fix(agent-loop): report turn failures at source

packages/core/agent-loop/tests/contract-regressions.spec.ts

@@ -1,6 +1,6 @@
 import { describe, expect, it } from 'vitest'
 import { Context } from 'cordis'
-import LlmService, { createUserMessage, freezeMessage, CallId, MessageSource, ProviderRequestId, StreamChunk  } from '@deepseek-ai/dsh-llm'
+import LlmService, { createUserMessage, freezeMessage, CallId, LlmError, MessageSource, ProviderRequestId, StreamChunk  } from '@deepseek-ai/dsh-llm'
 import SessionStore, { Session, SessionEvent, SessionId, TurnEndReason, type UserMessage } from '@deepseek-ai/dsh-session'
 import SystemPrompt from '@deepseek-ai/dsh-system-prompt'
 import ToolRegistry, { defineContentToolFixture, type PostToolDecision } from '@deepseek-ai/dsh-tools'
@@ -594,12 +594,20 @@ describe('a finish-error stream chunk ends the turn as error, not completed', ()
     const agent = ctx.agentLoop.create(SessionId('a-finish-error'), { provider: 'mock', model: 'mock' })
 
     const reasons: TurnEndReason[] = []
+    const errors: unknown[] = []
+    ctx.on('agent/error', (_agent, turn, step, error) => {
+      expect({ turn, step }).toEqual({ turn: 1, step: 1 })
+      errors.push(error)
+    })
     ctx.on('session/event', (_s, event) => { if (event.type === 'turn/end') reasons.push(event.data.reason) })
 
     send(agent, 'go')
     await waitForIdle(ctx, agent)
 
     expect(reasons).toEqual([{ kind: 'error', error: failure }])
+    expect(errors).toHaveLength(1)
+    expect(errors[0]).toBeInstanceOf(LlmError)
+    expect((errors[0] as LlmError).failure).toEqual(failure)
 
     const events = [...agent.session.events]
     const turnEnd = events.find(event => event.type === 'turn/end')
@@ -809,6 +817,7 @@ describe('turn and step boundary recovery', () => {
 
     expect(adapter.requests).toHaveLength(1)
     expect(errors.map(error => error.message)).toEqual([
+      'reject first step-end',
       'invariant violated by "@deepseek-ai/dsh-session": turn/end 1 while step 1 is still open',
     ])
     expect(boundaryCounts(agent)).toMatchObject({
@@ -842,6 +851,7 @@ describe('turn and step boundary recovery', () => {
       kind: 'error',
       error: { message: 'provider 500', code: 'SERVER' },
     })
+    expect(threw).toBe(true)
 
     // loop survives: a second turn runs to completion (invariants oracle would
     // throw on its turn/start if turn 1 had been left open).
@@ -1012,7 +1022,9 @@ describe('turn and step boundary recovery', () => {
     expect(e.some(x => x.type === 'step/end')).toBe(true)
     expect(e.some(x => x.type === 'turn/end')).toBe(true)
     expect(e.at(-1)?.type).toBe('turn/end')
-    expect(errors).toEqual([])
+    expect(errors).toHaveLength(1)
+    expect(errors[0]).toBeInstanceOf(LlmError)
+    expect((errors[0] as LlmError).failure).toEqual({ message: 'provider 500', code: 'SERVER' })
 
     // loop survives.
     send(agent, 'again')

packages/core/agent-loop/tests/coverage-edges.spec.ts

@@ -181,7 +181,10 @@ describe('durable error rendering', () => {
     const turnEnd = agent.session.events.find(e => e.type === 'turn/end')
     expect(turnEnd).toBeDefined()
     if (turnEnd?.type === 'turn/end' && turnEnd.data.reason.kind === 'error') {
-      expect(turnEnd.data.reason.error).toBe('server overloaded')
+      expect(turnEnd.data.reason.error).toEqual({
+        message: 'server overloaded',
+        code: 'RATE_LIMIT',
+      })
     }
   })
 })

packages/core/agent-loop/tests/loop.spec.ts

@@ -1,6 +1,6 @@
 import { describe, expect, it } from 'vitest'
 import { Context } from 'cordis'
-import LlmService, { createUserMessage, CallId, StreamChunk  } from '@deepseek-ai/dsh-llm'
+import LlmService, { createUserMessage, CallId, LlmError, StreamChunk  } from '@deepseek-ai/dsh-llm'
 import SessionStore, { SessionId, TurnEndReason } from '@deepseek-ai/dsh-session'
 import SystemPrompt from '@deepseek-ai/dsh-system-prompt'
 import ToolRegistry, { defineContentToolFixture } from '@deepseek-ai/dsh-tools'
@@ -200,7 +200,9 @@ describe('agent loop', () => {
     await waitForIdle(ctx, agent)
 
