refactor(agent-loop): simplify message machine

packages/session-title/session-title-all-messages-llm/tests/provider.spec.ts

@@ -32,7 +32,7 @@ async function settle(): Promise<void> {
 describe('all-messages LLM title provider', () => {
   it('includes seeded history and the latest prompt while inheriting the logged request route', async () => {
     const seeded = new Session(SessionId('seed-source'))
-    seeded.append('turn/start', { turn: 1, trigger: { kind: 'message', source: { kind: 'user' } } })
+    seeded.append('turn/start', { turn: 1 })
     const inherited = seeded.append('user/message', createUserMessage({
       content: [{ type: 'text', text: 'inherited prompt' }], source: { kind: 'user' },
     }), { surfaceOp: 'append' })
@@ -52,7 +52,7 @@ describe('all-messages LLM title provider', () => {
       seed: seeded.events,
       meta: { parentSession: seeded.id, seedLength: seeded.seq },
     })
-    session.append('turn/start', { turn: 2, trigger: { kind: 'message', source: { kind: 'user' } } })
+    session.append('turn/start', { turn: 2 })
     const latest = session.append('user/message', createUserMessage({
       content: [{ type: 'text', text: 'latest prompt' }], source: { kind: 'user' },
     }), { surfaceOp: 'append' })

packages/session-title/session-title-first-message-llm/tests/loader-composition.spec.ts

@@ -93,7 +93,6 @@ describe('session-title Loader composition', () => {
     const session = ctx.sessions.create(SessionId('loader-title'))
     session.append('turn/start', {
       turn: 1,
-      trigger: { kind: 'message', source: { kind: 'user' } },
     })
     const message = session.append('user/message', createUserMessage({
       content: [{ type: 'text', text: 'Compose a title through Loader' }],

packages/session-title/session-title-first-message-llm/tests/provider.e2e.ts

@@ -37,7 +37,6 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('first-message title provider wit
     const session = ctx.sessions.create(SessionId('real-title-provider'))
     session.append('turn/start', {
       turn: 1,
-      trigger: { kind: 'message', source: { kind: 'user' } },
     })
     const message = session.append('user/message', createUserMessage({
       content: [{ type: 'text', text: 'Explain why append-only logs make session titles durable.' }],

packages/session-title/session-title-first-message-llm/tests/provider.spec.ts

@@ -60,7 +60,7 @@ describe('first-message LLM title provider', () => {
     ctx.llm.registerAdapter(['title-route'], adapter)
     await ctx.plugin(providerPlugin, LLM_CONFIG)
     const session = ctx.sessions.create(SessionId('first-plugin'))
-    session.append('turn/start', { turn: 1, trigger: { kind: 'message', source: { kind: 'user' } } })
+    session.append('turn/start', { turn: 1 })
     const first = session.append('user/message', createUserMessage({
       content: [{ type: 'text', text: 'first input' }], source: { kind: 'user' },
     }), { surfaceOp: 'append' })

packages/session-title/session-title-llm/tests/llm.spec.ts

@@ -80,7 +80,6 @@ function request(ctx: Context, signal = new AbortController().signal): SessionTi
   const session = ctx.sessions.create(SessionId(`title-call-${++nextSession}`))
   session.append('turn/start', {
     turn: 1,
-    trigger: { kind: 'message', source: { kind: 'user' } },
   })
   const first = session.append('user/message', createUserMessage({
     content: [{ type: 'text', text: 'first prompt' }],

packages/session-title/session-title/tests/persistence.spec.ts

@@ -25,7 +25,6 @@ async function appendPersistedTitle(ctx: Context, id: ReturnType<typeof SessionI
   const session = ctx.sessions.create(id)
   session.append('turn/start', {
     turn: 1,
-    trigger: { kind: 'message', source: { kind: 'user' } },
   })
   session.append('user/message', createUserMessage({
     content: [{ type: 'text', text: 'Persist this session title' }],

packages/session-title/session-title/tests/projection.spec.ts

@@ -47,7 +47,7 @@ describe('title projection unit', () => {
     const firstSeq = appendTitle(session, 'First title')
     const secondSeq = appendTitle(session, 'Second title')
     // Unrelated event: same-reference apply, no notification.
-    session.append('turn/start', { turn: 1, trigger: { kind: 'message', source: { kind: 'user' } } })
+    session.append('turn/start', { turn: 1 })
     expect(changes).toEqual([
       { key: 'title', value: 'First title', seq: firstSeq },
       { key: 'title', value: 'Second title', seq: secondSeq },

