brianjfox · Nov 4, 2026 · Nov 4, 2026 · Nov 4, 2026 · Nov 4, 2026 · Nov 4, 2026
@@ -27,6 +27,7 @@ import {
   LiveApp,
   MAX_APPROVAL_PACKAGE_BYTES,
   MaterialReceipt,
+  MaterialRemovedReceipt,
 } from "@corbits-builder/schemas/artifact";
 import { ProjectActivity } from "@corbits-builder/schemas/activity";
 import {
@@ -398,6 +399,37 @@ export function mountArtifactRoutes(
       );
     },
   );
+  app.delete(
+    "/:projectId/materials/:artifactId",
+    describeRoute({
+      tags: ["Artifacts"],
+      operationId: "removeMaterial",
+      description:
+        "Takes an attached file back. The coordinator, when one runs, is told the file is withdrawn first, so a note that cannot be sent leaves the material in place for another try; then the material is archived, so it leaves the project's documents and the coordinator's filed materials while its versions stay. The message it was sent with keeps showing it. `told` says whether a coordinator was mailed.",
+      security,
+      responses: {
+        200: {
+          description: "The material taken back",
+          content: {
+            "application/json": { schema: resolver(MaterialRemovedReceipt) },
+          },
+        },
+        404: { description: "No such material in this project" },
+      },
+    }),
+    async (c) => {
+      const current = actorOf(c);
+      return c.json(
+        await service.removeMaterial(
+          current,
+          c.req.param("projectId"),
+          c.req.param("artifactId"),
+          (runId, content) =>
+            mailRunAsCaller(c, nativeFetch, current.tenantId, runId, content),
+        ),
+      );
+    },
+  );
   app.post(
     "/:projectId/design-concepts",
     describeRoute({

@@ -11,6 +11,7 @@ import {
   listArtifacts,
   listArtifactVersions,
   MAX_LIST_LIMIT,
+  setArtifactArchived,
   VersionConflictError,
   writeArtifactVersion,
   type ArtifactDb,
@@ -54,6 +55,7 @@ import {
   type AcceptedMaterials,
   type UserManual,
   type MaterialReceipt,
+  MaterialRemovedReceipt,
   type DesignTweaksReceipt,
   type DesignChoiceReceipt,
   type LiveApp,
@@ -144,7 +146,7 @@ import {
 import { awaitingApproval } from "../projects/deploy-tools.ts";
 import { frozenModelChoice, workflowBindings } from "../config/models.ts";
 import { modelDirectory } from "../settings/custom-providers.ts";
-import { materialsNote } from "../config/materials.ts";
+import { materialRemovedNote, materialsNote } from "../config/materials.ts";
 import { servingOffering } from "../workflows/install-for-tenant.ts";
 import {
   acceptedMaterials,
@@ -1248,6 +1250,36 @@ export function createArtifactService(
       return { materials };
     },
 
+    // A material the person takes back: the coordinator, when one runs, is told first, so a note
+    // that cannot be sent leaves the material in place for another try; then it is archived, so
+    // every list leaves it out while its versions stay.
+    async removeMaterial(
+      actor: Actor,
+      projectId: string,
+      artifactId: string,
+      mailRun: (runId: string, content: string) => Promise<void>,
+    ): Promise<MaterialRemovedReceipt> {
+      const allowed = await requireProject(actor, projectId, "manage");
+      if (!(await allowed(artifactResource(MATERIAL_KIND), "write")))
+        throw new ProjectError(403, "artifact_write_refused", {
+          kind: MATERIAL_KIND,
+        });
+      const row = await getArtifact(db, artifactId);
+      if (!row || row.tenantId !== actor.tenantId || row.kind !== MATERIAL_KIND)
+        throw new ProjectError(404, "material_not_found", { artifactId });
+      if (row.archivedAt !== null)
+        return { artifactId: row.id, title: row.title, told: false };
+      const coordinator = await activeCoordinator(projectId);
+      if (coordinator)
+        await mailRun(coordinator.runId, materialRemovedNote(row.title));
+      await setArtifactArchived(db, row, true);
+      return {
+        artifactId: row.id,
+        title: row.title,
+        told: coordinator !== null,
+      };
+    },
+
     // An imported document with no kind of its own, filed as a material without mail: the
     // import's opening message names it to the coordinator.
     async fileMaterial(

