diff --git a/app/src/components/flows/WorkflowCopilotPanel.tsx b/app/src/components/flows/WorkflowCopilotPanel.tsx
index 67902ae68..657e6bbb6 100644
--- a/app/src/components/flows/WorkflowCopilotPanel.tsx
+++ b/app/src/components/flows/WorkflowCopilotPanel.tsx
@@ -157,6 +157,7 @@ export default function WorkflowCopilotPanel({
   const {
     threadId,
     sending,
+    turnActive,
     proposal,
     capped,
     displayMessages,
@@ -529,6 +530,7 @@ export default function WorkflowCopilotPanel({
             <ToolTimelineBlock
               entries={toolTimeline}
               liveResponse={hasLiveText ? liveResponseText : undefined}
+              turnActive={turnActive}
             />
           </div>
         )}
diff --git a/app/src/features/conversations/Conversations.tsx b/app/src/features/conversations/Conversations.tsx
index aa3e6ef24..a25ff26c8 100644
--- a/app/src/features/conversations/Conversations.tsx
+++ b/app/src/features/conversations/Conversations.tsx
@@ -1983,6 +1983,15 @@ const Conversations = ({
             entries={selectedThreadToolTimeline}
             onViewDetails={openScopedDetail}
             onViewWholeRun={openWholeRunSource}
+            // Reuse `isSending` rather than a raw `in` membership check on
+            // `inferenceTurnLifecycleByThread`: that map also carries
+            // `'interrupted'` entries (a turn that crashed mid-flight in a
+            // PRIOR core process, written by `hydrateRuntimeFromSnapshot` on
+            // cold boot) which have no live driver and must NOT read as an
+            // active turn, or stale disclosure state leaks into a later
+            // retry. `isSending` already excludes it (only `'started'` /
+            // `'streaming'`, same as this component's own live-turn checks).
+            turnActive={isSending}
           />
         ) : (
           // Transcript-only turn: reasoning/narration was streamed but no tool
diff --git a/app/src/features/conversations/components/ToolTimelineBlock.tsx b/app/src/features/conversations/components/ToolTimelineBlock.tsx
index 8c8d1484c..33249b07f 100644
--- a/app/src/features/conversations/components/ToolTimelineBlock.tsx
+++ b/app/src/features/conversations/components/ToolTimelineBlock.tsx
@@ -1,5 +1,5 @@
 import createDebug from 'debug';
-import { useEffect, useRef, useState } from 'react';
+import { useState } from 'react';
 
 import WorktreeActions from '../../../components/worktree/WorktreeActions';
 import { useT } from '../../../lib/i18n/I18nContext';
@@ -454,6 +454,7 @@ export function ToolTimelineBlock({
   onViewWholeRun,
   expandAllRows = false,
   liveResponse,
+  turnActive,
 }: {
   entries: ToolTimelineEntry[];
   /** Opens the full-transcript drawer for a subagent row. When omitted,
@@ -479,6 +480,16 @@ export function ToolTimelineBlock({
    * Omitted/empty once the turn settles — the final answer is the message
    * bubble. */
   liveResponse?: string;
+  /** Whether a turn is in flight on this thread's lifecycle
+   * (`inferenceTurnLifecycleByThread`), the same signal the chat threads page
+   * uses. When provided, the sticky `userOverrideOpen` reset fires on THIS
+   * value's true→false edge — once per USER TURN — instead of on `isRunning`'s
+   * edge, which flips once PER SUB-AGENT within a single turn (each
+   * subagent spawn→settle) and made the panel flicker open/closed as
+   * sub-agents ran (regression from #5008). Falls back to `isRunning` when
+   * omitted, which is correct for a settled/past-turn render (there is no
+   * turn left to track). */
+  turnActive?: boolean;
 }) {
   const { t } = useT();
 
@@ -500,24 +511,44 @@ export function ToolTimelineBlock({
   const [userOverrideOpen, setUserOverrideOpen] = useState<boolean | null>(null);
 
