diff --git a/.lane/memory/packages/ui/src/components/timeline/layout.ts/01M53FDJQ4C0BGDGXNAY5GK09T-a-file-block-s-cache-key-inc.md b/.lane/memory/packages/ui/src/components/timeline/layout.ts/01M53FDJQ4C0BGDGXNAY5GK09T-a-file-block-s-cache-key-inc.md
index d5b2fbce..b980ddd1 100644
--- a/.lane/memory/packages/ui/src/components/timeline/layout.ts/01M53FDJQ4C0BGDGXNAY5GK09T-a-file-block-s-cache-key-inc.md
+++ b/.lane/memory/packages/ui/src/components/timeline/layout.ts/01M53FDJQ4C0BGDGXNAY5GK09T-a-file-block-s-cache-key-inc.md
@@ -4,9 +4,9 @@ anchor: '@file'
 created: 2026-10-16T23:05:41Z
 norm: '1'
 sig: ce515648b5bedef2
-body_hash: 433c39db9d6384fd
-raw_hash: ea74d2e9c0710659
-vouched: 2026-10-22T22:05:34Z
+body_hash: 91ade5f09dcd49cf
+raw_hash: 2c9b0b22266f1342
+vouched: 2026-10-27T14:07:44Z
 lines: 1-912
 ---
 
diff --git a/.lane/memory/packages/ui/src/components/timeline/layout.ts/01M5JTBNVCVRCB6KWWK6JSWF67-bubble-rows-measure-at-conte.md b/.lane/memory/packages/ui/src/components/timeline/layout.ts/01M5JTBNVCVRCB6KWWK6JSWF67-bubble-rows-measure-at-conte.md
index dda78807..a4cde673 100644
--- a/.lane/memory/packages/ui/src/components/timeline/layout.ts/01M5JTBNVCVRCB6KWWK6JSWF67-bubble-rows-measure-at-conte.md
+++ b/.lane/memory/packages/ui/src/components/timeline/layout.ts/01M5JTBNVCVRCB6KWWK6JSWF67-bubble-rows-measure-at-conte.md
@@ -4,8 +4,9 @@ anchor: function itemHeight
 created: 2026-10-22T22:05:29Z
 norm: '1'
 sig: 3c40d8dd5f73026a
-body_hash: 446268a0d25debb4
-raw_hash: e696d2f48fa62bb6
+body_hash: 9b7f5ad1d6fa2633
+raw_hash: c051d6140c4c9315
+vouched: 2026-10-27T14:07:44Z
 lines: 742-831
 ---
 
diff --git a/.lane/memory/packages/ui/src/components/timeline/layout.ts/01M5YV02MCCK1PGFNC7FJ58XPJ-itemheight-and-the-timeline.md b/.lane/memory/packages/ui/src/components/timeline/layout.ts/01M5YV02MCCK1PGFNC7FJ58XPJ-itemheight-and-the-timeline.md
new file mode 100644
index 00000000..2489de6f
--- /dev/null
+++ b/.lane/memory/packages/ui/src/components/timeline/layout.ts/01M5YV02MCCK1PGFNC7FJ58XPJ-itemheight-and-the-timeline.md
@@ -0,0 +1,12 @@
+---
+id: 01M5YV02MCCK1PGFNC7FJ58XPJ
+anchor: function toolGroupOpen
+created: 2026-10-27T14:07:31Z
+norm: '1'
+sig: 609e7680e155462e
+body_hash: 97cc55c00fcde4b1
+raw_hash: 34d7822a7841af58
+lines: 859-861
+---
+
+itemHeight and the timeline render must both decide a tool group's openness with toolGroupOpen, or measured heights drift from what renders
diff --git a/packages/channel/src/seed.ts b/packages/channel/src/seed.ts
index 96bca22d..9fe43e8b 100644
--- a/packages/channel/src/seed.ts
+++ b/packages/channel/src/seed.ts
@@ -72,7 +72,7 @@ async function history(harness: Harness, chat: ConversationId): Promise<EntryRec
 		entries.push(...page.items);
 		cursor = page.next;
 	} while (cursor);
-	return entries.reverse();
+	return entries.toReversed();
 }
 
