Merge remote-tracking branch 'origin/master' into xtr/react-loop-simplification

# Conflicts:
#	apps/web/tests/markdown-images.e2e.ts
#	docs/cordis-catalog/services.md
#	docs/core-data-structures/session.i18n.yaml
#	docs/event-producer-consumer.md
#	examples/acp-agent/tests/snapshots/cordis-inspect-jsdoc/session.jsonl
#	packages/compact/compact-basic/tests/compact-basic.spec.ts
#	packages/context/time-context/tests/invariant.spec.ts
#	packages/context/time-context/tests/time-context.spec.ts
#	packages/core/agent-loop/src/invariant.ts
#	packages/core/agent-loop/tests/contract-regressions.spec.ts
#	packages/core/agent-loop/tests/request-reconstruction.spec.ts
#	packages/core/agent/tests/agent.spec.ts
#	packages/core/session/README.i18n.yaml
#	packages/core/session/src/index.ts
#	packages/core/session/tests/derived-cache.spec.ts
#	packages/core/session/tests/request-header.spec.ts
#	packages/core/session/tests/session.spec.ts
#	packages/core/session/tests/surface.spec.ts
#	packages/fs/tool-str-replace-editor/tests/tools.spec.ts
#	packages/goal/goal/tests/goal.spec.ts
#	packages/plan/plan-mode/tests/plan-mode.spec.ts
#	packages/pty/pty-local/tests/index.spec.ts
#	packages/pty/pty-local/tests/local.spec.ts
#	packages/pty/pty/tests/service.spec.ts
#	packages/pty/tool-bash-persistent/tests/loader-composition.spec.ts
#	packages/pty/tool-bash-persistent/tests/tools.spec.ts
#	packages/pty/tool-pty/tests/loader-composition.spec.ts
#	packages/pty/tool-pty/tests/tools.spec.ts
#	packages/session-title/session-title-all-messages-llm/tests/provider.spec.ts
#	packages/tasks/tasks-local/tests/tasks.spec.ts
#	packages/ui/user-approval/tests/approval.spec.ts

packages/core/session/tests/session.spec.ts

@@ -2,6 +2,7 @@ import { describe, expect, expectTypeOf, it, vi } from 'vitest'
 import { Context } from 'cordis'
 import { createUserMessage, CallId, createMessage, createToolResultMessage, MessageId, ReasoningEffortId } from '@deepseek-ai/dsh-llm'
 import SessionStore, {
+  adoptSessionEvent,
   SESSION_FORMAT_VERSION,
   Session,
   SessionEvent,
@@ -13,7 +14,7 @@ import type { CreateSessionOptions, SessionEventType, SessionHeader, SessionSurf
 
 describe('Session', () => {
   it('finds the latest closed turn that entered a model step', () => {
-    const session = new Session(SessionId('last-message-turn'))
+    const session = Session.create(SessionId('last-message-turn'))
     session.append('turn/start', { turn: 1 })
     session.append('turn/end', { turn: 1, reason: { kind: 'blocked' } })
 
@@ -29,7 +30,7 @@ describe('Session', () => {
   })
 
   it('exposes one stable readonly surface view', () => {
-    const session = new Session(SessionId('surface-view'))
+    const session = Session.create(SessionId('surface-view'))
     const surface = session.surface
 
     expectTypeOf(surface).toEqualTypeOf<SessionSurface>()
@@ -37,7 +38,7 @@ describe('Session', () => {
   })
 
   it('derives message history from the event log', () => {
-    const session = new Session(SessionId('s1'))
+    const session = Session.create(SessionId('s1'))
     session.append('turn/start', { turn: 1 })
     session.append('user/message', createUserMessage({
       content: [{ type: 'text', text: 'hello' }], source: { kind: 'user' },
@@ -77,7 +78,7 @@ describe('Session', () => {
   it('accepts and round-trips a max-tokens turn/end reason', () => {
     // The max-tokens TurnEndReason variant carries no extra data, so it must
     // append and persist like any other reason (JSON-serializable, no fields).
-    const session = new Session(SessionId('s1'))
+    const session = Session.create(SessionId('s1'))
     session.append('turn/start', { turn: 1 })
     session.append('turn/end', { turn: 1, reason: { kind: 'max-tokens' } })
 
