diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-create-adoption.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-create-adoption.test.ts
index 60a16037880..a31b48c23bd 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-create-adoption.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-create-adoption.test.ts
@@ -139,12 +139,16 @@ it('refuses concurrent founding under a tab another chat already owns', async ()
   expect(rig.adapter.acquire).not.toHaveBeenCalled()
 })
 
-it('validates adoption history before founding anything', async () => {
+it('refuses history lost after discovery before founding anything', async () => {
   const params = await adoptedParams()
-  await writeFile(join(rig.root, 'rollout.jsonl'), 'not a transcript\n')
+  await rm(join(rig.root, 'rollout.jsonl'))
   expect(await rig.host.create(CALLER, params)).toMatchObject({
     ok: false,
-    refusal: { code: 'agent_session_identity_required' }
+    refusal: {
+      code: 'agent_session_identity_required',
+      details: { reason: 'transcriptUnreadable' },
+      createAttemptRefusedBeforeCommit: true
+    }
   })
   expect(rig.store.listRecords()).toEqual([])
   expect(rig.store.listOperationRows()).toEqual([])
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-create.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-create.ts
index 54bb3e6b4b8..d9c149c50af 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-create.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-create.ts
@@ -153,7 +153,15 @@ async function foundConversation(
     ? { ok: true as const, items: null }
     : await prepareAdoptedTranscript(params)
   if (!prepared.ok) {
-    return prepared
+    const { refusal } = prepared
+    return {
+      ok: false,
+      refusal:
+        refusal.code === 'agent_session_identity_required' &&
+        refusal.details?.reason === 'transcriptUnreadable'
+          ? { ...refusal, createAttemptRefusedBeforeCommit: true }
+          : refusal
+    }
   }
   const existing = context.sessions.get(sessionId)
   const opened = existing
diff --git a/src/main/runtime/rpc/methods/structured-agent-session-precommit-refusal.test.ts b/src/main/runtime/rpc/methods/structured-agent-session-precommit-refusal.test.ts
index 6675ab4a1f0..5a984264521 100644
--- a/src/main/runtime/rpc/methods/structured-agent-session-precommit-refusal.test.ts
+++ b/src/main/runtime/rpc/methods/structured-agent-session-precommit-refusal.test.ts
@@ -8,6 +8,7 @@ import { setStructuredAgentSessionHost } from '../../../native-chat/agent-sessio
 import { recordingStructuredAgentSessionLogger } from '../../../native-chat/agent-session-wire/structured-agent-session-logger-test-support'
 import { computeAgentSessionPayloadFingerprint } from '../../../../shared/agent-session-mutation-envelope'
 import { isDefinitiveAgentSessionCreateRefusal } from '../../../../shared/agent-session-definitive-refusal'
+import { agentSessionRefusalError } from '../../../../shared/agent-session-wire-refusals'
 import { STRUCTURED_AGENT_SESSION_RUNTIME_CAPABILITY } from '../../../../shared/protocol-version'
 import type { OrcaRuntimeService } from '../../orca-runtime'
 import type { RpcResponse } from '../core'
@@ -130,18 +131,20 @@ afterEach(() => {
 })
 
 describe('a create refused before it commits', () => {
-  it('answers a code-carrying refusal as a definitive envelope', async () => {
+  it('answers missing history before commit as a definite failed attempt', async () => {
     const response = await create({
       resolveStructuredAgentSessionCreateIntent: vi.fn(async () => {
-        throw new Error('structured_agent_session_unsupported')
+        throw agentSessionRefusalError('agent_session_identity_required', {
+          reason: 'transcriptNotFound'
+        })
       })
     })
 
