholder")) {
+      var name = node.attributes().get("name");
+      if (found.putIfAbsent(name, node) != null)
+        throw error(node, "Duplicate placeholder: " + name);
+      if (flag(node, "required") && !node.children().isEmpty())
+        throw error(node, "A required placeholder cannot also have default content: " + name);
+    }
+    for (var child : node.children()) collect(child, found);
+  }
+
+  private static List<Node> apply(
+      List<Node> nodes, Map<String, Node> fills, java.util.Set<String> used) {
+    var result = new ArrayList<Node>();
+    for (var node : nodes) {
+      var fill =
+          node.name().equals("placeholder") ? fills.get(node.attributes().get("name")) : null;
+      if (fill != null) {
+        used.add(node.attributes().get("name"));
+        var attributes = new LinkedHashMap<>(node.attributes());
+        attributes.remove("required");
+        // Keep the extension point so a further descendant can override it again.
+        result.add(new Node(node.name(), attributes, fill.children(), node.source(), node.line()));
+      } else result.add(node.withChildren(apply(node.children(), fills, used)));
+    }
+    return result;
+  }
+
+  private static List<Node> expand(List<Node> nodes) {
+    var result = new ArrayList<Node>();
+    for (var node : nodes) {
+      if (node.name().equals("placeholder")) {
+        if (flag(node, "required"))
+          throw error(node, "Missing required fill: " + node.attributes().get("name"));
+        result.addAll(expand(node.children()));
+      } else result.add(node.withChildren(expand(node.children())));
+    }
+    return result;
+  }
+
+  private static ScreenException error(Node node, String message) {
+    return new ScreenException(node.source(), node.line(), message);
+  }
+}
diff --git a/src/main/java/zone/moddev/mc/lib/gui/model/Element.java b/src/main/java/zone/moddev/mc/lib/gui/model/Element.java
index 3aefa420..a54791aa 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/model/Element.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/model/Element.java
@@ -277,6 +277,7 @@ record Label(Common common, Text text) implements Element {}
    * @param icons optional icons indexed by its boolean or whole-number value
    * @param valueLabels optional translated names for those states in the tooltip
    * @param flat whether to use a compact icon with a flat border and background
+   * @param processorKey a generic processor control's stable feature key, if present
    */
   record Button(
       Common common,
@@ -285,13 +286,25 @@ record Button(
       Optional<ViewRef> shows,
       List<ResourceLocation> icons,
       List<Text> valueLabels,
-      boolean flat)
+      boolean flat,
+      Optional<String> processorKey)
       implements Element {
     public Button {
       icons = List.copyOf(icons);
       valueLabels = List.copyOf(valueLabels);
     }
 
+    public Button(
+        Common common,
+        Optional<Text> text,
+        Optional<ResourceLocation> icon,
+        Optional<ViewRef> shows,
+        List<ResourceLocation> icons,
+        List<Text> valueLabels,
+        boolean flat) {
+      this(common, text, icon, shows, icons, valueLabels, flat, Optional.empty());
+    }
+
     public Button(
         Common common,
         Optional<Text> text,
diff --git a/src/main/java/zone/moddev/mc/lib/gui/model/ProcessorButtonState.java b/src/main/java/zone/moddev/mc/lib/gui/model/ProcessorButtonState.java
new file mode 100644
index 00000000..49b9083b
--- /dev/null
+++ b/src/main/java/zone/moddev/mc/lib/gui/model/ProcessorButtonState.java
@@ -0,0 +1,24 @@
+package zone.moddev.mc.lib.gui.model;
+
+import java.math.BigInteger;
+import java.util.Optional;
+
+/** Current processor activity shown by a generic button, independently of its click action. */
+public enum ProcessorButtonState {
+  PAUSED,
+  PROCESSING,
+  IDLE;
+
+  public static ProcessorButtonState of(boolean paused, boolean processing) {
+    return paused ? PAUSED : processing ? PROCESSING : IDLE;
+  }
+
+  public BigInteger wireValue() {
+    return BigInteger.valueOf(ordinal());
+  }
+
+  public static Optional<ProcessorButtonState> fromWire(Object value) {
+    for (var state : values()) if (state.wireValue().equals(value)) return Optional.of(state);
+    return Optional.empty();
+  }
+}
diff --git a/src/main/java/zone/moddev/mc/lib/gui/model/Screen.java b/src/main/java/zone/moddev/mc/lib/gui/model/Screen.java
index ff22b0fe..d099a606 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/model/Screen.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/model/Screen.java
@@ -2,6 +2,7 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 import java.util.Optional;
 import java.util.function.Consumer;
 
@@ -19,6 +20,8 @@
  *     player-inventory} element places it)
  * @param body the main panel's elements
  * @param tabs side tabs and pop-outs, in document order
+ * @param origins original XML files by element attributes; diagnostic only, excluded from the
+ *     fingerprint
  */
 public record Screen(
     ResourceLocation id,
@@ -27,11 +30,29 @@ public record Screen(
     String blockEntity,
     boolean playerInventory,
     List<Element> body,
-    List<Element> tabs) {
+    List<Element> tabs,
+    Map<Common, String> origins) {
   /** Copies the lists. */
   public Screen {
     body = List.copyOf(body);
     tabs = List.copyOf(tabs);
+    origins = java.util.Collections.unmodifiableMap(new java.util.IdentityHashMap<>(origins));
+  }
+
+  public Screen(
+      ResourceLocation id,
+      String source,
+      Text title,
+      String blockEntity,
+      boolean playerInventory,
+      List<Element> body,
+      List<Element> tabs) {
+    this(id, source, title, blockEntity, playerInventory, body, tabs, Map.of());
+  }
+
+  /** Original XML file of an element, including elements inherited from a base screen. */
+  public String source(Common common) {
+    return origins.getOrDefault(common, source);
   }
 
   /** Visits every element, depth first in document order: the body, then the tabs. */
diff --git a/src/main/java/zone/moddev/mc/lib/gui/runtime/AutomationMenu.java b/src/main/java/zone/moddev/mc/lib/gui/runtime/AutomationMenu.java
index 9921e276..1d78bd0c 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/runtime/AutomationMenu.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/runtime/AutomationMenu.java
@@ -49,7 +49,7 @@ public AutomationMenu(
     revisions = new long[generations.length];
     items =
         client
-            ? new ItemStackHandler(inventory.slots().getSlots()) {
+            ? new ItemStackHandler(inventory.addonSlots().getSlots()) {
               @Override
               public int getSlotLimit(int slot) {
                 return 1;
@@ -67,7 +67,7 @@ public boolean isItemValid(int slot, ItemStack stack) {
                     && addon.acceptsFilter(parent, stack);
               }
             }
-            : inventory.slots();
+            : inventory.addonSlots();
   }
 
   public int slotCount() {
diff --git a/src/main/java/zone/moddev/mc/lib/gui/runtime/MachineMenu.java b/src/main/java/zone/moddev/mc/lib/gui/runtime/MachineMenu.java
index 227fd540..02abb975 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/runtime/MachineMenu.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/runtime/MachineMenu.java
@@ -263,6 +263,7 @@ protected MachineMenu(int id, Inventory inventory, BlockEntity entity, boolean c
       if (element instanceof Element.SideConfig config && config.groups().size() > 682)
         throw new IllegalArgumentException("Too many side configuration groups");
     host = entity instanceof ScreenHost h ? h : null;
+    if (host != null) ScreenInventoryValidation.validate(bound.screen(), host);
     automation =
         host != null && host.screenAutomation() != null
             ? new AutomationMenu(this, host.screenAutomation(), owner, client)
@@ -447,6 +448,17 @@ public Object wireValue(int key) {
     return values.get(key);
   }
 
+  public boolean processorConflict(Element.Button button) {
+    return button.processorKey().isPresent()
+        && redstone != null
+        && zone.moddev.mc.lib.gui.model.ProcessorButtonState.fromWire(value(button, false))
+            .map(
+                state ->
+                    redstone.conflicts(
+                        state == zone.moddev.mc.lib.gui.model.ProcessorButtonState.PAUSED))
+            .orElse(false);
+  }
+
   public void apply(Map<Integer, Object> delta) {
     values.putAll(delta);
     if (items instanceof ClientMenuItems client)
@@ -708,6 +720,24 @@ public void action(Player player, ScreenNetwork.Action action) {
       return;
     }
     if (action.kind() != 0) return;
+    if (element instanceof Element.Button button && button.processorKey().isPresent()) {
+      if (action.button() != 0
+          || action.option() != 0
+          || host == null
+          || host.screenFeatures() == null) return;
+      var features = host.screenFeatures();
+      var key = button.processorKey().orElseThrow();
+      features
+          .processor(key)
+          .ifPresent(
+              processor -> {
+                if (features.setProcessorPaused(key, !processor.paused())) {
+                  ScreenSnapshots.invalidate(blockEntity);
+                  broadcastChanges();
+                }
+              });
+      return;
+    }
     var clicks = element.common().clicks();
     boolean shift = (action.modifiers() & 1) != 0;
     var normal = action.button() == 0 ? clicks.click() : clicks.rightClick();
diff --git a/src/main/java/zone/moddev/mc/lib/gui/runtime/RedstoneMenu.java b/src/main/java/zone/moddev/mc/lib/gui/runtime/RedstoneMenu.java
index 1ad6c87f..46f2cd27 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/runtime/RedstoneMenu.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/runtime/RedstoneMenu.java
@@ -1,8 +1,11 @@
 package zone.moddev.mc.lib.gui.runtime;
 
 import java.util.*;
+
 import net.minecraft.world.entity.player.Player;
+
 import net.neoforged.neoforge.network.PacketDistributor;
+
 import zone.moddev.mc.lib.api.redstone.*;
 import zone.moddev.mc.lib.gui.layout.*;
 
@@ -39,6 +42,21 @@ public boolean open() {
     return open;
   }
 
+  /** Whether any face is configured to gate processing from an input signal. */
+  public boolean watching() {
+    for (int face = 0; face < 6; face++) if (mode(face) == RedstoneControl.Mode.READ) return true;
+    return false;
+  }
+
+  /** Authoritative resolved gate, also synchronized while the drawer is closed. */
+  public boolean paused() {
+    return client ? state != null && state.paused() : control.paused();
+  }
+
+  public boolean conflicts(boolean manuallyPaused) {
+    return watching() && manuallyPaused != paused();
+  }
+
   public int selected() {
     return selected;
   }
diff --git a/src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenHost.java b/src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenHost.java
index c95707f6..0450afab 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenHost.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenHost.java
@@ -20,6 +20,11 @@ public interface ScreenHost {
    */
   IItemHandlerModifiable screenItems();
 
+  /** Registered machine features used by generic processor controls. */
+  default zone.moddev.mc.lib.machine.feature.FeatureHost screenFeatures() {
+    return null;
+  }
+
   /** Parts contributing statistics, in display order. Providers are only sampled on the server. */
   default java.util.List<? extends zone.moddev.mc.lib.api.stats.StatsProvider> screenStats() {
     return java.util.List.of();
diff --git a/src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenInventoryValidation.java b/src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenInventoryValidation.java
new file mode 100644
index 00000000..38761492
--- /dev/null
+++ b/src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenInventoryValidation.java
@@ -0,0 +1,55 @@
+package zone.moddev.mc.lib.gui.runtime;
+
+import zone.moddev.mc.lib.gui.model.Element;
+import zone.moddev.mc.lib.gui.model.Screen;
+
+/** Validates screen references against the actual host, before either side constructs slots. */
+public final class ScreenInventoryValidation {
+  private ScreenInventoryValidation() {}
+
+  /** Hosts can call this after constructing their storages; menus repeat validation on opening. */
+  public static void validate(net.minecraft.world.level.block.entity.BlockEntity owner) {
+    if (!(owner instanceof ScreenHost host)) return;
+    var id =
+        net.minecraft.core.registries.BuiltInRegistries.BLOCK_ENTITY_TYPE.getKey(owner.getType());
+    if (id != null)
+      zone.moddev.mc.lib.gui.Screens.get(id).ifPresent(bound -> validate(bound.screen(), host));
+  }
+
+  public static void validate(Screen screen, ScreenHost host) {
+    int count = host.screenItems().getSlots();
+    for (var element : screen.elements()) {
+      if (element instanceof Element.Button button && button.processorKey().isPresent()) {
+        var key = button.processorKey().orElseThrow();
+        if (host.screenFeatures() == null || host.screenFeatures().processor(key).isEmpty())
+          throw new zone.moddev.mc.lib.gui.load.ScreenException(
+              screen.source(button.common()),
+              button.common().line(),
+              "Unknown processor-key: " + key);
+      }
+      if (element instanceof Element.Slot slot
+          && slot.kind() != Element.SlotKind.GHOST
+          && (slot.index() < 0 || slot.index() >= count))
+        throw new IllegalArgumentException(
+            screen.id()
+                + ": slot "
+                + slot.common().id().orElse("<unnamed>")
+                + " index "
+                + slot.index()
+                + " outside storage of size "
+                + count);
+    }
+    var automation = host.screenAutomation();
+    if (automation == null) return;
+    for (var group : automation.groups())
+      for (String highlight : group.highlights())
+        if (screen.find(highlight).isEmpty())
+          throw new IllegalArgumentException(
+              screen.id()
+                  + ": resource group '"
+                  + group.id()
+                  + "' references missing screen element '"
+                  + highlight
+                  + "'");
+  }
+}
diff --git a/src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenSnapshots.java b/src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenSnapshots.java
index fff32816..bc4f452c 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenSnapshots.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenSnapshots.java
@@ -31,6 +31,19 @@ static Map<Integer, Object> read(BlockEntity entity, ScreenBinder.Bound bound) {
     var elements = bound.screen().elements();
     for (int i = 0; i < elements.size(); i++) {
       var e = elements.get(i);
+      if (e instanceof zone.moddev.mc.lib.gui.model.Element.Button button
+          && button.processorKey().isPresent()
+          && entity instanceof ScreenHost host
+          && host.screenFeatures() != null) {
+        var processor =
+            host.screenFeatures().processor(button.processorKey().orElseThrow()).orElse(null);
+        if (processor != null)
+          result.put(
+              i * 2,
+              zone.moddev.mc.lib.gui.model.ProcessorButtonState.of(
+                      processor.paused(), processor.processing())
+                  .wireValue());
+      }
       for (int max = 0; max < 2; max++) {
         var getter = (max == 0 ? bound.values() : bound.maxima()).get(e);
         if (getter == null) continue;
diff --git a/src/main/java/zone/moddev/mc/lib/machine/feature/FeatureHost.java b/src/main/java/zone/moddev/mc/lib/machine/feature/FeatureHost.java
index 2bbd4e0d..23fe31f1 100644
--- a/src/main/java/zone/moddev/mc/lib/machine/feature/FeatureHost.java
+++ b/src/main/java/zone/moddev/mc/lib/machine/feature/FeatureHost.java
@@ -1,20 +1,21 @@
 package zone.moddev.mc.lib.machine.feature;
 
+import java.util.ArrayList;
 import java.util.LinkedHashMap;
-import java.util.Map;
 import java.util.List;
-import java.util.ArrayList;
-import zone.moddev.mc.lib.api.redstone.IRedstoneOutput;
-import zone.moddev.mc.lib.api.redstone.RedstoneOutput;
-
-import org.jetbrains.annotations.Nullable;
-import org.slf4j.Logger;
+import java.util.Map;
 
 import com.mojang.logging.LogUtils;
 import com.mojang.serialization.DynamicOps;
 
 import net.minecraft.world.level.Level;
 
+import org.jetbrains.annotations.Nullable;
+import org.slf4j.Logger;
+
+import zone.moddev.mc.lib.api.redstone.IRedstoneOutput;
+import zone.moddev.mc.lib.api.redstone.RedstoneOutput;
+
 /**
  * Runs and saves a machine's {@link MachineFeature}s. The block entity ticks it and saves it with
  * its own data; a feature calls {@link #markChanged} when its state changes.
@@ -59,6 +60,27 @@ public FeatureHost add(MachineFeature<?> feature) {
     return this;
   }
 
+  public void reset() {
+    features.values().forEach(MachineFeature::reset);
+  }
+
+  /** Finds a recipe processor by its stable feature/persistence key. */
+  public java.util.Optional<RecipeProcessor> processor(String key) {
+    return features.get(key) instanceof RecipeProcessor processor
+        ? java.util.Optional.of(processor)
+        : java.util.Optional.empty();
+  }
+
+  /** Persists and synchronizes manual changes even while the host's processing tick is held. */
+  public boolean setProcessorPaused(String key, boolean paused) {
+    var processor = processor(key).orElse(null);
+    if (processor == null || processor.paused() == paused) return false;
+    processor.setPaused(paused);
+    onChange.run();
+    if (processor.syncsToClient()) onSync.run();
+    return true;
+  }
+
   /**
    * Ticks every feature, then sends if a feature marked a sync and {@link #SYNC_INTERVAL} ticks
    * have passed since the last send. Does nothing on the client.
diff --git a/src/main/java/zone/moddev/mc/lib/machine/feature/MachineFeature.java b/src/main/java/zone/moddev/mc/lib/machine/feature/MachineFeature.java
index df936823..a674ee7d 100644
--- a/src/main/java/zone/moddev/mc/lib/machine/feature/MachineFeature.java
+++ b/src/main/java/zone/moddev/mc/lib/machine/feature/MachineFeature.java
@@ -21,6 +21,9 @@ public interface MachineFeature<S> {
   /** Takes on loaded state. */
   void restore(S state);
 
+  /** Releases transient ownership before replacing storage contents or destroying the host. */
+  default void reset() {}
+
   /**
    * Whether nearby clients should hold this feature's state too, so a renderer or tooltip can read
    * it. The block entity sends it with {@link FeatureHost#saveForClient}.
diff --git a/src/main/java/zone/moddev/mc/lib/machine/feature/RecipeProcessor.java b/src/main/java/zone/moddev/mc/lib/machine/feature/RecipeProcessor.java
index 883fbde1..30afea48 100644
--- a/src/main/java/zone/moddev/mc/lib/machine/feature/RecipeProcessor.java
+++ b/src/main/java/zone/moddev/mc/lib/machine/feature/RecipeProcessor.java
@@ -287,12 +287,24 @@ public boolean paused() {
     return paused;
   }
 
+  /**
+   * Actual server-tick activity, including the completion tick; false while the host is suspended.
+   */
+  public boolean processing() {
+    return redstoneRunning;
+  }
+
   /**
    * Pauses the processor: stops drawing energy, releases the running cycle's reservations so its
    * items can be taken, and starts nothing new until {@link #resume}. Works without power and
    * whatever the status. The recipe and progress are kept for the resume.
    */
   public void interrupt() {
+    pause();
+  }
+
+  /** Pauses manually, preserving resumable progress and releasing item/fluid reservations. */
+  public void pause() {
     if (paused) return;
     if (cycle != null) {
       cycle.release(inventory);
@@ -320,6 +332,12 @@ public void resume() {
     changed = true;
   }
 
+  /** Sets the manual pause independently of redstone and other host processing gates. */
+  public void setPaused(boolean value) {
+    if (value) pause();
+    else resume();
+  }
+
   /** Cancels work, releases reservations and forgets progress and pause state. */
   public void reset() {
     if (cycle != null) cycle.release(inventory);
diff --git a/src/main/java/zone/moddev/mc/lib/machine/neoforge/MachineInventoryLifecycle.java b/src/main/java/zone/moddev/mc/lib/machine/neoforge/MachineInventoryLifecycle.java
new file mode 100644
index 00000000..125d4e07
--- /dev/null
+++ b/src/main/java/zone/moddev/mc/lib/machine/neoforge/MachineInventoryLifecycle.java
@@ -0,0 +1,145 @@
+package zone.moddev.mc.lib.machine.neoforge;
+
+import java.util.*;
+import java.util.function.Consumer;
+
+import net.minecraft.core.HolderLookup;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.nbt.NbtOps;
+import net.minecraft.world.level.block.entity.BlockEntity;
+
+import zone.moddev.mc.lib.api.automation.*;
+import zone.moddev.mc.lib.api.capabilities.*;
+import zone.moddev.mc.lib.machine.feature.FeatureHost;
+
+/**
+ * Composes storage persistence, processor restoration, transfer policy and displaced-content
+ * recovery.
+ */
+public final class MachineInventoryLifecycle {
+  public enum PausePolicy {
+    PROCESSING_ONLY(true, false),
+    TRANSFERS_ONLY(false, true),
+    BOTH(true, true),
+    NEITHER(false, false);
+    private final boolean processing, transfers;
+
+    PausePolicy(boolean processing, boolean transfers) {
+      this.processing = processing;
+      this.transfers = transfers;
+    }
+
+    public boolean processingEnabled(boolean paused) {
+      return !paused || !processing;
+    }
+
+    public boolean transfersEnabled(boolean paused) {
+      return !paused || !transfers;
+    }
+  }
+
+  private final BlockEntity owner;
+  private final FeatureHost features;
+  private final AutomationInventory automation;
+  private final EnergyBuffer power;
+  private final Map<String, Object> storages = new LinkedHashMap<>();
+
+  public MachineInventoryLifecycle(
+      BlockEntity owner, FeatureHost features, AutomationInventory automation, EnergyBuffer power) {
+    this.owner = Objects.requireNonNull(owner);
+    this.features = Objects.requireNonNull(features);
+    this.automation = Objects.requireNonNull(automation);
+    this.power = Objects.requireNonNull(power);
+  }
+
+  public MachineInventoryLifecycle items(String saveKey, ItemStorage storage) {
+    return add(saveKey, storage);
+  }
+
+  public MachineInventoryLifecycle fluids(String saveKey, FluidStorage storage) {
+    return add(saveKey, storage);
+  }
+
+  public MachineInventoryLifecycle energy(String saveKey, EnergyBuffer storage) {
+    return add(saveKey, storage);
+  }
+
+  private MachineInventoryLifecycle add(String key, Object storage) {
+    Objects.requireNonNull(storage);
+    if (key == null
+        || key.isBlank()
+        || key.equals("automation")
+        || key.equals("features")
+        || storages.containsKey(key)
+        || storages.containsValue(storage))
+      throw new IllegalArgumentException("Duplicate or reserved storage key: " + key);
+    storages.put(key, storage);
+    return this;
+  }
+
+  public void save(CompoundTag tag, HolderLookup.Provider registries) {
+    storages.forEach(
+        (key, storage) -> {
+          if (storage instanceof ItemStorage items) tag.put(key, items.serializeNBT(registries));
+          else if (storage instanceof FluidStorage fluids)
+            tag.put(key, fluids.serializeNBT(registries));
+          else tag.put(key, ((EnergyBuffer) storage).serializeNBT(registries));
+        });
+    tag.put("automation", automation.save(registries));
+    tag.put("features", features.save(registries.createSerializationContext(NbtOps.INSTANCE)));
+  }
+
+  public void load(CompoundTag tag, HolderLookup.Provider registries) {
+    features.reset();
+    storages.forEach(
+        (key, storage) -> {
+          if (storage instanceof ItemStorage items)
+            items.deserializeNBT(registries, tag.getCompound(key));
+          else if (storage instanceof FluidStorage fluids)
+            fluids.deserializeNBT(registries, tag.getCompound(key));
+          else if (tag.contains(key))
+            ((EnergyBuffer) storage).deserializeNBT(registries, tag.get(key));
+        });
+    automation.load(tag.getCompound("automation"), registries);
+    if (tag.contains("features"))
+      features.load(registries.createSerializationContext(NbtOps.INSTANCE), tag.get("features"));
+  }
+
+  public void tick(boolean processingAllowed, boolean paused, PausePolicy policy) {
+    var level = owner.getLevel();
+    if (level == null || level.isClientSide) return;
+    features.tick(level, processingAllowed && policy.processingEnabled(paused));
+    // Refunds are already owed; a pause must not prevent their return.
+    automation.settleRefund(power);
+    if (policy.transfersEnabled(paused)) AutomationTransfers.tick(automation, power);
+  }
+
+  /** Explicit destructive reset, including displaced contents and pending transfers. */
+  public void clear() {
+    features.reset();
+    automation.clear();
+    for (var storage : storages.values()) {
+      if (storage instanceof ItemStorage items) items.clear();
+      else if (storage instanceof FluidStorage fluids) fluids.clear();
+      else ((EnergyBuffer) storage).setStored(0);
+    }
+    owner.setChanged();
+  }
+
+  /**
+   * Ordinary fluid/energy destruction remains a host policy; displaced resources are always
+   * recovered.
+   */
+  public void dropContents(Consumer<CompoundTag> recoverResources) {
+    var level = owner.getLevel();
+    if (level == null || level.isClientSide) return;
+    for (var storage : storages.values()) {
+      if (storage instanceof ItemStorage items) items.recover(recoverResources);
+      else if (storage instanceof FluidStorage fluids) fluids.recover(recoverResources);
+    }
+    automation.dropAll(recoverResources);
+    features.reset();
+    for (var storage : storages.values())
+      if (storage instanceof ItemStorage items) items.dropAll(level, owner.getBlockPos());
+  }
+}
diff --git a/src/main/java/zone/moddev/mc/lib/machine/neoforge/MachineResources.java b/src/main/java/zone/moddev/mc/lib/machine/neoforge/MachineResources.java
new file mode 100644
index 00000000..fea9d02a
--- /dev/null
+++ b/src/main/java/zone/moddev/mc/lib/machine/neoforge/MachineResources.java
@@ -0,0 +1,201 @@
+package zone.moddev.mc.lib.machine.neoforge;
+
+import java.util.*;
+import java.util.function.Supplier;
+
+import net.minecraft.core.Direction;
+import net.minecraft.world.level.block.entity.BlockEntity;
+
+import net.neoforged.neoforge.energy.IEnergyStorage;
+import net.neoforged.neoforge.fluids.capability.IFluidHandler;
+import net.neoforged.neoforge.items.IItemHandler;
+
+import zone.moddev.mc.lib.api.automation.*;
+import zone.moddev.mc.lib.api.capabilities.*;
+import zone.moddev.mc.lib.machine.inventory.*;
+import zone.moddev.mc.lib.machine.recipe.MachineRecipeType;
+
+/** One definition of resource membership, adapted to automation and recipe access. */
+public final class MachineResources {
+  private record Binding(ResourceGroup<?> group, Object storage) {}
+
+  private final BlockEntity owner;
+  private final Supplier<Direction> facing;
+  private final Map<String, Binding> bindings = new LinkedHashMap<>();
+  private final Map<String, List<Binding>> recipeBindings = new LinkedHashMap<>();
+  private final Map<String, Set<MachineRecipeType>> inputTypes = new LinkedHashMap<>();
+  private MachineInventory recipes;
+  private AutomationInventory automation;
+
+  public MachineResources(BlockEntity owner, Supplier<Direction> facing) {
+    this.owner = Objects.requireNonNull(owner);
+    this.facing = Objects.requireNonNull(facing);
+  }
+
+  public MachineResources items(ResourceGroup<IItemHandler> group, ItemStorage storage) {
+    check(group, storage.getSlots(), storage::role);
+    add(group, storage);
+    group.bind(
+        facing,
+        side -> storage.view(index -> group.contains(index) ? group.mode(side) : IoMode.DISABLED));
+    return this;
+  }
+
+  public MachineResources fluids(ResourceGroup<IFluidHandler> group, FluidStorage storage) {
+    check(group, storage.getTanks(), storage::role);
+    add(group, storage);
+    group.bind(
+        facing,
+        side -> storage.view(index -> group.contains(index) ? group.mode(side) : IoMode.DISABLED));
+    return this;
+  }
+
+  public MachineResources energy(ResourceGroup<IEnergyStorage> group, EnergyBuffer storage) {
+    check(group, 1, index -> Role.STORAGE);
+    add(group, storage);
+    group.bind(facing, side -> storage.view(() -> group.mode(side)));
+    return this;
+  }
+
+  private void check(ResourceGroup<?> group, int size, java.util.function.IntFunction<Role> role) {
+    ensureOpen();
+    if (group.members().isEmpty()) throw invalid(group.id(), "no members");
+    for (int index : group.members()) {
+      if (index >= size)
+        throw invalid(group.id(), "member " + index + " outside storage of size " + size);
+      var allowed = role.apply(index);
+      if ((group.supported().canInsert() && !allowed.canInsert())
+          || (group.supported().canExtract() && !allowed.canExtract()))
+        throw invalid(
+            group.id(),
+            "member " + index + " role " + allowed + " conflicts with " + group.supported());
+    }
+  }
+
+  private void add(ResourceGroup<?> group, Object storage) {
+    if (bindings.containsKey(group.id())) throw invalid(group.id(), "duplicate ID");
+    // Membership is indexed by resource type, so a type must share one physical index space.
+    for (var binding : bindings.values()) {
+      if (binding.group.type() != group.type()) continue;
+      if (binding.storage != storage)
+        throw invalid(group.id(), "use a shared storage for this resource type");
+      if (group.members().stream().anyMatch(binding.group::contains))
+        throw invalid(group.id(), "overlapping members");
+    }
+    var binding = new Binding(group, storage);
+    bindings.put(group.id(), binding);
+    recipeBindings.put(group.id(), List.of(binding));
+  }
+
+  /** Derives an alternate recipe group, optionally combining several automation groups. */
+  public MachineResources recipeGroup(String key, String... groupIds) {
+    ensureOpen();
+    if (key == null || key.isBlank() || groupIds.length == 0)
+      throw invalid(key, "empty recipe mapping");
+    var selected = new ArrayList<Binding>();
+    for (String id : groupIds) {
+      var binding = bindings.get(id);
+      if (binding == null) throw invalid(key, "unknown resource group " + id);
+      if (selected.contains(binding)) throw invalid(key, "duplicate resource group " + id);
+      if (!selected.isEmpty() && selected.getFirst().storage != binding.storage)
+        throw invalid(key, "recipe group must use one storage");
+      selected.add(binding);
+    }
+    recipeBindings.put(key, List.copyOf(selected));
+    return this;
+  }
+
+  /** Links only input groups; several recipe types form a union, intersected with storage rules. */
+  public MachineResources recipeInputs(MachineRecipeType type, String... keys) {
+    ensureOpen();
+    for (String key : keys) {
+      if (!recipeBindings.containsKey(key)) throw invalid(key, "unknown recipe input group");
+      inputTypes.computeIfAbsent(key, ignored -> new LinkedHashSet<>()).add(type);
+    }
+    return this;
+  }
+
+  /** Freezes the definitions and installs reload-aware recipe input filters. */
+  public MachineResources build() {
+    ensureOpen();
+    var builder = MachineInventory.builder();
+    recipeBindings.forEach(
+        (key, values) -> {
+          var storage = values.getFirst().storage;
+          int[] members =
+              values.stream()
+                  .flatMap(b -> b.group.members().stream())
+                  .mapToInt(Integer::intValue)
+                  .toArray();
+          SlotGroup group =
+              storage instanceof ItemStorage items
+                  ? StorageGroups.items(items, members)
+                  : storage instanceof FluidStorage fluids
+                      ? StorageGroups.fluids(fluids, members)
+                      : StorageGroups.energy((EnergyBuffer) storage);
+          builder.group(key, group);
+        });
+    recipes = builder.build();
+    automation =
+        new AutomationInventory(owner, bindings.values().stream().map(Binding::group).toList());
+    var filters = new RecipeInputFilters(() -> owner.getLevel(), recipes);
+    // Collect by physical slot before installing: overlapping recipe aliases accept the union.
+    var itemRules = new IdentityHashMap<ItemStorage, Map<Integer, List<RecipeInputFilters.Link>>>();
+    var fluidRules =
+        new IdentityHashMap<FluidStorage, Map<Integer, List<RecipeInputFilters.Link>>>();
+    inputTypes.forEach(
+        (key, types) -> {
+          for (var binding : recipeBindings.get(key)) {
+            for (int member : binding.group.members()) {
+              var links =
+                  types.stream().map(type -> new RecipeInputFilters.Link(type, key)).toList();
+              if (binding.storage instanceof ItemStorage items)
+                itemRules
+                    .computeIfAbsent(items, ignored -> new LinkedHashMap<>())
+                    .computeIfAbsent(member, ignored -> new ArrayList<>())
+                    .addAll(links);
+              else if (binding.storage instanceof FluidStorage fluids)
+                fluidRules
+                    .computeIfAbsent(fluids, ignored -> new LinkedHashMap<>())
+                    .computeIfAbsent(member, ignored -> new ArrayList<>())
+                    .addAll(links);
+              else throw invalid(key, "recipe input filtering requires items or fluids");
+            }
+          }
+        });
+    itemRules.forEach(
+        (storage, rules) ->
+            rules.forEach(
+                (slot, links) ->
+                    storage.restrict(stack -> filters.acceptsItem(links, stack), slot)));
+    fluidRules.forEach(
+        (storage, rules) ->
+            rules.forEach(
+                (tank, links) ->
+                    storage.restrict(stack -> filters.acceptsFluid(links, stack), tank)));
+    return this;
+  }
+
+  public MachineInventory recipes() {
+    requireBuilt();
+    return recipes;
+  }
+
+  public AutomationInventory automation() {
+    requireBuilt();
+    return automation;
+  }
+
+  private void ensureOpen() {
+    if (recipes != null) throw new IllegalStateException("Resource definitions already built");
+  }
+
+  private void requireBuilt() {
+    if (recipes == null) throw new IllegalStateException("Build resource definitions first");
+  }
+
+  private IllegalArgumentException invalid(String group, String detail) {
+    return new IllegalArgumentException(
+        owner.getClass().getSimpleName() + " resource group '" + group + "': " + detail);
+  }
+}
diff --git a/src/main/java/zone/moddev/mc/lib/machine/neoforge/RecipeInputFilters.java b/src/main/java/zone/moddev/mc/lib/machine/neoforge/RecipeInputFilters.java
new file mode 100644
index 00000000..4a77c8c0
--- /dev/null
+++ b/src/main/java/zone/moddev/mc/lib/machine/neoforge/RecipeInputFilters.java
@@ -0,0 +1,79 @@
+package zone.moddev.mc.lib.machine.neoforge;
+
+import java.util.List;
+import java.util.function.Supplier;
+
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.level.Level;
+
+import net.neoforged.neoforge.fluids.FluidStack;
+
+import zone.moddev.mc.lib.machine.ingredient.MachineIngredient;
+import zone.moddev.mc.lib.machine.inventory.*;
+import zone.moddev.mc.lib.machine.recipe.*;
+
+/**
+ * Admission tests depend on recipe ingredients, never on currently available amounts or outputs.
+ */
+public final class RecipeInputFilters {
+  public record Link(MachineRecipeType type, String group) {}
+
+  private final Supplier<Level> level;
+  private final MachineInventory inventory;
+
+  public RecipeInputFilters(Supplier<Level> level, MachineInventory inventory) {
+    this.level = level;
+    this.inventory = inventory;
+  }
+
+  public boolean acceptsItem(List<Link> links, ItemStack stack) {
+    return inputs(links)
+        .anyMatch(
+            part -> part instanceof MachineIngredient.ItemPart item && item.items().test(stack));
+  }
+
+  public boolean acceptsFluid(List<Link> links, FluidStack stack) {
+    return inputs(links)
+        .anyMatch(
+            part ->
+                part instanceof MachineIngredient.FluidPart fluid
+                    && fluid.fluids().contains(stack.getFluid().builtInRegistryHolder()));
+  }
+
+  private java.util.stream.Stream<MachineIngredient> inputs(List<Link> links) {
+    var world = level.get();
+    if (world == null) return java.util.stream.Stream.empty();
+    // Consult the manager each time: replacements from server reload and client recipe sync apply
+    // immediately.
+    return links.stream()
+        .flatMap(
+            link ->
+                link.type.recipes(world.getRecipeManager()).stream()
+                    .map(holder -> holder.value().recipe())
+                    .filter(this::compatible)
+                    .flatMap(
+                        recipe -> recipe.inputs().getOrDefault(link.group, List.of()).stream()));
+  }
+
+  private boolean compatible(MachineRecipe recipe) {
+    for (var entry : recipe.inputs().entrySet()) {
+      var group = inventory.group(entry.getKey()).orElse(null);
+      if (group == null) return false;
+      for (var part : entry.getValue()) {
+        if (!(part instanceof MachineIngredient.ItemPart && group instanceof ItemGroup)
+            && !(part instanceof MachineIngredient.FluidPart && group instanceof FluidGroup)
+            && !(part instanceof MachineIngredient.EnergyPart && group instanceof EnergyGroup))
+          return false;
+      }
+    }
+    for (var entry : recipe.outputs().entrySet()) {
+      var group = inventory.group(entry.getKey()).orElse(null);
+      if (group == null) return false;
+      for (var product : entry.getValue())
+        if (!(product instanceof MachineProduct.ItemProduct && group instanceof ItemGroup)
+            && !(product instanceof MachineProduct.FluidProduct && group instanceof FluidGroup))
+          return false;
+    }
+    return true;
+  }
+}
diff --git a/src/main/java/zone/moddev/mc/lib/machine/neoforge/StorageGroups.java b/src/main/java/zone/moddev/mc/lib/machine/neoforge/StorageGroups.java
index 9c1e719c..12a995b6 100644
--- a/src/main/java/zone/moddev/mc/lib/machine/neoforge/StorageGroups.java
+++ b/src/main/java/zone/moddev/mc/lib/machine/neoforge/StorageGroups.java
@@ -168,7 +168,7 @@ private void track(int index, MachineTx tx) {
           new Key(storage, index),
           () -> {
             var before = storage.getStackInSlot(index).copy();
-            return () -> storage.setStackInSlot(index, before);
+            return () -> storage.restoreStack(index, before);
           });
     }
   }
@@ -223,9 +223,9 @@ public int insert(int tank, FluidAmount fluid, MachineTx tx) {
       if (!valid(tank) || fluid.isEmpty()) return 0;
       var handler = storage.tank(indexes[tank]);
       var stack = FluidStacks.stack(fluid);
-      if (handler.fill(stack, FluidAction.SIMULATE) <= 0) return 0;
+      if (storage.fillResult(indexes[tank], stack, FluidAction.SIMULATE) <= 0) return 0;
       track(indexes[tank], tx);
-      return handler.fill(stack, FluidAction.EXECUTE);
+      return storage.fillResult(indexes[tank], stack, FluidAction.EXECUTE);
     }
 