 /**
diff --git a/packages/ui/src/components/timeline/layout.ts b/packages/ui/src/components/timeline/layout.ts
index 5cfaf545..191ff6c1 100644
--- a/packages/ui/src/components/timeline/layout.ts
+++ b/packages/ui/src/components/timeline/layout.ts
@@ -780,7 +780,7 @@ function itemHeight(
 			let working = content - BUBBLE_PAD_X * 2;
 			let header = turn.final ? workingHeaderHeight(turn.recap, working) : 0;
 			let expanded = !turn.final || openWorking.has(group.id);
-			h += workingSectionHeight(turn.working, blocks, working, open, header, expanded);
+			h += workingSectionHeight(turn.working, blocks, working, open, header, expanded, !turn.final);
 			children++;
 		}
 
@@ -837,13 +837,14 @@ function workingSectionHeight(
 	open: Set<string>,
 	header: number,
 	expanded: boolean,
+	live: boolean,
 ): number {
 	let h = BUBBLE_PAD_Y * 2 + BUBBLE_BORDER * 2 + header;
 	if (!expanded) return h;
 	let content = 0;
 	let count = 0;
 	for (let item of items) {
-		content += workingHeight(item, blocks, width, open);
+		content += workingHeight(item, blocks, width, open, live);
 		count++;
 	}
 	if (count > 1) content += (count - 1) * CONTENT_GAP;
@@ -851,6 +852,19 @@ function workingSectionHeight(
 	return h + content;
 }
 
+/**
+ * While a turn runs, its tool groups are open so the work stays visible; once it finishes they
+ * fold. `open` holds the groups someone toggled away from that default, keyed by toolGroupKey.
+ */
+function toolGroupOpen(id: string, open: ReadonlySet<string>, live: boolean): boolean {
+	return open.has(toolGroupKey(id, live)) !== live;
+}
+
+/** A separate key while live, so closing a running group doesn't open it once the turn folds. */
+function toolGroupKey(id: string, live: boolean): string {
+	return live ? id + ":live" : id;
+}
+
 /** The folded turn's label row, below its recap when there is one. */
 function workingHeaderHeight(recap: string | undefined, width: number): number {
 	if (!recap) return WORKING_SUMMARY_HEIGHT;
@@ -864,6 +878,7 @@ function workingHeight(
 	blocks: Map<string, Block[]>,
 	width: number,
 	open: Set<string>,
+	live: boolean,
 ): number {
 	let b = blocks.get(item.id) || [];
 	if (item.type === "text") {
@@ -873,7 +888,7 @@ function workingHeight(
 	}
 
 	let h = TOOL_GROUP_ROW_HEIGHT + TOOL_GROUP_PAD_Y * 2;
-	if (!open.has(item.id) || !b.length) return h;
+	if (!toolGroupOpen(item.id, open, live) || !b.length) return h;
 	h += measureRow(b, width - TOOL_LIST_INDENT).height;
 	h += b.length * CONTENT_GAP;
 	return h;
@@ -910,6 +925,8 @@ export {
 	TOOL_GROUP_PAD_Y,
 	TOOL_GROUP_ROW_HEIGHT,
 	TOOL_LIST_INDENT,
+	toolGroupKey,
+	toolGroupOpen,
 	TURN_GAP,
 	useBlockMap,
 	WORKING_SUMMARY_HEIGHT,
diff --git a/packages/ui/src/components/timeline/timeline.tsx b/packages/ui/src/components/timeline/timeline.tsx
index 8b810679..9ed22868 100644
--- a/packages/ui/src/components/timeline/timeline.tsx
+++ b/packages/ui/src/components/timeline/timeline.tsx
@@ -80,6 +80,8 @@ import {
 	TOOL_GROUP_PAD_Y,
 	TOOL_GROUP_ROW_HEIGHT,
 	TOOL_LIST_INDENT,
+	toolGroupKey,
+	toolGroupOpen,
 	TURN_GAP,
 	useBlockMap,
 	WORKING_SUMMARY_HEIGHT,
@@ -469,7 +471,7 @@ function AgentWorkingContextView(
 					style={{ gap: CONTENT_GAP }}
 				>
 					{turn.working.map((w, index) => {
-						let open = w.type === "tools" && openGroups.has(w.id);
+						let open = w.type === "tools" && toolGroupOpen(w.id, openGroups, live);
 						return (
 							<AgentWorkingItemView
 								key={w.id}
@@ -478,7 +480,7 @@ function AgentWorkingContextView(
 								width={width}
 								open={open}
 								expanded={open}
-								onToggle={onToggleGroup}
+								onToggle={id => onToggleGroup(toolGroupKey(id, live))}
 								live={live}
 								index={index}
 							/>