-    const refusal = refusalOf(response)
-    expect(refusal?.code).toBe('structured_agent_session_unsupported')
-    expect(refusal?.message).toContain('structured agent chat')
-    expect(refusal?.message).not.toContain('Codex')
-    expect(isDefinitiveAgentSessionCreateRefusal(refusal?.code)).toBe(true)
+    expect(refusalOf(response)).toMatchObject({
+      code: 'agent_session_identity_required',
+      details: { reason: 'transcriptNotFound' },
+      createAttemptRefusedBeforeCommit: true
+    })
     expect(attach).not.toHaveBeenCalled()
   })
 
diff --git a/src/main/runtime/rpc/methods/structured-agent-session-precommit-refusal.ts b/src/main/runtime/rpc/methods/structured-agent-session-precommit-refusal.ts
index 4038fe9e40d..9ca93701bea 100644
--- a/src/main/runtime/rpc/methods/structured-agent-session-precommit-refusal.ts
+++ b/src/main/runtime/rpc/methods/structured-agent-session-precommit-refusal.ts
@@ -75,6 +75,13 @@ export async function resolveUncommittedStructuredCreate<TPrepared>(
   try {
     return await prepare()
   } catch (error) {
-    return { refusal: precommitRefusal(error) }
+    const refusal = precommitRefusal(error)
+    return {
+      refusal:
+        refusal.code === 'agent_session_identity_required' &&
+        refusal.details?.reason === 'transcriptNotFound'
+          ? { ...refusal, createAttemptRefusedBeforeCommit: true }
+          : refusal
+    }
   }
 }
diff --git a/src/renderer/src/components/native-chat/structured-agent-session-status-bridge-unconfirmed-start.test.tsx b/src/renderer/src/components/native-chat/structured-agent-session-status-bridge-unconfirmed-start.test.tsx
index 3318059ce0e..06d1dcd6b76 100644
--- a/src/renderer/src/components/native-chat/structured-agent-session-status-bridge-unconfirmed-start.test.tsx
+++ b/src/renderer/src/components/native-chat/structured-agent-session-status-bridge-unconfirmed-start.test.tsx
@@ -328,7 +328,8 @@ describe('a chat whose start was never confirmed', () => {
           envelope: expect.objectContaining({ clientOperationId: `operation-${CLAUDE_SESSION}` })
         })
       }),
-      expect.any(Function)
+      expect.any(Function),
+      true
     )
     expect(lifecycle()).toBeNull()
     expect(rows()).toEqual([])
diff --git a/src/renderer/src/components/right-sidebar/ai-vault-session-resume-in-chat-launch.test.ts b/src/renderer/src/components/right-sidebar/ai-vault-session-resume-in-chat-launch.test.ts
index fee3133f0ae..ba29f3cd9d8 100644
--- a/src/renderer/src/components/right-sidebar/ai-vault-session-resume-in-chat-launch.test.ts
+++ b/src/renderer/src/components/right-sidebar/ai-vault-session-resume-in-chat-launch.test.ts
@@ -102,8 +102,14 @@ describe('resumeAiVaultSessionInNewChat', () => {
     )
   })
 
-  it('toasts a conflict reported by the eventual settlement', async () => {
-    const error = Object.assign(new Error('held'), { code: 'agent_session_conflict' })
+  it.each([
+    ['agent_session_conflict', 'Another chat is already holding this conversation.'],
+    [
+      'agent_session_identity_required',
+      "This conversation's history could not be loaded, so it cannot be resumed in chat."
+    ]
+  ])('toasts the eventual %s refusal', async (code, message) => {
+    const error = Object.assign(new Error('Host diagnostic'), { code })
     mocks.beginStructuredAgentSessionProvisionalLaunch.mockReturnValue({
       sessionId: 'session-1',
       tab: { id: 'agent-session:session-1' },
@@ -111,11 +117,7 @@ describe('resumeAiVaultSessionInNewChat', () => {
     })
 
     await resumeAiVaultSessionInNewChat(session, 'codex', 'worktree-1', 'resume-click')
-    await vi.waitFor(() =>
-      expect(mocks.toastError).toHaveBeenCalledWith(
-        'Another chat is already holding this conversation.'
-      )
-    )
+    await vi.waitFor(() => expect(mocks.toastError).toHaveBeenCalledExactlyOnceWith(message))
   })
 
   it('keeps unknown outcomes silent for reconciliation', async () => {
diff --git a/src/renderer/src/lib/launch-structured-agent-session.test.ts b/src/renderer/src/lib/launch-structured-agent-session.test.ts
index 0b843806812..91f8b9839c6 100644
--- a/src/renderer/src/lib/launch-structured-agent-session.test.ts
+++ b/src/renderer/src/lib/launch-structured-agent-session.test.ts
@@ -499,23 +499,6 @@ describe('structured agent session launch', () => {
     expect(error).toBeInstanceOf(StructuredAgentSessionCreateUnknownOutcomeError)
   })
 