     @Override
@@ -293,7 +293,7 @@ private void track(int index, MachineTx tx) {
           new Key(storage, index),
           () -> {
             var before = storage.tank(index).getFluid().copy();
-            return () -> storage.tank(index).setFluid(before);
+            return () -> storage.restoreFluid(index, before);
           });
     }
   }
diff --git a/src/main/resources/assets/mmdlib/lang/en_us.json b/src/main/resources/assets/mmdlib/lang/en_us.json
index 86b46b20..568b7044 100644
--- a/src/main/resources/assets/mmdlib/lang/en_us.json
+++ b/src/main/resources/assets/mmdlib/lang/en_us.json
@@ -1,4 +1,13 @@
 {
+  "screen.mmdlib.processor.processing": "Working",
+  "screen.mmdlib.processor.idle": "Idle",
+  "screen.mmdlib.processor.paused": "Paused",
+  "screen.mmdlib.processor.toggle": "{value}\n{action}",
+  "screen.mmdlib.processor.action.unpause": "Click to unpause",
+  "screen.mmdlib.processor.action.stop": "Click to stop and clear reservations",
+  "screen.mmdlib.processor.action.pause": "Click to pause",
+  "screen.mmdlib.processor.conflict.manual": "Redstone settings conflict:\nManual pause takes priority.",
+  "screen.mmdlib.processor.conflict.redstone": "Redstone settings conflict:\nPaused by redstone.",
   "screen.mmdlib.reservation.input": "Reserved for input: %s",
   "screen.mmdlib.reservation.output": "Reserved output: %s x %s",
   "screen.mmdlib.energy": "{value} / {max} FE",
diff --git a/src/main/resources/assets/mmdlib/textures/gui/sprites/icon_processor_conflict.png b/src/main/resources/assets/mmdlib/textures/gui/sprites/icon_processor_conflict.png
new file mode 100644
index 0000000000000000000000000000000000000000..390065c9b4157e240a9a17111e29f5266d093035
GIT binary patch
literal 83
zcmeAS@N?(olHy`uVBq!ia0vp^tRT$61|)m))t&+=DNh&2kcwN$2@Fm8&z}8HoWU5&
fpy#+p!OWP^F4^##<0ZROKvfK$u6{1-oD!M<><bmE

literal 0
HcmV?d00001

diff --git a/src/main/resources/assets/mmdlib/textures/gui/sprites/icon_processor_pause.png b/src/main/resources/assets/mmdlib/textures/gui/sprites/icon_processor_pause.png
new file mode 100644
index 0000000000000000000000000000000000000000..c57039042c38a2c73065fcab291e48ee1bed17a8
GIT binary patch
literal 97
zcmeAS@N?(olHy`uVBq!ia0vp^JRr=$1|-8uW1a&k4Nn)xkcwN$2@9lu6r6c$&mk;y
uc*2!Smwxs8=cHsaFiv3ErDA4yi;1CjcD8HFyDj`cJq(_%elF{r5}E+JHyu0x

literal 0
HcmV?d00001

diff --git a/src/main/resources/assets/mmdlib/textures/gui/sprites/icon_processor_play.png b/src/main/resources/assets/mmdlib/textures/gui/sprites/icon_processor_play.png
new file mode 100644
index 0000000000000000000000000000000000000000..62e1e59f0e61030f68e2b6263dc4ac450a2a5c6b
GIT binary patch
literal 108
zcmeAS@N?(olHy`uVBq!ia0vp^JRr=$1|-8uW1a&kV^0^ykcwN$2@9k>b_RZ!pTcY4
zvx#kyNz&zpaAmXBsHmudo^a;4))P`4K^;6DVIIK@3?~-`PP2-has#NH!PC{xWt~$(
F69C5lAJG5+

literal 0
HcmV?d00001

diff --git a/src/main/resources/assets/mmdlib/textures/gui/sprites/icon_processor_stop.png b/src/main/resources/assets/mmdlib/textures/gui/sprites/icon_processor_stop.png
new file mode 100644
index 0000000000000000000000000000000000000000..9f4d543d726b69a68fc83fa2d7a2980b4da9c7f4
GIT binary patch
literal 91
zcmeAS@N?(olHy`uVBq!ia0vp^JRr=$1|-8uW1a&kB~KT}kcwN$2@9kv1fPAB7gvjH
oo;K~;|3F>?hDirnUy2`OFpBFtZ=iK{5l}UQr>mdKI;Vst0OsQwjQ{`u

literal 0
HcmV?d00001

diff --git a/src/main/resources/assets/mmdlib/textures/gui/sprites/icon_redstone_paused.png b/src/main/resources/assets/mmdlib/textures/gui/sprites/icon_redstone_paused.png
new file mode 100644
index 0000000000000000000000000000000000000000..ac9d556c70e24112910c97612b33bb77238cb192
GIT binary patch
literal 96
zcmeAS@N?(olHy`uVBq!ia0vp^>>$j+1|*LJg<l3z>Ygr+Ar-fhe-xZ~YtLcKz-Tm^
uG19@?`?bB%>}it}7#<y9nQ*g$kzvL+-^%+Jbk_m3FnGH9xvX<aXaWFgVH{`x

literal 0
HcmV?d00001

diff --git a/src/main/resources/assets/mmdlib/textures/gui/sprites/icon_redstone_running.png b/src/main/resources/assets/mmdlib/textures/gui/sprites/icon_redstone_running.png
new file mode 100644
index 0000000000000000000000000000000000000000..4aaee154fc76d0703f56d6763b7bd6adc24551b4
GIT binary patch
literal 96
zcmeAS@N?(olHy`uVBq!ia0vp^>>$j+1|*LJg<l3z>Ygr+Ar-fhJ$43un9nHA;CaX(
t&XdRWL{n5$Q~}TQBLXgL5v-hy3@-z8rDd}v7XY;|c)I$ztaD0e0ssk`7zh9W

literal 0
HcmV?d00001

diff --git a/src/main/resources/assets/mmdlib/textures/gui/sprites/icon_stop.png b/src/main/resources/assets/mmdlib/textures/gui/sprites/icon_stop.png
new file mode 100644
index 0000000000000000000000000000000000000000..292d42744d956f6ef8577a026055a4d172a7b962
GIT binary patch
literal 96
zcmeAS@N?(olHy`uVBq!ia0vp^0wB!61|;P_|4#%`>Ygr+Ar-fh6C~;$xXw6UA2TC~
tdCQh9|N5mI_?aCTmI#QaNw8jFXHe7VJI{Z5bvjTBgQu&X%Q~loCID(z8r1**

literal 0
HcmV?d00001

diff --git a/src/main/resources/mmdlib/schema/screen.xsd b/src/main/resources/mmdlib/schema/screen.xsd
index 697e16b2..eb4152fe 100644
--- a/src/main/resources/mmdlib/schema/screen.xsd
+++ b/src/main/resources/mmdlib/schema/screen.xsd
@@ -145,11 +145,13 @@
       <xs:element ref="progress"/>
       <xs:element ref="label"/>
       <xs:element ref="button"/>
+      <xs:element ref="processor-button"/>
       <xs:element ref="checkbox"/>
       <xs:element ref="radio-group"/>
       <xs:element ref="context"/>
       <xs:element ref="side-config"/>
       <xs:element ref="player-inventory"/>
+      <xs:element ref="placeholder"/>
     </xs:choice>
   </xs:group>
 
@@ -183,18 +185,23 @@
   <xs:element name="screen">
     <xs:annotation><xs:documentation>The root. title is a translation key; block-entity is the class whose getters #method values call.</xs:documentation></xs:annotation>
     <xs:complexType>
-      <xs:sequence>
-        <xs:group ref="widget" minOccurs="1" maxOccurs="unbounded"/>
-        <xs:element ref="inventory-controls" minOccurs="0"/>
-        <xs:choice minOccurs="0" maxOccurs="unbounded">
-          <xs:element ref="side-tab"/>
-          <xs:element ref="popout"/>
-        </xs:choice>
-      </xs:sequence>
-      <xs:attribute name="title" type="translationKey" use="required"/>
+      <xs:choice>
+        <xs:sequence>
+          <xs:group ref="widget" minOccurs="0" maxOccurs="unbounded"/>
+          <xs:element ref="inventory-controls" minOccurs="0"/>
+          <xs:choice minOccurs="0" maxOccurs="unbounded">
+            <xs:element ref="side-tab"/>
+            <xs:element ref="popout"/>
+          </xs:choice>
+        </xs:sequence>
+        <xs:element ref="fill" minOccurs="1" maxOccurs="unbounded"/>
+      </xs:choice>
+      <xs:attribute name="abstract" type="xs:boolean"/>
+      <xs:attribute name="extends" type="resourceId"/>
+      <xs:attribute name="title" type="translationKey"/>
       <xs:attribute name="title-fallback" type="xs:string"/>
-      <xs:attribute name="block-entity" type="className" use="required"/>
-      <xs:attribute name="inventory" default="default">
+      <xs:attribute name="block-entity" type="className"/>
+      <xs:attribute name="inventory">
         <xs:simpleType>
           <xs:restriction base="xs:string">
             <xs:enumeration value="default"/><xs:enumeration value="none"/>
@@ -204,9 +211,33 @@
     </xs:complexType>
   </xs:element>
 
+  <xs:complexType name="templateContent">
+    <xs:choice minOccurs="0" maxOccurs="unbounded">
+      <xs:group ref="widget"/>
+      <xs:element ref="inventory-controls"/>
+      <xs:element ref="side-tab"/>
+      <xs:element ref="popout"/>
+    </xs:choice>
+    <xs:attribute name="name" type="elementId" use="required"/>
+  </xs:complexType>
+
+  <xs:element name="fill" type="templateContent"/>
+  <xs:element name="placeholder">
+    <xs:complexType>
+      <xs:complexContent>
+        <xs:extension base="templateContent">
+          <xs:attribute name="required" type="xs:boolean"/>
+        </xs:extension>
+      </xs:complexContent>
+    </xs:complexType>
+  </xs:element>
+
   <xs:element name="inventory-controls">
     <xs:complexType>
-      <xs:sequence><xs:element ref="button" minOccurs="1" maxOccurs="unbounded"/></xs:sequence>
+      <xs:choice minOccurs="1" maxOccurs="unbounded">
+        <xs:element ref="button"/>
+        <xs:element ref="processor-button"/>
+      </xs:choice>
       <xs:attributeGroup ref="common"/>
     </xs:complexType>
   </xs:element>
@@ -364,6 +395,19 @@
     </xs:complexType>
   </xs:element>
 
+  <xs:element name="processor-button">
+    <xs:complexType>
+      <xs:complexContent>
+        <xs:extension base="leaf">
+          <xs:attribute name="processor-key" type="xs:string" use="required"/>
+          <xs:attribute name="text" type="translationKey"/>
+          <xs:attribute name="text-fallback" type="xs:string"/>
+          <xs:attribute name="flat" type="xs:boolean" default="true"/>
+        </xs:extension>
+      </xs:complexContent>
+    </xs:complexType>
+  </xs:element>
+
   <xs:element name="checkbox">
     <xs:complexType>
       <xs:complexContent>
diff --git a/src/runtimeTest/java/zone/moddev/mc/lib/smoke/InventoryArchitectureSmoke.java b/src/runtimeTest/java/zone/moddev/mc/lib/smoke/InventoryArchitectureSmoke.java
new file mode 100644
index 00000000..86d840df
--- /dev/null
+++ b/src/runtimeTest/java/zone/moddev/mc/lib/smoke/InventoryArchitectureSmoke.java
@@ -0,0 +1,400 @@
+package zone.moddev.mc.lib.smoke;
+
+import java.util.*;
+
+import net.minecraft.core.*;
+import net.minecraft.nbt.*;
+import net.minecraft.network.chat.Component;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.server.level.ServerLevel;
+import net.minecraft.world.item.*;
+import net.minecraft.world.item.crafting.*;
+import net.minecraft.world.level.block.Blocks;
+import net.minecraft.world.level.block.entity.ChestBlockEntity;
+import net.minecraft.world.level.material.Fluids;
+
+import net.neoforged.neoforge.fluids.FluidStack;
+import net.neoforged.neoforge.fluids.capability.IFluidHandler.FluidAction;
+import net.neoforged.neoforge.items.IItemHandler;
+
+import zone.moddev.mc.lib.api.automation.*;
+import zone.moddev.mc.lib.api.capabilities.*;
+import zone.moddev.mc.lib.machine.ingredient.MachineIngredient;
+import zone.moddev.mc.lib.machine.inventory.ItemGroup;
+import zone.moddev.mc.lib.machine.neoforge.*;
+import zone.moddev.mc.lib.machine.recipe.*;
+
+final class InventoryArchitectureSmoke {
+  private static void require(boolean condition, String message) {
+    if (!condition) throw new AssertionError(message);
+  }
+
+  static void itemMigration(ServerLevel level) {
+    var provider = level.registryAccess();
+    var original = new ItemStorage(3).slotId(0, "ore").slotId(1, "result").slotId(2, "removed");
+    original.restoreStack(0, new ItemStack(Items.IRON_ORE, 40));
+    original.restoreStack(1, new ItemStack(Items.GOLD_INGOT, 12));
+    original.restoreStack(2, new ItemStack(Items.DIAMOND, 7));
+    var smaller = new ItemStorage(2).slotId(0, "result").slotId(1, "ore").limit(16, 1);
+    smaller.deserializeNBT(provider, original.serializeNBT(provider));
+    require(
+        smaller.getStackInSlot(0).is(Items.GOLD_INGOT), "stable item identity survives reordering");
+    require(smaller.getStackInSlot(1).getCount() == 16, "reduced limit respected");
+    require(smaller.recoveryContents().size() == 2, "removed slot and excess count recovered");
+    for (int i = 0; i < 3; i++) smaller.deserializeNBT(provider, smaller.serializeNBT(provider));
+    require(smaller.recoveryContents().size() == 2, "repeated loading never duplicates recovery");
+    int recovered =
+        smaller.recoveryContents().stream()
+            .mapToInt(t -> ItemStack.parseOptional(provider, (CompoundTag) t).getCount())
+            .sum();
+    require(recovered == 31, "all 24 displaced iron and 7 diamonds preserved");
+    var expanded = new ItemStorage(3).slotId(0, "ore").slotId(1, "result").slotId(2, "removed");
+    expanded.deserializeNBT(provider, smaller.serializeNBT(provider));
+    require(
+        expanded.getStackInSlot(0).getCount() == 40
+            && expanded.getStackInSlot(2).getCount() == 7
+            && expanded.recoveryContents().isEmpty(),
+        "restored slots and limits recover all displaced items");
+    try {
+      smaller.recover(
+          payload -> {
+            throw new IllegalStateException("recovery refused");
+          });
+    } catch (IllegalStateException expected) {
+    }
+    require(smaller.recoveryContents().size() == 2, "failed ownership handoff retains contents");
+    var payloads = new ArrayList<CompoundTag>();
+    smaller.recover(payloads::add);
+    smaller.recover(payloads::add);
+    require(
+        payloads.size() == 1 && smaller.recoveryContents().isEmpty(),
+        "successful handoff exactly once");
+
+    var legacy = new ItemStorage(2);
+    legacy.restoreStack(1, new ItemStack(Items.EMERALD, 3));
+    var shrunk = new ItemStorage(1);
+    shrunk.deserializeNBT(provider, legacy.serializeNBT(provider));
+    require(shrunk.recoveryContents().size() == 1, "legacy out-of-range slot preserved");
+    var restored = new ItemStorage(2);
+    restored.deserializeNBT(provider, shrunk.serializeNBT(provider));
+    require(
+        restored.getStackInSlot(1).getCount() == 3 && restored.recoveryContents().isEmpty(),
+        "restored legacy slot recovers saved stack");
+    var remapped = new ItemStorage(2).slotId(0, "emeralds").slotId(1, "unused").limit(1, 0);
+    remapped.deserializeNBT(provider, legacy.serializeNBT(provider), slot -> 1 - slot);
+    require(
+        remapped.getStackInSlot(0).is(Items.EMERALD), "explicit legacy index migration applied");
+    var movedAgain = new ItemStorage(2).slotId(0, "unused").slotId(1, "emeralds");
+    movedAgain.deserializeNBT(provider, remapped.serializeNBT(provider));
+    require(
+        movedAgain.getStackInSlot(1).getCount() == 3 && movedAgain.recoveryContents().isEmpty(),
+        "legacy capacity overflow acquires stable identity before another migration");
+
+    var unknown = new CompoundTag();
+    unknown.putString("id", "removed_mod:lost_item");
+    unknown.putInt("count", 9);
+    unknown.putInt("Slot", 0);
+    var list = new ListTag();
+    list.add(unknown);
+    var tag = new CompoundTag();
+    tag.put("Items", list);
+    restored.deserializeNBT(provider, tag);
+    require(
+        restored.recoveryContents().getCompound(0).equals(unknown),
+        "unknown item NBT retained verbatim");
+  }
+
+  static void fluidMigration(ServerLevel level) {
+    var provider = level.registryAccess();
+    var original = new FluidStorage();
+    original.addTank(2000, Role.INPUT);
+    original.addTank(2000, Role.INPUT);
+    original.tankId(0, "water").tankId(1, "lava");
+    original.restoreFluid(0, new FluidStack(Fluids.WATER, 1500));
+    original.restoreFluid(1, new FluidStack(Fluids.LAVA, 700));
+    var smaller = new FluidStorage();
+    smaller.addTank(500, Role.INPUT);
+    smaller.tankId(0, "water");
+    smaller.deserializeNBT(provider, original.serializeNBT(provider));
+    require(smaller.getFluidInTank(0).getAmount() == 500, "reduced capacity respected");
+    require(smaller.recoveryContents().size() == 2, "removed tank and capacity excess preserved");
+    for (int i = 0; i < 3; i++) smaller.deserializeNBT(provider, smaller.serializeNBT(provider));
+    int recovered =
+        smaller.recoveryContents().stream()
+            .mapToInt(t -> FluidStack.parseOptional(provider, (CompoundTag) t).getAmount())
+            .sum();
+    require(recovered == 1700, "repeated fluid loading conserves displaced contents");
+    original.deserializeNBT(provider, smaller.serializeNBT(provider));
+    require(
+        original.getFluidInTank(0).getAmount() == 1500
+            && original.getFluidInTank(1).getAmount() == 700
+            && original.recoveryContents().isEmpty(),
+        "restored tanks and capacities recover all displaced fluid");
+    var reordered = new FluidStorage();
+    reordered.addTank(2000, Role.STORAGE);
+    reordered.addTank(2000, Role.STORAGE);
+    reordered.tankId(0, "lava").tankId(1, "water");
+    reordered.deserializeNBT(provider, original.serializeNBT(provider));
+    require(
+        reordered.getFluidInTank(0).is(Fluids.LAVA)
+            && reordered.getFluidInTank(1).getAmount() == 1500,
+        "tank identities survive reordering");
+    var payloads = new ArrayList<CompoundTag>();
+    smaller.recover(payloads::add);
+    smaller.recover(payloads::add);
+    require(payloads.size() == 1, "fluid recovery handed off exactly once");
+    var legacy = new FluidStorage();
+    legacy.addTank(2000, Role.INPUT);
+    legacy.addTank(2000, Role.INPUT);
+    legacy.restoreFluid(1, new FluidStack(Fluids.WATER, 1000));
+    var migrated = new FluidStorage();
+    migrated.addTank(100, Role.INPUT);
+    migrated.addTank(2000, Role.INPUT);
+    migrated.tankId(0, "water").tankId(1, "unused");
+    migrated.deserializeNBT(provider, legacy.serializeNBT(provider), tank -> 1 - tank);
+    require(
+        migrated.getFluidInTank(0).getAmount() == 100, "explicit legacy tank migration applied");
+    var expanded = new FluidStorage();
+    expanded.addTank(2000, Role.INPUT);
+    expanded.addTank(2000, Role.INPUT);
+    expanded.tankId(0, "unused").tankId(1, "water");
+    expanded.deserializeNBT(provider, migrated.serializeNBT(provider));
+    require(
+        expanded.getFluidInTank(1).getAmount() == 1000 && expanded.recoveryContents().isEmpty(),
+        "legacy fluid overflow follows acquired stable identity");
+  }
+
+  private static ResourceGroup<IItemHandler> items(String id, IoMode mode, Integer... members) {
+    return new ResourceGroup<>(
+        id,
+        Component.literal(id),
+        0x123456,
+        ResourceType.ITEMS,
+        mode,
+        List.of(members),
+        List.of(),
+        new SideConfig(mode));
+  }
+
+  private static ChestBlockEntity owner(ServerLevel level) {
+    var owner = new ChestBlockEntity(BlockPos.ZERO, Blocks.CHEST.defaultBlockState());
+    owner.setLevel(level);
+    return owner;
+  }
+
+  private static void rejected(Runnable action, String text) {
+    try {
+      action.run();
+    } catch (IllegalArgumentException e) {
+      require(
+          e.getMessage().contains(text),
+          "diagnostic names the invalid member/group: " + e.getMessage());
+      return;
+    }
+    throw new AssertionError("Expected rejection: " + text);
+  }
+
+  static void bindings(ServerLevel level) {
+    var owner = owner(level);
+    var storage = new ItemStorage(3).role(Role.INPUT, 0, 1).role(Role.OUTPUT, 2);
+    rejected(
+        () ->
+            new MachineResources(owner, () -> Direction.NORTH)
+                .items(items("bad", IoMode.INPUT, 4), storage),
+        "member 4");
+    rejected(
+        () ->
+            new MachineResources(owner, () -> Direction.NORTH)
+                .items(items("bad", IoMode.BOTH, 0), storage),
+        "role INPUT");
+    var left = items("left", IoMode.INPUT, 0);
+    var right = items("right", IoMode.INPUT, 1);
+    var resources =
+        new MachineResources(owner, () -> Direction.NORTH)
+            .items(left, storage)
+            .items(right, storage)
+            .items(items("result", IoMode.OUTPUT, 2), storage)
+            .recipeGroup("ingredients", "left", "right")
+            .build();
+    var port = left.port(Direction.NORTH);
+    require(port.getSlots() == 3, "group ports keep physical slot numbering");
+    require(
+        port.insertItem(1, new ItemStack(Items.IRON_ORE), false).getCount() == 1,
+        "group port cannot touch another input group");
+    require(
+        port.insertItem(0, new ItemStack(Items.IRON_ORE), false).isEmpty(),
+        "group port accepts its own member");
+    require(
+        ((ItemGroup) resources.recipes().group("ingredients").orElseThrow()).size() == 2,
+        "recipe group combines shared definitions");
+    left.sides().set(RelativeFace.FRONT, IoMode.DISABLED);
+    require(
+        port.insertItem(0, new ItemStack(Items.IRON_ORE), true).getCount() == 1,
+        "existing port follows side edits");
+    require(
+        left.port(null).insertItem(2, new ItemStack(Items.IRON_ORE), true).getCount() == 1,
+        "unsided port remains isolated");
+  }
+
+  static void screenValidation(ServerLevel level) throws Exception {
+    var storage = new ItemStorage(1);
+    var group =
+        new ResourceGroup<>(
+            "input",
+            Component.literal("Input"),
+            0x123456,
+            ResourceType.ITEMS,
+            IoMode.BOTH,
+            List.of(0),
+            List.of("input"),
+            new SideConfig(IoMode.BOTH));
+    var resources =
+        new MachineResources(owner(level), () -> Direction.NORTH).items(group, storage).build();
+    var host =
+        new zone.moddev.mc.lib.gui.runtime.ScreenHost() {
+          public ItemStorage screenItems() {
+            return storage;
+          }
+
+          public AutomationInventory screenAutomation() {
+            return resources.automation();
+          }
+        };
+    for (int variant = 0; variant < 3; variant++) {
+      String xml =
+          "<screen xmlns=\"https://moddev.zone/mmdlib/screen\" title=\"test\""
+              + " block-entity=\"net.minecraft.world.level.block.entity.ChestBlockEntity\"><slot"
+              + " id=\""
+              + (variant == 1 ? "wrong" : "input")
+              + "\" index=\""
+              + (variant == 2 ? 2 : 0)
+              + "\"/></screen>";
+      var screen =
+          zone.moddev.mc.lib.gui.load.ScreenReader.read(
+              ResourceLocation.parse("mmdlib_smoke:validation"),
+              "validation.xml",
+              new java.io.ByteArrayInputStream(
+                  xml.getBytes(java.nio.charset.StandardCharsets.UTF_8)));
+      if (variant == 0)
+        zone.moddev.mc.lib.gui.runtime.ScreenInventoryValidation.validate(screen, host);
+      else
+        rejected(
+            () -> zone.moddev.mc.lib.gui.runtime.ScreenInventoryValidation.validate(screen, host),
+            variant == 1 ? "missing screen element 'input'" : "index 2");
+    }
+  }
+
+  static void recipeFilters(ServerLevel level) {
+    var owner = owner(level);
+    var storage =
+        new ItemStorage(3)
+            .role(Role.INPUT, 0)
+            .role(Role.OUTPUT, 1, 2)
+            .filter(stack -> !stack.is(Items.DEEPSLATE_COPPER_ORE), 0);
+    var fluids = new FluidStorage();
+    fluids.addTank(4000, Role.STORAGE);
+    var water =
+        new ResourceGroup<>(
+            "water",
+            Component.literal("Water"),
+            0x334455,
+            ResourceType.FLUIDS,
+            IoMode.BOTH,
+            List.of(0),
+            List.of(),
+            new SideConfig(IoMode.BOTH));
+    var energy = new EnergyBuffer(10000, 1000);
+    var power =
+        new ResourceGroup<>(
+            "energy",
+            Component.literal("Energy"),
+            0x334455,
+            ResourceType.ENERGY,
+            IoMode.INPUT,
+            List.of(0),
+            List.of(),
+            new SideConfig(IoMode.INPUT));
+    var resources =
+        new MachineResources(owner, () -> Direction.NORTH)
+            .items(items("input", IoMode.INPUT, 0), storage)
+            .items(items("output", IoMode.OUTPUT, 1), storage)
+            .items(items("byproduct", IoMode.OUTPUT, 2), storage)
+            .fluids(water, fluids)
+            .energy(power, energy)
+            .recipeInputs(MachineRecipeTypeSmoke.GRINDING, "input", "water")
+            .build();
+    require(
+        storage.isItemValid(0, new ItemStack(Items.COPPER_ORE)),
+        "tag recipe admits input before other ingredients arrive");
+    require(
+        storage.isItemValid(0, new ItemStack(Items.IRON_ORE)),
+        "union of recipes admits alternative input");
+    require(!storage.isItemValid(0, new ItemStack(Items.DIAMOND)), "unrelated item refused");
+    require(
+        !storage.isItemValid(0, new ItemStack(Items.DEEPSLATE_COPPER_ORE)),
+        "explicit storage filter still applies");
+    storage.filter(stack -> true, 0);
+    require(
+        !storage.isItemValid(0, new ItemStack(Items.DIAMOND)),
+        "changing the base filter cannot erase linked recipe rules");
+    require(
+        storage.view(IoMode.INPUT).insertItem(0, new ItemStack(Items.DIAMOND), true).getCount()
+            == 1,
+        "automation obeys recipe filter");
+    require(
+        fluids.fill(new FluidStack(Fluids.LAVA, 100), FluidAction.EXECUTE) == 0,
+        "unrelated fluid refused");
+    require(
+        fluids.fill(new FluidStack(Fluids.WATER, 1), FluidAction.EXECUTE) == 1,
+        "input amount need not satisfy recipe yet");
+    fluids.restoreFluid(0, FluidStack.EMPTY);
+    require(
+        fluids.fillResult(0, new FluidStack(Fluids.LAVA, 10), FluidAction.EXECUTE) == 10,
+        "machine products bypass input-only rule");
+    require(
+        storage.insertResult(1, new ItemStack(Items.RAW_COPPER), false).isEmpty(),
+        "recipe products remain insertable");
+    var client = new zone.moddev.mc.lib.gui.runtime.ClientMenuItems(3, storage);
+    require(
+        !client.isItemValid(0, new ItemStack(Items.DIAMOND)), "menu prediction uses input rules");
+
+    var manager = level.getRecipeManager();
+    var original = new ArrayList<>(manager.getRecipes());
+    try {
+      var recipe =
+          new MachineRecipe(
+              Map.of(
+                  "input",
+                  List.of(new MachineIngredient.ItemPart(Ingredient.of(Items.DIAMOND), 32)),
+                  "water",
+                  List.of(
+                      new MachineIngredient.FluidPart(
+                          HolderSet.direct(Fluids.LAVA.builtInRegistryHolder()), 500))),
+              Map.of(),
+              20);
+      var changed = new ArrayList<RecipeHolder<?>>(original);
+      changed.removeIf(holder -> holder.value().getType() == MachineRecipeTypeSmoke.GRINDING);
+      changed.add(
+          new RecipeHolder<>(
+              ResourceLocation.parse("mmdlib_smoke:admission"),
+              new MachineRecipeEntry(MachineRecipeTypeSmoke.GRINDING, recipe)));
+      manager.replaceRecipes(changed);
+      require(
+          storage.isItemValid(0, new ItemStack(Items.DIAMOND))
+              && !storage.isItemValid(0, new ItemStack(Items.IRON_ORE)),
+          "recipe replacement immediately updates item admission");
+      require(
+          fluids.isFluidValid(0, new FluidStack(Fluids.LAVA, 1))
+              && !fluids.isFluidValid(0, new FluidStack(Fluids.WATER, 1)),
+          "recipe replacement immediately updates fluid admission");
+      changed.removeIf(holder -> holder.value().getType() == MachineRecipeTypeSmoke.GRINDING);
+      manager.replaceRecipes(changed);
+      require(
+          !storage.isItemValid(0, new ItemStack(Items.DIAMOND)),
+          "no recipes admits no linked inputs");
+    } finally {
+      manager.replaceRecipes(original);
+    }
+    require(storage.isItemValid(0, new ItemStack(Items.IRON_ORE)), "reload restoration observed");
+  }
+}
diff --git a/src/runtimeTest/java/zone/moddev/mc/lib/smoke/MMDLibGameTests.java b/src/runtimeTest/java/zone/moddev/mc/lib/smoke/MMDLibGameTests.java
index 9eaa5c32..2a3087ae 100644
--- a/src/runtimeTest/java/zone/moddev/mc/lib/smoke/MMDLibGameTests.java
+++ b/src/runtimeTest/java/zone/moddev/mc/lib/smoke/MMDLibGameTests.java
@@ -15,6 +15,36 @@
 @GameTestHolder("mmdlib")
 @PrefixGameTestTemplate(false)
 public final class MMDLibGameTests {
+  @GameTest(template = "empty")
+  public static void inventoryScreenReferences(GameTestHelper helper) throws Exception {
+    InventoryArchitectureSmoke.screenValidation(helper.getLevel());
+    helper.succeed();
+  }
+
+  @GameTest(template = "empty")
+  public static void inventoryItemMigration(GameTestHelper helper) {
+    InventoryArchitectureSmoke.itemMigration(helper.getLevel());
+    helper.succeed();
+  }
+
+  @GameTest(template = "empty")
+  public static void inventoryFluidMigration(GameTestHelper helper) {
+    InventoryArchitectureSmoke.fluidMigration(helper.getLevel());
+    helper.succeed();
+  }
+
+  @GameTest(template = "empty")
+  public static void inventoryGroupBindings(GameTestHelper helper) {
+    InventoryArchitectureSmoke.bindings(helper.getLevel());
+    helper.succeed();
+  }
+
+  @GameTest(template = "empty")
+  public static void inventoryRecipeAdmission(GameTestHelper helper) {
+    InventoryArchitectureSmoke.recipeFilters(helper.getLevel());
+    helper.succeed();
+  }
+
   @GameTest(template = "empty")
   public static void processorIdleSearchBackoff(GameTestHelper helper) {
     ProcessorSmoke.idleSearchBackoff(helper.getLevel());
@@ -30,7 +60,9 @@ private MMDLibGameTests() {}
 
