@@ -2151,11 +2151,6 @@ describe('useChat remount send recovery', () => {
     expect(allQueuedMessages()).toHaveLength(0)
   })
 
-  /**
-   * After a Stop of the first message, only the follow-up was the user's
-   * intent: the Stop's POST is left to the server, nothing withdraws it, and the
-   * next mount sends just the follow-up, once.
-   */
   /**
    * A first message held at the queue head after a remount may already be a
    * turn on the server. Editing it would send different text under a new id,
@@ -2204,6 +2199,199 @@ describe('useChat remount send recovery', () => {
     })
   })
 
+  /** A chat with a turn running, so anything sent to it waits in its queue. */
+  function renderBusyChat(id: string) {
+    const history: MothershipChatHistory = {
+      id,
+      mode: 'agent',
+      title: 'Busy',
+      messages: [],
+      activeStreamId: 'turn-still-running',
+      resources: [],
+    }
+    mockRequestJson.mockImplementation(() => Promise.resolve({ chat: history }))
+    vi.stubGlobal('fetch', async (input: RequestInfo | URL, init?: RequestInit) => {
+      if (String(input).includes('/api/mothership/chat/stream')) {
+        if (String(input).includes('batch=true')) {
+          return Response.json({ success: true, events: [], status: 'streaming' })
+        }
+        return new Response(new ReadableStream<Uint8Array>(), {
+          headers: { 'Content-Type': 'text/event-stream' },
+        })
+      }
+      return fetchStub(input, init)
+    })
+    return { history, ...renderUseChatInChat(id, history) }
+  }
+
+  /**
+   * A send another surface withdrew arrives here under its original id, through
+   * the send event or the stored handoff. Queued behind a running turn, it may
+   * already be a turn on the server, so it can't be edited either.
+   */
+  it('does not let a withdrawn send handed to a busy chat be edited', async () => {
+    const { history, getResult } = renderBusyChat('chat-busy-on-handoff')
+    await waitFor(() => getResult().isSending)
+    await act(async () => {
+      await getResult().sendMessage('handed over from another surface', undefined, undefined, {
+        resumeUserMessageId: 'withdrawn-attempt',
+      })
+    })
+    const queued = useMothershipQueueStore.getState().queues[history.id]?.[0]
+    expect(queued?.resumeUserMessageId).toBe('withdrawn-attempt')
+
+    let edited: ReturnType<ReturnType<typeof useChat>['editQueuedMessage']>
+    await act(async () => {
+      edited = getResult().editQueuedMessage(queued?.id ?? '')
+    })
+
+    expect(edited).toBeUndefined()
+    expect(getResult().editingQueuedId).toBeNull()
+  })
+
+  /** A follow-up whose dispatch got no answer may have reached the server too. */
+  it('does not let a queued follow-up be edited after its send got no answer', async () => {
+    const history: MothershipChatHistory = {
+      id: 'chat-follow-up-unanswered',
+      mode: 'agent',
+      title: 'Unanswered',
+      messages: [],
+      activeStreamId: null,
+      resources: [],
+    }
+    mockRequestJson.mockImplementation(() => Promise.resolve({ chat: history }))
+    vi.stubGlobal('fetch', async (input: RequestInfo | URL, init?: RequestInit) => {
+      if (String(input) === '/api/mothership/chat' && init?.method === 'POST') {
+        state.postBodies.push(JSON.parse(String(init.body)))
+        throw new TypeError('Failed to fetch')
+      }
+      return fetchStub(input, init)
+    })
+    useMothershipQueueStore
+      .getState()
+      .enqueue(history.id, { id: 'follow-up', content: 'and the second invoice' })
+    const { getResult } = renderUseChatInChat(history.id, history)
+    await waitFor(
+      () =>
+        useMothershipQueueStore.getState().queues[history.id]?.[0]?.resumeUserMessageId !==
+        undefined
+    )
+
+    let edited: ReturnType<ReturnType<typeof useChat>['editQueuedMessage']>
+    await act(async () => {
+      edited = getResult().editQueuedMessage('follow-up')
+    })
+
+    expect(edited).toBeUndefined()
+    expect(useMothershipQueueStore.getState().queues[history.id]?.[0]).toMatchObject({
+      content: 'and the second invoice',
+      resumeUserMessageId: state.postBodies[0].userMessageId,