@@ -88,10 +89,10 @@ describe('Session', () => {
   })
 
   it('round-trips an aborted turn with its cancellation cause', () => {
-    const session = new Session(SessionId('aborted'))
+    const session = Session.create(SessionId('aborted'))
     session.append('turn/start', { turn: 1 })
     session.append('turn/end', { turn: 1, reason: { kind: 'aborted', reason: { kind: 'user' } } })
-    const replayed = new Session(SessionId('aborted-replay'), structuredClone(session.events))
+    const replayed = Session.create(SessionId('aborted-replay'), structuredClone(session.events))
     expect(replayed.events.slice(0, -1)).toEqual(session.events)
     const turnEnd = replayed.events.findLast(event => event.type === 'turn/end')
     expect(turnEnd?.type === 'turn/end' && turnEnd.data.reason)
@@ -99,7 +100,7 @@ describe('Session', () => {
   })
 
   it('renders injected-context and user messages as plain user content', () => {
-    const session = new Session(SessionId('s2'))
+    const session = Session.create(SessionId('s2'))
     session.append('user/message', createUserMessage({
       content: [{ type: 'text', text: 'file changed: a.ts' }],
       source: { kind: 'plugin', plugin: 'watcher' },
@@ -117,7 +118,7 @@ describe('Session', () => {
   })
 
   it('keeps the exact identified context message in durable history and projection', () => {
-    const session = new Session(SessionId('s2-raw'))
+    const session = Session.create(SessionId('s2-raw'))
     const message = createUserMessage({
       content: [{ type: 'text', text: '<system-reminder>Additional instructions from: pkg/AGENTS.md</system-reminder>' }],
       source: { kind: 'plugin', plugin: 'workspace-context' },
@@ -130,7 +131,7 @@ describe('Session', () => {
   })
 
   it('replays identically from a seeded event log', () => {
-    const original = new Session(SessionId('s3'))
+    const original = Session.create(SessionId('s3'))
     original.append('turn/start', { turn: 1 })
     original.append('user/message', createUserMessage({
       content: [{ type: 'text', text: 'q' }], source: { kind: 'user' },
@@ -148,7 +149,7 @@ describe('Session', () => {
     }, { surfaceOp: 'append' })
     original.append('turn/end', { turn: 1, reason: { kind: 'completed' } })
 
-    const replayed = new Session(SessionId('s3-replay'), [...original.events])
+    const replayed = Session.create(SessionId('s3-replay'), [...original.events])
     expect(replayed.deriveMessages()).toEqual(original.deriveMessages())
     // The seed verbatim, plus the end-seed event the constructor appends.
     expect(replayed.events.slice(0, original.seq)).toEqual(original.events)
@@ -157,16 +158,16 @@ describe('Session', () => {
   })
 
   it('marks an explicitly empty seed without marking a fresh session', () => {
-    const fresh = new Session(SessionId('fresh-empty'))
+    const fresh = Session.create(SessionId('fresh-empty'))
     expect(fresh.events).toEqual([])
 
-    const resumed = new Session(SessionId('resumed-empty'), [])
+    const resumed = Session.create(SessionId('resumed-empty'), [])
     expect(resumed.firstLiveSeq).toBe(0)
     expect(resumed.events).toMatchObject([
       { type: 'session/end-seed', seq: 0, data: {} },
     ])
 
