Merge newest origin/master into token-meter-service

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

@@ -375,8 +375,8 @@ describe('agent/session-prefix', () => {
       expect(request.messages[0]).toEqual(reminder)
     }
     // The anchoring snapshot is the prefix's durable record — and the ONLY
-    // header event: reuse means no request/header-delta ever.
-    const headerEvents = events(agent).filter(e => e.type === 'request/header' || e.type === 'request/header-delta')
+    // header event: reuse means no changed snapshot ever.
+    const headerEvents = events(agent).filter(e => e.type === 'request/header')
     expect(headerEvents).toHaveLength(1)
     expect(headerEvents[0]?.type === 'request/header' && headerEvents[0].data.header.messagePrefix).toEqual([reminder])
     // Never session history: the derivation starts at the real user prompt.
@@ -492,7 +492,7 @@ describe('agent/session-prefix', () => {
     // cached prefix is a deep-frozen clone, so step 2's request is unchanged.
     held.content = [{ type: 'text', text: 'v2' }]
     expect(adapter.requests[1]!.messages[0]).toEqual({ role: 'user', content: [{ type: 'text', text: 'v1' }] })
-    expect(events(agent).filter(e => e.type === 'request/header-delta')).toHaveLength(0)
+    expect(events(agent).filter(e => e.type === 'request/header')).toHaveLength(1)
   })
 })
 

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

@@ -1,9 +1,8 @@
 /**
- * recordRequestHeader unit tests: exactly one of four things per request —
+ * recordRequestHeader unit tests: exactly one of three things per request —
  * an 'initial' snapshot (log has no header yet), a 'resume' snapshot (fresh
- * loop instance over a log that has one), nothing (header unchanged), a
- * round-tripping delta, or a 'fallback' snapshot when the delta encoding
- * cannot express the change (pure tool reordering).
+ * loop instance over a log that has one), nothing (header unchanged), or a
+ * full 'change' snapshot.
  */
 
 import { describe, expect, it } from 'vitest'
@@ -23,7 +22,7 @@ function openSession(id: string): Session {
 }
 
 function headerEvents(session: Session): SessionEvent[] {
-  return session.events.filter(e => e.type === 'request/header' || e.type === 'request/header-delta')
+  return session.events.filter(e => e.type === 'request/header')
 }
 
 describe('recordRequestHeader', () => {
@@ -53,8 +52,8 @@ describe('recordRequestHeader', () => {
     expect(events[1]?.type === 'request/header' && events[1].data.reason).toBe('resume')
   })
 
-  it('logs a round-tripping delta for a mid-run change, and the fold reproduces the header', () => {
-    const session = openSession('rl-delta')
+  it("logs a full 'change' snapshot for a mid-run change, and the fold reproduces the header", () => {
+    const session = openSession('rl-change')
     const state = createTransmissionLog()
     const first = canonicalHeader({ config: { provider: 'mock', model: 'm' }, system: 'a\nb', tools: [tool('t')] })
     recordRequestHeader(session, state, first)
@@ -63,12 +62,12 @@ describe('recordRequestHeader', () => {
     recordRequestHeader(session, state, second)
     const events = headerEvents(session)
     expect(events).toHaveLength(2)
-    expect(events[1]?.type).toBe('request/header-delta')
+    expect(events[1]?.type === 'request/header' && events[1].data.reason).toBe('change')
     expect(session.requestHeader()).toEqual(second)
   })
 
-  it("records a change the delta cannot express (pure reordering) as a 'fallback' snapshot", () => {
-    const session = openSession('rl-fallback')
+  it("records a pure tool reordering as a 'change' snapshot", () => {
+    const session = openSession('rl-reorder')
     const state = createTransmissionLog()
     const first = canonicalHeader({ config: { provider: 'mock', model: 'm' }, tools: [tool('a'), tool('b')] })
     recordRequestHeader(session, state, first)
@@ -77,9 +76,7 @@ describe('recordRequestHeader', () => {
     recordRequestHeader(session, state, reordered)
     const events = headerEvents(session)
     expect(events).toHaveLength(2)
-    expect(events[1]?.type === 'request/header' && events[1].data.reason).toBe('fallback')
-    // The fold still lands on the exact header — deltas are an encoding
-    // optimization, never a correctness dependency.
+    expect(events[1]?.type === 'request/header' && events[1].data.reason).toBe('change')
     expect(session.requestHeader()).toEqual(reordered)
   })
 })