   // Whether *any* entry is currently running — computed here (ahead of the
-  // `entries.length === 0` early return below) purely so the reset effect
-  // that follows is an unconditional hook call every render; order doesn't
-  // matter for this existence check, unlike `latestRunningEntryId` further
-  // down, which needs the seq-sorted order to pick a specific "latest" row.
+  // `entries.length === 0` early return below) purely so the render-time
+  // reset adjustment that follows runs every render; order doesn't matter for
+  // this existence check, unlike `latestRunningEntryId` further down, which
+  // needs the seq-sorted order to pick a specific "latest" row.
   const isRunning = entries.some(entry => entry.status === 'running');
 
-  // Reset the user's manual open/close override on the running→settled edge
-  // (a turn just finished) so the auto-collapse applies to the just-settled
-  // turn. The override only sticks WITHIN a turn — preventing involuntary
-  // mid-feedback collapse (#4942) — not permanently across turns.
-  const prevIsRunningRef = useRef(false);
-  useEffect(() => {
-    if (prevIsRunningRef.current && !isRunning) {
+  // The signal the reset below watches for a "turn just settled" edge. Prefer
+  // the real TURN lifecycle (`turnActive`, sourced from
+  // `inferenceTurnLifecycleByThread` — the same signal the chat threads page
+  // uses) when the caller supplies it: it flips true→false exactly once per
+  // USER TURN. `isRunning` is only a fallback for callers with no turn
+  // lifecycle to hand (e.g. a settled/past-turn render, where entries never
+  // change again anyway) — used directly it flips once PER SUB-AGENT within a
+  // single turn (each subagent spawn→settle), which reset the override (and
+  // so auto-collapsed the panel) repeatedly within one turn and made it
+  // flicker open/closed as sub-agents ran (#5008 regression).
+  const settleSignal = turnActive ?? isRunning;
+
+  // Reset the user's manual open/close override on the settleSignal's
+  // true→false edge (a turn just finished) so the auto-collapse applies to
+  // the just-settled turn. The override only sticks WITHIN a turn —
+  // preventing involuntary mid-feedback collapse (#4942) — not permanently
+  // across turns.
+  //
+  // Done as a render-time adjustment (comparing against `prevSettleSignal`
+  // state and calling both setters synchronously in the render body), not a
+  // `useEffect`, per React's documented pattern for resetting state on a prop
+  // transition: it bails out and re-renders with the reset applied before
+  // paint, instead of committing a stale (still-collapsed/expanded) frame
+  // and only correcting it a tick later once the effect runs.
+  const [prevSettleSignal, setPrevSettleSignal] = useState(settleSignal);
+  if (prevSettleSignal !== settleSignal) {
+    if (prevSettleSignal && !settleSignal) {
       log('agent-task-insights: turn settled (running→done), resetting user override');
       setUserOverrideOpen(null);
     }
-    prevIsRunningRef.current = isRunning;
-  }, [isRunning]);
+    setPrevSettleSignal(settleSignal);
+  }
 
   if (entries.length === 0) return null;
 
diff --git a/app/src/features/conversations/components/__tests__/ToolTimelineBlock.test.tsx b/app/src/features/conversations/components/__tests__/ToolTimelineBlock.test.tsx
index c8ddb1d6d..a054d60ff 100644
--- a/app/src/features/conversations/components/__tests__/ToolTimelineBlock.test.tsx
+++ b/app/src/features/conversations/components/__tests__/ToolTimelineBlock.test.tsx
@@ -581,6 +581,148 @@ describe('ToolTimelineBlock — agentic task insights surface', () => {
     });
   });
 