-    const reopened = new Session(SessionId('reopened-empty'), resumed.events)
+    const reopened = Session.create(SessionId('reopened-empty'), resumed.events)
     expect(reopened.firstLiveSeq).toBe(1)
     expect(reopened.events).toEqual(resumed.events)
   })
@@ -176,7 +177,7 @@ describe('Session', () => {
       type: 'request/header', seq: 0, time: 1,
       data: { header: { config: { model: 'old-model' } }, reason: 'initial' },
     } as unknown as SessionEvent
-    expect(() => new Session(SessionId('old-header'), [requestHeader]))
+    expect(() => Session.create(SessionId('old-header'), [requestHeader]))
       .toThrow('seed request/header at index 0 lacks provider/model')
 
     const assistantMessage = {
@@ -184,20 +185,20 @@ describe('Session', () => {
       data: { turn: 1, step: 1, content: [{ type: 'text', text: 'old' }] },
       surfaceOp: 'append',
     } as unknown as SessionEvent
-    expect(() => new Session(SessionId('old-assistant'), [assistantMessage]))
+    expect(() => Session.create(SessionId('old-assistant'), [assistantMessage]))
       .toThrow('seed assistant/message at index 0 lacks an identified message')
 
     const malformedHeader = {
       type: 'request/header', seq: 0, time: 1,
       data: { header: 'old-header' },
     } as unknown as SessionEvent
-    expect(() => new Session(SessionId('malformed-header'), [malformedHeader]))
+    expect(() => Session.create(SessionId('malformed-header'), [malformedHeader]))
       .toThrow('seed request/header at index 0 lacks provider/model')
 
     const unrelatedPrimitiveData = {
       type: 'plugin/event', seq: 0, time: 1, data: null,
     } as unknown as SessionEvent
-    expect(new Session(SessionId('primitive-plugin-data'), [unrelatedPrimitiveData]).events.slice(0, 1))
+    expect(Session.create(SessionId('primitive-plugin-data'), [unrelatedPrimitiveData]).events.slice(0, 1))
       .toEqual([unrelatedPrimitiveData])
   })
 
@@ -312,7 +313,7 @@ describe('Session', () => {
 
     for (const { name, event, message } of invalid) {
       expect(
-        () => new Session(SessionId(`invalid-${name}`), [event as unknown as SessionEvent]),
+        () => Session.create(SessionId(`invalid-${name}`), [event as unknown as SessionEvent]),
         name,
       ).toThrow(message)
     }
@@ -348,6 +349,45 @@ describe('Session', () => {
       .toEqual([{ type: 'plugin-block', value: 1 }])
   })
 
+  it('adopts exclusively owned messages in place and keeps snapshots detached', () => {
+    const owned = {
+      type: 'user/message',
+      seq: 0,
+      time: 1,
+      surfaceOp: 'append',
+      data: {
+        id: 'owned-message',
+        role: 'user',
+        content: [{ type: 'text', text: 'owned' }],
+        source: { kind: 'user' },
+      },
+    } as SessionEvent<'user/message'>
+    expect(adoptSessionEvent(owned)).toBe(owned)
+    expect(Object.isFrozen(owned.data)).toBe(true)
+    expect(Object.isFrozen(owned.data.content)).toBe(true)
+
+    const source = structuredClone(owned)
+    const snapshot = snapshotSessionEvent(source)
+    expect(snapshot).not.toBe(source)
+    expect(snapshot.data).not.toBe(source.data)
+    expect(snapshot.data.content).not.toBe(source.data.content)
+  })
+
+  it('validates message shape before adopting ownership', () => {
+    const malformed = {
+      type: 'user/message',
+      seq: 0,
+      time: 1,
+      data: {
+        id: 'wrong-role',
+        role: 'assistant',
+        content: [],
+        source: { kind: 'user' },
+      },
+    } as unknown as SessionEvent
+    expect(() => adoptSessionEvent(malformed)).toThrow('message must have role "user"')
+  })
+
   it('round-trips a non-empty reasoning effort and rejects invalid durable values', () => {
     const valid = {
       type: 'request/header',
@@ -364,7 +404,7 @@ describe('Session', () => {
         reason: 'initial',
       },
     } as const
-    expect(new Session(SessionId('reasoning-effort'), [valid]).events[0])
+    expect(Session.create(SessionId('reasoning-effort'), [valid]).events[0])
       .toEqual(valid)
 
