fix(subagent): preserve terminal turn precedence

packages/subagent/subagent-codex/src/run.ts

@@ -331,10 +331,7 @@ export async function startCodexRun(
   const result: Promise<SubagentResult> = settleRunResult({
     attempt: async () => {
       try {
-        const terminal = await Promise.race([
-          wire.runTurn(texts, runAbort.signal),
-          processFailure,
-        ])
+        const terminal = await wire.runTurn(texts, runAbort.signal)
         if (terminal.stopReason === 'completed') return terminal
         const facts = wire.collectFailure()
         return { ...terminal, diagnostic: recordFailureDiagnostic(facts) }
@@ -357,15 +354,11 @@ export async function startCodexRun(
             // The wire failure remains authoritative when exit observation fails.
           }
         }
-        const facts = error instanceof CodexRunFailure
-          ? error.facts
-          : endedBeforeTerminal && processFailureFacts !== undefined
+        const facts = endedBeforeTerminal && processFailureFacts !== undefined
           ? processFailureFacts
           : wire.collectFailure()
         recordFailureDiagnostic(facts)
-        throw error instanceof CodexRunFailure
-          ? error
-          : new CodexRunFailure(facts, thrown(error))
+        throw new CodexRunFailure(facts, thrown(error))
       }
     },
     collectOutput,

packages/subagent/subagent-codex/tests/subagent-codex.spec.ts

@@ -1612,6 +1612,7 @@ describe('run lifecycle and quiescence', () => {
         onError: (error) => { errors.push(error.message) },
       })
       child.settle(outcome)
+      child.fromChild.emit('end')
       await expect(run.result).resolves.toEqual({
         output: [],
         diagnostic: expectedFailureDiagnostic('process', 'process-exit', {
@@ -1649,8 +1650,7 @@ describe('run lifecycle and quiescence', () => {
       child.peer.send(turnCompleted('failed', 'turn-1', 'thread-1', {
         codexErrorInfo: 'other',
       }))
-      await nextTask()
-      child.fromChild.emit('end')
+      child.fromChild.end()
       child.settle({ exitCode: 17, signal: 'SIGABRT' })
       await expect(run.result).resolves.toEqual({
         output: [],
@@ -1659,6 +1659,22 @@ describe('run lifecycle and quiescence', () => {
       })
       await run.dispose().catch(() => {})
     }
+    {
+      const child = fakeChild({ exitOnTerminate: false })
+      const { run, turnStart } = await publishRun(child)
+      child.peer.respond(turnStart, { turn: { id: 'turn-1' } })
+      child.peer.send(
+        agentMessage('answer', 'final_answer'),
+        turnCompleted('completed'),
+      )
+      child.fromChild.end()
+      child.settle({ exitCode: 17, signal: 'SIGABRT' })
+      await expect(run.result).resolves.toEqual({
+        output: [{ type: 'text', text: 'answer' }],
+        stopReason: 'completed',
+      })
+      await run.dispose().catch(() => {})
+    }
     {
       const child = fakeChild()
       const { run, turnStart } = await publishRun(child, undefined, {