   @GameTest(template = EMPTY)
   public static void equippedContainer(GameTestHelper helper) {
-    ContainerDrawerSmoke.check(helper.getLevel(), helper.absolutePos(CENTER),
+    ContainerDrawerSmoke.check(
+        helper.getLevel(),
+        helper.absolutePos(CENTER),
         helper.makeMockPlayer(net.minecraft.world.level.GameType.SURVIVAL));
     helper.succeed();
   }
diff --git a/src/test/java/zone/moddev/mc/lib/gui/ProcessorButtonTest.java b/src/test/java/zone/moddev/mc/lib/gui/ProcessorButtonTest.java
new file mode 100644
index 00000000..764702a1
--- /dev/null
+++ b/src/test/java/zone/moddev/mc/lib/gui/ProcessorButtonTest.java
@@ -0,0 +1,100 @@
+package zone.moddev.mc.lib.gui;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.io.ByteArrayInputStream;
+import java.nio.charset.StandardCharsets;
+
+import net.minecraft.resources.ResourceLocation;
+
+import org.junit.jupiter.api.Test;
+
+import zone.moddev.mc.lib.gui.load.ScreenBinder;
+import zone.moddev.mc.lib.gui.load.ScreenException;
+import zone.moddev.mc.lib.gui.load.ScreenReader;
+import zone.moddev.mc.lib.gui.model.Element;
+import zone.moddev.mc.lib.gui.model.ProcessorButtonState;
+import zone.moddev.mc.lib.gui.model.Screen;
+
+class ProcessorButtonTest {
+  private Screen read(String body) throws Exception {
+    var xml =
+        "<screen xmlns=\"https://moddev.zone/mmdlib/screen\" title=\"test.screen\""
+            + " block-entity=\"zone.moddev.mc.lib.gui.ScreenLoaderTest$Press\">"
+            + body
+            + "</screen>";
+    return ScreenReader.read(
+        ResourceLocation.parse("test:screen"),
+        "processor.xml",
+        new ByteArrayInputStream(xml.getBytes(StandardCharsets.UTF_8)));
+  }
+
+  @Test
+  void showsCurrentPauseProcessingAndIdleStatesWithoutMachineSpecificBindings() throws Exception {
+    var button =
+        (Element.Button) read("<processor-button processor-key=\"lane_1\"/>").body().getFirst();
+    assertEquals("lane_1", button.processorKey().orElseThrow());
+    assertTrue(button.flat());
+    assertTrue(button.common().value().isEmpty());
+    assertFalse(button.common().clicks().any());
+    assertEquals(
+        ResourceLocation.parse("mmdlib:icon_processor_pause"),
+        button.iconFor(ProcessorButtonState.of(true, false).wireValue()).orElseThrow());
+    assertEquals(
+        ResourceLocation.parse("mmdlib:icon_processor_stop"),
+        button.iconFor(ProcessorButtonState.of(false, true).wireValue()).orElseThrow());
+    assertEquals(
+        ResourceLocation.parse("mmdlib:icon_processor_play"),
+        button.iconFor(ProcessorButtonState.of(false, false).wireValue()).orElseThrow());
+    assertEquals(ProcessorButtonState.PAUSED, ProcessorButtonState.of(true, true));
+    assertTrue(button.common().tooltip().isPresent());
+  }
+
+  @Test
+  void stateDecodingNeverTreatsAnUnknownSnapshotAsAManualPause() {
+    assertTrue(ProcessorButtonState.fromWire(null).isEmpty());
+    assertTrue(ProcessorButtonState.fromWire(java.math.BigInteger.valueOf(3)).isEmpty());
+    for (var state : ProcessorButtonState.values())
+      assertEquals(state, ProcessorButtonState.fromWire(state.wireValue()).orElseThrow());
+  }
+
+  @Test
+  void worksAlongsideOrdinaryButtonsInInventoryControls() throws Exception {
+    var screen =
+        read(
+            """
+            <slot index="0"/>
+            <inventory-controls>
+              <processor-button processor-key="a"/>
+              <button icon="mmdlib:icon_info" tooltip="test.info"/>
+              <processor-button processor-key="b" flat="false" text="test.b"/>
+            </inventory-controls>
+            """);
+    assertEquals(3, screen.body().get(1).children().size());
+    assertFalse(((Element.Button) screen.body().get(1).children().getLast()).flat());
+  }
+
+  @Test
+  void rejectsMissingKeysAndConflictingActionsOrBindings() {
+    for (var attributes :
+        new String[] {
+          "",
+          "processor-key=\"   \"",
+          "processor-key=\"x\" value=\"#getEnergy\"",
+          "processor-key=\"x\" max=\"#getEnergy\"",
+          "processor-key=\"x\" on-click=\"test:toggle\"",
+          "processor-key=\"x\" jei-recipes=\"test:recipe\""
+        })
+      assertThrows(
+          ScreenException.class, () -> read("<processor-button " + attributes + "/>"), attributes);
+  }
+
+  @Test
+  void requiresHostSupportAtBinding() throws Exception {
+    var screen = read("<processor-button processor-key=\"lane_0\"/>");
+    var error =
+        assertThrows(
+            ScreenException.class, () -> ScreenBinder.bind(screen, getClass().getClassLoader()));
+    assertTrue(error.getMessage().contains("requires a ScreenHost"));
+  }
+}
diff --git a/src/test/java/zone/moddev/mc/lib/gui/ScreenInheritanceTest.java b/src/test/java/zone/moddev/mc/lib/gui/ScreenInheritanceTest.java
new file mode 100644
index 00000000..b6dddbec
--- /dev/null
+++ b/src/test/java/zone/moddev/mc/lib/gui/ScreenInheritanceTest.java
@@ -0,0 +1,258 @@
+package zone.moddev.mc.lib.gui;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+import java.util.Map;
+
+import net.minecraft.resources.ResourceLocation;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import zone.moddev.mc.lib.common.loading.DefinitionLoader.SourceRoot;
+import zone.moddev.mc.lib.gui.load.ScreenBinder;
+import zone.moddev.mc.lib.gui.load.ScreenException;
+import zone.moddev.mc.lib.gui.load.ScreenLoader;
+import zone.moddev.mc.lib.gui.model.Element;
+
+class ScreenInheritanceTest {
+  @TempDir Path directory;
+
+  private static final String NS = " xmlns=\"https://moddev.zone/mmdlib/screen\"";
+  private static final String HOST =
+      " block-entity=\"zone.moddev.mc.lib.gui.ScreenLoaderTest$Press\"";
+
+  private Path write(String id, String attributes, String body) throws Exception {
+    var parts = id.split(":", 2);
+    var file = directory.resolve(parts[0]).resolve("screen").resolve(parts[1] + ".xml");
+    Files.createDirectories(file.getParent());
+    Files.writeString(file, "<screen" + NS + " " + attributes + ">\n" + body + "\n</screen>");
+    return file;
+  }
+
+  private void base(String body) throws Exception {
+    write("test:base", "abstract=\"true\"", body);
+  }
+
+  private void child(String body) throws Exception {
+    write("test:child", "extends=\"test:base\" title=\"test.child\"" + HOST, body);
+  }
+
+  private SourceRoot source(String namespace) {
+    return new SourceRoot(namespace, directory.resolve(namespace), getClass().getClassLoader());
+  }
+
+  private Map<ResourceLocation, ScreenBinder.Bound> load() {
+    return ScreenLoader.load(List.of(source("test")));
+  }
+
+  private String failure(String message) {
+    var error = assertThrows(ScreenException.class, this::load);
+    assertTrue(error.getMessage().contains(message), error.getMessage());
+    return error.getMessage();
+  }
+
+  @Test
+  void composesFrameAndBindsInheritedGettersAgainstConcreteHost() throws Exception {
+    base(
+        """
+        <hbox spacing="6">
+          <placeholder name="machine" required="true"/>
+          <energy-gauge id="energy" length="fill"/>
+        </hbox>
+        <player-inventory/>
+        """);
+    child(
+        """
+        <fill name="machine">
+          <slot id="input" index="2"/>
+          <progress value="#getProgress" max="#getProgressMax"/>
+          <slot id="output" index="5"/>
+        </fill>
+        """);
+    var loaded = load();
+    assertEquals(1, loaded.size());
+    var bound = loaded.get(ResourceLocation.parse("test:child"));
+    var screen = bound.screen();
+    var row = (Element.Box) screen.body().getFirst();
+    assertEquals(4, row.children().size());
+    assertEquals(2, ((Element.Slot) row.children().getFirst()).index());
+    assertEquals(5, ((Element.Slot) row.children().get(2)).index());
+    var energy = screen.find("energy").orElseThrow();
+    assertTrue(bound.values().containsKey(energy));
+    assertTrue(bound.maxima().containsKey(energy));
+    assertTrue(screen.playerInventory());
+    assertTrue(screen.source(energy.common()).endsWith("base.xml"));
+    assertTrue(screen.source(row.children().getFirst().common()).endsWith("child.xml"));
+  }
+
+  @Test
+  void resolvesAcrossNamespacesAndDiscoveryOrderUsingChildClassLoader() throws Exception {
+    write(
+        "other:z_base",
+        "abstract=\"1\"",
+        "<placeholder name=\"body\"><label text=\"test.default\"/></placeholder>");
+    write("test:a_child", "extends=\"other:z_base\" title=\"test.child\"" + HOST, "");
+    var inaccessible = new ClassLoader(null) {};
+    var loaded =
+        ScreenLoader.load(
+            List.of(
+                source("test"), new SourceRoot("other", directory.resolve("other"), inaccessible)));
+    assertEquals(1, loaded.size());
+    assertInstanceOf(
+        Element.Label.class,
+        loaded.get(ResourceLocation.parse("test:a_child")).screen().body().getFirst());
+  }
+
+  @Test
+  void supportsChainedOverridesDefaultsAndNewPlaceholders() throws Exception {
+    base(
+        "<vbox><placeholder name=\"machine\" required=\"true\"/><placeholder"
+            + " name=\"optional\"/></vbox>");
+    write(
+        "test:middle",
+        "abstract=\"true\" extends=\"test:base\"",
+        """
+        <fill name="machine"><hbox><placeholder name="input" required="true"/><slot index="1"/></hbox></fill>
+        <fill name="optional"><label id="default" text="test.default"/></fill>
+        """);
+    write(
+        "test:child",
+        "extends=\"test:middle\" title=\"test.child\"" + HOST,
+        "<fill name=\"input\"><slot index=\"0\"/></fill><fill name=\"optional\"/>");
+    var screen = load().get(ResourceLocation.parse("test:child")).screen();
+    assertEquals(2, screen.elements().stream().filter(e -> e instanceof Element.Slot).count());
+    assertTrue(screen.find("default").isEmpty());
+  }
+
+  @Test
+  void inheritsInventorySettingUnlessExplicitlyOverridden() throws Exception {
+    write("test:base", "abstract=\"true\" inventory=\"none\"", "<label text=\"test.body\"/>");
+    child("");
+    assertFalse(load().get(ResourceLocation.parse("test:child")).screen().playerInventory());
+    write(
+        "test:child",
+        "extends=\"test:base\" inventory=\"default\" title=\"test.child\"" + HOST,
+        "");
+    assertTrue(load().get(ResourceLocation.parse("test:child")).screen().playerInventory());
+  }
+
+  @Test
+  void validatesReferencesAcrossBaseAndChildAfterComposition() throws Exception {
+    base("<vbox><placeholder name=\"body\"/><side-config groups=\"input\"/></vbox>");
+    child("<fill name=\"body\"><slot id=\"input\" index=\"0\"/></fill>");
+    assertEquals(1, load().size());
+  }
+
+  @Test
+  void missingRequiredFillNamesBaseFileAndLine() throws Exception {
+    base("<placeholder name=\"machine\" required=\"true\"/>");
+    child("");
+    assertTrue(failure("Missing required fill: machine").contains("base.xml:2"));
+  }
+
+  @Test
+  void rejectsUnknownAndDuplicateFills() throws Exception {
+    base("<placeholder name=\"machine\"/>");
+    child("<fill name=\"typo\"/>");
+    assertTrue(failure("Unknown placeholder: typo").contains("child.xml:2"));
+    child("<fill name=\"machine\"/><fill name=\"machine\"/>");
+    failure("Duplicate fill: machine");
+  }
+
+  @Test
+  void rejectsAmbiguousAndContradictoryPlaceholdersEvenInUnusedBases() throws Exception {
+    base("<vbox><placeholder name=\"x\"/><placeholder name=\"x\"/></vbox>");
+    failure("Duplicate placeholder: x");
+    base("<placeholder name=\"x\" required=\"true\"><label text=\"test.x\"/></placeholder>");
+    failure("required placeholder cannot also have default");
+  }
+
+  @Test
+  void rejectsFillHiddenByOuterReplacement() throws Exception {
+    base("<placeholder name=\"outer\"><placeholder name=\"inner\"/></placeholder>");
+    child("<fill name=\"outer\"><label text=\"test.x\"/></fill><fill name=\"inner\"/>");
+    failure("Fill targets a replaced placeholder: inner");
+  }
+
+  @Test
+  void rejectsUnknownBaseAndCyclesEvenWithoutConcreteScreens() throws Exception {
+    child("");
+    failure("Unknown base screen: test:base");
+    write("test:base", "abstract=\"true\" extends=\"test:other\"", "");
+    write("test:other", "abstract=\"true\" extends=\"test:base\"", "");
+    failure("Screen inheritance cycle");
+  }
+
+  @Test
+  void rejectsMixedOrUnattachedFillsAndMissingConcreteMetadata() throws Exception {
+    base("<placeholder name=\"machine\"/>");
+    child("<slot index=\"0\"/>");
+    failure("supplies content through <fill> only");
+    write("test:child", "title=\"test.child\"" + HOST, "<fill name=\"machine\"/>");
+    failure("<fill> requires extends");
+    write("test:child", "extends=\"test:base\"" + HOST, "");
+    failure("requires its own title");
+    write("test:child", "extends=\"test:base\" title=\"test.child\"", "");
+    failure("requires its own block-entity");
+  }
+
+  @Test
+  void rejectsDuplicateSlotsAndIdsAcrossFiles() throws Exception {
+    base("<vbox><slot index=\"0\" id=\"fixed\"/><placeholder name=\"machine\"/></vbox>");
+    child("<fill name=\"machine\"><slot index=\"0\"/></fill>");
+    assertTrue(failure("Slot 0 is placed twice").contains("child.xml:2"));
+    child("<fill name=\"machine\"><slot index=\"1\" id=\"fixed\"/></fill>");
+    failure("Duplicate id: fixed");
+  }
+
+  @Test
+  void validatesExpandedStructureAndLayoutAtTheOriginalLocation() throws Exception {
+    base("<hbox><placeholder name=\"machine\"/></hbox>");
+    child("<fill name=\"machine\"><side-tab><slot index=\"0\"/></side-tab></fill>");
+    assertTrue(failure("side-tab").contains("child.xml:2"));
+    base("<vbox><placeholder name=\"machine\"/><energy-gauge length=\"fill\"/></vbox>");
+    child("<fill name=\"machine\"><slot index=\"0\"/></fill>");
+    assertTrue(failure("belongs directly in an <hbox>").contains("base.xml:2"));
+  }
+
+  @Test
+  void inheritedBindingErrorsNameBaseAndDoNotMutateOtherChildren() throws Exception {
+    base("<vbox><energy-gauge value=\"#missing\"/><placeholder name=\"machine\"/></vbox>");
+    child("<fill name=\"machine\"><slot index=\"0\"/></fill>");
+    assertTrue(failure("missing").contains("base.xml:2"));
+    base("<placeholder name=\"machine\"/>");
+    write(
+        "test:second",
+        "extends=\"test:base\" title=\"test.second\"" + HOST,
+        "<fill name=\"machine\"><slot index=\"5\"/></fill>");
+    var loaded = load();
+    assertEquals(
+        0,
+        ((Element.Slot) loaded.get(ResourceLocation.parse("test:child")).screen().body().getFirst())
+            .index());
+    assertEquals(
+        5,
+        ((Element.Slot)
+                loaded.get(ResourceLocation.parse("test:second")).screen().body().getFirst())
+            .index());
+  }
+
+  @Test
+  void fingerprintsExcludeMachineLocalSourcePathsButIncludeInheritedChanges() throws Exception {
+    base("<label text=\"test.first\"/>");
+    child("");
+    var first = load().get(ResourceLocation.parse("test:child")).screen().fingerprint();
+    var oldDirectory = directory;
+    directory = directory.resolve("relocated");
+    base("<label text=\"test.first\"/>");
+    child("");
+    assertEquals(first, load().get(ResourceLocation.parse("test:child")).screen().fingerprint());
+    base("<label text=\"test.changed\"/>");
+    assertNotEquals(first, load().get(ResourceLocation.parse("test:child")).screen().fingerprint());
+    directory = oldDirectory;
+  }
+}
diff --git a/src/test/java/zone/moddev/mc/lib/gui/ScreenLoaderTest.java b/src/test/java/zone/moddev/mc/lib/gui/ScreenLoaderTest.java
index ed0ce1a0..03cb7018 100644
--- a/src/test/java/zone/moddev/mc/lib/gui/ScreenLoaderTest.java
+++ b/src/test/java/zone/moddev/mc/lib/gui/ScreenLoaderTest.java
@@ -329,74 +329,56 @@ void statefulButtonsSelectIconsAndTranslatedValues() throws Exception {
 
   @Test
   void companionControlsSitAboveInventoryAtRightMargin() throws Exception {
+    var screens = companionScreens();
     for (var name : java.util.List.of("crusher", "transmuter", "dual_crusher")) {
-      try (var input =
-          java.nio.file.Files.newInputStream(
-              java.nio.file.Path.of("src/companion/resources/mmdlib/screen/" + name + ".xml"))) {
-        var screen =
-            ScreenReader.read(
-                ResourceLocation.parse("mmdlib_companion:" + name),
-                name + ".xml",
-                input,
-                companionLayoutWidgets());
-        var layout =
-            ScreenLayout.of(screen, text -> text.fallback().orElse(text.key()).length() * 6);
-        var controls = layout.bounds(screen.find("inventory_controls").orElseThrow());
-        require(screen.find("redstone").isEmpty());
-        var firstPause = layout.bounds(screen.find("toggle_0").orElseThrow());
-        var pause =
-            layout.bounds(
-                screen.find(name.equals("dual_crusher") ? "toggle_1" : "toggle_0").orElseThrow());
-        require(controls.y() > layout.bounds(screen.find("energy").orElseThrow()).bottom());
-        var inventory = layout.inventory().orElseThrow();
-        require(controls.y() == ScreenLayout.playerSlot(inventory, 39).y());
-        require(controls.bottom() + ScreenLayout.GAP == ScreenLayout.playerSlot(inventory, 9).y());
-        require(pause.right() == ScreenLayout.playerSlot(inventory, 17).right());
-        var colours = layout.inventoryColors().orElseThrow();
-        require(colours.x() == layout.inventory().orElseThrow().x());
-        require(colours.y() == firstPause.y() && colours.height() == firstPause.height());
-        require(colours.right() + ScreenLayout.GAP == firstPause.x());
-        require(firstPause.y() == pause.y());
-        require(pause.width() == 14 && pause.height() == 14);
-        require(((Element.Button) screen.find("toggle_0").orElseThrow()).flat());
-      }
+      var screen = screens.get(ResourceLocation.parse("mmdlib_companion:" + name));
+      var layout = ScreenLayout.of(screen, text -> text.fallback().orElse(text.key()).length() * 6);
+      var controls = layout.bounds(screen.find("inventory_controls").orElseThrow());
+      require(screen.find("redstone").isEmpty());
+      var firstPause = layout.bounds(screen.find("toggle_0").orElseThrow());
+      var pause =
+          layout.bounds(
+              screen.find(name.equals("dual_crusher") ? "toggle_1" : "toggle_0").orElseThrow());
+      require(controls.y() > layout.bounds(screen.find("energy").orElseThrow()).bottom());
+      var inventory = layout.inventory().orElseThrow();
+      require(controls.y() == ScreenLayout.playerSlot(inventory, 39).y());
+      require(controls.bottom() + ScreenLayout.GAP == ScreenLayout.playerSlot(inventory, 9).y());
+      require(pause.right() == ScreenLayout.playerSlot(inventory, 17).right());
+      var colours = layout.inventoryColors().orElseThrow();
+      require(colours.x() == layout.inventory().orElseThrow().x());
+      require(colours.y() == firstPause.y() && colours.height() == firstPause.height());
+      require(colours.right() + ScreenLayout.GAP == firstPause.x());
+      require(firstPause.y() == pause.y());
+      require(pause.width() == 14 && pause.height() == 14);
+      require(((Element.Button) screen.find("toggle_0").orElseThrow()).flat());
     }
   }
 
   @Test
   void allCompanionScreensPlaceBatteryAtRightMargin() throws Exception {
+    var screens = companionScreens();
     for (var name : java.util.List.of("crusher", "transmuter", "dual_crusher", "creative_power")) {
-      try (var input =
-          java.nio.file.Files.newInputStream(
-              java.nio.file.Path.of("src/companion/resources/mmdlib/screen/" + name + ".xml"))) {
-        var screen =
-            ScreenReader.read(
-                ResourceLocation.parse("mmdlib_companion:" + name),
-                name + ".xml",
-                input,
-                companionLayoutWidgets());
-        var layout =
-            ScreenLayout.of(screen, text -> text.fallback().orElse(text.key()).length() * 6);
-        var energy = screen.find("energy").orElseThrow();
-        require(energy instanceof Element.EnergyGauge);
-        var bounds = layout.bounds(energy);
-        require(bounds.right() == layout.panel().width() - 7);
-        require(bounds.height() == 54 && bounds.width() == 18);
-        for (var element : screen.elements()) {
-          if (screen.find("settings").filter(view -> containsElement(view, element)).isPresent())
-            continue;
-          if (element instanceof Element.Slot
-              || element instanceof Element.Progress
-              || element instanceof Element.Custom
-              || element instanceof Element.Checkbox
-              || element instanceof Element.Label) {
-            var other = layout.bounds(element);
-            require(
-                other.right() <= bounds.x()
-                    || other.x() >= bounds.right()
-                    || other.bottom() <= bounds.y()
-                    || other.y() >= bounds.bottom());
-          }
+      var screen = screens.get(ResourceLocation.parse("mmdlib_companion:" + name));
+      var layout = ScreenLayout.of(screen, text -> text.fallback().orElse(text.key()).length() * 6);
+      var energy = screen.find("energy").orElseThrow();
+      require(energy instanceof Element.EnergyGauge);
+      var bounds = layout.bounds(energy);
+      require(bounds.right() == layout.panel().width() - 7);
+      require(bounds.height() == 54 && bounds.width() == 18);
+      for (var element : screen.elements()) {
+        if (screen.find("settings").filter(view -> containsElement(view, element)).isPresent())
+          continue;
+        if (element instanceof Element.Slot
+            || element instanceof Element.Progress
+            || element instanceof Element.Custom
+            || element instanceof Element.Checkbox
+            || element instanceof Element.Label) {
+          var other = layout.bounds(element);
+          require(
+              other.right() <= bounds.x()
+                  || other.x() >= bounds.right()
+                  || other.bottom() <= bounds.y()
+                  || other.y() >= bounds.bottom());
         }
       }
     }
@@ -465,6 +447,16 @@ void settingsExpandAndCollapseThePanelAndInventory() throws Exception {
     }
   }
 
+  private static java.util.Map<ResourceLocation, Screen> companionScreens() {
+    return zone.moddev.mc.lib.gui.load.ScreenLoader.read(
+        java.util.List.of(
+            new zone.moddev.mc.lib.common.loading.DefinitionLoader.SourceRoot(
+                "mmdlib_companion",
+                java.nio.file.Path.of("src/companion/resources/mmdlib"),
+                ScreenLoaderTest.class.getClassLoader())),
+        companionLayoutWidgets());
+  }
+
   private static WidgetTypes companionLayoutWidgets() {
     // These checks only measure XML. The actual companion contract is exercised by game tests.
     var types = new WidgetTypes();

From d7e8956756b62b2ad2e862fe58165fd071cbb138 Mon Sep 17 00:00:00 2001
From: Face o' Cat <face@modcrafters.net>
Date: Sat, 7 Nov 2026 12:03:03 +0200
Subject: [PATCH 2/9] Default keyless processor buttons to the first registered
 processor

---
 .../mmdlib/screen/base_powered_machine.xml    |  2 +-
 .../resources/mmdlib/screen/crusher.xml       |  2 +-
 .../mc/companion/test/CompanionGameTests.java | 89 +++++++++++++++++++
 .../test/ProcessorButtonClientSmoke.java      |  2 +-
 .../mc/lib/gui/client/MachineScreen.java      |  4 +-
 .../moddev/mc/lib/gui/load/ScreenBinder.java  |  2 +-
 .../moddev/mc/lib/gui/load/ScreenReader.java  | 10 ++-
 .../zone/moddev/mc/lib/gui/model/Element.java | 27 +++++-
 .../mc/lib/gui/runtime/MachineMenu.java       |  8 +-
 .../runtime/ScreenInventoryValidation.java    |  7 +-
 .../mc/lib/gui/runtime/ScreenSnapshots.java   |  5 +-
 .../mc/lib/machine/feature/FeatureHost.java   | 10 +++
 src/main/resources/mmdlib/schema/screen.xsd   |  2 +-
 .../mc/lib/gui/ProcessorButtonTest.java       | 19 +++-
 .../mc/lib/gui/ScreenInheritanceTest.java     | 15 ++++
 15 files changed, 178 insertions(+), 26 deletions(-)

diff --git a/src/companion/resources/mmdlib/screen/base_powered_machine.xml b/src/companion/resources/mmdlib/screen/base_powered_machine.xml
index 2a1333a5..93682b98 100644
--- a/src/companion/resources/mmdlib/screen/base_powered_machine.xml
+++ b/src/companion/resources/mmdlib/screen/base_powered_machine.xml
@@ -9,7 +9,7 @@
   </vbox>
   <placeholder name="inventory_controls">
     <inventory-controls id="inventory_controls">
-      <processor-button id="toggle_0" processor-key="lane_0"/>
+      <processor-button id="toggle_0"/>
     </inventory-controls>
   </placeholder>
   <placeholder name="info"/>
diff --git a/src/companion/resources/mmdlib/screen/crusher.xml b/src/companion/resources/mmdlib/screen/crusher.xml
index dc15f28d..8e0c83b8 100644
--- a/src/companion/resources/mmdlib/screen/crusher.xml
+++ b/src/companion/resources/mmdlib/screen/crusher.xml
@@ -47,7 +47,7 @@
     </context>
   </vbox>
   <inventory-controls id="inventory_controls">
-    <processor-button id="toggle_0" processor-key="lane_0"/>
+    <processor-button id="toggle_0"/>
   </inventory-controls>
   <popout id="info" kind="info" edge="left" text="screen.mmdlib_companion.info.crusher" value="#getWarnings"/>
 </screen>
diff --git a/src/companionTest/java/zone/moddev/mc/companion/test/CompanionGameTests.java b/src/companionTest/java/zone/moddev/mc/companion/test/CompanionGameTests.java
index c27f4799..7db1c673 100644
--- a/src/companionTest/java/zone/moddev/mc/companion/test/CompanionGameTests.java
+++ b/src/companionTest/java/zone/moddev/mc/companion/test/CompanionGameTests.java
@@ -38,6 +38,95 @@
 public final class CompanionGameTests {
   private static final BlockPos CENTER = new BlockPos(2, 2, 2);
 
