diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-attach-flow.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-attach-flow.ts
index 49ce093c199..93d448d04fb 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-attach-flow.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-attach-flow.ts
@@ -82,11 +82,13 @@ export async function performAttach(
     if (reservedRecord && isAgentSessionPreSpawnError(error)) {
       const spawnToken = reservedRecord.lease.reservedSpawnToken
       if (spawnToken) {
-        await store.markReservationProcessless({
+        const processlessAt = input.now()
+        await store.setReservationProcesslessProof({
           sessionId,
           fence: reservedRecord.lease.runtimeFence,
           spawnToken,
-          now: input.now()
+          processlessAt,
+          now: processlessAt
         })
       }
     }
@@ -136,6 +138,14 @@ async function acquireOwner(
   if (!spawnToken) {
     throw new Error('agent_session_ownership_unknown')
   }
+  // Pre-spawn proof is single-use: this retry may create a child after the durable clear.
+  record = await input.store.setReservationProcesslessProof({
+    sessionId: record.sessionId,
+    fence,
+    spawnToken,
+    processlessAt: null,
+    now: input.now()
+  })
   await input.onAcquiring?.()
   const acquired = await input.adapter.acquire({
     identity: journalIdentityFor(record, input.params),
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-processless-reservation.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-processless-reservation.test.ts
index d33980d9ff5..a3451ff9037 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-processless-reservation.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-processless-reservation.test.ts
@@ -4,6 +4,7 @@ import { join } from 'node:path'
 import { afterEach, describe, expect, it, vi } from 'vitest'
 import { computeAgentSessionPayloadFingerprint } from '../../../shared/agent-session-mutation-envelope'
 import { AgentSessionRecordStore } from '../../runtime/agent-session-record-store'
+import { createStructuredAgentSessionOwnerProbe } from '../../runtime/structured-agent-session-runtime'
 import {
   AgentSessionPreSpawnError,
   type StructuredAgentSessionAdapter
@@ -103,4 +104,64 @@ describe('processless structured session reservation', () => {
       reservedSpawnToken: null
     })
   })
+
+  it('consumes stale pre-spawn proof before a retry can spawn', async () => {
+    root = await mkdtemp(join(tmpdir(), 'orca-processless-retry-'))
+    const storeDir = join(root, 'store')
+    const store = await AgentSessionRecordStore.open({ directory: storeDir, hostId: 'local' })
+    const adapter = {
+      acquire: vi
+        .fn<StructuredAgentSessionAdapter['acquire']>()
+        .mockRejectedValueOnce(new AgentSessionPreSpawnError(new Error('launch not ready')))
+        .mockResolvedValueOnce({
+          process: {
+            hostId: 'local',
+            pid: 4242,
+            processStartTimeMs: NOW,
+            spawnToken: 'spawn-a'
+          },
+          link: {
+            linkId: 'link-1',
+            handle: { provider: 'codex', threadId: 'thread-1' },
+            origin: 'created',
+            mintedAtFence: 1,
+            observedAt: NOW
+          }
+        })
+    } as unknown as StructuredAgentSessionAdapter
+    const input = {
+      store,
+      adapter,
+      journalRoot: root,
+      authority: {
+        spawnToken: 'spawn-a',
+        claimKeyId: 'key-1',
+        handoffOperationId: OPERATION,
+        probe: { outcome: 'reservation-unused' as const }
+      },
+      callerKey: 'client-1',
+      params: attachParams(),
+      now: () => NOW,
+      onAttached: () => {}
+    }
+
+    await expect(performAttach(input)).rejects.toThrow('launch not ready')
+    expect(store.getRecord(SESSION)?.lease.processlessAt).toBe(NOW)
+    vi.spyOn(store, 'commitProcessIdentity').mockRejectedValueOnce(new Error('simulated crash'))
+
+    await expect(performAttach(input)).rejects.toThrow('simulated crash')
+
+    const reopened = await AgentSessionRecordStore.open({ directory: storeDir, hostId: 'local' })
+    expect(reopened.getRecord(SESSION)?.lease.processlessAt).toBeNull()
+    await reopened.reconcileOnRestart({
+      probe: createStructuredAgentSessionOwnerProbe('local'),
+      now: NOW + 1
+    })
+    expect(reopened.getRecord(SESSION)?.lease).toMatchObject({
+      claimStatus: 'reserved',
+      handoffStage: 'recovering',
+      runtimeFence: 1,
+      processlessAt: null
+    })
+  })
 })
diff --git a/src/main/runtime/agent-session-processless-reservation.ts b/src/main/runtime/agent-session-processless-reservation.ts
index 52ab279e01d..9415ba8fcb7 100644
--- a/src/main/runtime/agent-session-processless-reservation.ts
+++ b/src/main/runtime/agent-session-processless-reservation.ts
@@ -7,23 +7,38 @@ export type AgentSessionReservationProcesslessProof = {
   now: number
 }
 
-export function markAgentSessionReservationProcessless(
-  args: AgentSessionReservationProcesslessProof & { record: AgentSessionRecord }
-): AgentSessionRecord {
-  const { record } = args
+function assertReservation(
+  record: AgentSessionRecord,
+  args: AgentSessionReservationProcesslessProof
+): void {
   if (record.lease.runtimeFence !== args.fence || record.lease.unreconciled) {
     throw new Error('agent_session_checkpoint_stale')
   }
   if (
     record.lease.claimStatus !== 'reserved' ||
-    record.lease.ownerProcess !== null ||
     record.lease.reservedSpawnToken !== args.spawnToken
   ) {
     throw new Error('agent_session_ownership_unknown')
   }
+}
+
+export function setAgentSessionReservationProcesslessProof(
+  args: AgentSessionReservationProcesslessProof & {
+    record: AgentSessionRecord
+    processlessAt: number | null
+  }
+): AgentSessionRecord {
+  const { record } = args
+  assertReservation(record, args)
+  if (args.processlessAt === null && record.lease.processlessAt == null) {
+    return record
+  }
+  if (record.lease.ownerProcess !== null) {
+    throw new Error('agent_session_ownership_unknown')
+  }
   return {
     ...record,
-    lease: { ...record.lease, processlessAt: args.now },
+    lease: { ...record.lease, processlessAt: args.processlessAt },
     updatedAt: args.now
   }
 }
diff --git a/src/main/runtime/agent-session-record-store.ts b/src/main/runtime/agent-session-record-store.ts
index f148d0064c9..f4d829698ac 100644
--- a/src/main/runtime/agent-session-record-store.ts
+++ b/src/main/runtime/agent-session-record-store.ts
@@ -42,7 +42,7 @@ import {
   type AgentSessionProcessIdentityCommit
 } from './agent-session-lease-transitions'
 import {
-  markAgentSessionReservationProcessless,
+  setAgentSessionReservationProcesslessProof,
   type AgentSessionReservationProcesslessProof
 } from './agent-session-processless-reservation'
 import {
@@ -178,11 +178,11 @@ export class AgentSessionRecordStore {
     )
   }
 
-  markReservationProcessless = (
-    args: AgentSessionReservationProcesslessProof
+  setReservationProcesslessProof = (
+    args: AgentSessionReservationProcesslessProof & { processlessAt: number | null }
   ): Promise<AgentSessionRecord> =>
     this.mutate(args.sessionId, (record) =>
-      markAgentSessionReservationProcessless({ ...args, record })
+      setAgentSessionReservationProcesslessProof({ ...args, record })
     )
 
   async proveOwner(args: {