+  // #5008 shipped the reset-on-settle fix using the `isRunning` true→false
+  // edge, but that edge fires once PER SUB-AGENT within a single turn (each
+  // subagent_spawned/subagent_completed pair toggles `isRunning`), not once
+  // per turn — so on a multi-sub-agent turn the panel's override reset (and
+  // its auto-collapse) fired repeatedly, flickering the panel open/closed
+  // as each sub-agent came and went. `turnActive` — sourced from
+  // `inferenceTurnLifecycleByThread`, the same lifecycle the chat threads
+  // page uses for `isSending` — transitions exactly once per USER TURN, so
+  // passing it in makes the reset track the turn instead of any single
+  // sub-agent.
+  describe('with turnActive prop', () => {
+    it('does not reset the user override while turnActive stays true across multiple isRunning toggles, only resetting (and auto-collapsing) when turnActive itself goes false', () => {
+      const subagentARunning: ToolTimelineEntry[] = [
+        { id: 'a', name: 'subagent:researcher', round: 1, seq: 0, status: 'running' },
+      ];
+      const { rerender } = renderInStore(
+        <ToolTimelineBlock entries={subagentARunning} turnActive />
+      );
+      // Sub-agent A running, turn active → auto-open (no override yet).
+      expect(screen.getByTestId('agent-task-insights')).toHaveAttribute('open');
+
+      // Sub-agent A settles: `isRunning` flips true→false, but the whole
+      // TURN is still active. Pre-fix this alone would have reset the
+      // (nonexistent, still null) override — here there's nothing to reset,
+      // but the auto rule alone already collapses it (autoOpen tracks
+      // `isRunning`, unchanged by this fix).
+      const subagentASettled: ToolTimelineEntry[] = [
+        { id: 'a', name: 'subagent:researcher', round: 1, seq: 0, status: 'success' },
+      ];
+      rerender(
+        <Provider store={store}>
+          <ToolTimelineBlock entries={subagentASettled} turnActive />
+        </Provider>
+      );
+      expect(screen.getByTestId('agent-task-insights')).not.toHaveAttribute('open');
+
+      // The user manually expands it while the turn is still in flight.
+      fireEvent.click(screen.getByText('Agentic task insights'));
+      expect(screen.getByTestId('agent-task-insights')).toHaveAttribute('open');
+
+      // Sub-agent B spawns: `isRunning` flips false→true again. Still one
+      // turn (`turnActive` unchanged) — the user's override must hold.
+      const subagentBRunning: ToolTimelineEntry[] = [
+        ...subagentASettled,
+        { id: 'b', name: 'subagent:coder', round: 1, seq: 1, status: 'running' },
+      ];
+      rerender(
+        <Provider store={store}>
+          <ToolTimelineBlock entries={subagentBRunning} turnActive />
+        </Provider>
+      );
+      expect(screen.getByTestId('agent-task-insights')).toHaveAttribute('open');
+
+      // Sub-agent B settles: `isRunning` flips true→false a second time
+      // within the SAME turn. This is exactly the edge that used to reset
+      // the override and cause the flicker (#5008 regression) — with
+      // `turnActive` supplied it must NOT reset; the user's expand sticks.
+      const subagentBSettled: ToolTimelineEntry[] = [
+        ...subagentASettled,
+        { id: 'b', name: 'subagent:coder', round: 1, seq: 1, status: 'success' },
+      ];
+      rerender(
+        <Provider store={store}>
+          <ToolTimelineBlock entries={subagentBSettled} turnActive />
+        </Provider>
+      );
+      expect(screen.getByTestId('agent-task-insights')).toHaveAttribute('open');
+
+      // Only when the TURN itself ends (`turnActive` true→false) does the
+      // override reset — the panel then auto-collapses since the run is done.
+      rerender(
+        <Provider store={store}>