+  @GameTest(template = "empty")
+  public static void keylessProcessorButtonSamplesAndTogglesTheFirstProcessor(GameTestHelper helper)
+      throws ReflectiveOperationException {
+    var machine = place(helper, CompanionMod.TRANSMUTER);
+    var player = helper.makeMockServerPlayerInLevel();
+    var pos = machine.getBlockPos();
+    player.setPos(pos.getX() + .5, pos.getY(), pos.getZ() + .5);
+    var menu = new MachineMenu(43, player.getInventory(), machine);
+    player.containerMenu = menu;
+    var button =
+        (zone.moddev.mc.lib.gui.model.Element.Button)
+            menu.bound.screen().find("toggle_0").orElseThrow();
+    require(
+        button.processorControl() && button.processorKey().isEmpty(),
+        "Inherited control uses no machine-specific key");
+    // Mock players have no negotiated GUI channel; inspect the actual server snapshot directly.
+    var read =
+        Class.forName("zone.moddev.mc.lib.gui.runtime.ScreenSnapshots")
+            .getDeclaredMethod(
+                "read", BlockEntity.class, zone.moddev.mc.lib.gui.load.ScreenBinder.Bound.class);
+    read.setAccessible(true);
+    var snapshot = (java.util.Map<?, ?>) read.invoke(null, machine, menu.bound);
+    require(
+        zone.moddev.mc.lib.gui.model.ProcessorButtonState.IDLE
+            .wireValue()
+            .equals(snapshot.get(menu.index(button) * 2)),
+        "Keyless control samples the first processor");
+    var action = new ScreenNetwork.Action(43, menu.index(button), 0, 0, 0, 0);
+    menu.action(player, action);
+    snapshot = (java.util.Map<?, ?>) read.invoke(null, machine, menu.bound);
+    require(
+        machine.lanes.getFirst().paused()
+            && zone.moddev.mc.lib.gui.model.ProcessorButtonState.PAUSED
+                .wireValue()
+                .equals(snapshot.get(menu.index(button) * 2)),
+        "Keyless click pauses and synchronizes the same processor");
+    menu.action(player, action);
+    require(!machine.lanes.getFirst().paused(), "Keyless click resumes the same processor");
+    var dual = place(helper, CompanionMod.DUAL_CRUSHER);
+    var features =
+        new zone.moddev.mc.lib.machine.feature.FeatureHost(() -> {})
+            .add(
+                new zone.moddev.mc.lib.machine.feature.MachineFeature<Integer>() {
+                  public String key() {
+                    return "auxiliary";
+                  }
+
+                  public com.mojang.serialization.Codec<Integer> codec() {
+                    return com.mojang.serialization.Codec.INT;
+                  }
+
+                  public Integer state() {
+                    return 0;
+                  }
+
+                  public void restore(Integer value) {}
+                })
+            .add(dual.lanes.get(1))
+            .add(dual.lanes.getFirst());
+    require(
+        features.processor(java.util.Optional.empty()).orElseThrow() == dual.lanes.get(1),
+        "Default is the first registered recipe processor, skipping other features");
+    require(
+        features.processor(java.util.Optional.of("lane_0")).orElseThrow() == dual.lanes.getFirst()
+            && features.processor(java.util.Optional.of("missing")).isEmpty(),
+        "Explicit keys never fall back to the first processor");
+    var emptyHost =
+        new zone.moddev.mc.lib.gui.runtime.ScreenHost() {
+          public zone.moddev.mc.lib.api.capabilities.ItemStorage screenItems() {
+            return machine.items;
+          }
+
+          public zone.moddev.mc.lib.machine.feature.FeatureHost screenFeatures() {
+            return new zone.moddev.mc.lib.machine.feature.FeatureHost(() -> {});
+          }
+        };
+    try {
+      zone.moddev.mc.lib.gui.runtime.ScreenInventoryValidation.validate(
+          menu.bound.screen(), emptyHost);
+      throw new AssertionError("A keyless processor control requires a processor");
+    } catch (zone.moddev.mc.lib.gui.load.ScreenException expected) {
+      require(
+          expected.getMessage().contains("at least one recipe processor"),
+          "Missing default processor has a clear error");
+    }
+    player.containerMenu = player.inventoryMenu;
+    helper.succeed();
+  }
+
   @GameTest(template = "empty")
   public static void processorActivityTracksWorkAndHostGates(GameTestHelper helper) {
     var machine = place(helper, CompanionMod.CRUSHER);
diff --git a/src/companionTest/java/zone/moddev/mc/companion/test/ProcessorButtonClientSmoke.java b/src/companionTest/java/zone/moddev/mc/companion/test/ProcessorButtonClientSmoke.java
index ccbde13b..5235cda2 100644
--- a/src/companionTest/java/zone/moddev/mc/companion/test/ProcessorButtonClientSmoke.java
+++ b/src/companionTest/java/zone/moddev/mc/companion/test/ProcessorButtonClientSmoke.java
@@ -31,7 +31,7 @@ static boolean run(MachineScreen screen) {
     if (step > 0 && !ready) return false;
     var menu = screen.getMenu();
     var button = (Element.Button) menu.bound.screen().find("toggle_0").orElseThrow();
-    if (button.processorKey().isEmpty())
+    if (!button.processorControl())
       throw new AssertionError("Companion must use the generic control");
     var wireState = menu.value(button, false);
     var state = ProcessorButtonState.fromWire(wireState).orElse(null);
diff --git a/src/main/java/zone/moddev/mc/lib/gui/client/MachineScreen.java b/src/main/java/zone/moddev/mc/lib/gui/client/MachineScreen.java
index ea4f5b9d..267ecd9f 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/client/MachineScreen.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/client/MachineScreen.java
@@ -762,7 +762,7 @@ public List<Component> tooltipLines(Element e, int mx, int my) {
                               .orElseGet(() -> ScreenText.number(menu.value(e, false), shift))
                           : ScreenText.number(menu.value(e, false), shift))
                   .replace("{max}", ScreenText.number(menu.value(e, true), shift));
-          if (e instanceof Element.Button button && button.processorKey().isPresent()) {
+          if (e instanceof Element.Button button && button.processorControl()) {
             var action =
                 ProcessorButtonState.fromWire(menu.value(button, false))
                     .map(
@@ -894,7 +894,7 @@ public boolean mouseClicked(double mx, double my, int button) {
                 button == 1 ? ItemStack.EMPTY : menu.getCarried().copyWithCount(1)));
         return true;
       }
-      if (e instanceof Element.Button b && b.processorKey().isPresent()) {
+      if (e instanceof Element.Button b && b.processorControl()) {
         if (button == 0) send(e, 0, button, 0);
         return true;
       }
diff --git a/src/main/java/zone/moddev/mc/lib/gui/load/ScreenBinder.java b/src/main/java/zone/moddev/mc/lib/gui/load/ScreenBinder.java
index 1f866e4f..71fecd8b 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/load/ScreenBinder.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/load/ScreenBinder.java
@@ -73,7 +73,7 @@ public static Bound bind(Screen screen, ClassLoader loader, WidgetTypes widgets)
       var c = element.common();
       var elementSource = screen.source(c);
       if (element instanceof Button button
-          && button.processorKey().isPresent()
+          && button.processorControl()
           && !zone.moddev.mc.lib.gui.runtime.ScreenHost.class.isAssignableFrom(owner))
         throw new ScreenException(
             elementSource, c.line(), "<processor-button> requires a ScreenHost");
diff --git a/src/main/java/zone/moddev/mc/lib/gui/load/ScreenReader.java b/src/main/java/zone/moddev/mc/lib/gui/load/ScreenReader.java
index dbb08580..9ee9ea20 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/load/ScreenReader.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/load/ScreenReader.java
@@ -328,7 +328,8 @@ private Element element(Node node) {
                     .toList(),
                 java.util.Set.of("true", "1")
                     .contains(node.attributes().getOrDefault("flat", "false")),
-                Optional.ofNullable(node.attributes().get("processor-key")));
+                Optional.ofNullable(node.attributes().get("processor-key")),
+                node.name().equals("processor-button"));
         case "checkbox" -> new Checkbox(c, text(node, "text").orElseThrow());
         case "radio-group" ->
             new RadioGroup(
@@ -393,7 +394,8 @@ private Node energyDefaults(Node node) {
     }
 
     private Node processorDefaults(Node node) {
-      if (node.attributes().get("processor-key").isBlank())
+      if (node.attributes().containsKey("processor-key")
+          && node.attributes().get("processor-key").isBlank())
         throw error(node, "processor-key must not be blank");
       var attributes = new LinkedHashMap<>(node.attributes());
       attributes.put(
@@ -574,7 +576,7 @@ private static void check(Screen screen) {
         throw new ScreenException(source, line, "max needs value");
       switch (element) {
         case Button button -> {
-          if (button.processorKey().isPresent()
+          if (button.processorControl()
               && (c.value().isPresent()
                   || c.max().isPresent()
                   || c.clicks().any()
@@ -591,7 +593,7 @@ private static void check(Screen screen) {
             throw new ScreenException(source, line, "<button> needs a tooltip saying what it does");
           if (button.text().isEmpty() && button.icon().isEmpty() && button.icons().isEmpty())
             throw new ScreenException(source, line, "<button> needs text or icon");
-          if (button.processorKey().isEmpty()
+          if (!button.processorControl()
               && (!button.icons().isEmpty() || !button.valueLabels().isEmpty()))
             requireValue(source, element, "a stateful <button>", false);
           if (!button.icons().isEmpty()
diff --git a/src/main/java/zone/moddev/mc/lib/gui/model/Element.java b/src/main/java/zone/moddev/mc/lib/gui/model/Element.java
index a54791aa..85c3d7d5 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/model/Element.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/model/Element.java
@@ -277,7 +277,8 @@ record Label(Common common, Text text) implements Element {}
    * @param icons optional icons indexed by its boolean or whole-number value
    * @param valueLabels optional translated names for those states in the tooltip
    * @param flat whether to use a compact icon with a flat border and background
-   * @param processorKey a generic processor control's stable feature key, if present
+   * @param processorKey a generic processor control's stable feature key; absent selects the first
+   * @param processorControl whether this button controls a processor
    */
   record Button(
       Common common,
@@ -287,13 +288,35 @@ record Button(
       List<ResourceLocation> icons,
       List<Text> valueLabels,
       boolean flat,
-      Optional<String> processorKey)
+      Optional<String> processorKey,
+      boolean processorControl)
       implements Element {
     public Button {
       icons = List.copyOf(icons);
       valueLabels = List.copyOf(valueLabels);
     }
 
+    public Button(
+        Common common,
+        Optional<Text> text,
+        Optional<ResourceLocation> icon,
+        Optional<ViewRef> shows,
+        List<ResourceLocation> icons,
+        List<Text> valueLabels,
+        boolean flat,
+        Optional<String> processorKey) {
+      this(
+          common,
+          text,
+          icon,
+          shows,
+          icons,
+          valueLabels,
+          flat,
+          processorKey,
+          processorKey.isPresent());
+    }
+
     public Button(
         Common common,
         Optional<Text> text,
diff --git a/src/main/java/zone/moddev/mc/lib/gui/runtime/MachineMenu.java b/src/main/java/zone/moddev/mc/lib/gui/runtime/MachineMenu.java
index 8df6ba96..6e184fde 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/runtime/MachineMenu.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/runtime/MachineMenu.java
@@ -450,7 +450,7 @@ public Object wireValue(int key) {
   }
 
   public boolean processorConflict(Element.Button button) {
-    return button.processorKey().isPresent()
+    return button.processorControl()
         && redstone != null
         && zone.moddev.mc.lib.gui.model.ProcessorButtonState.fromWire(value(button, false))
             .map(
@@ -723,18 +723,18 @@ public void action(Player player, ScreenNetwork.Action action) {
       return;
     }
     if (action.kind() != 0) return;
-    if (element instanceof Element.Button button && button.processorKey().isPresent()) {
+    if (element instanceof Element.Button button && button.processorControl()) {
       if (action.button() != 0
           || action.option() != 0
           || host == null
           || host.screenFeatures() == null) return;
       var features = host.screenFeatures();
-      var key = button.processorKey().orElseThrow();
+      var key = button.processorKey();
       features
           .processor(key)
           .ifPresent(
               processor -> {
-                if (features.setProcessorPaused(key, !processor.paused())) {
+                if (features.setProcessorPaused(processor.key(), !processor.paused())) {
                   ScreenSnapshots.invalidate(blockEntity);
                   broadcastChanges();
                 }
diff --git a/src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenInventoryValidation.java b/src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenInventoryValidation.java
index 38761492..72dbc104 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenInventoryValidation.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenInventoryValidation.java
@@ -19,13 +19,14 @@ public static void validate(net.minecraft.world.level.block.entity.BlockEntity o
   public static void validate(Screen screen, ScreenHost host) {
     int count = host.screenItems().getSlots();
     for (var element : screen.elements()) {
-      if (element instanceof Element.Button button && button.processorKey().isPresent()) {
-        var key = button.processorKey().orElseThrow();
+      if (element instanceof Element.Button button && button.processorControl()) {
+        var key = button.processorKey();
         if (host.screenFeatures() == null || host.screenFeatures().processor(key).isEmpty())
           throw new zone.moddev.mc.lib.gui.load.ScreenException(
               screen.source(button.common()),
               button.common().line(),
-              "Unknown processor-key: " + key);
+              key.map(value -> "Unknown processor-key: " + value)
+                  .orElse("<processor-button> requires at least one recipe processor"));
       }
       if (element instanceof Element.Slot slot
           && slot.kind() != Element.SlotKind.GHOST
diff --git a/src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenSnapshots.java b/src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenSnapshots.java
index bc4f452c..22b39b4b 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenSnapshots.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/runtime/ScreenSnapshots.java
@@ -32,11 +32,10 @@ static Map<Integer, Object> read(BlockEntity entity, ScreenBinder.Bound bound) {
     for (int i = 0; i < elements.size(); i++) {
       var e = elements.get(i);
       if (e instanceof zone.moddev.mc.lib.gui.model.Element.Button button
-          && button.processorKey().isPresent()
+          && button.processorControl()
           && entity instanceof ScreenHost host
           && host.screenFeatures() != null) {
-        var processor =
-            host.screenFeatures().processor(button.processorKey().orElseThrow()).orElse(null);
+        var processor = host.screenFeatures().processor(button.processorKey()).orElse(null);
         if (processor != null)
           result.put(
               i * 2,
diff --git a/src/main/java/zone/moddev/mc/lib/machine/feature/FeatureHost.java b/src/main/java/zone/moddev/mc/lib/machine/feature/FeatureHost.java
index 23fe31f1..07880ec2 100644
--- a/src/main/java/zone/moddev/mc/lib/machine/feature/FeatureHost.java
+++ b/src/main/java/zone/moddev/mc/lib/machine/feature/FeatureHost.java
@@ -71,6 +71,16 @@ public java.util.Optional<RecipeProcessor> processor(String key) {
         : java.util.Optional.empty();
   }
 
+  /** An omitted key selects the first recipe processor in feature registration order. */
+  public java.util.Optional<RecipeProcessor> processor(java.util.Optional<String> key) {
+    return key.isPresent()
+        ? processor(key.orElseThrow())
+        : features.values().stream()
+            .filter(RecipeProcessor.class::isInstance)
+            .map(RecipeProcessor.class::cast)
+            .findFirst();
+  }
+
   /** Persists and synchronizes manual changes even while the host's processing tick is held. */
   public boolean setProcessorPaused(String key, boolean paused) {
     var processor = processor(key).orElse(null);
diff --git a/src/main/resources/mmdlib/schema/screen.xsd b/src/main/resources/mmdlib/schema/screen.xsd
index eb4152fe..5f46be5d 100644
--- a/src/main/resources/mmdlib/schema/screen.xsd
+++ b/src/main/resources/mmdlib/schema/screen.xsd
@@ -399,7 +399,7 @@
     <xs:complexType>
       <xs:complexContent>
         <xs:extension base="leaf">
-          <xs:attribute name="processor-key" type="xs:string" use="required"/>
+          <xs:attribute name="processor-key" type="xs:string"/>
           <xs:attribute name="text" type="translationKey"/>
           <xs:attribute name="text-fallback" type="xs:string"/>
           <xs:attribute name="flat" type="xs:boolean" default="true"/>
diff --git a/src/test/java/zone/moddev/mc/lib/gui/ProcessorButtonTest.java b/src/test/java/zone/moddev/mc/lib/gui/ProcessorButtonTest.java
index 764702a1..906407db 100644
--- a/src/test/java/zone/moddev/mc/lib/gui/ProcessorButtonTest.java
+++ b/src/test/java/zone/moddev/mc/lib/gui/ProcessorButtonTest.java
@@ -17,6 +17,17 @@
 import zone.moddev.mc.lib.gui.model.Screen;
 
 class ProcessorButtonTest {
+  @Test
+  void omittedKeyStillCreatesAProcessorControl() throws Exception {
+    var button = (Element.Button) read("<processor-button/>").body().getFirst();
+    assertTrue(button.processorControl());
+    assertTrue(button.processorKey().isEmpty());
+    var ordinary =
+        (Element.Button)
+            read("<button icon=\"mmdlib:icon_info\" tooltip=\"test.tip\"/>").body().getFirst();
+    assertFalse(ordinary.processorControl());
+  }
+
   private Screen read(String body) throws Exception {
     var xml =
         "<screen xmlns=\"https://moddev.zone/mmdlib/screen\" title=\"test.screen\""
@@ -75,11 +86,13 @@ void worksAlongsideOrdinaryButtonsInInventoryControls() throws Exception {
   }
 
   @Test
-  void rejectsMissingKeysAndConflictingActionsOrBindings() {
+  void rejectsBlankKeysAndConflictingActionsOrBindings() {
     for (var attributes :
         new String[] {
-          "",
+          "processor-key=\"\"",
           "processor-key=\"   \"",
+          "value=\"#getEnergy\"",
+          "on-click=\"test:toggle\"",
           "processor-key=\"x\" value=\"#getEnergy\"",
           "processor-key=\"x\" max=\"#getEnergy\"",
           "processor-key=\"x\" on-click=\"test:toggle\"",
@@ -91,7 +104,7 @@ void rejectsMissingKeysAndConflictingActionsOrBindings() {
 
   @Test
   void requiresHostSupportAtBinding() throws Exception {
-    var screen = read("<processor-button processor-key=\"lane_0\"/>");
+    var screen = read("<processor-button/>");
     var error =
         assertThrows(
             ScreenException.class, () -> ScreenBinder.bind(screen, getClass().getClassLoader()));
diff --git a/src/test/java/zone/moddev/mc/lib/gui/ScreenInheritanceTest.java b/src/test/java/zone/moddev/mc/lib/gui/ScreenInheritanceTest.java
index b6dddbec..f9e98533 100644
--- a/src/test/java/zone/moddev/mc/lib/gui/ScreenInheritanceTest.java
+++ b/src/test/java/zone/moddev/mc/lib/gui/ScreenInheritanceTest.java
@@ -49,6 +49,21 @@ private Map<ResourceLocation, ScreenBinder.Bound> load() {
     return ScreenLoader.load(List.of(source("test")));
   }
 
+  @Test
+  void baseProcessorControlNeedsNoMachineSpecificKeyOrFill() throws Exception {
+    base(
+        "<label text=\"test.machine\"/><inventory-controls><processor-button"
+            + " id=\"toggle\"/></inventory-controls>");
+    child("");
+    var screen =
+        ScreenLoader.read(List.of(source("test")), new zone.moddev.mc.lib.gui.WidgetTypes())
+            .get(ResourceLocation.parse("test:child"));
+    var button = (Element.Button) screen.find("toggle").orElseThrow();
+    assertTrue(button.processorControl());
+    assertTrue(button.processorKey().isEmpty());
+    assertTrue(screen.source(button.common()).endsWith("base.xml"));
+  }
+
   private String failure(String message) {
     var error = assertThrows(ScreenException.class, this::load);
     assertTrue(error.getMessage().contains(message), error.getMessage());

From 2cf1745fa0ec822c2ec1ca4d3c2392b60e44d59c Mon Sep 17 00:00:00 2001
From: Face o' Cat <face@modcrafters.net>
Date: Sat, 7 Nov 2026 12:05:15 +0200
Subject: [PATCH 3/9] Ship the reusable powered-machine screen template in
 MMDLib

---
 src/companion/resources/mmdlib/screen/dual_crusher.xml        | 2 +-
 src/companion/resources/mmdlib/screen/transmuter.xml          | 2 +-
 .../resources/mmdlib/screen/base_powered_machine.xml          | 0
 src/test/java/zone/moddev/mc/lib/gui/ScreenLoaderTest.java    | 4 ++++
 4 files changed, 6 insertions(+), 2 deletions(-)
 rename src/{companion => main}/resources/mmdlib/screen/base_powered_machine.xml (100%)

diff --git a/src/companion/resources/mmdlib/screen/dual_crusher.xml b/src/companion/resources/mmdlib/screen/dual_crusher.xml
index 875c27c6..89d77f5d 100644
--- a/src/companion/resources/mmdlib/screen/dual_crusher.xml
+++ b/src/companion/resources/mmdlib/screen/dual_crusher.xml
@@ -1,5 +1,5 @@
 <screen xmlns="https://moddev.zone/mmdlib/screen" title="block.mmdlib_companion.dual_crusher" title-fallback="Dual Crusher"
-        block-entity="zone.moddev.mc.companion.ProcessorEntity" extends="mmdlib_companion:base_powered_machine">
+        block-entity="zone.moddev.mc.companion.ProcessorEntity" extends="mmdlib:base_powered_machine">
   <fill name="machine">
     <spacer/>
     <slot id="input" index="0"/>
diff --git a/src/companion/resources/mmdlib/screen/transmuter.xml b/src/companion/resources/mmdlib/screen/transmuter.xml
index 60cadb8b..a2c32bf9 100644
--- a/src/companion/resources/mmdlib/screen/transmuter.xml
+++ b/src/companion/resources/mmdlib/screen/transmuter.xml
@@ -1,5 +1,5 @@
 <screen xmlns="https://moddev.zone/mmdlib/screen" title="block.mmdlib_companion.transmuter" title-fallback="Iron-to-Gold Converter"
-        block-entity="zone.moddev.mc.companion.ProcessorEntity" extends="mmdlib_companion:base_powered_machine">
+        block-entity="zone.moddev.mc.companion.ProcessorEntity" extends="mmdlib:base_powered_machine">
   <fill name="heading">
     <label text="screen.mmdlib_companion.single" text-fallback="One iron in, one gold out"/>
   </fill>
diff --git a/src/companion/resources/mmdlib/screen/base_powered_machine.xml b/src/main/resources/mmdlib/screen/base_powered_machine.xml
similarity index 100%
rename from src/companion/resources/mmdlib/screen/base_powered_machine.xml
rename to src/main/resources/mmdlib/screen/base_powered_machine.xml
diff --git a/src/test/java/zone/moddev/mc/lib/gui/ScreenLoaderTest.java b/src/test/java/zone/moddev/mc/lib/gui/ScreenLoaderTest.java
index 03cb7018..fc605c6e 100644
--- a/src/test/java/zone/moddev/mc/lib/gui/ScreenLoaderTest.java
+++ b/src/test/java/zone/moddev/mc/lib/gui/ScreenLoaderTest.java
@@ -450,6 +450,10 @@ void settingsExpandAndCollapseThePanelAndInventory() throws Exception {
   private static java.util.Map<ResourceLocation, Screen> companionScreens() {
     return zone.moddev.mc.lib.gui.load.ScreenLoader.read(
         java.util.List.of(
+            new zone.moddev.mc.lib.common.loading.DefinitionLoader.SourceRoot(
+                "mmdlib",
+                java.nio.file.Path.of("src/main/resources/mmdlib"),
+                ScreenLoaderTest.class.getClassLoader()),
             new zone.moddev.mc.lib.common.loading.DefinitionLoader.SourceRoot(
                 "mmdlib_companion",
                 java.nio.file.Path.of("src/companion/resources/mmdlib"),

From d7ae4169b6cdef5dc4ce227b9915f9a699bce25e Mon Sep 17 00:00:00 2001
From: Face o' Cat <face@modcrafters.net>
Date: Sat, 7 Nov 2026 12:18:56 +0200
Subject: [PATCH 4/9] Add shared powered machine entity and migrate companion
 machines

---
 .../moddev/mc/companion/CompanionMod.java     |   7 +-
 .../mc/companion/CreativePowerEntity.java     |  59 ++---
 .../zone/moddev/mc/companion/DemoBlock.java   |  11 +-
 .../zone/moddev/mc/companion/DemoEntity.java  |  48 ----
 .../moddev/mc/companion/ProcessorEntity.java  | 109 ++-------
 .../mc/companion/test/CompanionGameTests.java |  68 +++++-
 .../mc/lib/gui/load/ScreenTemplates.java      |   7 +-
 .../mc/lib/machine/feature/FeatureHost.java   |   8 +
 .../machine/neoforge/BasePoweredMachine.java  | 227 ++++++++++++++++++
 .../neoforge/MachineInventoryLifecycle.java   |   4 +
 .../mmdlib/screen/base_powered_machine.xml    |   3 +-
 .../mc/lib/gui/ScreenInheritanceTest.java     |  28 +++
 12 files changed, 389 insertions(+), 190 deletions(-)
 delete mode 100644 src/companion/java/zone/moddev/mc/companion/DemoEntity.java
 create mode 100644 src/main/java/zone/moddev/mc/lib/machine/neoforge/BasePoweredMachine.java

diff --git a/src/companion/java/zone/moddev/mc/companion/CompanionMod.java b/src/companion/java/zone/moddev/mc/companion/CompanionMod.java
index 218889ef..3952c106 100644
--- a/src/companion/java/zone/moddev/mc/companion/CompanionMod.java
+++ b/src/companion/java/zone/moddev/mc/companion/CompanionMod.java
@@ -29,6 +29,7 @@
 import zone.moddev.mc.lib.api.MaterialExtensions;
 import zone.moddev.mc.lib.api.capabilities.MachineCapabilities;
 import zone.moddev.mc.lib.gui.runtime.ScreenClick;
+import zone.moddev.mc.lib.machine.neoforge.BasePoweredMachine;
 import zone.moddev.mc.lib.machine.neoforge.MachineRecipeTypes;
 import zone.moddev.mc.lib.machine.recipe.MachineRecipeType;
 
@@ -187,7 +188,7 @@ public static ResourceLocation id(String path) {
   /** Each block has its own type and XML screen, while processors share one implementation. */
   public static final class Machine {
     public final DeferredHolder<Block, DemoBlock> block;
-    public final DeferredHolder<BlockEntityType<?>, BlockEntityType<DemoEntity>> type;
+    public final DeferredHolder<BlockEntityType<?>, BlockEntityType<BasePoweredMachine>> type;
     private final ProcessorEntity.Kind kind;
 
     private Machine(String name, ProcessorEntity.Kind kind) {
@@ -205,11 +206,11 @@ private Machine(String name, ProcessorEntity.Kind kind) {
       ITEMS.register(name, () -> new BlockItem(block.get(), new Item.Properties()));
     }
 
-    private BlockEntityType<DemoEntity> entityType() {
+    private BlockEntityType<BasePoweredMachine> entityType() {
       return type.get();
     }
 
-    private DemoEntity create(BlockPos pos, BlockState state) {
+    private BasePoweredMachine create(BlockPos pos, BlockState state) {
       return kind == null
           ? new CreativePowerEntity(type.get(), pos, state)
           : new ProcessorEntity(type.get(), pos, state, kind);
diff --git a/src/companion/java/zone/moddev/mc/companion/CreativePowerEntity.java b/src/companion/java/zone/moddev/mc/companion/CreativePowerEntity.java
index faa9d4c8..3167c694 100644
--- a/src/companion/java/zone/moddev/mc/companion/CreativePowerEntity.java
+++ b/src/companion/java/zone/moddev/mc/companion/CreativePowerEntity.java
@@ -2,10 +2,8 @@
 
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
-import net.minecraft.core.HolderLookup;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.network.chat.Component;
-import net.minecraft.world.Clearable;
 import net.minecraft.world.level.Level;
 import net.minecraft.world.level.block.entity.BlockEntityType;
 import net.minecraft.world.level.block.state.BlockState;
@@ -18,18 +16,17 @@
 import zone.moddev.mc.lib.api.capabilities.IoMode;
 import zone.moddev.mc.lib.api.capabilities.ItemStorage;
 import zone.moddev.mc.lib.api.capabilities.SideConfig;
-import zone.moddev.mc.lib.common.runtime.DropsContents;
-import zone.moddev.mc.lib.gui.runtime.ScreenHost;
+import zone.moddev.mc.lib.machine.neoforge.BasePoweredMachine;
+import zone.moddev.mc.lib.machine.neoforge.MachineInventoryLifecycle;
 
 /** Refills each tick and supplies up to 1,000 FE per adjacent face per tick. */
-public final class CreativePowerEntity extends DemoEntity
-    implements ScreenHost, DropsContents, Clearable {
+public final class CreativePowerEntity extends BasePoweredMachine {
   private final ItemStorage empty = new ItemStorage(0);
   public final AutomationInventory automation;
+  private final MachineInventoryLifecycle inventoryLifecycle;
 
   public CreativePowerEntity(BlockEntityType<?> type, BlockPos pos, BlockState state) {
-    super(type, pos, state);
-    energy.setRates(0, 1_000);
+    super(type, pos, state, 100_000, 0, 1_000);
     energy.setStored(energy.capacity());
     var group =
         new ResourceGroup<>(
@@ -46,12 +43,17 @@ public CreativePowerEntity(BlockEntityType<?> type, BlockPos pos, BlockState sta
             .energy(group, energy)
             .build()
             .automation();
+    inventoryLifecycle = poweredInventory(automation);
     zone.moddev.mc.lib.gui.runtime.ScreenInventoryValidation.validate(this);
   }
 
   @Override
-  public void serverTick() {
+  protected void beforeMachineTick() {
     energy.insert(energy.space(), false);
+  }
+
+  @Override
+  protected void afterMachineTick() {
     for (var side : Direction.values()) {
       if (!automation.mode(ResourceType.ENERGY, 0, side).canExtract()) continue;
       var target = worldPosition.relative(side);
@@ -68,44 +70,23 @@ public ItemStorage screenItems() {
     return empty;
   }
 
-  @Override
-  public AutomationInventory screenAutomation() {
-    return automation;
-  }
-
   @Override
   public boolean screenAutomationAddons() {
     return false;
   }
 
   @Override
-  protected void saveAdditional(CompoundTag tag, HolderLookup.Provider registries) {
-    super.saveAdditional(tag, registries);
-    tag.put("automation", automation.save(registries));
-  }
-
-  @Override
-  protected void loadAdditional(CompoundTag tag, HolderLookup.Provider registries) {
-    super.loadAdditional(tag, registries);
-    if (tag.contains("automation")) automation.load(tag.getCompound("automation"), registries);
-  }
-
-  @Override
-  public void dropContents(Level level, BlockPos pos) {
-    automation.dropAll(
-        payload ->
-            net.minecraft.world.Containers.dropItemStack(
-                level,
-                pos.getX() + .5,
-                pos.getY() + .5,
-                pos.getZ() + .5,
-                RecoveryCapsuleItem.create(payload)));
+  protected MachineInventoryLifecycle machineInventory() {
+    return inventoryLifecycle;
   }
 
   @Override
-  public void clearContent() {
-    automation.clear();
-    energy.setStored(0);
-    setChanged();
+  protected void recoverResources(Level level, BlockPos pos, CompoundTag payload) {
+    net.minecraft.world.Containers.dropItemStack(
+        level,
+        pos.getX() + .5,
+        pos.getY() + .5,
+        pos.getZ() + .5,
+        RecoveryCapsuleItem.create(payload));
   }
 }
diff --git a/src/companion/java/zone/moddev/mc/companion/DemoBlock.java b/src/companion/java/zone/moddev/mc/companion/DemoBlock.java
index 93bf4fa2..85c947ed 100644
--- a/src/companion/java/zone/moddev/mc/companion/DemoBlock.java
+++ b/src/companion/java/zone/moddev/mc/companion/DemoBlock.java
@@ -28,14 +28,14 @@
 import net.neoforged.neoforge.fluids.FluidUtil;
 
 import zone.moddev.mc.lib.common.runtime.DropsContents;
-import zone.moddev.mc.lib.gui.runtime.ScreenRuntime;
+import zone.moddev.mc.lib.machine.neoforge.BasePoweredMachine;
 
 /** Explicit block hooks for a code-registered machine. */
 public final class DemoBlock extends Block implements EntityBlock {
   public static final DirectionProperty FACING = BlockStateProperties.HORIZONTAL_FACING;
-  private final Supplier<BlockEntityType<DemoEntity>> type;
+  private final Supplier<BlockEntityType<BasePoweredMachine>> type;
 
-  public DemoBlock(Properties properties, Supplier<BlockEntityType<DemoEntity>> type) {
+  public DemoBlock(Properties properties, Supplier<BlockEntityType<BasePoweredMachine>> type) {
     super(properties);
     this.type = type;
     registerDefaultState(stateDefinition.any().setValue(FACING, Direction.NORTH));
@@ -86,7 +86,7 @@ public BlockEntity newBlockEntity(BlockPos pos, BlockState state) {
   public <T extends BlockEntity> BlockEntityTicker<T> getTicker(
       Level level, BlockState state, BlockEntityType<T> requested) {
     if (level.isClientSide() || requested != type.get()) return null;
-    return (world, pos, blockState, entity) -> ((DemoEntity) entity).serverTick();
+    return (world, pos, blockState, entity) -> ((BasePoweredMachine) entity).serverTick();
   }
 