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

@@ -1,9 +1,8 @@
 /**
  * Loop-level reconstructability: every request the loop sends is a pure function of the
- * session log — messages are the derivation at the step/start boundary, the header is the fold
- * of request/header* events — and every request is an append-extension of its predecessor
- * unless a logged event (compaction replace, header change) explains the difference. Mock-adapter
- * requests are the observable, and the final offline rebuild states the full contract end to end.
+ * session log — messages derive at the step/start boundary and the header is the latest
+ * request/header snapshot. Each request extends its predecessor unless a logged compaction
+ * replacement or header change explains the difference.
  */
 
 import { describe, expect, it } from 'vitest'
@@ -85,7 +84,7 @@ describe('request stability across the loop', () => {
       expect(Object.isFrozen(request.messages)).toBe(true)
     }
     // One anchoring header snapshot; no further header events (nothing changed).
-    const headerEvents = agent.session.events.filter(e => e.type === 'request/header' || e.type === 'request/header-delta')
+    const headerEvents = agent.session.events.filter(e => e.type === 'request/header')
     expect(headerEvents).toHaveLength(1)
     expect(headerEvents[0]?.type === 'request/header' && headerEvents[0].data.reason).toBe('initial')
   })
@@ -122,8 +121,8 @@ describe('request stability across the loop', () => {
         content: [{ type: 'text', text: '[summary of turn 1]' }],
         source: { kind: 'plugin', plugin: 'test-compact' },
       }, {
-        surfaceOp: { op: 'replace', start: nodes[0]!.seq, end: nodes[1]!.seq },
-        sourceEventSeqs: [nodes[0]!.seq, nodes[1]!.seq],
+        surfaceOp: { op: 'replace', start: nodes[0]!, end: nodes[1]! },
+        sourceEventSeqs: [nodes[0]!, nodes[1]!],
       })
     })
 
@@ -137,7 +136,7 @@ describe('request stability across the loop', () => {
     expect(agent.session.events.filter(e => e.type === 'request/header')).toHaveLength(1)
   })
 
-  it('a real system-prompt change is a logged header delta; a stable prompt logs nothing', async () => {
+  it('a real system-prompt change is a full changed-header snapshot; a stable prompt logs nothing', async () => {
     const adapter = new MockAdapter([textResponse('one'), textResponse('two'), textResponse('three')])
     const ctx = await harness(adapter)
     const agent = ctx.agentLoop.create(AgentId('a1'), { provider: 'mock', model: 'mock' })
@@ -147,14 +146,15 @@ describe('request stability across the loop', () => {
     send(agent, 'second')
     await waitForIdle(ctx, agent)
     // Identical assembly re-rendered per step is NOT a change.
-    expect(agent.session.events.filter(e => e.type === 'request/header-delta')).toHaveLength(0)
+    expect(agent.session.events.filter(e => e.type === 'request/header')).toHaveLength(1)
 
     ctx.systemPrompt.section({ name: 'extra', order: 2, text: 'new guidance' })
     send(agent, 'third')
     await waitForIdle(ctx, agent)
 
-    const deltas = agent.session.events.filter(e => e.type === 'request/header-delta')
-    expect(deltas).toHaveLength(1)
+    const snapshots = agent.session.events.filter(e => e.type === 'request/header')
+    expect(snapshots).toHaveLength(2)
+    expect(snapshots[1]?.data.reason).toBe('change')
     expect(adapter.requests[2]!.system).toContain('new guidance')
     // History is preserved across the change — only the header moved.
     expect(adapter.requests[2]!.messages.length).toBeGreaterThan(adapter.requests[1]!.messages.length)
@@ -260,9 +260,9 @@ describe('request stability across the loop', () => {
     send(agent, 'second')
     await waitForIdle(ctx, agent)
 
-    // No delta was logged (nothing really changed), and the session's own
+    // No changed snapshot was logged (nothing really changed), and the session's own
     // fold is immutable state.
-    expect(agent.session.events.filter(e => e.type === 'request/header-delta')).toHaveLength(0)
+    expect(agent.session.events.filter(e => e.type === 'request/header')).toHaveLength(1)
     expect(Object.isFrozen(agent.session.requestHeader())).toBe(true)
     expect(adapter.requests[1]!.temperature).toBeUndefined()
   })
@@ -296,7 +296,7 @@ describe('request stability across the loop', () => {
       const rebuilt = new Session(SessionId(`rebuild-${index}`), structuredClone(events.slice(0, stepStart.seq)))
       expect(structuredClone(request.messages)).toEqual(rebuilt.deriveMessages())
 
-      // Header: the fold of request/header* events up to this step's dispatch
+      // Header: the latest request/header snapshot up to this step's dispatch
       // (its header event sits between step/start and the first chunk).
       const firstChunk = events.find(e => e.type === 'assistant/chunk' && e.seq > stepStart.seq)!
       const header = foldRequestHeader(events.slice(0, firstChunk.seq))!