-  it('preserves a definitive refusal code for the fallback path', async () => {
-    mockSupportedCreate(() => ({
-      ok: false,
-      refusal: {
-        code: 'structured_agent_session_unsupported',
-        message: 'Structured chat is unavailable.'
-      }
-    }))
-
-    const error = await launchStructuredAgentSession(
-      createStructuredAgentSessionLaunchIntent('workspace-unsupported', 'codex')
-    ).catch((caught: unknown) => caught)
-
-    expect(error).toBeInstanceOf(StructuredAgentSessionCreateRefusalError)
-    expect(error).toMatchObject({ code: 'structured_agent_session_unsupported' })
-  })
-
   it.each(['method_not_found', 'structured_agent_session_unsupported'])(
     'turns an old-host %s error into a definitive transport refusal',
     async (code) => {
diff --git a/src/renderer/src/lib/structured-agent-session-launch-create-call.ts b/src/renderer/src/lib/structured-agent-session-launch-create-call.ts
index be0f3c6b853..613686742b4 100644
--- a/src/renderer/src/lib/structured-agent-session-launch-create-call.ts
+++ b/src/renderer/src/lib/structured-agent-session-launch-create-call.ts
@@ -78,7 +78,8 @@ export type StructuredLaunchHostSeedListener = (seedOptions: LaunchSeed) => void
 
 export async function launchStructuredAgentSession(
   intent: StructuredAgentSessionLaunchIntent,
-  onHostSeed?: StructuredLaunchHostSeedListener
+  onHostSeed?: StructuredLaunchHostSeedListener,
+  priorCreateOutcomeUnknown = false
 ): Promise<StructuredAgentLaunchReceipt> {
   const hostSeed = await requireHostCreateSupport(intent)
   if (intent.target.kind !== 'local') {
@@ -119,8 +120,18 @@ export async function launchStructuredAgentSession(
   if (!result.ok) {
     const { code, message, ownerVerdict } = result.refusal
     const refusal = readAgentSessionRefusalReference(result.refusal)
-    // A failed operation whose provider is proven gone is a failure a new operation may retry.
-    if (!isDefinitiveAgentSessionCreateRefusal(code) && ownerVerdict !== 'exited') {
+    const transcriptRefusedBeforeCommit =
+      !priorCreateOutcomeUnknown &&
+      result.refusal.createAttemptRefusedBeforeCommit === true &&
+      refusal?.code === 'agent_session_identity_required' &&
+      (refusal.details?.reason === 'transcriptNotFound' ||
+        refusal.details?.reason === 'transcriptUnreadable')
+    // A proven precommit transcript refusal lets a new operation retry.
+    if (
+      !transcriptRefusedBeforeCommit &&
+      !isDefinitiveAgentSessionCreateRefusal(code) &&
+      ownerVerdict !== 'exited'
+    ) {
       // Keep the focus intent: the session may exist, and recovery still has to adopt it.
       throw new StructuredAgentSessionCreateUnknownOutcomeError(message, code, refusal)
     }
diff --git a/src/renderer/src/lib/structured-agent-session-launch-errors.ts b/src/renderer/src/lib/structured-agent-session-launch-errors.ts
index 2b94b0951a2..bf03c910570 100644
--- a/src/renderer/src/lib/structured-agent-session-launch-errors.ts
+++ b/src/renderer/src/lib/structured-agent-session-launch-errors.ts
@@ -12,10 +12,7 @@ export class StructuredAgentSessionCreateError extends Error {
   }
 }
 