     for (const reasoningEffort of ['', 1]) {
@@ -372,7 +412,7 @@ describe('Session', () => {
       if (invalid.type !== 'request/header') throw new Error('test fixture must be a request header')
       const config = invalid.data.header.config as unknown as Record<string, unknown>
       config.reasoningEffort = reasoningEffort
-      expect(() => new Session(SessionId('invalid-reasoning-effort'), [invalid]))
+      expect(() => Session.create(SessionId('invalid-reasoning-effort'), [invalid]))
         .toThrow('seed request/header at index 0 has an invalid reasoningEffort')
     }
   })
@@ -394,7 +434,7 @@ describe('Session', () => {
         reason: 'initial',
       },
     } as const
-    expect(new Session(SessionId('adapter-defaults'), [valid]).events[0]).toEqual(valid)
+    expect(Session.create(SessionId('adapter-defaults'), [valid]).events[0]).toEqual(valid)
 
     for (const adapterDefaults of [
       null,
@@ -406,13 +446,13 @@ describe('Session', () => {
       const invalid = structuredClone(valid) as unknown as SessionEvent
       if (invalid.type !== 'request/header') throw new Error('test fixture must be a request header')
       invalid.data.header.adapterDefaults = adapterDefaults as never
-      expect(() => new Session(SessionId('invalid-adapter-defaults'), [invalid]))
+      expect(() => Session.create(SessionId('invalid-adapter-defaults'), [invalid]))
         .toThrow('seed request/header at index 0 has invalid adapterDefaults')
     }
   })
 
   it('isolates the log from mutation through a derived message (append-only contract)', () => {
-    const session = new Session(SessionId('s4'))
+    const session = Session.create(SessionId('s4'))
     session.append('user/message', createUserMessage({
       content: [{ type: 'text', text: 'original' }], source: { kind: 'user' },
     }), { surfaceOp: 'append' })
@@ -446,7 +486,7 @@ describe('Session', () => {
   })
 
   it('rejects non-JSON-serializable event data at the source (incl. sparse arrays)', () => {
-    const session = new Session(SessionId('s5'))
+    const session = Session.create(SessionId('s5'))
     const bad = (extra: unknown) => () => session.append('user/message', { content: [{ type: 'text', text: 'x' }], source: { kind: 'user' }, extra } as never, { surfaceOp: 'append' })
     expect(bad(1n)).toThrow(/non-JSON-serializable/)
     expect(bad(() => 0)).toThrow(/non-JSON-serializable/)
@@ -473,7 +513,7 @@ describe('Session', () => {
   })
 
   it('rejects a surface-eligible append with no surfaceOp marker (runtime guard for the union-widening loophole)', () => {
-    const session = new Session(SessionId('s5b'))
+    const session = Session.create(SessionId('s5b'))
     session.append('turn/start', { turn: 1 })
     // A widened SessionEventType bypasses the overload's conditional requirement,
     // so the runtime guard must still reject the missing surface marker.
@@ -487,7 +527,7 @@ describe('Session', () => {
   })
 
   it('accepts dense arrays and nested plain objects', () => {
-    const session = new Session(SessionId('s6'))
+    const session = Session.create(SessionId('s6'))
     expect(() => session.append('user/message', { content: [{ type: 'text', text: 'x' }], source: { kind: 'user' }, extra: [1, 2, [3, { a: null, b: true }]] } as never, { surfaceOp: 'append' })).not.toThrow()
     expect(session.events).toHaveLength(1)
   })
@@ -498,7 +538,7 @@ describe('Session', () => {
     const badSeed = [
       { type: 'user/message' as const, seq: 0, time: 1, data: { content: [{ type: 'text' as const, text: 'x' }], source: { kind: 'user' as const }, bad: 1n } },
     ] as unknown as SessionEvent[]
-    expect(() => new Session(SessionId('seed-bad'), badSeed)).toThrow(/losslessly JSON-serializable/)
+    expect(() => Session.create(SessionId('seed-bad'), badSeed)).toThrow(/losslessly JSON-serializable/)
   })
 