packages/session-title/session-title/tests/provider.spec.ts

@@ -55,7 +55,6 @@ describe('SessionTitleService provider lifecycle', () => {
     const parent = ctx.sessions.create(SessionId('title-parent'))
     parent.append('turn/start', {
       turn: 1,
-      trigger: { kind: 'message', source: { kind: 'user' } },
     })
     const inheritedMessage = appendHumanPrompt(parent, 'Inherited title prompt')
     await settle()
@@ -77,7 +76,6 @@ describe('SessionTitleService provider lifecycle', () => {
     })
     child.append('turn/start', {
       turn: 2,
-      trigger: { kind: 'message', source: { kind: 'user' } },
     })
     const childMessage = appendHumanPrompt(child, 'Child follow-up prompt')
     await settle()
@@ -98,7 +96,6 @@ describe('SessionTitleService provider lifecycle', () => {
     })
     child.append('turn/start', {
       turn: 3,
-      trigger: { kind: 'message', source: { kind: 'user' } },
     })
     const latestMessage = appendHumanPrompt(child, 'Retitle the fork now')
     await settle()
@@ -136,7 +133,6 @@ describe('SessionTitleService provider lifecycle', () => {
     const session = ctx.sessions.create(SessionId('first-provider'))
     session.append('turn/start', {
       turn: 1,
-      trigger: { kind: 'message', source: { kind: 'user' } },
     })
     const first = appendHumanPrompt(session, 'Explain asynchronous title generation')
     await settle()
@@ -195,7 +191,6 @@ describe('SessionTitleService provider lifecycle', () => {
     const session = ctx.sessions.create(SessionId('dispose-provider'))
     session.append('turn/start', {
       turn: 1,
-      trigger: { kind: 'message', source: { kind: 'user' } },
     })
     const message = appendHumanPrompt(session, 'Generate this title')
     await settle()
@@ -245,7 +240,6 @@ describe('SessionTitleService provider lifecycle', () => {
     const session = ctx.sessions.create(SessionId('supersede'))
     session.append('turn/start', {
       turn: 1,
-      trigger: { kind: 'message', source: { kind: 'user' } },
     })
     const first = appendHumanPrompt(session, 'First prompt')
     await settle()
@@ -286,7 +280,6 @@ describe('SessionTitleService provider lifecycle', () => {
     const session = ctx.sessions.create(SessionId('unchanged-route'))
     session.append('turn/start', {
       turn: 1,
-      trigger: { kind: 'message', source: { kind: 'user' } },
     })
     const first = appendHumanPrompt(session, 'First routed prompt')
     await settle()
@@ -298,7 +291,6 @@ describe('SessionTitleService provider lifecycle', () => {
 
     session.append('turn/start', {
       turn: 2,
-      trigger: { kind: 'message', source: { kind: 'user' } },
     })
     const second = appendHumanPrompt(session, 'Second prompt on the same route')
     await settle()
@@ -345,7 +337,6 @@ describe('SessionTitleService provider lifecycle', () => {
     const pending = ctx.sessions.create(SessionId('unmatched-boundary'))
     pending.append('turn/start', {
       turn: 1,
-      trigger: { kind: 'message', source: { kind: 'user' } },
     })
     appendHumanPrompt(pending, 'Wait for a matching request boundary')
     await settle()
@@ -369,7 +360,6 @@ describe('SessionTitleService provider lifecycle', () => {
     const session = ctx.sessions.create(SessionId('failure'))
     session.append('turn/start', {
       turn: 1,
-      trigger: { kind: 'message', source: { kind: 'user' } },
     })
     appendHumanPrompt(session, 'Keep a fallback')
     await settle()

packages/session-title/session-title/tests/service-contracts.spec.ts

@@ -37,7 +37,6 @@ function startSession(ctx: Context, id: string): ReturnType<Context['sessions'][
   const session = ctx.sessions.create(SessionId(id))
   session.append('turn/start', {
     turn: 1,
-    trigger: { kind: 'message', source: { kind: 'user' } },
   })
   return session
 }
@@ -151,7 +150,6 @@ describe('SessionTitleService configuration and refresh boundaries', () => {
     disposeCtx.sessions.announce(disposed)
     disposed.append('turn/start', {
       turn: 1,
-      trigger: { kind: 'message', source: { kind: 'user' } },
     })
     const disposedMessage = appendPrompt(disposed, 'Dispose this session')
     await settle()
@@ -168,7 +166,6 @@ describe('SessionTitleService configuration and refresh boundaries', () => {
     const seed = new Session(SessionId('fallback-concurrency-seed'))
     seed.append('turn/start', {
       turn: 1,
-      trigger: { kind: 'message', source: { kind: 'user' } },
     })
     const source = appendPrompt(seed, 'Create exactly one fallback title')
     seed.append('turn/end', { turn: 1, reason: { kind: 'completed' } })
@@ -337,7 +334,6 @@ describe('SessionTitleService configuration and refresh boundaries', () => {
     })
     session.append('turn/start', {
       turn: 1,
-      trigger: { kind: 'message', source: { kind: 'user' } },
     })
     appendPrompt(session, 'Detach before the fallback microtask')
     await settle()

packages/session-title/session-title/tests/session-title.spec.ts

@@ -43,7 +43,6 @@ describe('SessionTitleService', () => {
     const session = ctx.sessions.create(SessionId('fresh'))
     session.append('turn/start', {
       turn: 1,
-      trigger: { kind: 'message', source: { kind: 'user' } },
     })
     const message = session.append('user/message', createUserMessage({
       content: [{ type: 'text', text: '  Build\nlog-backed session titles please  ' }],
@@ -80,7 +79,6 @@ describe('SessionTitleService', () => {
     const session = ctx.sessions.create(SessionId('prefixed-title'))
     session.append('turn/start', {
       turn: 1,
-      trigger: { kind: 'message', source: { kind: 'user' } },
     })
     session.append('user/message', createUserMessage({
       content: [{ type: 'text', text: 'Explain this referenced session' }],
@@ -99,7 +97,6 @@ describe('SessionTitleService', () => {
     const session = ctx.sessions.create(SessionId('eligibility'))
     session.append('turn/start', {
       turn: 1,
-      trigger: { kind: 'message', source: { kind: 'user' } },
     })
     session.append('user/message', createUserMessage({
       content: [{ type: 'text', text: 'plugin text' }],