-/**
- * The host proved it created nothing. The class itself is the verdict:
- * `launchStructuredAgentSession` is the only place that decides it against the shared allowlist.
- */
+/** A known create failure; the launch classifier keeps uncertain earlier attempts recoverable. */
 export class StructuredAgentSessionCreateRefusalError extends StructuredAgentSessionCreateError {
   constructor(
     message: string,
diff --git a/src/renderer/src/lib/structured-agent-session-launch-exited-owner.test.ts b/src/renderer/src/lib/structured-agent-session-launch-exited-owner.test.ts
index 7ef9e0f9ac2..c90c22da7b6 100644
--- a/src/renderer/src/lib/structured-agent-session-launch-exited-owner.test.ts
+++ b/src/renderer/src/lib/structured-agent-session-launch-exited-owner.test.ts
@@ -46,6 +46,7 @@ vi.mock('@/lib/agent-catalog', () => ({
 import {
   getStructuredAgentSessionLaunchLifecycle,
   retryStructuredAgentSessionLaunch,
+  shouldRetainStructuredAgentSessionLaunchTab,
   startStructuredAgentLaunch
 } from './structured-agent-session-launch'
 import {
@@ -53,6 +54,7 @@ import {
   resetStructuredAgentLaunchRegistryForTests
 } from './structured-agent-session-launch-registry'
 import { resetStructuredAgentLaunchPersistenceForTests } from './structured-agent-session-launch-persistence'
+import { structuredSessionNotices } from '@/components/native-chat/native-chat-structured-session-notices'
 
 const WORKTREE = 'wt-1'
 const EXIT_REASON = 'claude stream-json exited (code 1): stderr tail'
@@ -62,6 +64,7 @@ const HOST_REFUSAL = { kind: 'refused', code: 'agent_session_operation_invalid'
 let replayVerdict: AgentSessionOwnerVerdict | undefined
 /** A host that answers the proven exit on the first call, not only on replay. */
 let refuseFirstCall = false
+let missingHistory: boolean | 'legacy' = false
 let failedOperation: string | null = null
 let publishedSessionId: string | null = null
 const createdOperations: string[] = []
@@ -79,7 +82,13 @@ function hostCreate(envelope: AgentSessionMutationEnvelope): unknown {
     throw new Error(EXIT_REASON)
   }
   const refusal: AgentSessionWireRefusal = {
-    code: 'agent_session_operation_invalid',
+    ...(missingHistory
+      ? {
+          code: 'agent_session_identity_required' as const,
+          details: { reason: 'transcriptNotFound' as const },
+          ...(missingHistory === true ? { createAttemptRefusedBeforeCommit: true as const } : {})
+        }
+      : { code: 'agent_session_operation_invalid' as const }),
     message: EXIT_REASON,
     ...(replayVerdict ? { ownerVerdict: replayVerdict } : {})
   }
@@ -106,6 +115,7 @@ beforeEach(() => {
   resetStructuredAgentLaunchRegistryForTests()
   replayVerdict = 'exited'
   refuseFirstCall = false
+  missingHistory = false
   failedOperation = null
   publishedSessionId = null
   createdOperations.length = 0
@@ -144,13 +154,26 @@ describe('structured launch after a host-failed create', () => {
     expect(getStructuredAgentSessionLaunchLifecycle(WORKTREE, sessionId)).toBeNull()
   })
 
-  it('fails on the first answer when the host already refuses with the proven exit', async () => {
+  it('retains a missing-history failed tab with Retry, then starts a new attempt', async () => {
     refuseFirstCall = true
+    missingHistory = true
+    replayVerdict = undefined
     const sessionId = launch()
     await settle(sessionId)
     expect(getStructuredAgentSessionLaunchLifecycle(WORKTREE, sessionId)).toBe('failed')
-    // The host's message is for its log; the Retry line words the refusal.
-    expect(getStructuredAgentSessionLaunchFailure(WORKTREE, sessionId)).toEqual(HOST_REFUSAL)
+    expect(shouldRetainStructuredAgentSessionLaunchTab(WORKTREE, sessionId)).toBe(true)
+    expect(
+      structuredSessionNotices({
+        launch: {
+          lifecycle: 'failed',
+          failure: getStructuredAgentSessionLaunchFailure(WORKTREE, sessionId),
+          retry: () => {}
+        },
+        agentLabel: 'Codex',
+        sessionError: null,
+        composerError: null
+      })
+    ).toMatchObject([{ text: 'Chat could not be started.', action: { label: 'Retry' } }])
     expect(createdOperations).toEqual([failedOperation])
     expect(retryStructuredAgentSessionLaunch(WORKTREE, sessionId)).toBe(true)
     await settle(sessionId)
@@ -160,13 +183,20 @@ describe('structured launch after a host-failed create', () => {
 