   it('validates seed events: rejects a non-contiguous seq', () => {
@@ -506,7 +546,7 @@ describe('Session', () => {
       { type: 'turn/start' as const, seq: 0, time: 1, data: { turn: 1 } },
       { type: 'turn/end' as const, seq: 5, time: 2, data: { turn: 1, reason: { kind: 'completed' as const } } }, // gap: expected seq 1
     ] as SessionEvent[]
-    expect(() => new Session(SessionId('seed-gap'), gapSeed)).toThrow(/contiguous|seq/)
+    expect(() => Session.create(SessionId('seed-gap'), gapSeed)).toThrow(/contiguous|seq/)
   })
 
   it('validates seed events: rejects a surface-eligible event missing its surfaceOp marker', () => {
@@ -521,7 +561,7 @@ describe('Session', () => {
       }) },
       { type: 'turn/end' as const, seq: 2, time: 3, data: { turn: 1, reason: { kind: 'completed' as const } } },
     ] as SessionEvent[]
-    expect(() => new Session(SessionId('seed-no-marker'), markerlessSeed)).toThrow(/requires a surfaceOp marker/)
+    expect(() => Session.create(SessionId('seed-no-marker'), markerlessSeed)).toThrow(/requires a surfaceOp marker/)
   })
 
   it('accepts a well-formed contiguous serializable seed', () => {
@@ -532,7 +572,7 @@ describe('Session', () => {
       }), surfaceOp: 'append' as const },
       { type: 'turn/end' as const, seq: 2, time: 3, data: { turn: 1, reason: { kind: 'completed' as const } } },
     ] as SessionEvent[]
-    const session = new Session(SessionId('seed-ok'), goodSeed)
+    const session = Session.create(SessionId('seed-ok'), goodSeed)
     expect(session.events.slice(0, 3)).toEqual(goodSeed)
     expect(session.firstLiveSeq).toBe(3)
   })
@@ -555,7 +595,7 @@ describe('Session', () => {
       },
     })
 
-    const session = new Session(SessionId('seed-entry-snapshot'), seed)
+    const session = Session.create(SessionId('seed-entry-snapshot'), seed)
 
     expect(reads).toBe(1)
     expect(session.events.slice(0, 1)).toEqual([accepted])
@@ -572,7 +612,7 @@ describe('Session', () => {
     })
     const seed = [{ type: 'test/unstable', seq: 0, time: 1, data }] as unknown as SessionEvent[]
 
-    const session = new Session(SessionId('seed-nested-drift'), seed)
+    const session = Session.create(SessionId('seed-nested-drift'), seed)
 
     expect(reads).toBe(1)
     expect(session.events[0]!.data).toEqual({ value: 'accepted' })
@@ -589,7 +629,7 @@ describe('Session', () => {
       surfaceOp: { op: 'replace', start: 1n, end: 2 },
     }] as unknown as SessionEvent[]
 
-    expect(() => new Session(SessionId('seed-bad-metadata'), seed))
+    expect(() => Session.create(SessionId('seed-bad-metadata'), seed))
       .toThrow(/losslessly JSON-serializable/)
   })
 
@@ -609,7 +649,7 @@ describe('Session', () => {
       surfaceOp: new ReplaceOp(),
     }] as unknown as SessionEvent[]
 
-    expect(() => new Session(SessionId('seed-exotic-metadata'), seed))
+    expect(() => Session.create(SessionId('seed-exotic-metadata'), seed))
       .toThrow(/losslessly JSON-serializable/)
   })
 
@@ -622,7 +662,7 @@ describe('Session', () => {
     }
     const seed: SessionEvent[] = [new SeedEvent()]
 