+          <ToolTimelineBlock entries={subagentBSettled} turnActive={false} />
+        </Provider>
+      );
+      expect(screen.getByTestId('agent-task-insights')).not.toHaveAttribute('open');
+    });
+
+    it('keeps a mid-turn manual collapse intact across a sub-agent settling, only reopening per the auto rule once turnActive ends', () => {
+      const subagentARunning: ToolTimelineEntry[] = [
+        { id: 'a', name: 'subagent:researcher', round: 1, seq: 0, status: 'running' },
+      ];
+      const { rerender } = renderInStore(
+        <ToolTimelineBlock entries={subagentARunning} turnActive />
+      );
+      expect(screen.getByTestId('agent-task-insights')).toHaveAttribute('open');
+
+      // The user explicitly collapses it while sub-agent A is still running.
+      fireEvent.click(screen.getByText('Agentic task insights'));
+      expect(screen.getByTestId('agent-task-insights')).not.toHaveAttribute('open');
+
+      // Sub-agent A settles, sub-agent B spawns and settles too — all within
+      // the same turn (`turnActive` stays true throughout). None of these
+      // `isRunning` toggles may reopen the panel against the user's choice.
+      const afterSubagentB: ToolTimelineEntry[] = [
+        { id: 'a', name: 'subagent:researcher', round: 1, seq: 0, status: 'success' },
+        { id: 'b', name: 'subagent:coder', round: 1, seq: 1, status: 'running' },
+      ];
+      rerender(
+        <Provider store={store}>
+          <ToolTimelineBlock entries={afterSubagentB} turnActive />
+        </Provider>
+      );
+      expect(screen.getByTestId('agent-task-insights')).not.toHaveAttribute('open');
+
+      const bothSettled: ToolTimelineEntry[] = [
+        { id: 'a', name: 'subagent:researcher', round: 1, seq: 0, status: 'success' },
+        { id: 'b', name: 'subagent:coder', round: 1, seq: 1, status: 'success' },
+      ];
+      rerender(
+        <Provider store={store}>
+          <ToolTimelineBlock entries={bothSettled} turnActive />
+        </Provider>
+      );
+      expect(screen.getByTestId('agent-task-insights')).not.toHaveAttribute('open');
+
+      // The turn ends — override resets; auto rule (settled, not running)
+      // keeps it collapsed, same outcome but for the right reason now.
+      rerender(
+        <Provider store={store}>
+          <ToolTimelineBlock entries={bothSettled} turnActive={false} />
+        </Provider>
+      );
+      expect(screen.getByTestId('agent-task-insights')).not.toHaveAttribute('open');
+
+      // Both sides of that transition read "collapsed", which a STALE `false`
+      // override would also produce — prove the override actually reset (not
+      // just that it happened to still agree with the auto rule) by starting
+      // a brand-new turn: the auto rule alone (isRunning) should now govern,
+      // reopening the panel with no further user interaction.
+      const newTurnRunning: ToolTimelineEntry[] = [
+        { id: 'c', name: 'subagent:researcher', round: 2, seq: 0, status: 'running' },
+      ];
+      rerender(
+        <Provider store={store}>
+          <ToolTimelineBlock entries={newTurnRunning} turnActive />
+        </Provider>
+      );
+      expect(screen.getByTestId('agent-task-insights')).toHaveAttribute('open');
+    });
+  });
+
   it('renders the tool result output inside the expanded row', () => {
     const entries: ToolTimelineEntry[] = [
       {
diff --git a/app/src/hooks/useWorkflowBuilderChat.test.ts b/app/src/hooks/useWorkflowBuilderChat.test.ts
index 20cf47c07..78caf651f 100644
--- a/app/src/hooks/useWorkflowBuilderChat.test.ts
+++ b/app/src/hooks/useWorkflowBuilderChat.test.ts
@@ -2,7 +2,7 @@ import { act, renderHook, waitFor } from '@testing-library/react';
 import { beforeEach, describe, expect, it, vi } from 'vitest';
 