   it.each([
     ['the host could not prove the process gone', 'unverifiable'],
-    ['the host predates the verdict', undefined]
-  ] as const)('stays unknown when %s', async (_label, verdict) => {
-    replayVerdict = verdict
-    const sessionId = launch()
-    await settle(sessionId)
+    ['the host predates the missing-history proof', undefined, 'legacy'],
+    ['an earlier reply was lost before the missing-history refusal', undefined, true]
+  ] as const)(
+    'stays unknown when %s',
+    async (_label, verdict, transcriptRefusal: boolean | 'legacy' = false) => {
+      replayVerdict = verdict
+      missingHistory = transcriptRefusal
+      const sessionId = launch()
+      await settle(sessionId)
 
-    expect(getStructuredAgentSessionLaunchLifecycle(WORKTREE, sessionId)).toBe('visibility-unknown')
-    expect(createdOperations.every((operation) => operation === failedOperation)).toBe(true)
-  })
+      expect(getStructuredAgentSessionLaunchLifecycle(WORKTREE, sessionId)).toBe(
+        'visibility-unknown'
+      )
+      expect(createdOperations.every((operation) => operation === failedOperation)).toBe(true)
+    }
+  )
 })
diff --git a/src/renderer/src/lib/structured-agent-session-launch-recovery.ts b/src/renderer/src/lib/structured-agent-session-launch-recovery.ts
index 5badfaf0496..d41ae102f05 100644
--- a/src/renderer/src/lib/structured-agent-session-launch-recovery.ts
+++ b/src/renderer/src/lib/structured-agent-session-launch-recovery.ts
@@ -74,7 +74,7 @@ export async function recoverPublishedSessionReceipt(
       )
     : undefined
   if (state.intent.params.firstMessage && !firstMessage) {
-    return launchStructuredAgentSession(state.intent, state.onHostSeed)
+    return launchStructuredAgentSession(state.intent, state.onHostSeed, true)
   }
   if (state.intent.createMessageSupport === true) {
     publishStructuredAgentSessionCreateHydration(state.intent, history.page, fence)
@@ -88,7 +88,7 @@ async function retrySameIntent(
 ): Promise<StructuredAgentLaunchReceipt> {
   throwIfLaunchCancelled(state)
   try {
-    const receipt = await launchStructuredAgentSession(state.intent, state.onHostSeed)
+    const receipt = await launchStructuredAgentSession(state.intent, state.onHostSeed, true)
     throwIfLaunchCancelled(state)
     if (state.intent.createMessageSupport !== true) {
       await verifyPublishedSession(state)
diff --git a/src/renderer/src/lib/structured-agent-session-launch-reload.test.ts b/src/renderer/src/lib/structured-agent-session-launch-reload.test.ts
index 8922deabfe1..4ab7ee061d6 100644
--- a/src/renderer/src/lib/structured-agent-session-launch-reload.test.ts
+++ b/src/renderer/src/lib/structured-agent-session-launch-reload.test.ts
@@ -178,7 +178,8 @@ describe('structured agent launch reload recovery', () => {
           })
         })
       }),
-      expect.any(Function)
+      expect.any(Function),
+      true
     )
   })
 })
diff --git a/src/shared/agent-session-wire-refusals.ts b/src/shared/agent-session-wire-refusals.ts
index 8fd1602377b..414dfb93c07 100644
--- a/src/shared/agent-session-wire-refusals.ts
+++ b/src/shared/agent-session-wire-refusals.ts
@@ -62,6 +62,8 @@ export type AgentSessionRefusalOf<C extends AgentSessionWireRefusalCode> = {
     message: string
     /** Absent from older hosts. */
     details?: AgentSessionRefusalDetails<K>
+    /** This create attempt refused before commit; earlier attempts may still have committed. */
+    createAttemptRefusedBeforeCommit?: true
   } & AgentSessionLegacyRefusalFields
 }[C]