   @Override
@@ -122,7 +122,8 @@ protected ItemInteractionResult useItemOn(
   @Override
   protected InteractionResult useWithoutItem(
       BlockState state, Level level, BlockPos pos, Player player, BlockHitResult hit) {
-    return ScreenRuntime.open(player, level.getBlockEntity(pos))
+    return level.getBlockEntity(pos) instanceof BasePoweredMachine machine
+            && machine.openScreen(player)
         ? InteractionResult.sidedSuccess(level.isClientSide())
         : InteractionResult.PASS;
   }
diff --git a/src/companion/java/zone/moddev/mc/companion/DemoEntity.java b/src/companion/java/zone/moddev/mc/companion/DemoEntity.java
deleted file mode 100644
index 23f28794..00000000
--- a/src/companion/java/zone/moddev/mc/companion/DemoEntity.java
+++ /dev/null
@@ -1,48 +0,0 @@
-package zone.moddev.mc.companion;
-
-import net.minecraft.core.BlockPos;
-import net.minecraft.core.HolderLookup;
-import net.minecraft.nbt.CompoundTag;
-import net.minecraft.world.level.block.entity.BlockEntity;
-import net.minecraft.world.level.block.entity.BlockEntityType;
-import net.minecraft.world.level.block.state.BlockState;
-
-import zone.moddev.mc.lib.api.capabilities.EnergyBuffer;
-
-public abstract class DemoEntity extends BlockEntity {
-  public final EnergyBuffer energy = new EnergyBuffer(100_000, 1_000, 0).onChange(this::setChanged);
-
-  protected DemoEntity(BlockEntityType<?> type, BlockPos pos, BlockState state) {
-    super(type, pos, state);
-  }
-
-  public abstract void serverTick();
-
-  public net.minecraft.core.Direction facing() {
-    return zone.moddev.mc.lib.api.capabilities.RelativeFace.facing(getBlockState());
-  }
-
-  public java.util.List<? extends zone.moddev.mc.lib.api.stats.StatsProvider> screenStats() {
-    return java.util.List.of(energy);
-  }
-
-  public long getEnergy() {
-    return energy.stored();
-  }
-
-  public long getEnergyCapacity() {
-    return energy.capacity();
-  }
-
-  @Override
-  protected void saveAdditional(CompoundTag tag, HolderLookup.Provider registries) {
-    super.saveAdditional(tag, registries);
-    tag.put("energy", energy.serializeNBT(registries));
-  }
-
-  @Override
-  protected void loadAdditional(CompoundTag tag, HolderLookup.Provider registries) {
-    super.loadAdditional(tag, registries);
-    if (tag.contains("energy")) energy.deserializeNBT(registries, tag.get("energy"));
-  }
-}
diff --git a/src/companion/java/zone/moddev/mc/companion/ProcessorEntity.java b/src/companion/java/zone/moddev/mc/companion/ProcessorEntity.java
index f0aa42fd..7b55c7a4 100644
--- a/src/companion/java/zone/moddev/mc/companion/ProcessorEntity.java
+++ b/src/companion/java/zone/moddev/mc/companion/ProcessorEntity.java
@@ -7,11 +7,7 @@
 import net.minecraft.core.HolderLookup;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.network.chat.Component;
-import net.minecraft.network.protocol.Packet;
-import net.minecraft.network.protocol.game.ClientGamePacketListener;
-import net.minecraft.network.protocol.game.ClientboundBlockEntityDataPacket;
 import net.minecraft.resources.ResourceLocation;
-import net.minecraft.world.Clearable;
 import net.minecraft.world.level.Level;
 import net.minecraft.world.level.block.entity.BlockEntityType;
 import net.minecraft.world.level.block.state.BlockState;
@@ -26,17 +22,13 @@
 import zone.moddev.mc.lib.api.capabilities.Role;
 import zone.moddev.mc.lib.api.redstone.RedstoneControl;
 import zone.moddev.mc.lib.api.redstone.RedstoneOutput;
-import zone.moddev.mc.lib.common.runtime.DropsContents;
-import zone.moddev.mc.lib.gui.runtime.ScreenHost;
-import zone.moddev.mc.lib.machine.feature.FeatureHost;
 import zone.moddev.mc.lib.machine.feature.RecipeProcessor;
-import zone.moddev.mc.lib.machine.neoforge.FeatureSync;
+import zone.moddev.mc.lib.machine.neoforge.BasePoweredMachine;
 import zone.moddev.mc.lib.machine.neoforge.MachineInventoryLifecycle;
 import zone.moddev.mc.lib.machine.neoforge.MachineResources;
 
 /** The dual crusher deliberately runs two lanes over the same input and output groups. */
-public final class ProcessorEntity extends DemoEntity
-    implements ScreenHost, DropsContents, Clearable {
+public final class ProcessorEntity extends BasePoweredMachine {
   public enum Kind {
     CRUSHER,
     TRANSMUTER,
@@ -50,8 +42,6 @@ public enum Kind {
   public final MachineInventoryLifecycle inventoryLifecycle;
   public final FluidStorage fluids = new FluidStorage().onChange(this::setChanged);
   public final List<RecipeProcessor> lanes;
-  public final FeatureHost features =
-      new FeatureHost(this::setChanged, () -> FeatureSync.send(this));
   private final Kind kind;
   public final RedstoneControl redstone;
   private String machineName = "Crusher";
@@ -159,10 +149,7 @@ public ProcessorEntity(BlockEntityType<?> type, BlockPos pos, BlockState state,
     }
     lanes = List.copyOf(processors);
     inventoryLifecycle =
-        new MachineInventoryLifecycle(this, features, automation, energy)
-            .items("items", items)
-            .fluids("fluids", fluids)
-            .energy("energy", energy);
+        poweredInventory(automation).items("items", items).fluids("fluids", fluids);
     var outputParts = new ArrayList<Object>();
     for (var group : automation.groups())
       outputParts.add(
@@ -217,25 +204,6 @@ public RedstoneControl screenRedstone() {
     return redstone;
   }
 
-  @Override
-  public FeatureHost screenFeatures() {
-    return features;
-  }
-
-  public AutomationInventory screenAutomation() {
-    return automation;
-  }
-
-  @Override
-  public void serverTick() {
-    redstone.readInputs();
-    inventoryLifecycle.tick(
-        kind != Kind.LOGISTICS && energy.stored() >= energy.capacity() * reservePercent / 100,
-        !redstoneAllowsRun(),
-        MachineInventoryLifecycle.PausePolicy.PROCESSING_ONLY);
-    redstone.updateOutputs();
-  }
-
   public FluidStack getTank1() {
     return fluids.getFluidInTank(1);
   }
@@ -258,18 +226,6 @@ public void toggle(int index) {
     features.setProcessorPaused(processor.key(), !processor.paused());
   }
 
-  public int getProgress() {
-    return lanes.getFirst().progress();
-  }
-
-  @Override
-  public List<zone.moddev.mc.lib.api.stats.StatsProvider> screenStats() {
-    var parts = new ArrayList<zone.moddev.mc.lib.api.stats.StatsProvider>();
-    parts.add(energy);
-    parts.addAll(lanes);
-    return List.copyOf(parts);
-  }
-
   public boolean hasTank() {
     return fluids.getTanks() > 0;
   }
@@ -282,10 +238,6 @@ public int getTankCapacity() {
     return fluids.getTankCapacity(0);
   }
 
-  public int getTime() {
-    return lanes.getFirst().time();
-  }
-
   public int getSecondProgress() {
     return lanes.size() == 2 ? lanes.get(1).progress() : 0;
   }
@@ -294,10 +246,6 @@ public int getSecondTime() {
     return lanes.size() == 2 ? lanes.get(1).time() : 0;
   }
 
-  public boolean getPaused() {
-    return lanes.getFirst().paused();
-  }
-
   public List<Component> getWarnings() {
     var warnings = new ArrayList<Component>();
     if (energy.stored() < energy.capacity() * reservePercent / 100)
@@ -333,41 +281,13 @@ public int[] screenRecipeSlots(ResourceLocation category) {
   }
 
   @Override
-  public void dropContents(Level level, BlockPos pos) {
-    inventoryLifecycle.dropContents(
-        payload ->
-            net.minecraft.world.Containers.dropItemStack(
-                level,
-                pos.getX() + .5,
-                pos.getY() + .5,
-                pos.getZ() + .5,
-                RecoveryCapsuleItem.create(payload)));
-  }
-
-  @Override
-  public void clearContent() {
-    inventoryLifecycle.clear();
-    FeatureSync.send(this);
-  }
-
-  @Override
-  protected void saveAdditional(CompoundTag tag, HolderLookup.Provider registries) {
-    super.saveAdditional(tag, registries);
-    inventoryLifecycle.save(tag, registries);
-    tag.put("redstone_control", redstone.save(registries));
+  protected void saveMachineData(CompoundTag tag, HolderLookup.Provider registries) {
     tag.putString("machine_name", machineName);
     tag.putInt("reserve_percent", reservePercent);
   }
 
   @Override
-  protected void loadAdditional(CompoundTag tag, HolderLookup.Provider registries) {
-    if (FeatureSync.read(features, tag, registries)) return;
-    super.loadAdditional(tag, registries);
-    int savedMode = tag.getInt("redstone_mode");
-    int redstoneMode = savedMode >= 0 && savedMode <= 2 ? savedMode : 0;
-    if (tag.contains("redstone_control"))
-      redstone.load(tag.getCompound("redstone_control"), registries);
-    else redstone.migrate(redstoneMode);
+  protected void loadMachineData(CompoundTag tag, HolderLookup.Provider registries) {
     String savedName = tag.getString("machine_name");
     machineName =
         !savedName.isBlank()
@@ -376,16 +296,25 @@ protected void loadAdditional(CompoundTag tag, HolderLookup.Provider registries)
             ? savedName.strip()
             : "Crusher";
     reservePercent = Math.clamp(tag.getInt("reserve_percent"), 0, 100);
-    inventoryLifecycle.load(tag, registries);
   }
 
   @Override
-  public CompoundTag getUpdateTag(HolderLookup.Provider registries) {
-    return FeatureSync.updateTag(features, registries);
+  protected MachineInventoryLifecycle machineInventory() {
+    return inventoryLifecycle;
+  }
+
+  @Override
+  protected boolean processingAllowed() {
+    return kind != Kind.LOGISTICS && energy.stored() >= energy.capacity() * reservePercent / 100;
   }
 
   @Override
-  public Packet<ClientGamePacketListener> getUpdatePacket() {
-    return ClientboundBlockEntityDataPacket.create(this);
+  protected void recoverResources(Level level, BlockPos pos, CompoundTag payload) {
+    net.minecraft.world.Containers.dropItemStack(
+        level,
+        pos.getX() + .5,
+        pos.getY() + .5,
+        pos.getZ() + .5,
+        RecoveryCapsuleItem.create(payload));
   }
 }
diff --git a/src/companionTest/java/zone/moddev/mc/companion/test/CompanionGameTests.java b/src/companionTest/java/zone/moddev/mc/companion/test/CompanionGameTests.java
index 7db1c673..718b6d92 100644
--- a/src/companionTest/java/zone/moddev/mc/companion/test/CompanionGameTests.java
+++ b/src/companionTest/java/zone/moddev/mc/companion/test/CompanionGameTests.java
@@ -38,6 +38,71 @@
 public final class CompanionGameTests {
   private static final BlockPos CENTER = new BlockPos(2, 2, 2);
 
+  @GameTest(template = "empty")
+  public static void poweredBasePreservesSavesAndSeparatesFeatureUpdates(GameTestHelper helper) {
+    var level = helper.getLevel();
+    var registries = level.registryAccess();
+    var pos = helper.absolutePos(CENTER);
+    for (var definition :
+        java.util.List.of(
+            CompanionMod.CRUSHER,
+            CompanionMod.TRANSMUTER,
+            CompanionMod.DUAL_CRUSHER,
+            CompanionMod.LOGISTICS,
+            CompanionMod.CREATIVE_POWER)) {
+      level.setBlock(pos, definition.block.get().defaultBlockState(), 3);
+      var machine =
+          (zone.moddev.mc.lib.machine.neoforge.BasePoweredMachine) level.getBlockEntity(pos);
+      machine.energy.setStored(7_321);
+      require(
+          machine.getEnergy() == 7_321 && machine.getEnergyCapacity() == 100_000,
+          "Shared getters expose the owned buffer");
+      require(
+          machine.screenFeatures() == machine.features
+              && machine.screenStats().getFirst() == machine.energy,
+          "Screen features and statistics use the same owned parts");
+      if (machine instanceof ProcessorEntity processor) {
+        processor.items.insertItem(0, new ItemStack(Items.IRON_INGOT), false);
+        processor.setReservePercent(25);
+        processor.features.setProcessorPaused("lane_0", true);
+        processor.redstone.migrate(1);
+      }
+      var saved = machine.saveWithFullMetadata(registries);
+      var copy =
+          (zone.moddev.mc.lib.machine.neoforge.BasePoweredMachine)
+              BlockEntity.loadStatic(pos, machine.getBlockState(), saved, registries);
+      require(copy.getEnergy() == 7_321, "Power survives a full save/load for every machine");
+      if (copy instanceof ProcessorEntity processor) {
+        require(
+            processor.getPaused() && processor.getReservePercent() == 25,
+            "Base feature state and subclass metadata both survive loading");
+        require(
+            processor.redstone.save(registries).equals(saved.getCompound("redstone_control")),
+            "Redstone configuration survives loading");
+      }
+      var beforeUpdate = copy.saveWithFullMetadata(registries);
+      copy.loadWithComponents(machine.getUpdateTag(registries), registries);
+      var afterUpdate = copy.saveWithFullMetadata(registries);
+      for (var key :
+          java.util.List.of(
+              "energy",
+              "items",
+              "fluids",
+              "automation",
+              "redstone_control",
+              "machine_name",
+              "reserve_percent"))
+        require(
+            java.util.Objects.equals(beforeUpdate.get(key), afterUpdate.get(key)),
+            "Feature update preserves " + key);
+      copy.clearContent();
+      require(copy.getEnergy() == 0, "Shared clear resets owned power");
+      machine.clearContent();
+      level.setBlock(pos, Blocks.AIR.defaultBlockState(), 3);
+    }
+    helper.succeed();
+  }
+
   @GameTest(template = "empty")
   public static void keylessProcessorButtonSamplesAndTogglesTheFirstProcessor(GameTestHelper helper)
       throws ReflectiveOperationException {
@@ -845,7 +910,8 @@ public static void placementFacingKeepsNeighboursAndPortsOnTheSameSide(GameTestH
             state.getValue(zone.moddev.mc.companion.DemoBlock.FACING) == look.getOpposite(),
             "Placed machine faces its player: " + look);
         level.setBlock(pos, state, 3);
-        var entity = (zone.moddev.mc.companion.DemoEntity) level.getBlockEntity(pos);
+        var entity =
+            (zone.moddev.mc.lib.machine.neoforge.BasePoweredMachine) level.getBlockEntity(pos);
         var host = (zone.moddev.mc.lib.gui.runtime.ScreenHost) entity;
         for (var group : host.screenAutomation().groups())
           require(
diff --git a/src/main/java/zone/moddev/mc/lib/gui/load/ScreenTemplates.java b/src/main/java/zone/moddev/mc/lib/gui/load/ScreenTemplates.java
index 71e35cf7..3c074bf2 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/load/ScreenTemplates.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/load/ScreenTemplates.java
@@ -53,8 +53,9 @@ Node resolve(ResourceLocation id) {
         if (!used.contains(entry.getKey()))
           throw error(entry.getValue(), "Fill targets a replaced placeholder: " + entry.getKey());
       var attributes = new LinkedHashMap<>(root.attributes());
-      if (!attributes.containsKey("inventory") && base.attributes().containsKey("inventory"))
-        attributes.put("inventory", base.attributes().get("inventory"));
+      for (var attribute : List.of("inventory", "block-entity"))
+        if (!attributes.containsKey(attribute) && base.attributes().containsKey(attribute))
+          attributes.put(attribute, base.attributes().get(attribute));
       result = new Node(root.name(), attributes, children, root.source(), root.line());
     } else {
       for (var child : root.children())
@@ -63,7 +64,7 @@ Node resolve(ResourceLocation id) {
     placeholders(result); // Reject ambiguous names, including newly introduced extension points.
     if (!flag(root, "abstract")) {
       for (var attribute : List.of("title", "block-entity"))
-        if (!root.attributes().containsKey(attribute))
+        if (!result.attributes().containsKey(attribute))
           throw error(root, "A concrete screen requires its own " + attribute);
     }
     visiting.remove(id);
diff --git a/src/main/java/zone/moddev/mc/lib/machine/feature/FeatureHost.java b/src/main/java/zone/moddev/mc/lib/machine/feature/FeatureHost.java
index 07880ec2..e494a609 100644
--- a/src/main/java/zone/moddev/mc/lib/machine/feature/FeatureHost.java
+++ b/src/main/java/zone/moddev/mc/lib/machine/feature/FeatureHost.java
@@ -81,6 +81,14 @@ public java.util.Optional<RecipeProcessor> processor(java.util.Optional<String>
             .findFirst();
   }
 
+  /** Feature statistics in registration order; features without statistics are omitted. */
+  public List<zone.moddev.mc.lib.api.stats.StatsProvider> statisticsProviders() {
+    return features.values().stream()
+        .filter(zone.moddev.mc.lib.api.stats.StatsProvider.class::isInstance)
+        .map(zone.moddev.mc.lib.api.stats.StatsProvider.class::cast)
+        .toList();
+  }
+
   /** Persists and synchronizes manual changes even while the host's processing tick is held. */
   public boolean setProcessorPaused(String key, boolean paused) {
     var processor = processor(key).orElse(null);
diff --git a/src/main/java/zone/moddev/mc/lib/machine/neoforge/BasePoweredMachine.java b/src/main/java/zone/moddev/mc/lib/machine/neoforge/BasePoweredMachine.java
new file mode 100644
index 00000000..c4301c3e
--- /dev/null
+++ b/src/main/java/zone/moddev/mc/lib/machine/neoforge/BasePoweredMachine.java
@@ -0,0 +1,227 @@
+package zone.moddev.mc.lib.machine.neoforge;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import net.minecraft.core.BlockPos;
+import net.minecraft.core.Direction;
+import net.minecraft.core.HolderLookup;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.nbt.NbtOps;
+import net.minecraft.network.protocol.Packet;
+import net.minecraft.network.protocol.game.ClientGamePacketListener;
+import net.minecraft.network.protocol.game.ClientboundBlockEntityDataPacket;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.world.Clearable;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.level.Level;
+import net.minecraft.world.level.block.entity.BlockEntity;
+import net.minecraft.world.level.block.entity.BlockEntityType;
+import net.minecraft.world.level.block.state.BlockState;
+
+import zone.moddev.mc.lib.api.automation.AutomationInventory;
+import zone.moddev.mc.lib.api.capabilities.EnergyBuffer;
+import zone.moddev.mc.lib.api.capabilities.RelativeFace;
+import zone.moddev.mc.lib.api.stats.StatsProvider;
+import zone.moddev.mc.lib.common.runtime.DropsContents;
+import zone.moddev.mc.lib.gui.runtime.ScreenHost;
+import zone.moddev.mc.lib.gui.runtime.ScreenRuntime;
+import zone.moddev.mc.lib.machine.feature.FeatureHost;
+import zone.moddev.mc.lib.machine.feature.RecipeProcessor;
+
+/**
+ * Shared power, features, persistence and screen contract for code-defined machines. Concrete
+ * screen XML can extend {@code mmdlib:base_powered_machine}; inherited getters and the keyless
+ * processor button work without per-machine bindings. Slot/tank definitions, recipes, capabilities
+ * and block registration remain the consumer's choices.
+ */
+public abstract class BasePoweredMachine extends BlockEntity
+    implements ScreenHost, DropsContents, Clearable {
+  public static final ResourceLocation SCREEN_TEMPLATE =
+      ResourceLocation.parse("mmdlib:base_powered_machine");
+
+  public final EnergyBuffer energy;
+  public final FeatureHost features =
+      new FeatureHost(this::setChanged, () -> FeatureSync.send(this));
+
+  protected BasePoweredMachine(BlockEntityType<?> type, BlockPos pos, BlockState state) {
+    this(type, pos, state, 100_000, 1_000, 0);
+  }
+
+  protected BasePoweredMachine(
+      BlockEntityType<?> type,
+      BlockPos pos,
+      BlockState state,
+      long capacity,
+      long maxInput,
+      long maxOutput) {
+    super(type, pos, state);
+    energy = new EnergyBuffer(capacity, maxInput, maxOutput).onChange(this::setChanged);
+  }
+
+  public Direction facing() {
+    return RelativeFace.facing(getBlockState());
+  }
+
+  public long getEnergy() {
+    return energy.stored();
+  }
+
+  public long getEnergyCapacity() {
+    return energy.capacity();
+  }
+
+  public int getProgress() {
+    return features.processor(java.util.Optional.empty()).map(RecipeProcessor::progress).orElse(0);
+  }
+
+  public int getTime() {
+    return features.processor(java.util.Optional.empty()).map(RecipeProcessor::time).orElse(0);
+  }
+
+  public boolean getPaused() {
+    return features
+        .processor(java.util.Optional.empty())
+        .map(RecipeProcessor::paused)
+        .orElse(false);
+  }
+
+  @Override
+  public final FeatureHost screenFeatures() {
+    return features;
+  }
+
+  @Override
+  public List<? extends StatsProvider> screenStats() {
+    var parts = new ArrayList<StatsProvider>();
+    parts.add(energy);
+    parts.addAll(features.statisticsProviders());
+    return List.copyOf(parts);
+  }
+
+  /** Opens the concrete screen registered under this entity type's ID. */
+  public final boolean openScreen(Player player) {
+    return ScreenRuntime.open(player, this);
+  }
+
+  /**
+   * Return the lifecycle configured by the subclass after its inventories are constructed. It must
+   * include this machine's energy buffer under the save key {@code energy}. Without a lifecycle,
+   * the base persists energy and features only.
+   */
+  protected MachineInventoryLifecycle machineInventory() {
+    return null;
+  }
+
+  /** Starts a lifecycle with this base's power storage and feature host already wired. */
+  protected final MachineInventoryLifecycle poweredInventory(AutomationInventory automation) {
+    return new MachineInventoryLifecycle(this, features, automation, energy)
+        .energy("energy", energy);
+  }
+
+  @Override
+  public AutomationInventory screenAutomation() {
+    var inventory = machineInventory();
+    return inventory == null ? null : inventory.automation();
+  }
+
+  protected boolean processingAllowed() {
+    return true;
+  }
+
+  protected MachineInventoryLifecycle.PausePolicy pausePolicy() {
+    return MachineInventoryLifecycle.PausePolicy.PROCESSING_ONLY;
+  }
+
+  protected void beforeMachineTick() {}
+
+  protected void afterMachineTick() {}
+
+  public final void serverTick() {
+    if (level == null || level.isClientSide) return;
+    var redstone = screenRedstone();
+    if (redstone != null) redstone.readInputs();
+    beforeMachineTick();
+    boolean paused = redstone != null && redstone.paused();
+    var inventory = machineInventory();
+    if (inventory != null) inventory.tick(processingAllowed(), paused, pausePolicy());
+    else features.tick(level, processingAllowed() && pausePolicy().processingEnabled(paused));
+    afterMachineTick();
+    if (redstone != null) redstone.updateOutputs();
+  }
+
+  /** Additional machine metadata; common inventories/features/redstone are already saved. */
+  protected void saveMachineData(CompoundTag tag, HolderLookup.Provider registries) {}
+
+  /** Additional machine metadata; never called for a feature-only client update. */
+  protected void loadMachineData(CompoundTag tag, HolderLookup.Provider registries) {}
+
+  @Override
+  protected final void saveAdditional(CompoundTag tag, HolderLookup.Provider registries) {
+    super.saveAdditional(tag, registries);
+    var inventory = machineInventory();
+    if (inventory != null) inventory.save(tag, registries);
+    else {
+      tag.put("energy", energy.serializeNBT(registries));
+      tag.put("features", features.save(registries.createSerializationContext(NbtOps.INSTANCE)));
+    }
+    var redstone = screenRedstone();
+    if (redstone != null) tag.put("redstone_control", redstone.save(registries));
+    saveMachineData(tag, registries);
+  }
+
+  @Override
+  protected final void loadAdditional(CompoundTag tag, HolderLookup.Provider registries) {
+    if (FeatureSync.read(features, tag, registries)) return;
+    super.loadAdditional(tag, registries);
+    var inventory = machineInventory();
+    if (inventory != null) inventory.load(tag, registries);
+    else {
+      features.reset();
+      if (tag.contains("energy")) energy.deserializeNBT(registries, tag.get("energy"));
+      if (tag.contains("features"))
+        features.load(registries.createSerializationContext(NbtOps.INSTANCE), tag.get("features"));
+    }
+    var redstone = screenRedstone();
+    if (redstone != null) {
+      if (tag.contains("redstone_control"))
+        redstone.load(tag.getCompound("redstone_control"), registries);
+      else {
+        int mode = tag.getInt("redstone_mode");
+        redstone.migrate(mode >= 0 && mode <= 2 ? mode : 0);
+      }
+    }
+    loadMachineData(tag, registries);
+  }
+
+  @Override
+  public final CompoundTag getUpdateTag(HolderLookup.Provider registries) {
+    return FeatureSync.updateTag(features, registries);
+  }
+
+  @Override
+  public final Packet<ClientGamePacketListener> getUpdatePacket() {
+    return ClientboundBlockEntityDataPacket.create(this);
+  }
+
+  @Override
+  public void clearContent() {
+    var inventory = machineInventory();
+    if (inventory != null) inventory.clear();
+    else {
+      features.reset();
+      energy.setStored(0);
+      setChanged();
+    }
+    FeatureSync.send(this);
+  }
+
+  @Override
+  public void dropContents(Level level, BlockPos pos) {
+    var inventory = machineInventory();
+    if (inventory != null) inventory.dropContents(payload -> recoverResources(level, pos, payload));
+  }
+
+  /** Preserve displaced resources in a consumer-owned recovery item or equivalent durable sink. */
+  protected abstract void recoverResources(Level level, BlockPos pos, CompoundTag payload);
+}
diff --git a/src/main/java/zone/moddev/mc/lib/machine/neoforge/MachineInventoryLifecycle.java b/src/main/java/zone/moddev/mc/lib/machine/neoforge/MachineInventoryLifecycle.java
index 125d4e07..c3c38020 100644
--- a/src/main/java/zone/moddev/mc/lib/machine/neoforge/MachineInventoryLifecycle.java
+++ b/src/main/java/zone/moddev/mc/lib/machine/neoforge/MachineInventoryLifecycle.java
@@ -64,6 +64,10 @@ public MachineInventoryLifecycle energy(String saveKey, EnergyBuffer storage) {
     return add(saveKey, storage);
   }
 
+  public AutomationInventory automation() {
+    return automation;
+  }
+
   private MachineInventoryLifecycle add(String key, Object storage) {
     Objects.requireNonNull(storage);
     if (key == null
diff --git a/src/main/resources/mmdlib/screen/base_powered_machine.xml b/src/main/resources/mmdlib/screen/base_powered_machine.xml
index 93682b98..a8e30cbb 100644
--- a/src/main/resources/mmdlib/screen/base_powered_machine.xml
+++ b/src/main/resources/mmdlib/screen/base_powered_machine.xml
@@ -1,4 +1,5 @@
-<screen xmlns="https://moddev.zone/mmdlib/screen" abstract="true">
+<screen xmlns="https://moddev.zone/mmdlib/screen" abstract="true"
+        block-entity="zone.moddev.mc.lib.machine.neoforge.BasePoweredMachine">
   <vbox padding="7" spacing="4">
     <placeholder name="heading"/>
     <hbox spacing="6" align="center">
diff --git a/src/test/java/zone/moddev/mc/lib/gui/ScreenInheritanceTest.java b/src/test/java/zone/moddev/mc/lib/gui/ScreenInheritanceTest.java
index f9e98533..95eeacfe 100644
--- a/src/test/java/zone/moddev/mc/lib/gui/ScreenInheritanceTest.java
+++ b/src/test/java/zone/moddev/mc/lib/gui/ScreenInheritanceTest.java
@@ -49,6 +49,34 @@ private Map<ResourceLocation, ScreenBinder.Bound> load() {
     return ScreenLoader.load(List.of(source("test")));
   }
 
+  @Test
+  void poweredTemplateSuppliesItsEntityAndCommonBindings() throws Exception {
+    write(
+        "test:powered",
+        "extends=\"mmdlib:base_powered_machine\" title=\"test.powered\"",
+        "<fill name=\"machine\"><progress id=\"progress\" value=\"#getProgress\""
+            + " max=\"#getTime\"/></fill>");
+    var bound =
+        ScreenLoader.load(
+                List.of(
+                    source("test"),
+                    new SourceRoot(
+                        "mmdlib",
+                        Path.of("src/main/resources/mmdlib"),
+                        getClass().getClassLoader())))
+            .get(ResourceLocation.parse("test:powered"));
+    assertEquals(
+        "zone.moddev.mc.lib.machine.neoforge.BasePoweredMachine", bound.screen().blockEntity());
+    for (var id : List.of("energy", "progress")) {
+      var element = bound.screen().find(id).orElseThrow();
+      assertTrue(bound.values().containsKey(element));
+      assertTrue(bound.maxima().containsKey(element));
+    }
+    var button = (Element.Button) bound.screen().find("toggle_0").orElseThrow();
+    assertTrue(button.processorControl());
+    assertTrue(button.processorKey().isEmpty());
+  }
+
   @Test
   void baseProcessorControlNeedsNoMachineSpecificKeyOrFill() throws Exception {
     base(

From 7bcc8e1399c80625459ee110386d5468be151c68 Mon Sep 17 00:00:00 2001
From: Face o' Cat <face@modcrafters.net>
Date: Sat, 7 Nov 2026 12:22:35 +0200
Subject: [PATCH 5/9] Inherit crusher processor controls from powered screen
 base

---
 .../resources/mmdlib/screen/crusher.xml       | 103 +++++++++---------
 .../mmdlib/screen/base_powered_machine.xml    |  18 +--
 .../moddev/mc/lib/gui/ScreenLoaderTest.java   |  63 ++++-------
 3 files changed, 86 insertions(+), 98 deletions(-)

diff --git a/src/companion/resources/mmdlib/screen/crusher.xml b/src/companion/resources/mmdlib/screen/crusher.xml
index 8e0c83b8..7a6f869e 100644
--- a/src/companion/resources/mmdlib/screen/crusher.xml
+++ b/src/companion/resources/mmdlib/screen/crusher.xml
@@ -1,53 +1,54 @@
 <screen xmlns="https://moddev.zone/mmdlib/screen" title="block.mmdlib_companion.crusher" title-fallback="Crusher"
-        block-entity="zone.moddev.mc.companion.ProcessorEntity">
-  <vbox padding="7" spacing="4">
-    <context id="panel">
-    <view id="machine">
-    <hbox spacing="6" align="center">
-      <gauge id="tank" length="3s" value="#getTankFluid" max="#getTankCapacity"
-             tooltip="screen.mmdlib_companion.tank.tip" tooltip-fallback="Water or lava: {value} / {max} mB. Click with a fluid container to transfer."
-             on-click="mmdlib_companion:tank_container" on-right-click="mmdlib_companion:tank_container"/>
-      <spacer/>
-      <slot id="input" index="0"/>
-      <custom id="progress" type="mmdlib_companion:progress_dial" width="24" height="24"
-              value="#getProgress" max="#getTime"
-              on-click="mmdlib_companion:toggle_0"
-              tooltip="screen.mmdlib_companion.progress_dial"
-              tooltip-fallback="Progress: {value} / {max} ticks. Click to pause or resume.">
-        <property name="color" value="#55CC88"/>
-      </custom>
-      <hbox spacing="2">
-        <slot id="output" index="1"/>
-        <slot id="output_2" index="2"/>
-      </hbox>
-      <spacer/>
-      <energy-gauge id="energy" length="3s"/>
-    </hbox>
-    <hbox id="controls" spacing="2" align="center">
-      <button text="screen.mmdlib_companion.recipes" text-fallback="Recipes"
-              tooltip="screen.mmdlib_companion.recipes.tip" tooltip-fallback="Show crushing recipes in JEI, when installed."
-              jei-recipes="mmdlib_companion:crushing"/>
-      <button id="open_settings" text="screen.mmdlib_companion.settings" text-fallback="Settings"
-              tooltip="screen.mmdlib_companion.settings.tip" tooltip-fallback="Edit the machine name, energy reserve and lane state."
-              shows="panel:settings"/>
-      <spacer/>
-    </hbox>
-    </view>
-    <view id="settings" title="screen.mmdlib_companion.settings" title-fallback="Settings">
-      <label text="screen.mmdlib_companion.name" text-fallback="Machine name"/>
-      <custom id="name_editor" type="mmdlib_companion:name_editor" width="162" height="42"
-              value="#getMachineName"/>
-      <custom id="reserve_slider" type="mmdlib_companion:reserve_slider" width="162" height="30"
-              value="#getReservePercent"/>
-      <custom id="lane_selector" type="mmdlib_companion:lane_selector" width="162" height="30"
-              value="#getPaused">
-        <property name="lane" value="0"/>
-      </custom>
-    </view>
-    </context>
-  </vbox>
-  <inventory-controls id="inventory_controls">
-    <processor-button id="toggle_0"/>
-  </inventory-controls>
-  <popout id="info" kind="info" edge="left" text="screen.mmdlib_companion.info.crusher" value="#getWarnings"/>
+        block-entity="zone.moddev.mc.companion.ProcessorEntity" extends="mmdlib:base_powered_machine">
+  <fill name="body">
+    <vbox padding="7" spacing="4">
+      <context id="panel">
+        <view id="machine">
+          <hbox spacing="6" align="center">
+            <gauge id="tank" length="3s" value="#getTankFluid" max="#getTankCapacity"
+                   tooltip="screen.mmdlib_companion.tank.tip" tooltip-fallback="Water or lava: {value} / {max} mB. Click with a fluid container to transfer."
+                   on-click="mmdlib_companion:tank_container" on-right-click="mmdlib_companion:tank_container"/>
+            <spacer/>
+            <slot id="input" index="0"/>
+            <custom id="progress" type="mmdlib_companion:progress_dial" width="24" height="24"
+                    value="#getProgress" max="#getTime"
+                    on-click="mmdlib_companion:toggle_0"
+                    tooltip="screen.mmdlib_companion.progress_dial"
+                    tooltip-fallback="Progress: {value} / {max} ticks. Click to pause or resume.">
+              <property name="color" value="#55CC88"/>
+            </custom>
+            <hbox spacing="2">
+              <slot id="output" index="1"/>
+              <slot id="output_2" index="2"/>
+            </hbox>
+            <spacer/>
+            <energy-gauge id="energy" length="3s"/>
+          </hbox>
+          <hbox id="controls" spacing="2" align="center">
+            <button text="screen.mmdlib_companion.recipes" text-fallback="Recipes"
+                    tooltip="screen.mmdlib_companion.recipes.tip" tooltip-fallback="Show crushing recipes in JEI, when installed."
+                    jei-recipes="mmdlib_companion:crushing"/>
+            <button id="open_settings" text="screen.mmdlib_companion.settings" text-fallback="Settings"
+                    tooltip="screen.mmdlib_companion.settings.tip" tooltip-fallback="Edit the machine name, energy reserve and lane state."
+                    shows="panel:settings"/>
+            <spacer/>
+          </hbox>
+        </view>
+        <view id="settings" title="screen.mmdlib_companion.settings" title-fallback="Settings">
+          <label text="screen.mmdlib_companion.name" text-fallback="Machine name"/>
+          <custom id="name_editor" type="mmdlib_companion:name_editor" width="162" height="42"
+                  value="#getMachineName"/>
+          <custom id="reserve_slider" type="mmdlib_companion:reserve_slider" width="162" height="30"
+                  value="#getReservePercent"/>
+          <custom id="lane_selector" type="mmdlib_companion:lane_selector" width="162" height="30"
+                  value="#getPaused">
+            <property name="lane" value="0"/>
+          </custom>
+        </view>
+      </context>
+    </vbox>
+  </fill>
+  <fill name="info">
+    <popout id="info" kind="info" edge="left" text="screen.mmdlib_companion.info.crusher" value="#getWarnings"/>
+  </fill>
 </screen>
diff --git a/src/main/resources/mmdlib/screen/base_powered_machine.xml b/src/main/resources/mmdlib/screen/base_powered_machine.xml
index a8e30cbb..1be4d82b 100644
--- a/src/main/resources/mmdlib/screen/base_powered_machine.xml
+++ b/src/main/resources/mmdlib/screen/base_powered_machine.xml
@@ -1,13 +1,15 @@
 <screen xmlns="https://moddev.zone/mmdlib/screen" abstract="true"
         block-entity="zone.moddev.mc.lib.machine.neoforge.BasePoweredMachine">
-  <vbox padding="7" spacing="4">
-    <placeholder name="heading"/>
-    <hbox spacing="6" align="center">
-      <placeholder name="machine" required="true"/>
-      <spacer/>
-      <energy-gauge id="energy" length="3s"/>
-    </hbox>
-  </vbox>
+  <placeholder name="body">
+    <vbox padding="7" spacing="4">
+      <placeholder name="heading"/>
+      <hbox spacing="6" align="center">
+        <placeholder name="machine" required="true"/>
+        <spacer/>
+        <energy-gauge id="energy" length="3s"/>
+      </hbox>
+    </vbox>
+  </placeholder>
   <placeholder name="inventory_controls">
     <inventory-controls id="inventory_controls">
       <processor-button id="toggle_0"/>
diff --git a/src/test/java/zone/moddev/mc/lib/gui/ScreenLoaderTest.java b/src/test/java/zone/moddev/mc/lib/gui/ScreenLoaderTest.java
index fc605c6e..db00a85e 100644
--- a/src/test/java/zone/moddev/mc/lib/gui/ScreenLoaderTest.java
+++ b/src/test/java/zone/moddev/mc/lib/gui/ScreenLoaderTest.java
@@ -351,6 +351,11 @@ void companionControlsSitAboveInventoryAtRightMargin() throws Exception {
       require(firstPause.y() == pause.y());
       require(pause.width() == 14 && pause.height() == 14);
       require(((Element.Button) screen.find("toggle_0").orElseThrow()).flat());
+      if (!name.equals("dual_crusher"))
+        require(
+            screen
+                .source(screen.find("toggle_0").orElseThrow().common())
+                .endsWith("base_powered_machine.xml"));
     }
   }
 