 import type { BuilderTurnResult } from '../services/api/flowsApi';
-import type { WorkflowProposal } from '../store/chatRuntimeSlice';
+import type { InferenceTurnLifecycle, WorkflowProposal } from '../store/chatRuntimeSlice';
 import type { ThreadMessage } from '../types/thread';
 import { useWorkflowBuilderChat, type WorkflowBuilderSendResult } from './useWorkflowBuilderChat';
 
@@ -21,6 +21,7 @@ const selectorState = vi.hoisted(() => ({
   messagesByThreadId: {} as Record<string, unknown[]>,
   toolTimelineByThread: {} as Record<string, unknown[]>,
   streamingAssistantByThread: {} as Record<string, { content: string }>,
+  inferenceTurnLifecycleByThread: {} as Record<string, InferenceTurnLifecycle>,
 }));
 vi.mock('../store/hooks', () => ({
   useAppDispatch: () => dispatch,
@@ -31,6 +32,7 @@ vi.mock('../store/hooks', () => ({
         pendingWorkflowProposalsByThread: selectorState.proposals,
         toolTimelineByThread: selectorState.toolTimelineByThread,
         streamingAssistantByThread: selectorState.streamingAssistantByThread,
+        inferenceTurnLifecycleByThread: selectorState.inferenceTurnLifecycleByThread,
       },
     }),
 }));
@@ -43,6 +45,8 @@ vi.mock('../store/threadSlice', () => ({
   THREAD_NOT_FOUND_MESSAGE,
 }));
 vi.mock('../store/chatRuntimeSlice', () => ({
+  beginInferenceTurn: (p: unknown) => ({ type: 'beginInferenceTurn', p }),
+  endInferenceTurn: (p: unknown) => ({ type: 'endInferenceTurn', p }),
   clearWorkflowProposalForThread: (p: unknown) => ({ type: 'clearProposal', p }),
   setWorkflowProposalForThread: (p: unknown) => ({ type: 'setProposal', p }),
   fetchAndHydrateTurnState: (threadId: string) => ({ type: 'fetchAndHydrateTurnState', threadId }),
@@ -68,6 +72,7 @@ describe('useWorkflowBuilderChat', () => {
     selectorState.messagesByThreadId = {};
     selectorState.toolTimelineByThread = {};
     selectorState.streamingAssistantByThread = {};
+    selectorState.inferenceTurnLifecycleByThread = {};
     dispatch.mockReset().mockImplementation((action: { type: string }) => {
       if (action.type === 'createNewThread') {
         return { unwrap: () => Promise.resolve({ id: 'builder-1' }) };
@@ -107,6 +112,86 @@ describe('useWorkflowBuilderChat', () => {
     await waitFor(() => expect(result.current.threadId).toBe('builder-1'));
   });
 