+    })
+  })
+
+  /**
+   * Send-now on a resumed message whose Stop of the running turn does not
+   * settle sends nothing. That says nothing about the earlier attempt the
+   * message resumes, so it must stay uneditable.
+   */
+  it('keeps a resumed message uneditable when its Send-now Stop does not settle', async () => {
+    state.abortSettlements = [false, false, false, false]
+    const { getResult } = renderUseChatInChat('chat-a')
+    await act(async () => {
+      void getResult().sendMessage('Original request')
+    })
+    await waitFor(() => state.postBodies.length === 1 && getResult().isSending)
+    await act(async () => {
+      await getResult().sendMessage('handed over from another surface', undefined, undefined, {
+        resumeUserMessageId: 'withdrawn-attempt',
+      })
+    })
+    await waitFor(() => useMothershipQueueStore.getState().queues['chat-a']?.length === 1)
+
+    await act(async () => {
+      await getResult()
+        .sendNow()
+        .catch(() => {})
+      await sleep(200)
+    })
+    const queued = useMothershipQueueStore.getState().queues['chat-a']?.[0]
+    let edited: ReturnType<ReturnType<typeof useChat>['editQueuedMessage']>
+    await act(async () => {
+      edited = getResult().editQueuedMessage(queued?.id ?? '')
+    })
+
+    expect(state.postBodies).toHaveLength(1)
+    expect(queued).toMatchObject({
+      content: 'handed over from another surface',
+      resumeUserMessageId: 'withdrawn-attempt',
+      admissionUnknown: true,
+    })
+    expect(edited).toBeUndefined()
+  })
+
+  /**
+   * A held message the server then refuses as busy is known not to be a turn
+   * there: the server answers a retry of an admitted id as a duplicate, never
+   * as busy. The user can edit it again.
+   */
+  it('lets a held message be edited again once the server refuses it as busy', async () => {
+    const history: MothershipChatHistory = {
+      id: 'chat-held-then-refused',
+      mode: 'agent',
+      title: 'Refused',
+      messages: [],
+      activeStreamId: null,
+      resources: [],
+    }
+    mockRequestJson.mockImplementation(() => Promise.resolve({ chat: history }))
+    vi.stubGlobal('fetch', async (input: RequestInfo | URL, init?: RequestInit) => {
+      const url = String(input)
+      if (url === '/api/mothership/chat' && init?.method === 'POST') {
+        state.postBodies.push(JSON.parse(String(init.body)))
+        return Response.json(
+          {
+            error: 'A response is already in progress for this chat.',
+            activeStreamId: 'turn-from-another-tab',
+          },
+          { status: 409 }
+        )
+      }
+      if (url.includes('/api/mothership/chat/stream')) {
+        if (url.includes('batch=true')) {
+          return Response.json({ success: true, events: [], status: 'streaming' })
+        }
+        return new Response(new ReadableStream<Uint8Array>(), {
+          headers: { 'Content-Type': 'text/event-stream' },
+        })
+      }
+      return fetchStub(input, init)
+    })
+    useMothershipQueueStore.getState().enqueue(history.id, {
+      id: 'held-first',
+      content: 'inspect the workspace',
+      resumeUserMessageId: 'first-attempt',
+      admissionUnknown: true,
+    })
+    const { getResult } = renderUseChatInChat(history.id, history)
+    await waitFor(() => state.postBodies.length === 1)
+    await waitFor(
+      () => useMothershipQueueStore.getState().queues[history.id]?.[0]?.id === 'held-first'
+    )
+
+    let edited: ReturnType<ReturnType<typeof useChat>['editQueuedMessage']>
+    await act(async () => {
+      edited = getResult().editQueuedMessage('held-first')
+    })
+
+    expect(edited?.content).toBe('inspect the workspace')
+    expect(getResult().editingQueuedId).toBe('held-first')
+  })
+
+  /**
+   * After a Stop of the first message, only the follow-up was the user's
+   * intent: the Stop's POST is left to the server, nothing withdraws it, and the
+   * next mount sends just the follow-up, once.
+   */
   it('sends only the follow-up after a failed Stop when the new-chat surface remounts', async () => {
     stubFirstPostPendingThenAdmitted()
     const first = renderHomeLikeSurface()
 