@@ -386,17 +391,7 @@ void allCompanionScreensPlaceBatteryAtRightMargin() throws Exception {
 
   @Test
   void crusherPlacesProcessingBeforeRightEnergyGauge() throws Exception {
-    Screen screen;
-    try (var input =
-        java.nio.file.Files.newInputStream(
-            java.nio.file.Path.of("src/companion/resources/mmdlib/screen/crusher.xml"))) {
-      screen =
-          ScreenReader.read(
-              ResourceLocation.parse("mmdlib_companion:crusher"),
-              "crusher.xml",
-              input,
-              companionLayoutWidgets());
-    }
+    var screen = companionScreens().get(ResourceLocation.parse("mmdlib_companion:crusher"));
     var layout = ScreenLayout.of(screen, text -> text.fallback().orElse(text.key()).length() * 6);
     var energy = layout.bounds(screen.find("energy").orElseThrow());
     var tank = layout.bounds(screen.find("tank").orElseThrow());
@@ -416,34 +411,24 @@ void crusherPlacesProcessingBeforeRightEnergyGauge() throws Exception {
   @Test
   void settingsExpandAndCollapseThePanelAndInventory() throws Exception {
     String name = "crusher";
-    try (var input =
-        java.nio.file.Files.newInputStream(
-            java.nio.file.Path.of("src/companion/resources/mmdlib/screen/" + name + ".xml"))) {
-      var screen =
-          ScreenReader.read(
-              ResourceLocation.parse("mmdlib_companion:" + name),
-              name + ".xml",
-              input,
-              companionLayoutWidgets());
-      TextMeasure text = t -> t.fallback().orElse(t.key()).length() * 6;
-      var compact = ScreenLayout.of(screen, text, true);
-      var expanded = ScreenLayout.of(screen, text, true, java.util.Map.of("panel", "settings"));
-      var collapsed = ScreenLayout.of(screen, text, true, java.util.Map.of("panel", "machine"));
-      var context = screen.find("panel").orElseThrow();
-      int growth = expanded.panel().height() - compact.panel().height();
-      org.junit.jupiter.api.Assertions.assertTrue(growth > 0, name);
-      require(expanded.bounds(context).height() - compact.bounds(context).height() == growth);
-      require(
-          expanded.inventory().orElseThrow().y() - compact.inventory().orElseThrow().y() == growth);
-      require(compact.panel().equals(collapsed.panel()));
-      for (var element : screen.elements())
-        require(compact.bounds(element).equals(collapsed.bounds(element)));
-      for (var layout : java.util.List.of(compact, expanded)) {
-        var inventory = layout.inventory().orElseThrow();
-        require(inventory.bottom() == layout.panel().bottom() - ScreenLayout.PANEL_MARGIN);
-        require(
-            layout.bounds(screen.find("inventory_controls").orElseThrow()).y() == inventory.y());
-      }
+    var screen = companionScreens().get(ResourceLocation.parse("mmdlib_companion:" + name));
+    TextMeasure text = t -> t.fallback().orElse(t.key()).length() * 6;
+    var compact = ScreenLayout.of(screen, text, true);
+    var expanded = ScreenLayout.of(screen, text, true, java.util.Map.of("panel", "settings"));
+    var collapsed = ScreenLayout.of(screen, text, true, java.util.Map.of("panel", "machine"));
+    var context = screen.find("panel").orElseThrow();
+    int growth = expanded.panel().height() - compact.panel().height();
+    org.junit.jupiter.api.Assertions.assertTrue(growth > 0, name);
+    require(expanded.bounds(context).height() - compact.bounds(context).height() == growth);
+    require(
+        expanded.inventory().orElseThrow().y() - compact.inventory().orElseThrow().y() == growth);
+    require(compact.panel().equals(collapsed.panel()));
+    for (var element : screen.elements())
+      require(compact.bounds(element).equals(collapsed.bounds(element)));
+    for (var layout : java.util.List.of(compact, expanded)) {
+      var inventory = layout.inventory().orElseThrow();
+      require(inventory.bottom() == layout.panel().bottom() - ScreenLayout.PANEL_MARGIN);
+      require(layout.bounds(screen.find("inventory_controls").orElseThrow()).y() == inventory.y());
     }
   }
 

From fb4306ec5b37aa80770f24b12c9d077c161b81b5 Mon Sep 17 00:00:00 2001
From: Face o' Cat <face@modcrafters.net>
Date: Sat, 7 Nov 2026 12:30:22 +0200
Subject: [PATCH 6/9] Inherit machine info panels with concrete machine
 translation keys

---
 .../moddev/mc/companion/ProcessorEntity.java  |  1 +
 .../assets/mmdlib_companion/lang/en_us.json   |  8 +--
 .../mmdlib/screen/creative_power.xml          |  2 +-
 .../resources/mmdlib/screen/crusher.xml       |  3 --
 .../resources/mmdlib/screen/dual_crusher.xml  |  3 --
 .../resources/mmdlib/screen/logistics.xml     |  2 +-
 .../resources/mmdlib/screen/transmuter.xml    |  3 --
 .../moddev/mc/lib/gui/load/ScreenReader.java  | 14 +++--
 .../machine/neoforge/BasePoweredMachine.java  |  6 +++
 .../mmdlib/screen/base_powered_machine.xml    |  4 +-
 .../mc/lib/gui/ScreenInheritanceTest.java     | 52 +++++++++++++++++++
 11 files changed, 78 insertions(+), 20 deletions(-)

diff --git a/src/companion/java/zone/moddev/mc/companion/ProcessorEntity.java b/src/companion/java/zone/moddev/mc/companion/ProcessorEntity.java
index 7b55c7a4..adb55b40 100644
--- a/src/companion/java/zone/moddev/mc/companion/ProcessorEntity.java
+++ b/src/companion/java/zone/moddev/mc/companion/ProcessorEntity.java
@@ -246,6 +246,7 @@ public int getSecondTime() {
     return lanes.size() == 2 ? lanes.get(1).time() : 0;
   }
 
+  @Override
   public List<Component> getWarnings() {
     var warnings = new ArrayList<Component>();
     if (energy.stored() < energy.capacity() * reservePercent / 100)
diff --git a/src/companion/resources/assets/mmdlib_companion/lang/en_us.json b/src/companion/resources/assets/mmdlib_companion/lang/en_us.json
index 0020c1a4..b81d2612 100644
--- a/src/companion/resources/assets/mmdlib_companion/lang/en_us.json
+++ b/src/companion/resources/assets/mmdlib_companion/lang/en_us.json
@@ -20,7 +20,7 @@
   "screen.mmdlib_companion.lane_b": "Lane B",
   "screen.mmdlib_companion.single": "One iron in, one gold out",
   "screen.mmdlib_companion.power": "Powers adjacent blocks on enabled sides",
-  "screen.mmdlib_companion.info.creative_power": "*Creative Power Source*\n\nSupplies up to 1,000 FE per enabled face each tick.\n\nUse the side configuration panel to enable or disable outputs. Statistics shows the measured output rate.",
+  "mmdlib_companion:creative_power.info": "*Creative Power Source*\n\nSupplies up to 1,000 FE per enabled face each tick.\n\nUse the side configuration panel to enable or disable outputs. Statistics shows the measured output rate.",
   "screen.mmdlib_companion.rate": "1,000 FE per face per tick",
   "status.mmdlib_companion.stalled": "Needs power",
   "status.mmdlib_companion.blocked": "Blocked",
@@ -49,9 +49,9 @@
   "screen.mmdlib_companion.recipes.tip": "Show crushing recipes in JEI, when installed.",
   "screen.mmdlib_companion.tank.tip": "Water or lava: {value} / {max} mB. Click with a fluid container to transfer.",
   "screen.mmdlib_companion.tank.refused": "Cannot transfer fluid. The tank holds water or lava, one type at a time, up to 4 buckets.",
-  "screen.mmdlib_companion.info.crusher": "*Crusher*\n\nCrush ore into raw materials, or stone into gravel and sand.\n\nPlace a power source beside the machine. Pause to release reserved items.\n\nThe left tank holds 4 buckets of water or lava for display. Click the gauge with a fluid container on the cursor to fill or drain it, or right-click the block with a bucket. Empty the tank before changing fluids. Crushing does not use the fluid.",
-  "screen.mmdlib_companion.info.transmuter": "*Iron to gold*\n\nInsert one iron ingot. The same slot holds the gold when the cycle finishes.\n\nSupply power from an adjacent block. Pause to release the input.",
-  "screen.mmdlib_companion.info.dual_crusher": "*Dual crusher*\n\nTwo lanes share the input and output slots. Each lane reserves its own items and space.\n\nPause either lane independently to release its share.",
+  "mmdlib_companion:crusher.info": "*Crusher*\n\nCrush ore into raw materials, or stone into gravel and sand.\n\nPlace a power source beside the machine. Pause to release reserved items.\n\nThe left tank holds 4 buckets of water or lava for display. Click the gauge with a fluid container on the cursor to fill or drain it, or right-click the block with a bucket. Empty the tank before changing fluids. Crushing does not use the fluid.",
+  "mmdlib_companion:transmuter.info": "*Iron to gold*\n\nInsert one iron ingot. The same slot holds the gold when the cycle finishes.\n\nSupply power from an adjacent block. Pause to release the input.",
+  "mmdlib_companion:dual_crusher.info": "*Dual crusher*\n\nTwo lanes share the input and output slots. Each lane reserves its own items and space.\n\nPause either lane independently to release its share.",
   "item.mmdlib_companion.mechanical_puller": "Mechanical Puller",
   "item.mmdlib_companion.mechanical_pusher": "Mechanical Pusher",
   "item.mmdlib_companion.input_pump": "Input Pump",
diff --git a/src/companion/resources/mmdlib/screen/creative_power.xml b/src/companion/resources/mmdlib/screen/creative_power.xml
index 889ef8e6..d95f3f1e 100644
--- a/src/companion/resources/mmdlib/screen/creative_power.xml
+++ b/src/companion/resources/mmdlib/screen/creative_power.xml
@@ -12,5 +12,5 @@
       <energy-gauge id="energy" length="3s"/>
     </hbox>
   </vbox>
-  <popout id="info" kind="info" edge="left" text="screen.mmdlib_companion.info.creative_power"/>
+  <popout id="info" kind="info" edge="left" text="{machineId}.info"/>
 </screen>
diff --git a/src/companion/resources/mmdlib/screen/crusher.xml b/src/companion/resources/mmdlib/screen/crusher.xml
index 7a6f869e..3133e3cc 100644
--- a/src/companion/resources/mmdlib/screen/crusher.xml
+++ b/src/companion/resources/mmdlib/screen/crusher.xml
@@ -48,7 +48,4 @@
       </context>
     </vbox>
   </fill>
-  <fill name="info">
-    <popout id="info" kind="info" edge="left" text="screen.mmdlib_companion.info.crusher" value="#getWarnings"/>
-  </fill>
 </screen>
diff --git a/src/companion/resources/mmdlib/screen/dual_crusher.xml b/src/companion/resources/mmdlib/screen/dual_crusher.xml
index 89d77f5d..b17ad63d 100644
--- a/src/companion/resources/mmdlib/screen/dual_crusher.xml
+++ b/src/companion/resources/mmdlib/screen/dual_crusher.xml
@@ -23,7 +23,4 @@
       <processor-button id="toggle_1" processor-key="lane_1"/>
     </inventory-controls>
   </fill>
-  <fill name="info">
-    <popout id="info" kind="info" edge="left" text="screen.mmdlib_companion.info.dual_crusher" value="#getWarnings"/>
-  </fill>
 </screen>
diff --git a/src/companion/resources/mmdlib/screen/logistics.xml b/src/companion/resources/mmdlib/screen/logistics.xml
index 832a3c7b..774dc10c 100644
--- a/src/companion/resources/mmdlib/screen/logistics.xml
+++ b/src/companion/resources/mmdlib/screen/logistics.xml
@@ -10,6 +10,6 @@
     <spacer/>
     <energy-gauge id="energy" length="3s"/>
   </hbox></vbox>
-  <popout id="info" kind="info" edge="left" text="screen.mmdlib_companion.logistics.info"
+  <popout id="info" kind="info" edge="left" text="{machineId}.info"
           text-fallback="Seven independent inventories. Install a module, enable a side, and configure its optional filter."/>
 </screen>
diff --git a/src/companion/resources/mmdlib/screen/transmuter.xml b/src/companion/resources/mmdlib/screen/transmuter.xml
index a2c32bf9..f8fa10ff 100644
--- a/src/companion/resources/mmdlib/screen/transmuter.xml
+++ b/src/companion/resources/mmdlib/screen/transmuter.xml
@@ -8,7 +8,4 @@
     <slot id="input" index="0"/>
     <progress id="progress" value="#getProgress" max="#getTime" jei-recipes="mmdlib_companion:transmuting"/>
   </fill>
-  <fill name="info">
-    <popout id="info" kind="info" edge="left" text="screen.mmdlib_companion.info.transmuter" value="#getWarnings"/>
-  </fill>
 </screen>
diff --git a/src/main/java/zone/moddev/mc/lib/gui/load/ScreenReader.java b/src/main/java/zone/moddev/mc/lib/gui/load/ScreenReader.java
index 9ee9ea20..a9ff4540 100644
--- a/src/main/java/zone/moddev/mc/lib/gui/load/ScreenReader.java
+++ b/src/main/java/zone/moddev/mc/lib/gui/load/ScreenReader.java
@@ -76,7 +76,7 @@ public static Screen read(
   static Screen build(ResourceLocation id, Node root, WidgetTypes widgets) {
     validateExpanded(root);
     String source = root.source();
-    var screen = new Builder(source, widgets).screen(id, root);
+    var screen = new Builder(id, source, widgets).screen(id, root);
     check(screen);
     return screen;
   }
@@ -226,11 +226,13 @@ public void fatalError(SAXParseException ex) throws SAXException {
   // Conversion to the model
 
   private static final class Builder {
+    private final String machineId;
     private final String source;
     private final WidgetTypes widgets;
     private final Map<Common, String> origins = new java.util.IdentityHashMap<>();
 
-    Builder(String source, WidgetTypes widgets) {
+    Builder(ResourceLocation id, String source, WidgetTypes widgets) {
+      this.machineId = id.toString();
       this.source = source;
       this.widgets = widgets;
     }
@@ -324,7 +326,7 @@ private Element element(Node node) {
                 Optional.ofNullable(node.attributes().get("shows")).map(ViewRef::parse),
                 words(node, "icons").stream().map(ResourceLocation::parse).toList(),
                 words(node, "value-labels").stream()
-                    .map(key -> new Text(key, Optional.empty()))
+                    .map(key -> new Text(translationKey(key), Optional.empty()))
                     .toList(),
                 java.util.Set.of("true", "1")
                     .contains(node.attributes().getOrDefault("flat", "false")),
@@ -447,7 +449,11 @@ private Optional<Text> text(Node node, String name) {
           throw error(node, name + "-fallback needs " + name + " (a translation key)");
         return Optional.empty();
       }
-      return Optional.of(new Text(key, fallback));
+      return Optional.of(new Text(translationKey(key), fallback));
+    }
+
+    private String translationKey(String key) {
+      return key.replace("{machineId}", machineId);
     }
 
     private List<String> words(Node node, String name) {
diff --git a/src/main/java/zone/moddev/mc/lib/machine/neoforge/BasePoweredMachine.java b/src/main/java/zone/moddev/mc/lib/machine/neoforge/BasePoweredMachine.java
index c4301c3e..73035e2c 100644
--- a/src/main/java/zone/moddev/mc/lib/machine/neoforge/BasePoweredMachine.java
+++ b/src/main/java/zone/moddev/mc/lib/machine/neoforge/BasePoweredMachine.java
@@ -8,6 +8,7 @@
 import net.minecraft.core.HolderLookup;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.nbt.NbtOps;
+import net.minecraft.network.chat.Component;
 import net.minecraft.network.protocol.Packet;
 import net.minecraft.network.protocol.game.ClientGamePacketListener;
 import net.minecraft.network.protocol.game.ClientboundBlockEntityDataPacket;
@@ -71,6 +72,11 @@ public long getEnergyCapacity() {
     return energy.capacity();
   }
 
+  /** Dynamic messages appended to the inherited info panel. */
+  public List<Component> getWarnings() {
+    return List.of();
+  }
+
   public int getProgress() {
     return features.processor(java.util.Optional.empty()).map(RecipeProcessor::progress).orElse(0);
   }
diff --git a/src/main/resources/mmdlib/screen/base_powered_machine.xml b/src/main/resources/mmdlib/screen/base_powered_machine.xml
index 1be4d82b..f560de4b 100644
--- a/src/main/resources/mmdlib/screen/base_powered_machine.xml
+++ b/src/main/resources/mmdlib/screen/base_powered_machine.xml
@@ -15,5 +15,7 @@
       <processor-button id="toggle_0"/>
     </inventory-controls>
   </placeholder>
-  <placeholder name="info"/>
+  <placeholder name="info">
+    <popout id="info" kind="info" edge="left" text="{machineId}.info" value="#getWarnings"/>
+  </placeholder>
 </screen>
diff --git a/src/test/java/zone/moddev/mc/lib/gui/ScreenInheritanceTest.java b/src/test/java/zone/moddev/mc/lib/gui/ScreenInheritanceTest.java
index 95eeacfe..ec9ba5ef 100644
--- a/src/test/java/zone/moddev/mc/lib/gui/ScreenInheritanceTest.java
+++ b/src/test/java/zone/moddev/mc/lib/gui/ScreenInheritanceTest.java
@@ -75,6 +75,58 @@ void poweredTemplateSuppliesItsEntityAndCommonBindings() throws Exception {
     var button = (Element.Button) bound.screen().find("toggle_0").orElseThrow();
     assertTrue(button.processorControl());
     assertTrue(button.processorKey().isEmpty());
+    var info = (Element.Popout) bound.screen().find("info").orElseThrow();
+    assertEquals("test:powered.info", info.text().orElseThrow().key());
+    assertTrue(bound.values().containsKey(info));
+  }
+
+  @Test
+  void translationTokensUseEachConcreteChildIdAcrossNamespacesAndInheritanceChains()
+      throws Exception {
+    write(
+        "library:base",
+        "abstract=\"true\"",
+        """
+        <placeholder name="body">
+          <label id="label" text="{machineId}.label" text-fallback="Literal {machineId}"
+              tooltip="{machineId}.tip" tooltip-fallback="{value} / {max}"/>
+          <button id="button" value="#getProgress" icons="mmdlib:off mmdlib:on"
+              value-labels="{machineId}.off {machineId}.on" tooltip="{machineId}.state"/>
+        </placeholder>
+        <placeholder name="info"><popout id="info" kind="info" text="{machineId}.info"/></placeholder>
+        """);
+    write("test:middle", "abstract=\"true\" extends=\"library:base\"", "");
+    for (var name : List.of("first", "nested/second"))
+      write("test:" + name, "extends=\"test:middle\" title=\"{machineId}.title\"" + HOST, "");
+    var screens = ScreenLoader.load(List.of(source("library"), source("test")));
+    for (var name : List.of("first", "nested/second")) {
+      var id = "test:" + name;
+      var screen = screens.get(ResourceLocation.parse(id)).screen();
+      assertEquals(id + ".title", screen.title().key());
+      var label = (Element.Label) screen.find("label").orElseThrow();
+      assertEquals(id + ".label", label.text().key());
+      assertEquals("Literal {machineId}", label.text().fallback().orElseThrow());
+      assertEquals(id + ".tip", label.common().tooltip().orElseThrow().key());
+      assertEquals(
+          "{value} / {max}", label.common().tooltip().orElseThrow().fallback().orElseThrow());
+      var button = (Element.Button) screen.find("button").orElseThrow();
+      assertEquals(
+          List.of(id + ".off", id + ".on"),
+          button.valueLabels().stream().map(zone.moddev.mc.lib.gui.model.Text::key).toList());
+      var info = (Element.Popout) screen.find("info").orElseThrow();
+      assertEquals(id + ".info", info.text().orElseThrow().key());
+      assertTrue(screen.source(info.common()).endsWith("base.xml"));
+    }
+    write(
+        "test:custom",
+        "extends=\"test:middle\" title=\"test.custom\"" + HOST,
+        "<fill name=\"info\"><popout id=\"info\" kind=\"info\" text=\"custom.info\"/></fill>");
+    var custom =
+        ScreenLoader.load(List.of(source("library"), source("test")))
+            .get(ResourceLocation.parse("test:custom"));
+    assertEquals(
+        "custom.info",
+        ((Element.Popout) custom.screen().find("info").orElseThrow()).text().orElseThrow().key());
   }
 
   @Test

From e9377730c8a943ca64b4fc14e6c48e3704becbc0 Mon Sep 17 00:00:00 2001
From: Face o' Cat <face@modcrafters.net>
Date: Sat, 7 Nov 2026 12:34:39 +0200
Subject: [PATCH 7/9] Inherit info panels for creative power and logistics
 screens

---
 .../assets/mmdlib_companion/lang/en_us.json   |  1 +
 .../mmdlib/screen/creative_power.xml          | 22 +++++++--------
 .../resources/mmdlib/screen/logistics.xml     | 27 ++++++++++---------
 .../moddev/mc/lib/gui/ScreenLoaderTest.java   | 11 +++++++-
 4 files changed, 34 insertions(+), 27 deletions(-)

diff --git a/src/companion/resources/assets/mmdlib_companion/lang/en_us.json b/src/companion/resources/assets/mmdlib_companion/lang/en_us.json
index b81d2612..c26695a9 100644
--- a/src/companion/resources/assets/mmdlib_companion/lang/en_us.json
+++ b/src/companion/resources/assets/mmdlib_companion/lang/en_us.json
@@ -63,6 +63,7 @@
   "item.mmdlib_companion.tag_filter": "Tag Filter",
   "item.mmdlib_companion.fluid_filter": "Fluid Filter",
   "block.mmdlib_companion.logistics": "Logistics Workbench",
+  "mmdlib_companion:logistics.info": "Seven independent inventories. Install a module, enable a side, and configure its optional filter.",
   "screen.mmdlib_companion.group.input": "Item input",
   "screen.mmdlib_companion.group.output": "Item output",
   "screen.mmdlib_companion.group.energy": "Energy",
diff --git a/src/companion/resources/mmdlib/screen/creative_power.xml b/src/companion/resources/mmdlib/screen/creative_power.xml
index d95f3f1e..b692ccac 100644
--- a/src/companion/resources/mmdlib/screen/creative_power.xml
+++ b/src/companion/resources/mmdlib/screen/creative_power.xml
@@ -1,16 +1,12 @@
 <screen xmlns="https://moddev.zone/mmdlib/screen" title="block.mmdlib_companion.creative_power" title-fallback="Creative Power Source"
-        block-entity="zone.moddev.mc.companion.CreativePowerEntity" inventory="none">
-  <vbox padding="7" spacing="4">
-    <hbox spacing="6" align="center">
-      <vbox spacing="4">
-        <spacer/>
-        <label text="screen.mmdlib_companion.power" text-fallback="Powers adjacent blocks on enabled sides"/>
-        <label text="screen.mmdlib_companion.rate" text-fallback="1,000 FE per face per tick"/>
-        <spacer/>
-      </vbox>
+        block-entity="zone.moddev.mc.companion.CreativePowerEntity" inventory="none" extends="mmdlib:base_powered_machine">
+  <fill name="machine">
+    <vbox spacing="4">
       <spacer/>
-      <energy-gauge id="energy" length="3s"/>
-    </hbox>
-  </vbox>
-  <popout id="info" kind="info" edge="left" text="{machineId}.info"/>
+      <label text="screen.mmdlib_companion.power" text-fallback="Powers adjacent blocks on enabled sides"/>
+      <label text="screen.mmdlib_companion.rate" text-fallback="1,000 FE per face per tick"/>
+      <spacer/>
+    </vbox>
+  </fill>
+  <fill name="inventory_controls"/>
 </screen>
diff --git a/src/companion/resources/mmdlib/screen/logistics.xml b/src/companion/resources/mmdlib/screen/logistics.xml
index 774dc10c..2c6cdfb7 100644
--- a/src/companion/resources/mmdlib/screen/logistics.xml
+++ b/src/companion/resources/mmdlib/screen/logistics.xml
@@ -1,15 +1,16 @@
 <screen xmlns="https://moddev.zone/mmdlib/screen" title="block.mmdlib_companion.logistics" title-fallback="Logistics Workbench"
-        block-entity="zone.moddev.mc.companion.ProcessorEntity">
-  <vbox padding="7"><hbox spacing="4" align="center">
-    <gauge id="tank" length="3s" value="#getTankFluid" max="#getTankCapacity"/>
-    <gauge id="tank_1" length="3s" value="#getTank1" max="#getTankCapacity"/>
-    <slot id="input" index="0"/>
-    <slot id="output" index="1"/>
-    <gauge id="tank_2" length="3s" value="#getTank2" max="#getTankCapacity"/>
-    <gauge id="tank_3" length="3s" value="#getTank3" max="#getTankCapacity"/>
-    <spacer/>
-    <energy-gauge id="energy" length="3s"/>
-  </hbox></vbox>
-  <popout id="info" kind="info" edge="left" text="{machineId}.info"
-          text-fallback="Seven independent inventories. Install a module, enable a side, and configure its optional filter."/>
+        block-entity="zone.moddev.mc.companion.ProcessorEntity" extends="mmdlib:base_powered_machine">
+  <fill name="body">
+    <vbox padding="7"><hbox spacing="4" align="center">
+      <gauge id="tank" length="3s" value="#getTankFluid" max="#getTankCapacity"/>
+      <gauge id="tank_1" length="3s" value="#getTank1" max="#getTankCapacity"/>
+      <slot id="input" index="0"/>
+      <slot id="output" index="1"/>
+      <gauge id="tank_2" length="3s" value="#getTank2" max="#getTankCapacity"/>
+      <gauge id="tank_3" length="3s" value="#getTank3" max="#getTankCapacity"/>
+      <spacer/>
+      <energy-gauge id="energy" length="3s"/>
+    </hbox></vbox>
+  </fill>
+  <fill name="inventory_controls"/>
 </screen>
diff --git a/src/test/java/zone/moddev/mc/lib/gui/ScreenLoaderTest.java b/src/test/java/zone/moddev/mc/lib/gui/ScreenLoaderTest.java
index db00a85e..8a5bfa1f 100644
--- a/src/test/java/zone/moddev/mc/lib/gui/ScreenLoaderTest.java
+++ b/src/test/java/zone/moddev/mc/lib/gui/ScreenLoaderTest.java
@@ -362,8 +362,17 @@ void companionControlsSitAboveInventoryAtRightMargin() throws Exception {
   @Test
   void allCompanionScreensPlaceBatteryAtRightMargin() throws Exception {
     var screens = companionScreens();
-    for (var name : java.util.List.of("crusher", "transmuter", "dual_crusher", "creative_power")) {
+    for (var name :
+        java.util.List.of("crusher", "transmuter", "dual_crusher", "creative_power", "logistics")) {
       var screen = screens.get(ResourceLocation.parse("mmdlib_companion:" + name));
+      var info = (Element.Popout) screen.find("info").orElseThrow();
+      require(screen.source(info.common()).endsWith("base_powered_machine.xml"));
+      require(info.text().orElseThrow().key().equals("mmdlib_companion:" + name + ".info"));
+      if (name.equals("creative_power") || name.equals("logistics"))
+        require(
+            screen.elements().stream()
+                .noneMatch(e -> e instanceof Element.Button button && button.processorControl()));
+      require(screen.playerInventory() != name.equals("creative_power"));
       var layout = ScreenLayout.of(screen, text -> text.fallback().orElse(text.key()).length() * 6);
       var energy = screen.find("energy").orElseThrow();
       require(energy instanceof Element.EnergyGauge);

From 0a6f9335416177490fa2f05ad3f25986d94de727 Mon Sep 17 00:00:00 2001
From: Face o' Cat <face@modcrafters.net>
Date: Sat, 7 Nov 2026 12:43:03 +0200
Subject: [PATCH 8/9] Harden powered machine lifecycle and add warnings and
 client sync hooks

---
 .../moddev/mc/companion/ProcessorEntity.java  |  21 +-
 .../assets/mmdlib_companion/lang/en_us.json   |   4 -
 .../test/BasePoweredMachineTests.java         | 305 ++++++++++++++++++
 .../mc/lib/machine/feature/FeatureHost.java   |   8 +
 .../machine/neoforge/BasePoweredMachine.java  |  76 ++++-
 .../neoforge/MachineInventoryLifecycle.java   |   8 +
 .../resources/assets/mmdlib/lang/en_us.json   |   5 +
 7 files changed, 390 insertions(+), 37 deletions(-)
 create mode 100644 src/companionTest/java/zone/moddev/mc/companion/test/BasePoweredMachineTests.java

diff --git a/src/companion/java/zone/moddev/mc/companion/ProcessorEntity.java b/src/companion/java/zone/moddev/mc/companion/ProcessorEntity.java
index adb55b40..337127b7 100644
--- a/src/companion/java/zone/moddev/mc/companion/ProcessorEntity.java
+++ b/src/companion/java/zone/moddev/mc/companion/ProcessorEntity.java
@@ -216,10 +216,6 @@ public FluidStack getTank3() {
     return fluids.getFluidInTank(3);
   }
 