-    expect(() => new Session(SessionId('seed-exotic-shell'), seed))
+    expect(() => Session.create(SessionId('seed-exotic-shell'), seed))
       .toThrow(/not losslessly JSON-serializable/)
   })
 
@@ -634,7 +674,7 @@ describe('Session', () => {
       data: { turn: 1 },
     }) as unknown as SessionEvent
 
-    const session = new Session(SessionId('seed-null-prototype'), [event])
+    const session = Session.create(SessionId('seed-null-prototype'), [event])
 
     expect(session.events.slice(0, 1)).toEqual([{ ...event }])
   })
@@ -667,7 +707,7 @@ describe('Session', () => {
       sourceEventSeqs: [0],
     }] as unknown as SessionEvent[]
 
-    const session = new Session(SessionId('seed-unstable-metadata'), seed)
+    const session = Session.create(SessionId('seed-unstable-metadata'), seed)
     const event = session.events[1]!
     if (event.type !== 'user/message') throw new Error('test fixture must remain a user/message')
 
@@ -704,7 +744,7 @@ describe('Session', () => {
     }] as unknown as SessionEvent[]
 
     try {
-      expect(() => new Session(SessionId('seed-non-error-metadata-failure'), seed))
+      expect(() => Session.create(SessionId('seed-non-error-metadata-failure'), seed))
         .toThrow(`invalid seed event at index 1: ${expected}`)
     } finally {
       hasOwn.mockRestore()
@@ -721,7 +761,7 @@ describe('Session', () => {
       }, surfaceOp: 'append' as const },
       { type: 'turn/end' as const, seq: 2, time: 3, data: { turn: 1, reason: { kind: 'completed' as const } } },
     ] as SessionEvent[]
-    const session = new Session(SessionId('seed-snapshot'), seed)
+    const session = Session.create(SessionId('seed-snapshot'), seed)
     // Mutate the ORIGINAL seed objects after construction: a shared reference
     // would let this rewrite the forked log (or reintroduce non-serializable
     // data past validation). The snapshot must shield session.events.
@@ -734,7 +774,7 @@ describe('Session', () => {
   })
 
   it('snapshots append data: mutating the passed object after append does not affect session.events', () => {
-    const session = new Session(SessionId('append-snapshot'))
+    const session = Session.create(SessionId('append-snapshot'))
     const data = {
       id: MessageId('append-input'),
       role: 'user' as const,
@@ -754,7 +794,7 @@ describe('Session', () => {
   })
 
   it('reads a nested append-data getter once and stores its first JSON value', () => {
-    const session = new Session(SessionId('append-nested-drift'))
+    const session = Session.create(SessionId('append-nested-drift'))
     let reads = 0
     const data = Object.defineProperty({}, 'value', {
       enumerable: true,
@@ -772,7 +812,7 @@ describe('Session', () => {
   })
 
   it('rejects non-JSON surface metadata before appending the event', () => {
-    const session = new Session(SessionId('append-bad-metadata'))
+    const session = Session.create(SessionId('append-bad-metadata'))
 
     expect(() => session.append(
       'user/message',
@@ -790,7 +830,7 @@ describe('Session', () => {
       readonly start = 0
       readonly end = 0
     }
-    const session = new Session(SessionId('append-exotic-metadata'))
+    const session = Session.create(SessionId('append-exotic-metadata'))
 
     expect(() => session.append(
       'user/message',
@@ -803,7 +843,7 @@ describe('Session', () => {
   })
 
   it('reads a nested append-metadata getter once and stores its first JSON value', () => {
-    const session = new Session(SessionId('append-unstable-metadata'))
+    const session = Session.create(SessionId('append-unstable-metadata'))
     const source = session.append(
       'user/message',
       createUserMessage({
@@ -834,7 +874,7 @@ describe('Session', () => {
   })
 