@@ -3,3 +3,8 @@
 export function materialsNote(names: readonly string[]): string {
   return `I attached ${names.join(", ")}. Each is filed as a material.`;
 }
+
+// The person's message when they take an attached file back; the material is archived with it.
+export function materialRemovedNote(name: string): string {
+  return `I removed the attached file ${name}. It is no longer among the materials, so leave it out from here on.`;
+}
@@ -219,6 +219,12 @@ export async function attachMaterials(
   return productClient().attachMaterials(tenantId, projectId, files, message);
 }
 
+/** Takes an attached file back; the coordinator is told and the file leaves the documents. */
+export async function removeMaterial(projectId: string, artifactId: string) {
+  const tenantId = await workspaceTenantId();
+  return productClient().removeMaterial(tenantId, projectId, artifactId);
+}
+
 export async function downloadPackageZip(
   projectId: string,
   version: number,

@@ -914,6 +914,15 @@ export const wording = {
   passage: { addToPrompt: "Add to prompt" },
   documentBar: "Document controls",
   printDocument: "Save as PDF or print",
+  removeAttachment: {
+    menu: "Remove attachment…",
+    confirm: "Yes, remove it",
+    done: (name: string, told: boolean) =>
+      told
+        ? `${name} is removed; the coordinator has been told.`
+        : `${name} is removed.`,
+    failed: "The attachment could not be removed.",
+  },
   versions: {
     menu: (version: number) => `Version ${String(version)}, choose a version`,
     comparePrevious: "Compare with previous",

@@ -1,4 +1,4 @@
-import { FileText, Printer } from "lucide-react";
+import { FileText, Printer, Trash2 } from "lucide-react";
 import {
   useEffect,
   useRef,
@@ -81,6 +81,9 @@ function filterVisibleDeliverables(
 
 const TAB_PREFIX = "workspace-document";
 const DRAFT_TAB = "design-draft";
+// The page names each attached file's tab "material:<artifact id>"; only those can be taken back.
+export const MATERIAL_TAB_PREFIX = "material:";
+const removable = (id: string) => id.startsWith(MATERIAL_TAB_PREFIX);
 const draftIds = panelTabIds(TAB_PREFIX, DRAFT_TAB);
 const MANUAL_TAB = "user-manual";
 const manualIds = panelTabIds(TAB_PREFIX, MANUAL_TAB);
@@ -249,6 +252,7 @@ export function ArtifactPane({
   selected,
   state,
   onSelect,
+  onRemove,
   paneRef,
   changesOpen,
   onToggleChanges,
@@ -278,6 +282,8 @@ export function ArtifactPane({
   selected: Deliverable | null;
   state: DeliverableState | undefined;
   onSelect: (id: string) => void;
+  /** Takes an attached file back, for a tab that is one; absent where nothing can be removed. */
+  onRemove?: ((id: string) => void) | undefined;
   paneRef?: Ref<HTMLElement>;
   changesOpen: boolean;
   onToggleChanges: () => void;
@@ -422,8 +428,11 @@ export function ArtifactPane({
     y: number;
   } | null>(null);
   const printing = useRef<string | null>(null);
+  // Removing takes two clicks, both in the menu: the second item only exists after the first.
+  const [confirmingRemove, setConfirmingRemove] = useState(false);
   const openTabMenu = (value: string, x: number, y: number) => {
     choose(value);
+    setConfirmingRemove(false);
     setTabMenu({ value, x, y });
   };
   const tabMenuProps = (value: string) => ({
@@ -452,6 +461,29 @@ export function ArtifactPane({
     if (item !== undefined && pane !== null)
       printDocument(pane, item.title, documentStatus(item));
   };
+  // The menu's remove item for an attached file's tab: a first click asks, the second removes.
+  const removeItem = (value: string) => {
+    if (onRemove === undefined || !removable(value)) return null;
+    if (confirmingRemove)
+      return (
+        <MenuItem className="menu-danger" onSelect={() => onRemove(value)}>
+          <Trash2 size={16} aria-hidden="true" />
+          {wording.removeAttachment.confirm}
+        </MenuItem>
+      );
+    return (
+      <MenuItem
+        className="menu-danger"
+        onSelect={(event) => {
+          event.preventDefault();
+          setConfirmingRemove(true);
+        }}
+      >
+        <Trash2 size={16} aria-hidden="true" />
+        {wording.removeAttachment.menu}
+      </MenuItem>
+    );
+  };
   const outputs =
     visibleDeliverables.length > 0 || draftShown || conceptViews.length > 0;
   const hasTabs = outputs || themes !== null;
@@ -619,7 +651,11 @@ export function ArtifactPane({
           {tabMenu === null ? null : (
             <Menu
               open
-              onOpenChange={(open) => (open ? undefined : setTabMenu(null))}
+              onOpenChange={(open) => {
+                if (open) return;
+                setTabMenu(null);
+                setConfirmingRemove(false);
+              }}
             >
               <MenuTrigger asChild>
                 <span
@@ -644,6 +680,7 @@ export function ArtifactPane({
                   <Printer size={16} aria-hidden="true" />
                   {wording.printDocument}
                 </MenuItem>
+                {removeItem(tabMenu.value)}
               </MenuContent>
             </Menu>
           )}

