refactor(agent-loop): simplify observable state machine

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

@@ -155,7 +155,7 @@ describe('dsh-subagent-fork', () => {
     // 1 from the seeded parent turn + 1 from the child's own completed turn.
     expect(seedTurnEnds.length).toBe(2)
 
-    parent.cancel()
+    parent.cancel({ kind: 'user' })
     await run.dispose()
   })
 

packages/subagent/subagent-inprocess/tests/structured.spec.ts

@@ -1,7 +1,6 @@
 import { describe, expect, it } from 'vitest'
 import { Context } from 'cordis'
 import { CallId, type ContentBlock, type GenerateOptions } from '@deepseek-ai/dsh-llm'
-import type { ContinuationDecision } from '@deepseek-ai/dsh-agent'
 import { SessionId } from '@deepseek-ai/dsh-session'
 import AgentLoop from '@deepseek-ai/dsh-agent-loop'
 import { mountAgentLoopTestDependencies } from '@deepseek-ai/dsh-agent-loop-testkit'
@@ -116,8 +115,7 @@ describe('in-process structured output', () => {
     ])
     const run = await ctx.subagents.start('spawn', structuredRequest(parent))
     await run.result
-    // Default continuation would run a second step after the tool call; the
-    // structured runtime's turn-continuation veto stops the turn instead.
+    // The structured tool marks its successful result as turn-concluding.
     expect(adapter.requests.length).toBe(1)
     await run.dispose()
   })
@@ -219,63 +217,6 @@ describe('in-process structured output', () => {
     await run.dispose()
   })
 
-  it('a later-prepended continuation wrapper cannot resurrect a captured turn', async () => {
-    const { ctx, parent, adapter } = await setup([
-      toolCallResponse('c1', STRUCTURED_OUTPUT_TOOL, { answer: 7 }),
-      textResponse('MUST NOT BE CONSUMED'),
-    ])
-    ctx.on('agent/turn-continuation', () => Promise.resolve<ContinuationDecision>({ action: 'stop' }))
-    let wrapperInstalled = false
-    // Register before ready-only start: structured output is attached before session-start and the
-    // loop. The wrapper waits for a downstream stop, rewrites it to continue, and must still lose
-    // to the later terminal checkpoint.
-    ctx.on('agent/session-start', (child) => {
-      if (child === parent) return
-      wrapperInstalled = true
-      child.ctx.on('agent/turn-continuation', async (_subject, _turn, _decision, _signal, next): Promise<ContinuationDecision> => {
-        const downstream = await next()
-        expect(downstream).toEqual({ action: 'stop' })
-        return { action: 'continue' }
-      }, { prepend: true })
-    })
-    const run = await ctx.subagents.start('spawn', structuredRequest(parent))
-    const result = await run.result
-    expect(wrapperInstalled).toBe(true)
-    expect(result.structured).toEqual({ answer: 7 })
-    expect(result.stopReason).toBe('completed')
-    expect(adapter.requests).toHaveLength(1)
-    await run.dispose()
-  })
-
-  it('a continuation wrapper cannot carry steering past a captured terminal stop', async () => {
-    const { ctx, parent, adapter } = await setup([
-      toolCallResponse('c1', STRUCTURED_OUTPUT_TOOL, { answer: 9 }),
-      textResponse('MUST NOT BE CONSUMED'),
-    ])
-    // A downstream policy stops, then a later wrapper delegates and queues steering that ordinary
-    // folding would turn into continue. The terminal checkpoint must discard that steering.
-    ctx.on('agent/turn-continuation', () => Promise.resolve<ContinuationDecision>({ action: 'stop' }))
-    const run = await ctx.subagents.start('spawn', structuredRequest(parent))
-    ctx.on('agent/session-start', (child) => {
-      if (child.id !== run.id) return
-      child.ctx.on('agent/turn-continuation', async (subject, _turn, _decision, _signal, next): Promise<ContinuationDecision> => {
-        const downstream = await next()
-        expect(downstream).toEqual({ action: 'stop' })
-        subject.steer([{ type: 'text', text: 'late steering after downstream stop' }])
-        return downstream
-      }, { prepend: true })
-    })
-
-    const result = await run.result
-    const child = ctx.agents.get(run.id)
-
-    expect(result.structured).toEqual({ answer: 9 })
-    expect(adapter.requests).toHaveLength(1)
-    expect(child?.session.events.filter(event => event.type === 'turn/start')).toHaveLength(1)
-    expect(child?.session.events.filter(event => event.type === 'steering/message')).toHaveLength(0)
-    await run.dispose()
-  })
-
   it('an invalid call gets an INVALID_ARGS isError result and the model retries in-turn', async () => {
     const { ctx, parent } = await setup([
       toolCallResponse('c1', STRUCTURED_OUTPUT_TOOL, { answer: 'not-a-number' }),