   it('rejects invalid plain surface metadata shapes at append', () => {
-    const session = new Session(SessionId('append-invalid-surface-shape'))
+    const session = Session.create(SessionId('append-invalid-surface-shape'))
     const appendRaw = session.append.bind(session) as unknown as (
       type: SessionEventType,
       data: unknown,
@@ -855,7 +895,7 @@ describe('Session', () => {
   })
 
   it('rejects surface metadata on non-surface append and seed events', () => {
-    const session = new Session(SessionId('non-surface-metadata'))
+    const session = Session.create(SessionId('non-surface-metadata'))
     const appendRaw = session.append.bind(session) as unknown as (
       type: SessionEventType,
       data: unknown,
@@ -867,7 +907,7 @@ describe('Session', () => {
       { turn: 1 },
       { surfaceOp: 'append' },
     )).toThrow(/not surface-eligible and cannot carry surfaceOp/)
-    expect(() => new Session(SessionId('non-surface-metadata-seed'), [{
+    expect(() => Session.create(SessionId('non-surface-metadata-seed'), [{
       type: 'turn/start',
       seq: 0,
       time: 1,
@@ -878,7 +918,7 @@ describe('Session', () => {
   })
 
   it('deep-freezes seeded and appended event snapshots', () => {
-    const seeded = new Session(SessionId('seed-frozen'), [{
+    const seeded = Session.create(SessionId('seed-frozen'), [{
       type: 'turn/start',
       seq: 0,
       time: 1,
@@ -890,7 +930,7 @@ describe('Session', () => {
     expect(Object.isFrozen(seededEvent.data)).toBe(true)
     expect(() => { seededEvent.data.turn = 99 }).toThrow(TypeError)
 
-    const appended = new Session(SessionId('append-frozen'))
+    const appended = Session.create(SessionId('append-frozen'))
     const appendedEvent = appended.append('todo/write', {
       todos: [{ content: 'first', status: 'pending' }],
     })
@@ -902,7 +942,7 @@ describe('Session', () => {
   })
 
   it('returns cached frozen event-array snapshots that do not grow after append', () => {
-    const session = new Session(SessionId('events-snapshot'))
+    const session = Session.create(SessionId('events-snapshot'))
     session.append('turn/start', { turn: 1 })
     const before = session.events
     const beforeEvent = before[0]!
@@ -931,7 +971,7 @@ describe('Session', () => {
       seedLength: 2,
     }
 
-    const session = new Session(SessionId('header-owned'), undefined, input)
+    const session = Session.create(SessionId('header-owned'), undefined, input)
     input.cwd = '/caller-mutated'
 
     expect(session.header).toEqual({
@@ -956,15 +996,15 @@ describe('Session', () => {
       readonly createdAt = 123
     }
 
-    expect(() => new Session(SessionId('header-invalid'), undefined, new ExoticHeader()))
+    expect(() => Session.create(SessionId('header-invalid'), undefined, new ExoticHeader()))
       .toThrow(/not losslessly JSON-serializable/)
-    expect(() => new Session(SessionId('header-invalid'), undefined, {
+    expect(() => Session.create(SessionId('header-invalid'), undefined, {
       version: SESSION_FORMAT_VERSION,
       id: SessionId('header-invalid'),
       createdAt: 123,
       parentSession: 1n,
     } as unknown as SessionHeader)).toThrow(/not losslessly JSON-serializable/)
-    expect(() => new Session(SessionId('header-invalid'), undefined, {
+    expect(() => Session.create(SessionId('header-invalid'), undefined, {
       version: SESSION_FORMAT_VERSION,
       id: SessionId('other'),
       createdAt: 123,
@@ -991,7 +1031,7 @@ describe('Session', () => {
     ]
 
     for (const { header, error } of cases) {
-      expect(() => new Session(SessionId('header-shape'), undefined, header as SessionHeader)).toThrow(error)
+      expect(() => Session.create(SessionId('header-shape'), undefined, header as SessionHeader)).toThrow(error)
     }
   })
 