+  it('seeds and clears the shared turn-lifecycle entry around the blocking flows_build call', async () => {
+    // Regression test: `turnActive` (derived from `inferenceTurnLifecycleByThread`
+    // below) must reflect a REAL turn in flight, or `ToolTimelineBlock`'s
+    // `turnActive ?? isRunning` fallback is defeated — a `false` `turnActive`
+    // (as opposed to `undefined`) short-circuits nullish coalescing and never
+    // falls back to `isRunning`, permanently disabling the panel's settle-edge
+    // override reset for the copilot surface this hook drives.
+    let sawActiveDuringCall = false;
+    buildWorkflow.mockImplementation(async () => {
+      // `beginInferenceTurn` must have been dispatched — and not yet cleared —
+      // by the time the blocking RPC is in flight.
+      sawActiveDuringCall = dispatch.mock.calls.some(
+        ([a]) => (a as { type: string }).type === 'beginInferenceTurn'
+      );
+      return okResult();
+    });
+
+    const { result } = renderHook(() => useWorkflowBuilderChat());
+    await act(async () => {
+      await result.current.send({
+        displayText: 'hi',
+        request: { mode: 'create', instruction: 'x' },
+      });
+    });
+
+    expect(sawActiveDuringCall).toBe(true);
+    const calls = dispatch.mock.calls.map(([a]) => a as { type: string; p?: unknown });
+    const beginIndex = calls.findIndex(a => a.type === 'beginInferenceTurn');
+    const endIndex = calls.findIndex(a => a.type === 'endInferenceTurn');
+    expect(beginIndex).toBeGreaterThanOrEqual(0);
+    expect(endIndex).toBeGreaterThan(beginIndex);
+    expect(calls[beginIndex].p).toEqual({ threadId: 'builder-1' });
+    expect(calls[endIndex].p).toEqual({ threadId: 'builder-1' });
+  });
+
+  it('clears the turn-lifecycle entry even when the blocking flows_build call throws', async () => {
+    buildWorkflow.mockRejectedValue(new Error('network blip'));
+
+    const { result } = renderHook(() => useWorkflowBuilderChat());
+    await act(async () => {
+      await result.current.send({
+        displayText: 'hi',
+        request: { mode: 'create', instruction: 'x' },
+      });
+    });
+
+    // A failed turn must not leak the lifecycle entry — otherwise `turnActive`
+    // would stay stuck `true` forever, since no `chat_done` ever arrives for a
+    // turn that never reached the server.
+    expect(dispatch).toHaveBeenCalledWith(
+      expect.objectContaining({ type: 'endInferenceTurn', p: { threadId: 'builder-1' } })
+    );
+  });
+
+  it("treats an 'interrupted' lifecycle entry as NOT active (no live driver behind it)", () => {
+    // 'interrupted' is written by `hydrateRuntimeFromSnapshot` for a turn that
+    // crashed mid-flight in a PRIOR core process (cold-boot rehydrate) — there
+    // is no live driver streaming for it, so `turnActive` must stay `false`,
+    // or stale disclosure state (from before the crash) leaks into whatever
+    // the user does next on this thread.
+    const interrupted: InferenceTurnLifecycle = 'interrupted';
+    selectorState.inferenceTurnLifecycleByThread = { 'builder-1': interrupted };
+
+    const { result } = renderHook(() => useWorkflowBuilderChat('builder-1'));
+
+    expect(result.current.turnActive).toBe(false);
+  });
+
+  it("treats 'started'/'streaming' lifecycle entries as active", () => {
+    const started: InferenceTurnLifecycle = 'started';
+    selectorState.inferenceTurnLifecycleByThread = { 'builder-1': started };
+    const { result: startedResult } = renderHook(() => useWorkflowBuilderChat('builder-1'));
+    expect(startedResult.current.turnActive).toBe(true);
+
+    const streaming: InferenceTurnLifecycle = 'streaming';
+    selectorState.inferenceTurnLifecycleByThread = { 'builder-1': streaming };
+    const { result: streamingResult } = renderHook(() => useWorkflowBuilderChat('builder-1'));
+    expect(streamingResult.current.turnActive).toBe(true);
+  });
+
   it('surfaces the proposal the builder returned by dispatching it into the store', async () => {
     const proposal: WorkflowProposal = {
       name: 'Digest',
diff --git a/app/src/hooks/useWorkflowBuilderChat.ts b/app/src/hooks/useWorkflowBuilderChat.ts
index fa2710243..d17bce0f1 100644
--- a/app/src/hooks/useWorkflowBuilderChat.ts
+++ b/app/src/hooks/useWorkflowBuilderChat.ts
@@ -27,9 +27,15 @@
 import createDebug from 'debug';
 import { useCallback, useEffect, useMemo, useRef, useState } from 'react';
 
-import { type BuilderTurnRequest, buildWorkflow } from '../services/api/flowsApi';
 import {
+  type BuilderTurnRequest,
+  type BuilderTurnResult,
+  buildWorkflow,
+} from '../services/api/flowsApi';
+import {
+  beginInferenceTurn,
   clearWorkflowProposalForThread,
+  endInferenceTurn,
   fetchAndHydrateTurnHistory,
   fetchAndHydrateTurnState,
   setWorkflowProposalForThread,
@@ -94,6 +100,15 @@ export interface UseWorkflowBuilderChat {
   threadId: string | null;
   /** True while a builder turn is in flight on this thread. */
   sending: boolean;
+  /**
+   * Whether a turn is in flight on this thread per the runtime's
+   * `inferenceTurnLifecycleByThread` — the same turn-lifecycle signal the main
+   * chat threads page uses to derive `isSending`. Passed through as
+   * `ToolTimelineBlock`'s `turnActive` prop so the panel's sticky
+   * open/collapse override resets once per TURN instead of once per
+   * sub-agent (see that component's doc for the #5008 flicker this fixes).
+   */
+  turnActive: boolean;
   /** The latest proposal the agent returned on this thread, or `null`. */
   proposal: WorkflowProposal | null;
   /**
@@ -196,6 +211,21 @@ export function useWorkflowBuilderChat(seedThreadId?: string | null): UseWorkflo
   const streamingAssistantByThread = useAppSelector(
     state => state.chatRuntime.streamingAssistantByThread
   );
+  const inferenceTurnLifecycleByThread = useAppSelector(
+    state => state.chatRuntime.inferenceTurnLifecycleByThread
+  );
+
+  // A turn is in flight on this thread iff its lifecycle entry is `'started'`
+  // or `'streaming'` — NOT `'interrupted'`, which `hydrateRuntimeFromSnapshot`
+  // (chatRuntimeSlice.ts) writes for a turn that crashed mid-flight in a PRIOR
+  // core process (cold-boot rehydrate): there is no live driver behind it, so
+  // treating it as "active" would leak stale disclosure state into a later,
+  // genuinely new turn on this same thread. Mirrors `Conversations.tsx`'s
+  // `isSending` derivation (same explicit two-state check, not a broad `in`
+  // membership test) so the copilot's `ToolTimelineBlock` resets its sticky
+  // override on the same real turn-settle edge the main chat uses.
+  const threadLifecycle = threadId != null ? inferenceTurnLifecycleByThread[threadId] : undefined;
+  const turnActive = threadLifecycle === 'started' || threadLifecycle === 'streaming';
 