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

@@ -80,7 +80,7 @@ describe('startInProcessRun', () => {
     const child = ctx.agents.get(run.id)!
 
     expect(child.session.events.findLast(event => event.type === 'turn/end'))
-      .toMatchObject({ data: { reason: { kind: 'completed' } } })
+      .toMatchObject({ data: { reason: { kind: 'max-tokens' } } })
     expect(result.stopReason).toBe('max-tokens')
     await run.dispose()
   })

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

@@ -1,7 +1,7 @@
 import { describe, expect, it } from 'vitest'
-import { Context } from 'cordis'
+import { Context, symbols, type EffectMeta } from 'cordis'
 import Loader from '@cordisjs/plugin-loader'
-import AgentRegistry from '@deepseek-ai/dsh-agent'
+import AgentRegistry, { type Agent } from '@deepseek-ai/dsh-agent'
 import { SessionId } from '@deepseek-ai/dsh-session'
 import AgentLoop from '@deepseek-ai/dsh-agent-loop'
 import { mountAgentLoopTestDependencies } from '@deepseek-ai/dsh-agent-loop-testkit'
@@ -52,6 +52,17 @@ function start(ctx: Context, provider: string, request: Omit<SubagentStartReques
   return ctx.subagents.start(provider, { signal: request.signal ?? new AbortController().signal, ...request })
 }
 
+/** Invoke the child lifecycle effect while its parent-owned setup is still unpublished. */
+function disposeChildLifecycle(parent: Agent): void {
+  const lifecycle = [...parent.ctx.fiber._disposables]
+    .find((dispose) => {
+      const effect = (dispose as typeof dispose & { [symbols.effect]?: EffectMeta })[symbols.effect]
+      return effect?.label.startsWith('agentLoop.lifecycle(') === true
+    })
+  if (lifecycle === undefined) throw new Error('child lifecycle effect not found')
+  void lifecycle()
+}
+
 describe('dsh-subagent-spawn', () => {
   it('runs a fresh child to completion and returns its final assistant output', async () => {
     // One model call for the child: a plain text answer.
@@ -460,6 +471,12 @@ describe('dsh-subagent-spawn', () => {
     ctx.on('session/created', () => void published.push('session/created'))
     ctx.on('agent/created', () => void published.push('agent/created'))
     ctx.on('agent/session-start', () => void published.push('agent/session-start'))
+    let teardownStarted = false
+    ctx.on('internal/plugin', (fiber) => {
+      if (teardownStarted || fiber.name !== 'scope') return
+      teardownStarted = true
+      disposeChildLifecycle(parentHandle.agent)
+    })
 
     const starting = start(ctx, 'spawn', {
       prompt: [{ type: 'text', text: 'must never run' }],
@@ -468,8 +485,8 @@ describe('dsh-subagent-spawn', () => {
     // The factory has entered its awaited unpublished setup transaction. The
     // parent context owns that transaction, so disposal wins without an
     // observer ever seeing the child.
-    await parentHandle.dispose()
     await expect(starting).rejects.toThrow(/owner disposed during setup|inactive context/)
+    await parentHandle.dispose()
 
     expect(published).toEqual([])
   })