-  private boolean redstoneAllowsRun() {
-    return !redstone.paused();
-  }
-
   public void toggle(int index) {
     if (index < 0 || index >= lanes.size()) return;
     var processor = lanes.get(index);
@@ -248,25 +244,10 @@ public int getSecondTime() {
 
   @Override
   public List<Component> getWarnings() {
-    var warnings = new ArrayList<Component>();
+    var warnings = new ArrayList<Component>(super.getWarnings());
     if (energy.stored() < energy.capacity() * reservePercent / 100)
       warnings.add(
           Component.translatable("screen.mmdlib_companion.reserve.waiting", reservePercent));
-    if (!redstoneAllowsRun())
-      warnings.add(Component.translatable("screen.mmdlib_companion.redstone.waiting"));
-    for (int i = 0; i < lanes.size(); i++) {
-      var status = lanes.get(i).status();
-      if (status == RecipeProcessor.Status.STALLED
-          || status == RecipeProcessor.Status.BLOCKED
-          || status == RecipeProcessor.Status.HELD)
-        warnings.add(
-            Component.translatable("screen.mmdlib_companion.lane_" + (i == 0 ? "a" : "b"))
-                .append(": ")
-                .append(
-                    Component.translatable(
-                        "status.mmdlib_companion."
-                            + status.name().toLowerCase(java.util.Locale.ROOT))));
-    }
     return warnings;
   }
 
diff --git a/src/companion/resources/assets/mmdlib_companion/lang/en_us.json b/src/companion/resources/assets/mmdlib_companion/lang/en_us.json
index c26695a9..7ce3e7fd 100644
--- a/src/companion/resources/assets/mmdlib_companion/lang/en_us.json
+++ b/src/companion/resources/assets/mmdlib_companion/lang/en_us.json
@@ -15,16 +15,12 @@
   "screen.mmdlib_companion.redstone.high": "Run when powered",
   "screen.mmdlib_companion.redstone.low": "Run when unpowered",
   "screen.mmdlib_companion.redstone.tip": "Redstone: {value}. Click to cycle Ignore / Powered / Unpowered.",
-  "screen.mmdlib_companion.redstone.waiting": "Waiting for redstone",
   "screen.mmdlib_companion.lane_a": "Lane A",
   "screen.mmdlib_companion.lane_b": "Lane B",
   "screen.mmdlib_companion.single": "One iron in, one gold out",
   "screen.mmdlib_companion.power": "Powers adjacent blocks on enabled sides",
   "mmdlib_companion:creative_power.info": "*Creative Power Source*\n\nSupplies up to 1,000 FE per enabled face each tick.\n\nUse the side configuration panel to enable or disable outputs. Statistics shows the measured output rate.",
   "screen.mmdlib_companion.rate": "1,000 FE per face per tick",
-  "status.mmdlib_companion.stalled": "Needs power",
-  "status.mmdlib_companion.blocked": "Blocked",
-  "status.mmdlib_companion.held": "Held by machine controls",
   "block.mmdlib_companion.crusher": "Crusher",
   "block.mmdlib_companion.transmuter": "Iron-to-Gold Converter",
   "block.mmdlib_companion.dual_crusher": "Dual Crusher",
diff --git a/src/companionTest/java/zone/moddev/mc/companion/test/BasePoweredMachineTests.java b/src/companionTest/java/zone/moddev/mc/companion/test/BasePoweredMachineTests.java
new file mode 100644
index 00000000..394cedff
--- /dev/null
+++ b/src/companionTest/java/zone/moddev/mc/companion/test/BasePoweredMachineTests.java
@@ -0,0 +1,305 @@
+package zone.moddev.mc.companion.test;
+
+import java.util.List;
+import java.util.Optional;
+
+import com.mojang.serialization.Codec;
+
+import net.minecraft.core.BlockPos;
+import net.minecraft.core.HolderLookup;
+import net.minecraft.gametest.framework.GameTest;
+import net.minecraft.gametest.framework.GameTestHelper;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.network.chat.Component;
+import net.minecraft.network.chat.contents.TranslatableContents;
+import net.minecraft.network.protocol.game.ClientboundBlockEntityDataPacket;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.Items;
+import net.minecraft.world.level.Level;
+
+import net.neoforged.neoforge.gametest.GameTestHolder;
+import net.neoforged.neoforge.gametest.PrefixGameTestTemplate;
+
+import zone.moddev.mc.companion.CompanionMod;
+import zone.moddev.mc.companion.ProcessorEntity;
+import zone.moddev.mc.lib.api.automation.*;
+import zone.moddev.mc.lib.api.capabilities.*;
+import zone.moddev.mc.lib.api.redstone.RedstoneControl;
+import zone.moddev.mc.lib.machine.feature.*;
+import zone.moddev.mc.lib.machine.neoforge.*;
+
+@GameTestHolder(CompanionMod.ID)
+@PrefixGameTestTemplate(false)
+public final class BasePoweredMachineTests {
+  private static void require(boolean condition, String message) {
+    if (!condition) throw new AssertionError(message);
+  }
+
+  @GameTest(template = "empty")
+  public static void ownedPowerSurvivesEvenWhenCustomLifecycleOmitsIt(GameTestHelper helper) {
+    var registries = helper.getLevel().registryAccess();
+    for (int mode = 0; mode < 3; mode++) {
+      var original = new Probe(helper, mode);
+      original.energy.setStored(1234);
+      original.featureValue = 7;
+      if (mode != 0) original.items.setStackInSlot(0, new ItemStack(Items.DIAMOND, 3));
+      var saved = original.saveWithoutMetadata(registries);
+      var restored = new Probe(helper, mode);
+      restored.loadWithComponents(saved, registries);
+      require(
+          restored.getEnergy() == 1234 && restored.getEnergyCapacity() == 3210,
+          "Base owns power persistence with no lifecycle, a raw lifecycle, or its factory");
+      require(
+          restored.powerAtRestore == 1234 && restored.featureValue == 7,
+          "Owned power loads before feature restoration");
+      if (mode != 0)
+        require(restored.items.getStackInSlot(0).getCount() == 3, "Custom storage also survives");
+      restored.clearContent();
+      require(
+          restored.getEnergy() == 0
+              && restored.featureValue == 0
+              && restored.items.getStackInSlot(0).isEmpty(),
+          "Clear includes power even when the subclass omitted it");
+    }
+    var conflict = new Probe(helper, 1);
+    conflict.lifecycle.energy("energy", new EnergyBuffer(100, 10));
+    try {
+      conflict.saveWithoutMetadata(registries);
+      throw new AssertionError("A conflicting energy binding must fail");
+    } catch (IllegalArgumentException expected) {
+      require(expected.getMessage().contains("energy"), "Binding error identifies energy");
+    }
+    helper.succeed();
+  }
+
+  @GameTest(template = "empty")
+  public static void customClientUpdatesAreIsolatedFromPersistence(GameTestHelper helper) {
+    var registries = helper.getLevel().registryAccess();
+    var server = new Probe(helper, 1);
+    server.featureValue = 9;
+    server.visual = 42;
+    var client = new Probe(helper, 1);
+    client.energy.setStored(2345);
+    client.items.setStackInSlot(0, new ItemStack(Items.EMERALD, 4));
+    client.metadata = 61;
+    var packet = (ClientboundBlockEntityDataPacket) server.getUpdatePacket();
+    client.loadWithComponents(packet.getTag(), registries);
+    require(
+        client.featureValue == 9 && client.visual == 42 && client.clientReads == 1,
+        "Normal update packets carry features and custom renderer state together");
+    require(
+        client.getEnergy() == 2345
+            && client.items.getStackInSlot(0).getCount() == 4
+            && client.metadata == 61
+            && client.worldReads == 0,
+        "Client hook data cannot overwrite common storage or run world-load hooks");
+    client.loadWithComponents(FeatureSync.updateTag(server.features, registries), registries);
+    require(
+        client.visual == 42 && client.clientReads == 1,
+        "Older feature-only updates do not reset custom client state");
+    server.visual = 0;
+    client.loadWithComponents(server.getUpdateTag(registries), registries);
+    require(
+        client.visual == 0 && client.clientReads == 2,
+        "Custom state can be cleared by a later update");
+    var saved = client.saveWithoutMetadata(registries);
+    require(!saved.contains("mmdlib_machine"), "Client-only payload is not written to world saves");
+    var restored = new Probe(helper, 1);
+    restored.visual = 88;
+    restored.loadWithComponents(saved, registries);
+    require(
+        restored.metadata == 61
+            && restored.visual == 88
+            && restored.clientReads == 0
+            && restored.worldReads == 1,
+        "World saves use their own metadata hook without invoking the client hook");
+    server.sendVisualUpdate();
+    helper.succeed();
+  }
+
+  @GameTest(template = "empty")
+  public static void baseWarningsDescribeProcessorsAndRespectPausePolicy(GameTestHelper helper) {
+    var probe = new Probe(helper, 0);
+    var resources =
+        new ProcessorEntity(
+            CompanionMod.DUAL_CRUSHER.type.get(),
+            probe.getBlockPos(),
+            CompanionMod.DUAL_CRUSHER.block.get().defaultBlockState(),
+            ProcessorEntity.Kind.DUAL);
+    for (var lane : resources.lanes) probe.features.add(lane);
+    require(
+        probe.getWarnings().isEmpty(),
+        "Idle processors and unrelated features produce no warnings");
+    var first = resources.lanes.getFirst();
+    for (var status : RecipeProcessor.Status.values()) {
+      first.restoreOnClient(
+          new RecipeProcessor.State(
+              status == RecipeProcessor.Status.PAUSED,
+              0,
+              Optional.empty(),
+              0,
+              Optional.empty(),
+              Optional.of(status)));
+      var key =
+          switch (status) {
+            case STALLED -> "screen.mmdlib.machine.stalled";
+            case BLOCKED -> "screen.mmdlib.machine.blocked";
+            case HELD -> "screen.mmdlib.machine.held";
+            default -> null;
+          };
+      var warnings = probe.getWarnings();
+      if (key == null) require(warnings.isEmpty(), "Normal/manual states are not automatic holds");
+      else {
+        require(warnings.size() == 1, "Exactly one warning for the affected processor");
+        var text = (TranslatableContents) warnings.getFirst().getContents();
+        require(
+            text.getArgs()[0].equals(first.displayName()),
+            "Warnings use the registered processor name");
+        require(
+            ((Component) text.getArgs()[1]).getContents() instanceof TranslatableContents cause
+                && cause.getKey().equals(key),
+            "Warning uses the library's status translation");
+      }
+    }
+    probe.redstone.migrate(1);
+    probe.redstone.readInputs();
+    require(
+        probe.redstone.paused() && probe.getWarnings().size() == 1, "Redstone hold is reported");
+    probe.policy = MachineInventoryLifecycle.PausePolicy.TRANSFERS_ONLY;
+    require(
+        probe.getWarnings().isEmpty(), "A transfer-only pause does not claim processing is held");
+    resources.setReservePercent(50);
+    require(
+        resources.getWarnings().stream()
+            .anyMatch(
+                c ->
+                    c.getContents() instanceof TranslatableContents t
+                        && t.getKey().equals("screen.mmdlib_companion.reserve.waiting")),
+        "Subclasses retain custom warnings");
+    helper.succeed();
+  }
+
+  private static final class Probe extends BasePoweredMachine {
+    final ItemStorage items = new ItemStorage(1);
+    final MachineInventoryLifecycle lifecycle;
+    final RedstoneControl redstone = new RedstoneControl(this, List.of());
+    MachineInventoryLifecycle.PausePolicy policy =
+        MachineInventoryLifecycle.PausePolicy.PROCESSING_ONLY;
+    int featureValue, visual, metadata, clientReads, worldReads;
+    long powerAtRestore;
+
+    Probe(GameTestHelper helper, int mode) {
+      super(
+          CompanionMod.CRUSHER.type.get(),
+          helper.absolutePos(new BlockPos(2, 2, 2)),
+          CompanionMod.CRUSHER.block.get().defaultBlockState(),
+          3210,
+          40,
+          20);
+      setLevel(helper.getLevel());
+      var group =
+          new ResourceGroup<net.neoforged.neoforge.energy.IEnergyStorage>(
+              "energy",
+              Component.literal("Energy"),
+              0xffffff,
+              ResourceType.ENERGY,
+              IoMode.BOTH,
+              List.of(0),
+              List.of("energy"),
+              new SideConfig(IoMode.BOTH));
+      var automation = new AutomationInventory(this, List.of(group));
+      lifecycle =
+          mode == 0
+              ? null
+              : (mode == 1
+                      ? new MachineInventoryLifecycle(this, features, automation, energy)
+                      : poweredInventory(automation))
+                  .items("items", items);
+      features.add(
+          new MachineFeature<Integer>() {
+            public String key() {
+              return "probe";
+            }
+
+            public Codec<Integer> codec() {
+              return Codec.INT;
+            }
+
+            public Integer state() {
+              return featureValue;
+            }
+
+            public void restore(Integer value) {
+              featureValue = value;
+              powerAtRestore = energy.stored();
+            }
+
+            public void reset() {
+              featureValue = 0;
+            }
+
+            public boolean syncsToClient() {
+              return true;
+            }
+          });
+    }
+
+    @Override
+    public ItemStorage screenItems() {
+      return items;
+    }
+
+    @Override
+    public RedstoneControl screenRedstone() {
+      return redstone;
+    }
+
+    @Override
+    protected MachineInventoryLifecycle machineInventory() {
+      return lifecycle;
+    }
+
+    @Override
+    protected MachineInventoryLifecycle.PausePolicy pausePolicy() {
+      return policy;
+    }
+
+    @Override
+    protected void saveMachineData(CompoundTag tag, HolderLookup.Provider registries) {
+      tag.putInt("metadata", metadata);
+    }
+
+    @Override
+    protected void loadMachineData(CompoundTag tag, HolderLookup.Provider registries) {
+      metadata = tag.getInt("metadata");
+      worldReads++;
+    }
+
+    @Override
+    protected void saveClientData(CompoundTag tag, HolderLookup.Provider registries) {
+      tag.putInt("visual", visual);
+      tag.putInt("expected_feature", featureValue);
+      // These names must remain isolated from the base's persistence and sync envelopes.
+      tag.putLong("energy", -1);
+      tag.putString("mmdlib_features", "custom");
+    }
+
+    @Override
+    protected void loadClientData(CompoundTag tag, HolderLookup.Provider registries) {
+      require(
+          featureValue == tag.getInt("expected_feature"),
+          "Features restore before custom client state");
+      visual = tag.getInt("visual");
+      clientReads++;
+    }
+
+    void sendVisualUpdate() {
+      syncToClient();
+    }
+
+    @Override
+    protected void recoverResources(Level level, BlockPos pos, CompoundTag payload) {
+      throw new AssertionError("Unexpected recovery");
+    }
+  }
+}
diff --git a/src/main/java/zone/moddev/mc/lib/machine/feature/FeatureHost.java b/src/main/java/zone/moddev/mc/lib/machine/feature/FeatureHost.java
index e494a609..f2b86432 100644
--- a/src/main/java/zone/moddev/mc/lib/machine/feature/FeatureHost.java
+++ b/src/main/java/zone/moddev/mc/lib/machine/feature/FeatureHost.java
@@ -89,6 +89,14 @@ public List<zone.moddev.mc.lib.api.stats.StatsProvider> statisticsProviders() {
         .toList();
   }
 
+  /** Recipe processors in registration order, excluding unrelated features. */
+  public List<RecipeProcessor> processors() {
+    return features.values().stream()
+        .filter(RecipeProcessor.class::isInstance)
+        .map(RecipeProcessor.class::cast)
+        .toList();
+  }
+
   /** Persists and synchronizes manual changes even while the host's processing tick is held. */
   public boolean setProcessorPaused(String key, boolean paused) {
     var processor = processor(key).orElse(null);
diff --git a/src/main/java/zone/moddev/mc/lib/machine/neoforge/BasePoweredMachine.java b/src/main/java/zone/moddev/mc/lib/machine/neoforge/BasePoweredMachine.java
index 73035e2c..1bc0af44 100644
--- a/src/main/java/zone/moddev/mc/lib/machine/neoforge/BasePoweredMachine.java
+++ b/src/main/java/zone/moddev/mc/lib/machine/neoforge/BasePoweredMachine.java
@@ -8,6 +8,7 @@
 import net.minecraft.core.HolderLookup;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.nbt.NbtOps;
+import net.minecraft.nbt.Tag;
 import net.minecraft.network.chat.Component;
 import net.minecraft.network.protocol.Packet;
 import net.minecraft.network.protocol.game.ClientGamePacketListener;
@@ -40,6 +41,7 @@ public abstract class BasePoweredMachine extends BlockEntity
     implements ScreenHost, DropsContents, Clearable {
   public static final ResourceLocation SCREEN_TEMPLATE =
       ResourceLocation.parse("mmdlib:base_powered_machine");
+  private static final String CLIENT_DATA = "mmdlib_machine";
 
   public final EnergyBuffer energy;
   public final FeatureHost features =
@@ -72,9 +74,28 @@ public long getEnergyCapacity() {
     return energy.capacity();
   }
 
-  /** Dynamic messages appended to the inherited info panel. */
+  /** Common warnings for the inherited info panel; subclasses may append their own messages. */
   public List<Component> getWarnings() {
-    return List.of();
+    var warnings = new ArrayList<Component>();
+    var redstone = screenRedstone();
+    if (redstone != null && !pausePolicy().processingEnabled(redstone.paused()))
+      warnings.add(Component.translatable("screen.mmdlib.machine.redstone_waiting"));
+    for (var processor : features.processors()) {
+      var key =
+          switch (processor.status()) {
+            case STALLED -> "screen.mmdlib.machine.stalled";
+            case BLOCKED -> "screen.mmdlib.machine.blocked";
+            case HELD -> "screen.mmdlib.machine.held";
+            default -> null;
+          };
+      if (key != null)
+        warnings.add(
+            Component.translatable(
+                "screen.mmdlib.machine.processor_warning",
+                processor.displayName(),
+                Component.translatable(key)));
+    }
+    return List.copyOf(warnings);
   }
 
   public int getProgress() {
@@ -111,14 +132,20 @@ public final boolean openScreen(Player player) {
   }
 
   /**
-   * Return the lifecycle configured by the subclass after its inventories are constructed. It must
-   * include this machine's energy buffer under the save key {@code energy}. Without a lifecycle,
-   * the base persists energy and features only.
+   * Return the lifecycle configured by the subclass after its inventories are constructed. The base
+   * registers its energy buffer under {@code energy} automatically and rejects conflicting
+   * bindings. Without a lifecycle, the base persists energy and features only.
    */
   protected MachineInventoryLifecycle machineInventory() {
     return null;
   }
 
+  private MachineInventoryLifecycle configuredInventory() {
+    var inventory = machineInventory();
+    if (inventory != null) inventory.bindPower(this, features, energy);
+    return inventory;
+  }
+
   /** Starts a lifecycle with this base's power storage and feature host already wired. */
   protected final MachineInventoryLifecycle poweredInventory(AutomationInventory automation) {
     return new MachineInventoryLifecycle(this, features, automation, energy)
@@ -127,7 +154,7 @@ protected final MachineInventoryLifecycle poweredInventory(AutomationInventory a
 
   @Override
   public AutomationInventory screenAutomation() {
-    var inventory = machineInventory();
+    var inventory = configuredInventory();
     return inventory == null ? null : inventory.automation();
   }
 
@@ -149,7 +176,7 @@ public final void serverTick() {
     if (redstone != null) redstone.readInputs();
     beforeMachineTick();
     boolean paused = redstone != null && redstone.paused();
-    var inventory = machineInventory();
+    var inventory = configuredInventory();
     if (inventory != null) inventory.tick(processingAllowed(), paused, pausePolicy());
     else features.tick(level, processingAllowed() && pausePolicy().processingEnabled(paused));
     afterMachineTick();
@@ -162,10 +189,25 @@ protected void saveMachineData(CompoundTag tag, HolderLookup.Provider registries
   /** Additional machine metadata; never called for a feature-only client update. */
   protected void loadMachineData(CompoundTag tag, HolderLookup.Provider registries) {}
 
+  /**
+   * Writes extra client state into a dedicated compound, separate from storage and feature data.
+   */
+  protected void saveClientData(CompoundTag tag, HolderLookup.Provider registries) {}
+
+  /** Reads extra client state after feature synchronization, never while loading a world save. */
+  protected void loadClientData(CompoundTag tag, HolderLookup.Provider registries) {}
+
+  /**
+   * Sends current feature and custom client state; call setChanged separately for persistent edits.
+   */
+  protected final void syncToClient() {
+    FeatureSync.send(this);
+  }
+
   @Override
   protected final void saveAdditional(CompoundTag tag, HolderLookup.Provider registries) {
     super.saveAdditional(tag, registries);
-    var inventory = machineInventory();
+    var inventory = configuredInventory();
     if (inventory != null) inventory.save(tag, registries);
     else {
       tag.put("energy", energy.serializeNBT(registries));
@@ -178,9 +220,13 @@ protected final void saveAdditional(CompoundTag tag, HolderLookup.Provider regis
 
   @Override
   protected final void loadAdditional(CompoundTag tag, HolderLookup.Provider registries) {
-    if (FeatureSync.read(features, tag, registries)) return;
+    if (FeatureSync.read(features, tag, registries)) {
+      if (tag.contains(CLIENT_DATA, Tag.TAG_COMPOUND))
+        loadClientData(tag.getCompound(CLIENT_DATA), registries);
+      return;
+    }
     super.loadAdditional(tag, registries);
-    var inventory = machineInventory();
+    var inventory = configuredInventory();
     if (inventory != null) inventory.load(tag, registries);
     else {
       features.reset();
@@ -202,7 +248,11 @@ protected final void loadAdditional(CompoundTag tag, HolderLookup.Provider regis
 
   @Override
   public final CompoundTag getUpdateTag(HolderLookup.Provider registries) {
-    return FeatureSync.updateTag(features, registries);
+    var tag = FeatureSync.updateTag(features, registries);
+    var clientData = new CompoundTag();
+    saveClientData(clientData, registries);
+    tag.put(CLIENT_DATA, clientData);
+    return tag;
   }
 
   @Override
@@ -212,7 +262,7 @@ public final Packet<ClientGamePacketListener> getUpdatePacket() {
 
   @Override
   public void clearContent() {
-    var inventory = machineInventory();
+    var inventory = configuredInventory();
     if (inventory != null) inventory.clear();
     else {
       features.reset();
@@ -224,7 +274,7 @@ public void clearContent() {
 
   @Override
   public void dropContents(Level level, BlockPos pos) {
-    var inventory = machineInventory();
+    var inventory = configuredInventory();
     if (inventory != null) inventory.dropContents(payload -> recoverResources(level, pos, payload));
   }
 
diff --git a/src/main/java/zone/moddev/mc/lib/machine/neoforge/MachineInventoryLifecycle.java b/src/main/java/zone/moddev/mc/lib/machine/neoforge/MachineInventoryLifecycle.java
index c3c38020..68f307af 100644
--- a/src/main/java/zone/moddev/mc/lib/machine/neoforge/MachineInventoryLifecycle.java
+++ b/src/main/java/zone/moddev/mc/lib/machine/neoforge/MachineInventoryLifecycle.java
@@ -68,6 +68,14 @@ public AutomationInventory automation() {
     return automation;
   }
 
+  /** Ensures a powered base cannot omit its owned buffer or attach another machine's lifecycle. */
+  void bindPower(BlockEntity owner, FeatureHost features, EnergyBuffer power) {
+    if (this.owner != owner || this.features != features || this.power != power)
+      throw new IllegalArgumentException(
+          "Powered lifecycle must use its machine's owner, features and energy");
+    if (storages.get("energy") != power) add("energy", power);
+  }
+
   private MachineInventoryLifecycle add(String key, Object storage) {
     Objects.requireNonNull(storage);
     if (key == null
diff --git a/src/main/resources/assets/mmdlib/lang/en_us.json b/src/main/resources/assets/mmdlib/lang/en_us.json
index 568b7044..1d4e8032 100644
--- a/src/main/resources/assets/mmdlib/lang/en_us.json
+++ b/src/main/resources/assets/mmdlib/lang/en_us.json
@@ -1,4 +1,9 @@
 {
+  "screen.mmdlib.machine.redstone_waiting": "Redstone input does not permit processing",
+  "screen.mmdlib.machine.processor_warning": "%s: %s",
+  "screen.mmdlib.machine.stalled": "Needs power",
+  "screen.mmdlib.machine.blocked": "Recipe cannot finish",
+  "screen.mmdlib.machine.held": "Held by machine controls",
   "screen.mmdlib.processor.processing": "Working",
   "screen.mmdlib.processor.idle": "Idle",
   "screen.mmdlib.processor.paused": "Paused",

From f0d1af48f145dfde9ef004d2f7e6d1c0045a7c21 Mon Sep 17 00:00:00 2001
From: Face o' Cat <face@modcrafters.net>
Date: Sat, 7 Nov 2026 13:06:53 +0200
Subject: [PATCH 9/9] Document powered machine lifecycle, inherited screens and
 inventory contracts

---
 docs/block-entities.md       | 132 ++++++++++++++++++++++++++++++++---
 docs/capabilities.md         |  39 ++++++++++-
 docs/gui-screens.md          | 125 +++++++++++++++++++++++++++++++--
 docs/gui-sprites.md          |   4 ++
 docs/inventory-automation.md |  56 ++++++++++++++-
 docs/machine-companion.md    |  66 +++++++++++++-----
 docs/mod-author-guide.md     |   9 +++
 7 files changed, 396 insertions(+), 35 deletions(-)

diff --git a/docs/block-entities.md b/docs/block-entities.md
index 0e6357f1..5ab08b03 100644
--- a/docs/block-entities.md
+++ b/docs/block-entities.md
@@ -131,11 +131,117 @@ The block delegates `newBlockEntity` and `getTicker` to `binding.prepared()`, as
 it, `DropsContents` is never called and nothing reports the missing hook. It reads `binding.type()` only after registration (for example
 when a block entity is created), never in its constructor.
 
+## BasePoweredMachine
+
+`zone.moddev.mc.lib.machine.neoforge.BasePoweredMachine` is an optional abstract `BlockEntity`
+for code-defined machines. It implements `ScreenHost`, `DropsContents` and `Clearable`. It owns
+`energy` and `features`, exposes their screen/statistics bindings, and supplies ticking, persistence,
+feature synchronization and common warnings. It does not register blocks, capabilities, recipes
+or a recovery item for the consuming mod.
+
+The default constructor configures 100,000 FE capacity, 1,000 FE input and no external output.
+The overload `(type, pos, state, capacity, maxInput, maxOutput)` accepts different values, including
+an output-only generator. The owning machine's energy operations bypass external transfer rates.
+
+Define items/tanks and resource groups in the subclass, then connect them once:
+
+```java
+// In a BasePoweredMachine subclass constructor, after defining the three ResourceGroups:
+resources = new MachineResources(this, this::facing)
+    .items(inputGroup, items)
+    .items(outputGroup, items)
+    .energy(energyGroup, energy)
+    .recipeInputs(MyRecipes.PRESSING, "input")
+    .build();
+features.add(new RecipeProcessor("work", MyRecipes.PRESSING, resources.recipes(),
+    Component.translatable("example.press.processor")));
+inventory = poweredInventory(resources.automation())
+    .items("items", items)
+    .fluids("fluids", fluids);
+ScreenInventoryValidation.validate(this);
+
+// Subclass methods; inventory is the configured MachineInventoryLifecycle field.
+@Override public ItemStorage screenItems() { return items; }
+@Override protected MachineInventoryLifecycle machineInventory() { return inventory; }
+@Override protected void recoverResources(Level level, BlockPos pos, CompoundTag payload) {
+    // Consumer-owned item that durably retains the complete payload:
+    Containers.dropItemStack(level, pos.getX() + .5, pos.getY() + .5, pos.getZ() + .5,
+        MyRecoveryItem.create(payload));
+}
+```
+
+Group IDs in this fragment are `input`, `output` and `energy`; recipe files must use the matching
+keys. See [resource definitions and filtering](inventory-automation.md#shared-machine-resource-definitions).
+`MyRecipes` and `MyRecoveryItem` are consumer implementations, not library registrations.
+
+The base automatically registers its own buffer under the save key `energy`, even when the
+subclass returns a directly constructed lifecycle instead of using `poweredInventory`. A lifecycle
+must belong to this entity and use its `features` and `energy`; conflicting energy bindings are
+rejected. Without a lifecycle, the base saves/restores features and energy only. Custom items and
+tanks must be registered with the lifecycle to participate in persistence, clearing and dropping.
+
+| Base behavior | Subclass extension |
+|---|---|
+| `getEnergy()`, `getEnergyCapacity()` | Backed by the owned buffer |
+| `getProgress()`, `getTime()`, `getPaused()` | First registered recipe processor; zero/false if none |
+| `screenFeatures()`, `screenStats()` | Owned host; statistics include energy and all feature statistics providers |
+| `screenAutomation()` | Lifecycle's automation inventory, when configured |
+| `getWarnings()` | Redstone processing gate plus `STALLED`, `BLOCKED`, `HELD` processor warnings, using each processor's display name; append custom messages to `super.getWarnings()` |
+| `screenRedstone()` | Opt in with a configured `RedstoneControl`; base reads it before processing and updates outputs afterward |
+| `processingAllowed()` | Additional processing gate, default true |
+| `pausePolicy()` | Default `PROCESSING_ONLY`; controls redstone gating of processing and automation transfers |
+| `beforeMachineTick()`, `afterMachineTick()` | Work around the common processing/transfer tick, such as generator refilling and output |
+| `saveMachineData()`, `loadMachineData()` | Additional persistent metadata, after the common lifecycle; never used for client-only packets |
+| `recoverResources()` | Required durable handoff for displaced storage and transfer escrow |
+
+The final no-argument `serverTick()` is server-only. Register its block ticker with
+`(level, pos, state, entity) -> entity.serverTick()`. Custom before/after tick hooks run even when
+the processing gate is held, so gate any custom work explicitly if necessary. Manual processor
+pause remains independent of the redstone transfer policy.
+
+`MachineInventoryLifecycle` resets features before loading storage, then restores automation and
+features, so reservations are rebuilt against loaded contents. It settles owed energy refunds even
+when transfers are paused. `clearContent()` destructively clears registered contents, recovery,
+automation and feature state. `dropContents()` recovers displaced contents and transfer escrow,
+releases plans and drops ordinary items. Normal tank contents and stored power are not converted
+to recovery payloads on destruction. Custom blocks still need the `DropsContents.onRemove` hook.
+
+Screen XML extends `mmdlib:base_powered_machine`; `SCREEN_TEMPLATE` exposes that ID in Java.
+The final `openScreen(player)` opens the concrete type's screen, not the abstract template.
+See [screen inheritance](gui-screens.md#inherited-screens) for the shared energy display,
+processor control, info text and placeholders. The mod still supplies a screen under each type ID.
+
+### Additional client state
+
+The base's final update packet/tag methods always include feature synchronization. Extend them
+through these protected hooks instead of overriding the packet methods:
+
+```java
+@Override protected void saveClientData(CompoundTag tag, HolderLookup.Provider registries) {
+    tag.putInt("visual_mode", visualMode);
+}
+@Override protected void loadClientData(CompoundTag tag, HolderLookup.Provider registries) {
+    visualMode = tag.getInt("visual_mode");
+}
+// After a server-side change that should reach tracking clients:
+syncToClient();
+```
+
+Custom data occupies a separate `mmdlib_machine` compound; it cannot replace the root feature or
+storage fields. Features restore first, followed by `loadClientData`. Older feature-only packets
+leave custom client state alone. World saves never invoke these hooks, and packet loads never
+invoke `loadMachineData` or reload inventories. Persist any value that must survive a world reload
+separately in the machine-data hooks and call `setChanged()` when changing it; `syncToClient()`
+only sends current state. Exact screen values still use the menu's getter synchronization.
+
 ## Machine features
 
 The separately packaged [machine companion](machine-companion.md) provides playable examples of
 the processor, a one-slot converter, shared lanes and a creative power source.
 
+The manual wiring below is for a plain `BlockEntity`. When extending `BasePoweredMachine`, use its
+owned `features` and lifecycle instead of redeclaring the host or overriding final save/tick methods.
+
 A `FeatureHost` runs a machine's `MachineFeature`s, such as a `RecipeProcessor`, and saves each
 under its key. The block entity ticks it from `serverTick` with `features.tick(level)`, and saves
 and loads it through a `DynamicOps`, after the storages, since a processor checks the loaded
@@ -164,8 +270,9 @@ BlockEntityTicker<CrusherEntity> ticker =
 
 `status()` is one of: `IDLE`, no cycle is running; `RUNNING`, a cycle is running; `STALLED`, a
 cycle is waiting for energy and keeps its progress and reservations; `BLOCKED`, a cycle has run its
-time but cannot finish, say an input was taken, and retries each tick; and `PAUSED`, held by an
-interrupt. `progress()` and `time()` give the ticks done and the ticks the cycle takes, for a
+time but cannot finish, say an input was taken, and retries each tick; `HELD`, suspended by a host
+gate with progress and reservations retained; and `PAUSED`, held by a manual interrupt.
+`progress()` and `time()` give the ticks done and the ticks the cycle takes, for a
 screen; `time()` is 0 when idle or paused.
 