@@ -234,6 +234,18 @@ interface WithdrawnSendResult {
   busy?: boolean
   /** Not sent at all (its Stop handoff failed); kept queued for the user to send. */
   held?: boolean
+  /**
+   * The server refused this id outright (busy, or a predecessor still shutting
+   * down). It answers a retry of an admitted id as a duplicate instead, so the
+   * server is known not to have it, and its queue entry can be edited.
+   */
+  notAdmitted?: boolean
+  /**
+   * This attempt never reached the server (its Stop did not settle). That says
+   * nothing about an earlier attempt the message resumes, whose uncertainty it
+   * keeps.
+   */
+  neverSent?: boolean
 }
 
 /**
@@ -3887,7 +3899,7 @@ export function useChat(
             setError(getErrorMessage(err, 'Failed to stop the previous response'))
             /* Nothing was sent. Hand the message back so it stays in its chat's queue
                even if the user has switched chats since the Stop began. */
-            return { userMessageId, held: true }
+            return { userMessageId, held: true, neverSent: true }
           }
         }
 
@@ -4004,7 +4016,7 @@ export function useChat(
               }
               if (viewOnSend)
                 setError('Previous response is still shutting down; queued message was restored.')
-              return { userMessageId, held: true }
+              return { userMessageId, held: true, notAdmitted: true }
             }
             /** Withdraws this refused send so the queue retries it, under the same id, later. */
             const releaseRefusedSend = () => {
@@ -4040,7 +4052,7 @@ export function useChat(
                   exact: true,
                   refetchType: 'none',
                 })
-              return { userMessageId, busy: true }
+              return { userMessageId, busy: true, notAdmitted: true }
             }
             /* "Already sent" with no stream for it means the earlier attempt is still
                in flight on the server (or died before starting a turn), not that a turn
@@ -4414,6 +4426,11 @@ export function useChat(
           : {}),
         ...(result.held ? { retryRequired: true } : {}),
         ...(result.busy ? busyRetry(1) : {}),
+        admissionUnknown: result.notAdmitted
+          ? false
+          : result.neverSent
+            ? options?.resumeUserMessageId !== undefined
+            : true,
         ...((result.unreachable || result.busy) && activeChatKey.startsWith(PENDING_CHAT_KEY_PREFIX)
           ? { heldSurface: heldSendSurface }
           : {}),
@@ -5043,6 +5060,17 @@ export function useChat(
             ? { heldSurface: heldSendSurface }
             : {}),
           ...(withdrawnUserMessageId ? { resumeUserMessageId: withdrawnUserMessageId } : {}),
+          /* A refusal of this id settles it; an attempt that never left keeps the
+             earlier uncertainty; any other withdrawal may have reached the server. */
+          ...(withdrawn
+            ? {
+                admissionUnknown: withdrawn.notAdmitted
+                  ? false
+                  : withdrawn.neverSent
+                    ? dispatched.admissionUnknown === true
+                    : true,
+              }
+            : {}),
         })
       }
 
 
@@ -35,9 +35,10 @@ export interface QueuedMessage {
   assistantSearch?: WorkspaceSearchFilters
   assistantSearchLevel?: AssistantSearchLevel
   /**
-   * A first message withdrawn before the server answered. The server may
-   * already hold it as sent, so it goes out exactly as written, under its
-   * original id, and cannot be edited into a different message.
+   * An earlier attempt at this message got no answer, so the server may
+   * already hold it as sent. It goes out exactly as written, under that
+   * attempt's id, and cannot be edited into a different message. False once
+   * the server is known not to have it (it refused it, or it was never sent).
    */
   admissionUnknown?: boolean
 }
 
@@ -0,0 +1,42 @@
+/**
+ * @vitest-environment jsdom
+ */
+import { beforeEach, describe, expect, it } from 'vitest'
+import { useMothershipQueueStore } from '@/stores/mothership-queue/store'
+
+describe('useMothershipQueueStore rehydration', () => {
+  beforeEach(() => {
+    useMothershipQueueStore.getState().reset()
+    sessionStorage.clear()
+  })
+
+  it('treats a resumed message saved before the edit guard as possibly sent', async () => {
+    sessionStorage.setItem(
+      'mothership-queue',
+      JSON.stringify({
+        state: {
+          queues: {
+            'chat-A': [
+              { id: 'saved-before', content: 'original', resumeUserMessageId: 'attempt-1' },
+              {
+                id: 'refused',
+                content: 'original',
+                resumeUserMessageId: 'attempt-2',
+                admissionUnknown: false,
+              },
+              { id: 'plain', content: 'never sent' },
+            ],
+          },
+        },
+        version: 0,
+      })
+    )
+
+    await useMothershipQueueStore.persist.rehydrate()
+
+    const [savedBefore, refused, plain] = useMothershipQueueStore.getState().queues['chat-A'] ?? []
+    expect(savedBefore?.admissionUnknown).toBe(true)
+    expect(refused?.admissionUnknown).toBe(false)
+    expect(plain?.admissionUnknown).toBeUndefined()
+  })
+})
@@ -30,6 +30,24 @@ describe('useMothershipQueueStore', () => {
   })
 
   describe('replaceAt', () => {
+    it('treats any message resuming an earlier attempt as possibly sent, unless told otherwise', () => {
+      useMothershipQueueStore
+        .getState()
+        .enqueue('chat-A', { id: 'resumed', content: 'original', resumeUserMessageId: 'attempt-1' })
+      useMothershipQueueStore.getState().insertAt('chat-A', 0, {
+        id: 'refused',
+        content: 'original',
+        resumeUserMessageId: 'attempt-2',
+        admissionUnknown: false,
+      })
+      useMothershipQueueStore.getState().replaceAt('chat-A', 'resumed', { content: 'edited' })
+      useMothershipQueueStore.getState().replaceAt('chat-A', 'refused', { content: 'edited' })
+
+      const [refused, resumed] = useMothershipQueueStore.getState().queues['chat-A'] ?? []
+      expect(resumed).toMatchObject({ content: 'original', resumeUserMessageId: 'attempt-1' })
+      expect(refused?.content).toBe('edited')
+    })
+
     it('leaves a first message the server may already hold unchanged, with its id', () => {
       useMothershipQueueStore.getState().enqueue('chat-A', {
         id: 'm1',
@@ -50,6 +68,8 @@ describe('useMothershipQueueStore', () => {
         content: 'original',
         retryRequired: true,
         resumeUserMessageId: 'prior-request',
+        /** Its Stop never settled, so it was never sent: the server cannot hold it. */
+        admissionUnknown: false,
         queuedSendHandoff: {
           id: 'm1',
           chatId: 'chat-A',