@@ -1015,7 +1055,7 @@ describe('Session', () => {
     ]
 
     for (const [index, event] of cases.entries()) {
-      expect(() => new Session(SessionId(`bad-envelope-${index}`), [event as SessionEvent]))
+      expect(() => Session.create(SessionId(`bad-envelope-${index}`), [event as SessionEvent]))
         .toThrow(/invalid event envelope/)
     }
   })
@@ -1103,7 +1143,7 @@ describe('SessionStore', () => {
     const secondCtx = new Context()
     await firstCtx.plugin(SessionStore)
     await secondCtx.plugin(SessionStore)
-    const session = new Session(SessionId('owned-key'))
+    const session = Session.create(SessionId('owned-key'))
     const detachFirst = firstCtx.sessions.enter(session)
 
     expect(() => secondCtx.sessions.enter(session)).toThrow(/already attached to a store/)
@@ -1260,7 +1300,7 @@ describe('SessionStore', () => {
   })
 
   it('a bare Session() constructed without the store still exposes a current-version header', () => {
-    const session = new Session(SessionId('bare'))
+    const session = Session.create(SessionId('bare'))
     expect(session.header).toMatchObject({ version: SESSION_FORMAT_VERSION, id: 'bare' })
     expect(typeof session.header.createdAt).toBe('number')
   })
@@ -1578,7 +1618,7 @@ describe('SessionStore', () => {
   it('does not let internal dispatch replace the disposed callback tuple', async () => {
     const ctx = new Context()
     await ctx.plugin(SessionStore)
-    const replacement = new Session(SessionId('replacement-disposed'))
+    const replacement = Session.create(SessionId('replacement-disposed'))
     const heard: Session[] = []
     ctx.on('internal/dispatch', (_mode, name, args) => {
       if (name === 'session/disposed') args[0] = replacement
@@ -1596,7 +1636,7 @@ describe('SessionStore', () => {
 
 describe('todo/write event', () => {
   it('appends the whole-list snapshot and isolates the log from later mutation', () => {
-    const session = new Session(SessionId('t1'))
+    const session = Session.create(SessionId('t1'))
     const todos: TodoItem[] = [
       { content: 'plan the work', status: 'in_progress' },
       { content: 'write the code', status: 'pending' },
@@ -1618,7 +1658,7 @@ describe('todo/write event', () => {
   })
 
   it('is last-write-wins: the current list is the most recent todo/write', () => {
-    const session = new Session(SessionId('t2'))
+    const session = Session.create(SessionId('t2'))
     session.append('todo/write', { todos: [{ content: 'first', status: 'pending' }] })
     session.append('todo/write', { todos: [
       { content: 'first', status: 'completed' },
@@ -1633,7 +1673,7 @@ describe('todo/write event', () => {
   })
 
   it('is NOT a surface event: it produces no derived message and joins no surface node', () => {
-    const session = new Session(SessionId('t3'))
+    const session = Session.create(SessionId('t3'))
     session.append('user/message', createUserMessage({
       content: [{ type: 'text', text: 'q' }], source: { kind: 'user' },
     }), { surfaceOp: 'append' })
@@ -1646,12 +1686,12 @@ describe('todo/write event', () => {
   })
 
   it('round-trips through a seeded replay identically (durable, no surfaceOp needed)', () => {
-    const original = new Session(SessionId('t4'))
+    const original = Session.create(SessionId('t4'))
     original.append('turn/start', { turn: 1 })
     original.append('todo/write', { todos: [{ content: 'only', status: 'completed' }] })
     original.append('turn/end', { turn: 1, reason: { kind: 'completed' } })
     // Seeding a non-surface event with no surfaceOp must not throw.
-    const replayed = new Session(SessionId('t4-replay'), [...original.events])
+    const replayed = Session.create(SessionId('t4-replay'), [...original.events])
     expect(replayed.events.findLast(e => e.type === 'todo/write')!.data.todos)
       .toEqual([{ content: 'only', status: 'completed' }])
     expect(replayed.events.slice(0, original.seq)).toEqual(original.events)