 On `/reload` a running cycle finishes as planned, and the next cycle uses the new recipes.
@@ -181,13 +288,17 @@ until `resume()`; `paused()` says whether it is held. It works without power and
 status. It also releases the running cycle's reservations, so the items it locked can be taken
 out. This is the trap for players: an unpowered machine keeps its inputs and outputs locked, and
 the only ways to get them back are an interrupt or breaking the block. A mod should give the
-player a button, an `Element.Button` in the screen XML with a `gui-click` handler (see
-[GUI screens](gui-screens.md)) that calls `interrupt()` or `resume()`. Resuming reserves the paused
+player a generic `<processor-button>` (see [GUI screens](gui-screens.md#generic-processor-control)).
+`pause()`, `resume()` and `setPaused(boolean)` expose the same processor operations. For actions
+on a hosted processor, use `FeatureHost.setProcessorPaused(key, paused)`: it marks changes dirty
+and synchronizes immediately, even while host processing is held. Direct processor calls require
+the caller to arrange persistence/sync. Resuming reserves the paused
 recipe again if it still can. Progress is kept only if that recipe still exists, can reserve its
 inputs and output space again, and has the same `time`; otherwise progress resets.
 
-**Groups.** The processor reaches storage through the inventory's group keys. Groups in one
-inventory must not overlap: use one key for each set of slots or tanks. Multiple processor lanes
+**Groups.** The processor reaches storage through the inventory's group keys. Physical groups in
+`MachineResources` cannot overlap; recipe aliases may expose the same storage through alternate
+keys. Avoid describing the same physical input/output twice within one recipe. Multiple processor lanes
 can share that inventory and reserve the same slot, provided enough unreserved inputs and output
 space remain; each lane holds only its own share of the slot's plan.
 
@@ -217,7 +328,8 @@ given back.
 Custom blocks can call `DropsContents.onRemove(state, level, pos, replacement)` before their
 superclass removal hook to use the same server-only, different-block guard.
 
-**Syncing to clients.** Nothing is sent to clients unless the block entity opts in. A feature that
+**Syncing to clients.** `BasePoweredMachine` wires this automatically. A plain block entity must
+opt in. A feature that
 should be readable on the client, for a renderer, particles or a tooltip, returns true from
 `syncsToClient()`; `RecipeProcessor` does. The block entity then wires `FeatureSync`:
 
@@ -243,8 +355,10 @@ protected void loadAdditional(CompoundTag tag, HolderLookup.Provider registries)
 }
 ```
 
-The host sends at most once every 10 ticks (`FeatureHost.SYNC_INTERVAL`), and always sends the
-latest change. Storages are not part of the update.
+Tick-driven feature changes are throttled to one send every 10 ticks (`FeatureHost.SYNC_INTERVAL`),
+with the latest change retained. Hosted manual pause changes synchronize immediately. Storages
+are not part of the feature update. `features.tick(level, false)` still calls each feature's
+`suspended(host)` hook, allowing processors to publish `HELD` rather than leaving stale running state.
 
 A feature controls what clients get with two methods. `clientState()` is the state to send, by
 default what `state()` saves; a feature overrides it for a moment clients shouldn't see.
diff --git a/docs/capabilities.md b/docs/capabilities.md
index 1fe28fa9..4e972fb6 100644
--- a/docs/capabilities.md
+++ b/docs/capabilities.md
@@ -68,6 +68,38 @@ What a plan does to the calls on the storage:
 Plans are not saved by the storages. A feature saves its own cycle and puts the plans back when it
 loads, so load the storages first.
 
+## Stable storage identities and recovery
+
+Assign durable identities with `items.slotId(index, "input")` and `fluids.tankId(index, "coolant")`.
+IDs must be nonblank and unique within that storage. They are save identities, separate from
+numeric recipe/menu indexes and from resource-group or XML element IDs.
+
+Saves include `SlotId` / `TankId` where configured. Loading matches identified entries by ID;
+an unknown ID never falls back to its former numeric position. Saves without identities load by
+index, or through the explicit `deserializeNBT(registries, tag, IntUnaryOperator)` migration
+overload. Select that mapping by your machine's save version; it applies only to legacy entries.
+Keep slot/tank IDs stable when reordering a definition.
+
+Storage keeps its configured shape. Removed slots/tanks, overflow after reducing limits/capacity,
+incompatible colliding contents and undecodable entries are retained in raw `Recovery` data,
+instead of being discarded. Subsequent loads retry recovery entries, allowing returning IDs or
+registrations to make them usable again. Loading restores existing contents without treating them
+as a new insertion through recipe filters.
+
+`recoveryContents()` returns a snapshot. `recover(Consumer<CompoundTag>)` hands displaced contents
+to a durable consumer-owned sink, clearing them only after the callback succeeds. `StorageRecovery`
+uses the same `resources` envelope as automation escrow, with `mmdlib:items` / `mmdlib:fluids`
+payloads. MMDLib does not register a recovery item; the companion demonstrates a Recovery Capsule.
+Use `MachineInventoryLifecycle` or [BasePoweredMachine](block-entities.md#basepoweredmachine) to
+coordinate storage, reservations, saving, clearing and this handoff. Explicit `clear()` destroys
+both ordinary and recovery contents; stop/reset owning features first.
+
+External admission rules can be combined with `restrict(predicate, indexes...)`. Recipe-linked
+input rules are installed by [MachineResources](inventory-automation.md#shared-machine-resource-definitions).
+They supplement existing filters and reservations. Machine products use `insertResult` for items
+or `fillResult` for fluids to bypass external admission rules; fluid products still obey the
+tank's structural filter and capacity. Restoring a saved item explicitly can use `restoreStack`.
+
 ## Example
 
 ```java
@@ -126,10 +158,11 @@ is checked every tick, keep a NeoForge `BlockCapabilityCache` instead.
   the block entity returns them from `ScreenHost.screenSides()`. A view still takes one mode per
   face for the whole storage, so the mod's `sides` function decides how groups combine. When
   groups differ by `Role`, take insert from the input group and extract from the output group.
-  A per-slot mode in the views, which would remove that step, is not implemented.
+  Per-slot/per-tank mode functions are also supported. Prefer `MachineResources` and
+  `automation.mode(type, index, side)` for independent groups sharing a storage.
 
-- `ItemStorage` keeps the slot count given to its constructor. Loading a save that has more
-  slots drops the stacks that no longer fit. `FluidStorage` loads its tanks by index.
+- `ItemStorage` keeps its configured slot count and `FluidStorage` its configured tanks. Entries
+  that cannot be restored remain in recovery; see stable identities above.
 - `EnergyBuffer` stores up to `Long.MAX_VALUE`. Screens show the full `long` through a getter
   such as `#getEnergy` (`stored()`), while other mods see at most `Integer.MAX_VALUE`.
 - The runtime smoke test covers roles, filters, limits, faces, out-of-range indices, transfer,
diff --git a/docs/gui-screens.md b/docs/gui-screens.md
index 0d705e62..0446db6d 100644
--- a/docs/gui-screens.md
+++ b/docs/gui-screens.md
@@ -1,4 +1,4 @@
-# GUI screens (design)
+# GUI screens
 
 > **Status: implemented; runtime validation is described below.** Screens load at startup,
 > open through `block-right-click`, and use one generic menu with custom value packets.
@@ -17,6 +17,7 @@ embedded editor without adding per-filter XML to each screen.
 | Reading and checks | `gui.load.ScreenReader`: hardened SAX parser (no DOCTYPE, no external entities), schema validation, then the checks below | Done |
 | Getter binding | `gui.load.ScreenBinder`: `#method` / `Class#method` resolved to method handles, return kinds checked per element | Done |
 | Discovery | `gui.load.ScreenLoader`, called at startup; results in `gui.Screens` | Done |
+| Inheritance | `gui.load.ScreenTemplates`: cross-mod bases, placeholders/fills, source-aware expansion | Done |
 | Layout | `gui.layout.ScreenLayout`: positions in GUI pixels; tab fit checked at load | Done |
 | Menu and opening | `gui.runtime.MachineMenu`, `ScreenRuntime`, `BlockEvents.openMenu` | Implemented |
 | Value sync | `gui.runtime.ScreenNetwork`, `ScreenValues`, `ScreenSnapshots` | Implemented |
@@ -24,7 +25,8 @@ embedded editor without adding per-filter XML to each screen.
 | Optional JEI | `client.jei.MachineJei`, loaded only by the JEI plugin | Implemented |
 
 Checks made at load, beyond the schema: unique `id`s and slot indexes; `shows`, `hover-shows`
-and `side-config groups` name existing elements; buttons have a tooltip and text or an icon; a
+and `side-config groups` name existing elements; buttons have a tooltip and text or an icon
+(generic processor controls supply their own defaults); a
 `-fallback` attribute has its key; `max` has a `value`; gauges, meters and progress indicators
 have both; checkboxes and radio groups have a `value`; info pop-outs have text and
 warning/error pop-outs a `value`; `spacer` sits directly in a box; at most one
@@ -444,6 +446,118 @@ to the module's ID. Adding one later would break nothing, while removing one wou
 existing packs, so it will be added only if early users ask for it. If it is added, it must
 not hide a missing or misnamed screen file without a log entry.
 
+## Inherited screens
+
+Use `abstract="true"` for a template and `extends="namespace:screen_id"` for a child. Templates
+are discovered across mod namespaces but are not bound or opened themselves. Each concrete screen
+still has its own file ID and must provide its own `title`. It can inherit `block-entity` and
+`inventory`, or override either; getters bind against the resulting block-entity class.
+Inheritance does not replace the type-ID screen lookup described above.
+
+```xml
+<!-- mmdlib/screen/base_press.xml in mod example -->
+<screen xmlns="https://moddev.zone/mmdlib/screen" abstract="true"
+        block-entity="example.PressEntity">
+  <vbox padding="7">
+    <placeholder name="machine" required="true"/>
+  </vbox>
+  <placeholder name="help">
+    <popout kind="info" text="{machineId}.info"/>
+  </placeholder>
+</screen>
+```
+
+```xml
+<!-- mmdlib/screen/press.xml in mod example -->
+<screen xmlns="https://moddev.zone/mmdlib/screen" extends="example:base_press"
+        title="block.example.press">
+  <fill name="machine"><slot id="input" index="0"/></fill>
+</screen>
+```
+
+- Children supply content only through top-level `<fill name="...">` elements. A fill replaces
+  the named placeholder's contents; an empty fill removes its default content.
+- An unfilled optional placeholder uses its children, or nothing when it has none. A required
+  placeholder must be filled and cannot also have default content.
+- Chains can introduce placeholders and override earlier fills. Replacing an outer placeholder
+  removes its nested extension points; also filling a removed inner point is an error.
+- Unknown bases/fills, duplicate placeholders/fills and cycles fail at load. Expanded slots, IDs,
+  widget structure, bindings and layout are validated together. Errors retain the originating
+  file and line; a sibling's fills never mutate the shared template.
+
+`{machineId}` in translation keys expands to the concrete screen ID, including namespace and any
+path, after inheritance: `{machineId}.info` becomes `example:press.info`, never the base ID.
+It works in `text`, `title`, `label`, `tooltip`, `tooltip-shift` and button `value-labels`.
+Literal `*-fallback` strings and runtime placeholders such as `{value}` / `{max}` are unchanged.
+Declare the resulting key in the consuming mod's language file.
+
+### Library powered-machine screen
+
+MMDLib ships `mmdlib:base_powered_machine`, paired with
+[`BasePoweredMachine`](block-entities.md#basepoweredmachine). A one-processor child can be:
+
+```xml
+<screen xmlns="https://moddev.zone/mmdlib/screen"
+        extends="mmdlib:base_powered_machine" title="block.example.press">
+  <fill name="machine">
+    <slot id="input" index="0"/>
+    <progress value="#getProgress" max="#getTime"/>
+    <slot id="output" index="1"/>
+  </fill>
+</screen>
+```
+
+The base supplies the entity binding, padded layout, right-side energy gauge, default player
+inventory, keyless processor control and left info popout. Its info text is `{machineId}.info`,
+with dynamic `#getWarnings` from the entity. Override `block-entity` when child widgets use getters
+available only on the concrete subclass. Inventory/redstone/statistics drawers still come from
+runtime host interfaces; XML inheritance does not configure their backing data.
+
+| Placeholder | Default |
+|---|---|
+| `body` | Entire padded machine area; replace for layouts with contexts/settings views |
+| `heading` | Empty, above the machine row |
+| `machine` | Required machine-specific contents, before the energy gauge |
+| `inventory_controls` | `<inventory-controls id="inventory_controls"><processor-button id="toggle_0"/></inventory-controls>` |
+| `info` | `<popout id="info" kind="info" edge="left" text="{machineId}.info" value="#getWarnings"/>` |
+
+Replacing `body` also replaces its nested `heading` and `machine` placeholders. Machines without
+a recipe processor use `<fill name="inventory_controls"/>`; generators can also set
+`inventory="none"`. Multi-processor machines can fill that control area with explicitly keyed buttons.
+
+### Generic processor control
+
+```xml
+<processor-button id="pause"/>
+<!-- Or select a particular registered RecipeProcessor: -->
+<processor-button id="pause_second" processor-key="lane_1"/>
+```
+
+The host exposes a `FeatureHost` through `screenFeatures()`; `BasePoweredMachine` supplies it.
+An omitted key selects the first registered **recipe processor**, skipping other features. An
+explicit key must match exactly and never falls back; blank keys and hosts with no matching
+processor are errors. The menu validates this before opening and resolves clicks on the server.
+The control owns its state binding and pause action, so it needs no per-machine getter or click
+handler. Do not supply its `value`, `max`, `on-click`, `on-right-click`, `shows`, `icons` or `value-labels`.
+
+Icons show the current state, not the next action:
+
+| Processor state | Icon | Tooltip lines / click |
+|---|---|---|
+| Manually paused | Pause | `Paused` / `Click to unpause` |
+| Not paused and processing | Stop | `Working` / `Click to stop and clear reservations` |
+| Not paused and not processing | Play | `Idle` / `Click to pause` |
+
+Tooltips are compact and multiline. Manual pause releases reservations, keeps resumable progress,
+marks the machine changed and synchronizes immediately. Redstone/host holds preserve reservations
+and cannot override a manual pause. Removing a redstone hold never resumes a manually paused lane.
+
+When input watching is configured, a small red dot at the button's bottom right marks disagreement
+between manual pause and the redstone gate. The extra tooltip explains either that manual pause
+takes priority or that redstone is preventing processing. The redstone drawer icon has a small
+green play overlay when watched inputs allow processing, or a yellow pause overlay when they
+block it. With no input watching, neither the overlay nor conflict dot is shown.
+
 ## Example
 
 A processing machine with an energy gauge, an input, a progress arrow, two outputs, a fluid tank,
@@ -652,7 +766,8 @@ player, menu, and element before running the handler. Hover never reaches the se
 
 | Element | Purpose | Notable attributes |
 |---|---|---|
-| `screen` | Root | `title`, `block-entity`, `inventory` |
+| `screen` | Root | `title`, `block-entity`, `inventory`, `abstract`, `extends` |
+| `placeholder`, `fill` | Template extension point / child replacement | `name`; placeholders can be `required` |
 | `vbox`, `hbox` | Layout boxes | `padding`, `spacing`, `align` |
 | `spacer` | Fills leftover room in a box | |
 | `group` | Recessed grouping panel | `label`, `tint`, `padding` |
@@ -663,6 +778,8 @@ player, menu, and element before running the handler. Hover never reaches the se
 | `progress` | Fill-in progress indicator | `icon` (default arrow), `direction`, `jei-recipes` |
 | `label` | Text | `text` |
 | `button` | Vanilla-style button | `text` or `icon`, `tooltip` (required), `shows` (`context:view`) |
+| `processor-button` | Generic server-controlled pause/stop/resume button | Optional `processor-key`; built-in state icons, tooltip and action |
+| `inventory-controls` | Controls above player slots, right-aligned alongside the colour selector | Top-level container after the machine body |
 | `checkbox` | Checkbox | `text` |
 | `radio-group`, `radio` | Radio buttons; the group's value is the selected index | `label`, `text` |
 | `side-tab` | Tab growing out of the panel edge | `edge` |
@@ -925,7 +1042,7 @@ bright green incoming strength for Read, orange emitted strength for Emit, with
   simplify only the info text to For N / Except N; ranges touching 0 or 15 use a single
   above/below condition (including equality for Between). The icon stays unchanged. Processing pauses when
   the face receives a highlighted level.
-  The default is Between 1–15. Dragging previews locally, release applies both endpoints atomically,
+  The default is Between 1–15. Dragging previews locally, release applies both endpoints atomically,
   and Escape cancels the drag. Any Read face requesting pause holds processing.
 - **Emit:** click the colour swatch or sprite and source name to cycle outputs; right-click
   cycles backwards. Resource fullness entries come first in the companion, followed by each
diff --git a/docs/gui-sprites.md b/docs/gui-sprites.md
index 3e172a71..d40768cc 100644
--- a/docs/gui-sprites.md
+++ b/docs/gui-sprites.md
@@ -29,6 +29,10 @@ icons and progress arrows are full colour.
 | `icon_side_config` | 16×16 | none | Central machine with connected cyan/orange ports for the side-configuration drawer |
 | `side_mode_input`, `side_mode_output`, `side_mode_both`, `side_mode_disabled` | 14×14 | none | Outlined cyan insertion arrow, orange extraction arrow, opposing arrows, or grey cross. The drawer draws 7×7 corner badges: input at top-right, output at bottom-right, both badges for bidirectional sides, or a bottom-right cross when disabled. |
 | `icon_pause`, `icon_resume` | 16×16 | none | Gold pause bars and green play triangle; `_a` and `_b` variants identify independent lanes |
+| `icon_processor_pause`, `icon_processor_stop`, `icon_processor_play` | 12×12 | none | Centered current-state glyphs for the generic processor control: manually paused, working, idle |
+| `icon_processor_conflict` | 5×5 | none | Red bottom-right conflict overlay for manual pause versus watched redstone inputs |
+| `icon_redstone_running`, `icon_redstone_paused` | 5×5 | none | Green play / yellow pause overlays for the redstone drawer's input permission |
+| `icon_stop` | 16×16 | none | Standalone stop glyph |
 | `button_flat`, `button_flat_highlighted` | 14×14 | nine-slice, border 1 | Compact button with a uniform dark outline and flat grey fill; hover lightens only the interior |
 | `icon_filter_whitelist`, `icon_filter_blacklist` | 10×10 | none | White/black list cards on the filter's flat grey mode toggle |
 | `icon_processor_progress` | 16x16 | none | Three rising blue bars for per-processor recipe progress. |
diff --git a/docs/inventory-automation.md b/docs/inventory-automation.md
index c3a6289d..555483ad 100644
--- a/docs/inventory-automation.md
+++ b/docs/inventory-automation.md
@@ -27,6 +27,59 @@ height. All drawers share the same frame renderer and four-pixel top inset. The
 drawer can grow to the available screen height; inventory drawers retain the panel's bottom inset. Info drawers fit their text up to the inset bottom or the screen edge, whichever
 comes first.
 
+## Shared machine resource definitions
+
+`machine.neoforge.MachineResources` defines group membership once for automation, recipes and
+screen highlights. Construct it after defining the physical `ItemStorage`, `FluidStorage` and
+`EnergyBuffer`; resource-group IDs are separate from stable slot/tank save IDs.
+
+```java
+var resources = new MachineResources(this, this::facing)
+    .items(inputGroup, items)
+    .items(outputGroup, items)
+    .fluids(coolantGroup, fluids)
+    .energy(energyGroup, energy)
+    .recipeInputs(MyRecipes.PROCESSING, "input", "coolant")
+    .build();
+automation = resources.automation();
+features.add(new RecipeProcessor("work", MyRecipes.PROCESSING, resources.recipes()));
+```
+
+Here the supplied groups have IDs `input`, `output`, `coolant` and `energy`. The resulting recipe
+inventory uses those IDs as keys. `recipeGroup("combined", "left", "right")` can define an alternate
+recipe mapping over groups from the same physical storage; it creates no extra automation group.
+Finish all bindings/aliases/input links before the single `build()` call.
+
+Validation rejects duplicate group IDs, empty/out-of-range membership, overlapping physical groups,
+role/IO contradictions, and multiple physical storages for the same resource type. A group's active
+transfer view is restricted to its own members. `recipes()` and `automation()` require a completed
+build. `ScreenInventoryValidation.validate(this)` can validate after construction; menus repeat
+validation on opening, checking real slot bounds, highlight IDs and processor-button targets.
+
+`recipeInputs(type, keys...)` links admission rules only to specified input groups. Items/fluids
+are accepted if an input ingredient of a compatible recipe allows them; matching current amounts,
+available power and output room is not required just to insert an ingredient. Compatibility means
+the machine exposes all referenced input/output groups with the required resource kinds.
+Several types or overlapping recipe aliases accept their union; the result is intersected with
+the storage's existing rules. Unlinked decorative tanks or general storage keep their own filters.
+If there is no level or no compatible recipe, a linked input accepts nothing. Lookups consult the
+current recipe manager, so server reloads and client recipe synchronization update admission rules.
+Product insertion and save restoration do not pass through these external recipe-input checks.
+
+Use `MachineInventoryLifecycle(owner, features, automation, energy)` to compose persistence and
+recovery. Register storage through `.items(saveKey, items)`, `.fluids(saveKey, fluids)` and
+`.energy(saveKey, energy)`. Save keys must be unique, cannot be `features` or `automation`, and
+each physical storage is registered once. `BasePoweredMachine` supplies this integration and
+guarantees its own `energy` binding; see [block entities](block-entities.md#basepoweredmachine).
+
+The lifecycle saves storages, automation and features together. Loading resets old feature plans,
+loads contents, then automation and feature state. Its `tick(processingAllowed, paused, policy)`
+can pause processing only, transfers only, both or neither; the separate processing gate always
+applies. Owed energy refunds settle even during a pause. Destruction hands off displaced storage
+and escrow before clearing ownership, releases plans and drops ordinary item contents. Normal
+fluid/buffer destruction remains the machine's policy. Explicit `clear()` discards all registered
+contents and resets features, including manual pause and resumable progress.
+
 ## Define independent resource groups
 
 A `ResourceGroup<T>` declares a stable save ID, translated name, RGB colour, `ResourceType<T>`,
@@ -60,7 +113,8 @@ cleared. Do not also drop the same addon slots separately. This hook handles tra
 normal tank/buffer contents remain the host's separate break policy.
 
 The companion drops a **Recovery Capsule**, a companion item carrying this data. Use it on a
-companion machine to restore fluids into accepting tanks and energy into available buffer space.
+companion machine to restore displaced items into accepting slots, fluids into accepting tanks
+and energy into available buffer space.
 Partial restoration leaves the remainder in the same capsule; a fully restored capsule is consumed,
 including in creative mode. Unknown resource payloads remain preserved. No recovery item is
 registered by MMDLib itself.
diff --git a/docs/machine-companion.md b/docs/machine-companion.md
index 5d23dbe7..83fa0e7f 100644
--- a/docs/machine-companion.md
+++ b/docs/machine-companion.md
@@ -1,6 +1,6 @@
 # Machine companion
 
-The optional `mmdlib_companion` mod contains four playable examples of the machine processor.
+The optional `mmdlib_companion` mod contains five playable machine examples.
 It uses Minecraft 1.21.1, NeoForge 21.1.247 and this branch's MMDLib. Its classes and resources live
 in `src/companion` and are packaged separately from the library.
 
@@ -26,14 +26,17 @@ choose their front from placement. Walking around a machine does not change its
 Faces cycle between Output and Disabled. Disabled faces block both automatic delivery and
 external extraction; settings survive reloads. Existing sources start with all six faces enabled.
 
-JEI is included in development runs; add `-PwithoutJei`
-to run without it.
+JEI and Jade are included in playable companion development runs. Add `-PwithoutJei`
+to run without JEI; Jade remains installed. Neither mod is bundled into the companion jar.
+Mock server GameTests exclude Jade and Curios because their fake connections cannot negotiate
+those mods' login payloads; real client smoke runs include them.
 
 | Block ID (prefix `mmdlib_companion:`) | What it does |
 | --- | --- |
 | `crusher` | One input slot, two output slots, one processor, and a water/lava preview tank |
 | `transmuter` | One slot limited to one item; converts an iron ingot into a gold ingot |
 | `dual_crusher` | Two independently pausable processors share the same input and output slots |
+| `logistics` | Seven independent resource groups for testing automation, filters and side configuration; no recipe processing |
 | `creative_power` | Refills its buffer and supplies up to 1,000 FE per enabled adjacent face per tick |
 
 The crusher recipes take 100 ticks and 2,000 FE per cycle: cobblestone becomes gravel, gravel becomes
@@ -51,16 +54,24 @@ starting empty. The Dual Crusher keeps its existing shared single-output layout.
 
 The bottom of each processor panel has a compact, right-aligned row of icon buttons above the inventory,
 with thin dark borders and flat grey backgrounds.
-Click the pause icon to interrupt a lane and release its reservations; it becomes a green play
-icon while paused. Click again to resume. This works without power. The Dual Crusher has separate
-buttons marked A and B; pausing one lane releases only its share, and the other can continue.
-The redstone button cycles **Ignore / Run when powered / Run when unpowered**. Redstone holds
-progress and energy use while keeping reservations; it never overrides manual pause. Both the
-selected redstone mode and each lane's pause state survive save/load. Hover a button for its state
-and action. The yellow info tab opens a matching drawer to the left with machine guidance and
-any current power-stall or blocked-finish warnings. Click the icon again to close it; scroll
-inside to read longer text. All four screens place a vertical battery on the right, using the
-reusable `<energy-gauge>` XML widget. Its red charge bars fill upwards inside a slim casing.
+The generic processor button shows its **current** state: pause when manually paused, stop while
+working, play while idle. Click to unpause, stop and release reservations, or pause idle work,
+respectively. Resumable progress is retained. The Dual Crusher targets each lane explicitly;
+pausing one releases only its share. Single-processor machines inherit a keyless button from the base.
+
+Redstone face settings control whether processing may run. A redstone hold keeps progress and
+reservations; manual pause takes priority and is never undone by a signal change. With input
+watching configured, the drawer icon adds a green play or yellow pause overlay for the resolved
+gate. A small red dot on a processor button marks disagreement with manual pause; its compact
+multiline tooltip explains which setting prevents work. Settings and manual pause survive saves.
+See [redstone face controls](gui-screens.md#redstone-face-drawer) for the per-face modes and ranges.
+
+Every screen inherits the yellow Info popout from `mmdlib:base_powered_machine`. Its translation is
+`{machineId}.info`, such as `mmdlib_companion:transmuter.info`, plus dynamic warnings from the base
+entity. The base reports processor power stalls, blocked finishes and host holds; Crusher can also
+report its configured energy reserve. Click the icon to close the drawer; scroll longer text.
+All five screens place a vertical battery on the right using `<energy-gauge>`.
+Its red charge bars fill upwards inside a slim casing.
 The energy and fluid gauges share matching edges and medium-grey empty backgrounds, darker than slots.
 Energy bars are thin with a soft reflection; cylindrical glass shading covers only the fluid.
 The Crusher centers its input, a circular progress dial and two adjacent output slots. The dial is a
@@ -98,7 +109,9 @@ fully before switching between water and lava. Rejected bucket transfers leave t
 The tank saves with the machine and is only a display example; crushing recipes do not consume it.
 Breaking the machine discards its fluid.
 
-Hoppers and pipes can insert into input slots and extract from output slots on any face. The
+Hoppers and pipes obey each group's configured side modes and storage roles. Recipe-linked
+inputs accept only ingredients allowed by compatible recipes; decorative tanks retain their own
+filters. Recipe reloads update those admission rules. The
 converter's single slot permits both operations, subject to reservations. Its capacity of one is
 deliberate: leftover iron would prevent a gold product from fitting. Remove the gold before adding
 the next iron. Because the converter shares one slot for input and output, an extracting hopper can
@@ -115,6 +128,7 @@ including reserved inputs. Normal `/setblock` and `/fill` replacement clears con
 ```sh
 ./gradlew build companionJar
 ./gradlew check
+# Optional full graphical check; normally covered by CI:
 ./gradlew runCompanionClientSmoke
 ```
 
@@ -127,8 +141,8 @@ publication. Release uploads select only the exact library, sources and Javadoc
 the tag. Run `./gradlew clean` when updating a checkout that still has companion jars in
 `build/libs`; packaging verification rejects those stale jars.
 
-`check` includes the companion's thirteen server game tests and checks both jars for leaked classes and
-resources. `runCompanionGameTestServer` runs just those tests. They cover all four registrations and
+`check` includes the companion server game tests and checks both jars for leaked classes and
+resources. `runCompanionGameTestServer` runs just those tests. They cover all five registrations and
 menus, recipe loading, adjacent power, the one-slot limit and interruption through the menu, two
 shared lanes across save/load, command replacement versus destruction, tank capacity and persistence,
 refusal to mix fluids, bucket filling/draining through the block interaction, and cursor-container
@@ -139,7 +153,7 @@ Redstone tests cover all modes on all three processors, signal changes, independ
 retained reservations, saved settings, and safe defaults for older or invalid saves.
 
 `runCompanionClientSmoke` creates a separate test world under `build/companion-client-smoke`, opens
-all four menus over the network and captures them under its `screenshots` directory. It is separate
+all five menus over the network and captures them under its `screenshots` directory. It is separate
 from `check` because it needs a graphical client. It also accepts `-PwithoutJei`.
 The shared `build_status.yml` workflow runs `check`, builds both jars, and runs the companion
 and library GUI smoke tests. The library smoke is exercised with and without JEI.
@@ -148,11 +162,27 @@ It also clicks the gauge to drain a lava bucket and pour it back, verifying curs
 The client smoke also clicks pause and redstone controls and waits for their synchronized states;
 `crusher-paused.png` and `crusher-redstone.png` capture their alternate icons.
 
+All five entities extend `BasePoweredMachine`, and all five XML screens extend the library base.
+Creative Power and Logistics remove the inherited processor-control area with an empty fill.
+Crusher replaces the body to retain its settings context. The shared Info popup is never duplicated
+in a child screen; each machine supplies its own language entry.
+
+Stable slot/tank IDs preserve contents when definitions move. Displaced contents remain in recovery
+and are handed to the companion's Recovery Capsule on removal; use the capsule on a machine to
+restore items, fluids or power, retaining any remainder. Ordinary fluid and energy destruction is
+still separate from displaced-content recovery. See [storage recovery](capabilities.md#stable-storage-identities-and-recovery).
+
+For local edits, run focused XML/layout/processor tests and relevant server GameTests. Do not run
+the full UI smoke suite after every edit or PR update; CI supplies full GUI coverage. Run it locally
+when explicitly requested or when a broad regression needs it. The base regression fixture also
+checks omitted power registration, common warnings, custom client packets and world-save isolation.
+
 ## Code to read
 
 - `CompanionMod`: registers blocks, items, block-entity types, recipe types, capabilities and actions.
 - `DemoBlock`: block creation, server ticking, menu opening and the contents-drop hook.
-- `ProcessorEntity`: storages, group keys, shared lanes, saving after storages, and feature sync.
+- `BasePoweredMachine` (in MMDLib): owned power, common ticking/persistence, warnings and client-sync hooks.
+- `ProcessorEntity`: resource groups, recipe-linked inputs, shared lanes and machine-specific metadata.
 - `CreativePowerEntity`: the external energy capability and adjacent transfer.
 - `src/companion/resources/mmdlib/screen`: XML screens, bound to public getters at startup.
 - `src/companion/resources/data/mmdlib_companion/recipe`: data-driven machine recipes.
diff --git a/docs/mod-author-guide.md b/docs/mod-author-guide.md
index 70423559..6d296282 100644
--- a/docs/mod-author-guide.md
+++ b/docs/mod-author-guide.md
@@ -448,6 +448,15 @@ optional mods when their requiredMod gate is set.
 
 ## 8. Verify in a running mod
 
+For code-defined powered machines, [BasePoweredMachine](block-entities.md#basepoweredmachine)
+provides energy, feature lifecycle, warnings and client-sync hooks. Define resources with
+[MachineResources](inventory-automation.md#shared-machine-resource-definitions), including stable
+slot/tank identities and recipe-linked input filtering, then extend the library's
+[`mmdlib:base_powered_machine` screen](gui-screens.md#library-powered-machine-screen). The consuming
+mod still registers blocks/types/capabilities, supplies recipes and machine-specific inventories,
+and preserves displaced contents through its recovery callback. The
+[companion](machine-companion.md) demonstrates all of these together.
+
 The MMDLib build checks definition codecs and planning. Your consuming mod still
 needs to verify registration, resource reloads, harvesting levels, repair tags,
 scythe protection events, crackhammer counts/durability, all block placement states,