     expect(adapter.requests).toHaveLength(0) // the request was never sent
-    expect(errors).toEqual([])
+    expect(errors.map(error => error.message)).toEqual([
+      'prompt variable "{{cwd}}" has no value for this assembly (section "deployment:persona")',
+    ])
     const turnEnd = agent.session.events.find(e => e.type === 'turn/end')
     expect(turnEnd?.type === 'turn/end' && turnEnd.data.reason.kind).toBe('error')
     expect(turnEnd?.type === 'turn/end' && turnEnd.data.reason.kind === 'error'
@@ -346,7 +348,7 @@ describe('agent loop', () => {
     expect(JSON.stringify(adapter.requests[0]?.messages)).toContain('second idle steer')
   })
 
-  it('contains a throwing step observer and carries steering into a replacement turn', async () => {
+  it('stops after a throwing step observer and retains steering until a later wakeup', async () => {
     const adapter = new MockAdapter([textResponse('recovered')])
     const ctx = await harness(adapter)
     const agent = ctx.agentLoop.create(SessionId('failed-steering'), { provider: 'mock', model: 'mock' })
@@ -361,6 +363,13 @@ describe('agent loop', () => {
     send(agent, 'prompt')
     await waitForIdle(ctx, agent)
 
+    expect(adapter.requests).toHaveLength(0)
+    expect(agent.session.events.filter(event => event.type === 'turn/start')).toHaveLength(1)
+    expect(agent.inbox.nextStep).toHaveLength(1)
+
+    send(agent, 'resume')
+    await waitForIdle(ctx, agent)
+
     expect(adapter.requests).toHaveLength(1)
     expect(agent.session.events.filter(event => event.type === 'turn/start')).toHaveLength(2)
     expect(agent.session.events.some(event => event.type === 'steering/message')).toBe(false)
@@ -658,7 +667,7 @@ describe('agent loop', () => {
     send(agent, 'first')
     await waitForIdle(ctx, agent)
     // The first turn failed at step 1 before a model call.
-    expect(errors).toEqual([])
+    expect(errors.map(error => error.message)).toEqual(['boom in pre-step'])
     expect(adapter.requests.length).toBe(0)
     const firstTurnEnd = agent.session.events.find(e => e.type === 'turn/end')
     expect(firstTurnEnd?.type === 'turn/end' && firstTurnEnd.data.reason).toMatchObject({ kind: 'error' })
@@ -1085,20 +1094,24 @@ describe('agent loop', () => {
     const ctx = await harness(adapter)
     const agent = ctx.agentLoop.create(SessionId('a1'), { provider: 'mock', model: 'mock' })
 
-    const errors: Error[] = []
+    const errors: unknown[] = []
     const reasons: TurnEndReason[] = []
     ctx.on('agent/error', (_agent, _turn, _step, error) => {
-      if (error instanceof Error) errors.push(error)
+      errors.push(error)
     })
     ctx.on('session/event', (_s, event) => { if (event.type === 'turn/end') reasons.push(event.data.reason) })
 
     send(agent, 'hi')
     await waitForIdle(ctx, agent)
 
-    expect(errors).toEqual([])
+    expect(errors).toHaveLength(1)
+    expect(errors[0]).toBeInstanceOf(LlmError)
+    expect((errors[0] as LlmError).failure).toEqual({
+      message: 'MockAdapter: script exhausted',
+      code: 'UNKNOWN',
+    })
     expect(reasons[0]).toMatchObject({ kind: 'error' })
-    // The durable failure lives entirely on turn/end.reason (with the failing
-    // step), not a standalone error event.
+    // The durable failure and live relay describe the same failed turn.
     const turnEnd = agent.session.events.find(e => e.type === 'turn/end')
     expect(turnEnd?.type === 'turn/end' && turnEnd.data.reason).toMatchObject({ kind: 'error' })
   })

packages/core/agent-loop/tests/request-reconstruction.spec.ts

@@ -359,7 +359,12 @@ describe('request stability across the loop', () => {
       await waitForIdle(ctx, agent)
 
       expect(agent.session.events.findLast(event => event.type === 'turn/end')).toMatchObject({
-        data: { reason: { kind: 'error', error: failure.message } },
+        data: {
+          reason: {
+            kind: 'error',
+            error: failure instanceof LlmError ? failure.failure : failure.message,
+          },
+        },
       })
       expect(adapter.requests).toHaveLength(0)
     },