   // Prefer the runtime's streamed proposal (populated on this thread by
   // `ChatRuntimeProvider` as the builder's `propose_workflow`/`revise_workflow`
@@ -343,8 +373,37 @@ export function useWorkflowBuilderChat(seedThreadId?: string | null): UseWorkflo
         // slices as the turn runs, so this hook must NOT also append the agent
         // reply (doing so would double it — B26). We still await the blocking
         // result for its `proposal`/`error` signal.
+        //
+        // Seed the shared turn-lifecycle entry for this thread (mirrors
+        // `Conversations.tsx`'s `beginInferenceTurn` dispatch on send) so
+        // `turnActive` above (`threadId in inferenceTurnLifecycleByThread`)
+        // reflects a REAL turn in flight. Without this, nothing ever creates
+        // an entry for the builder's dedicated thread — `ChatRuntimeProvider`
+        // only *updates* an existing entry (`markInferenceTurnStreaming` is a
+        // no-op unless one is already present) — so `turnActive` would stay
+        // `false` for the entire life of every builder turn. Because it's a
+        // *boolean* `false` rather than `undefined`, that permanently defeats
+        // `ToolTimelineBlock`'s `turnActive ?? isRunning` fallback (nullish
+        // coalescing only falls back on null/undefined, never on `false`),
+        // so the panel's settle-edge override reset — the entire point of
+        // this fix — would never fire for the copilot surface it targets.
+        dispatch(beginInferenceTurn({ threadId: targetThreadId }));
         log('send: running flows_build thread=%s mode=%s', targetThreadId, request.mode);
-        const result = await buildWorkflow(request, targetThreadId);
+        let result: BuilderTurnResult;
+        try {
+          result = await buildWorkflow(request, targetThreadId);
+        } finally {
+          // The blocking RPC settling (success or error) IS the turn ending —
+          // clear eagerly here rather than relying solely on
+          // `ChatRuntimeProvider`'s generic `chat_done` listener (which also
+          // calls `endInferenceTurn` for this thread — redundant but
+          // harmless, since it's a plain delete). If the server-side turn
+          // never reaches `chat_done` (e.g. this call throws before the core
+          // ever starts one), that listener never fires and the lifecycle
+          // entry would otherwise leak, stranding `turnActive` — and the
+          // panel it drives — permanently `true`.
+          dispatch(endInferenceTurn({ threadId: targetThreadId }));
+        }
 
         // Surface the proposal via the same store slice the streamed path used,
         // so `WorkflowProposalCard` / the copilot preview render unchanged. This
@@ -412,6 +471,7 @@ export function useWorkflowBuilderChat(seedThreadId?: string | null): UseWorkflo
   return {
     threadId,
     sending,
+    turnActive,
     proposal,
     capped,
     messages,