@@ -60,6 +60,7 @@ import { subscribeWorkflowRun } from "../../api/run-stream.ts";
 import {
   acceptedMaterials,
   attachMaterials,
+  removeMaterial,
   readArtifact,
 } from "../../api/artifacts.ts";
 import { documentsForPane } from "./document-read.ts";
@@ -797,6 +798,29 @@ export function StageWorkspace({
   };
   const chooseDocument = (id: string) =>
     setDocumentChoice({ id, filedCount: filed.length });
+  // An attached file taken back: its tab goes with the next room read, and the person hears so.
+  const removeAttachment = (id: string) => {
+    if (!id.startsWith(MATERIAL_TAB)) return;
+    const artifactId = id.slice(MATERIAL_TAB.length);
+    const item = paneDeliverables.find((entry) => entry.kind === id);
+    void takeBack(artifactId, item?.title);
+  };
+  const takeBack = async (artifactId: string, title: string | undefined) => {
+    try {
+      const removed = await removeMaterial(projectId, artifactId);
+      setDocumentChoice(null);
+      toast.success(
+        wording.removeAttachment.done(
+          title === undefined ? removed.title : title,
+          removed.told,
+        ),
+      );
+      reloadRef.current();
+      onChanged();
+    } catch (cause) {
+      toast.error(humanFault(cause, wording.removeAttachment.failed));
+    }
+  };
   const openDocument = (id: string) => {
     setPaneTab({ value: id });
     if (conceptOfTab(id) === undefined) chooseDocument(id);
@@ -1595,6 +1619,7 @@ export function StageWorkspace({
                     }
                   : {})}
                 onSelect={chooseDocument}
+                onRemove={removeAttachment}
                 changesOpen={selected !== null && changesFor === selected.kind}
                 onToggleChanges={() =>
                   setChangesFor((current) =>

@@ -29,6 +29,7 @@ export function buildArtifactsMethods(
   | "chooseDesign"
   | "acceptedMaterials"
   | "attachMaterials"
+  | "removeMaterial"
   | "downloadPackageZip"
   | "approvalRounds"
   | "startApprovalRound"
@@ -169,6 +170,14 @@ export function buildArtifactsMethods(
         signal,
       );
     },
+    removeMaterial(tenantId, projectId, artifactId, signal) {
+      return request(
+        `${projectPath(tenantId, projectId)}/materials/${encodeURIComponent(artifactId)}`,
+        signal,
+        null,
+        "DELETE",
+      );
+    },
     async attachMaterials(tenantId, projectId, files, message, signal) {
       const body = new FormData();
       for (const file of files) body.append("file", file);

@@ -61,6 +61,7 @@ import type {
   InFlightRun,
   LiveApp,
   MaterialReceipt,
+  MaterialRemovedReceipt,
 } from "@corbits-builder/schemas/artifact";
 import type {
   ApprovalRound,
@@ -544,6 +545,13 @@ export type ProductApiClient = Readonly<{
     message?: string,
     signal?: AbortSignal,
   ): Promise<MaterialReceipt>;
+  /** Takes an attached file back: the material is archived and the coordinator told. */
+  removeMaterial(
+    tenantId: string,
+    projectId: string,
+    artifactId: string,
+    signal?: AbortSignal,
+  ): Promise<MaterialRemovedReceipt>;
   /** A filed approval_package version as a deterministic zip of its deck, PDF, README, manifest and documents. */
   downloadPackageZip(
     tenantId: string,

@@ -468,6 +468,16 @@ export const MaterialReceipt = type({
 });
 export type MaterialReceipt = typeof MaterialReceipt.infer;
 
+// A material the person took back: archived, so it leaves every list while its versions stay.
+export const MaterialRemovedReceipt = type({
+  "+": "reject",
+  artifactId: "string > 0",
+  title: "string",
+  // Whether a running coordinator was told the file is withdrawn.
+  told: "boolean",
+});
+export type MaterialRemovedReceipt = typeof MaterialRemovedReceipt.infer;
+
 // The attachment types the project's coordinator model reads, and Interchange's attachment limits.
 // Empty when the model's catalog offering declares neither vision-input nor document-input.
 export const AcceptedMaterials = type({