fix(apiproxy): harden cold session metadata probing

packages/core/session/src/index.ts

@@ -26,7 +26,7 @@ export type { SessionPreparationOptions } from './preparation.ts'
 export type { AssistantMessage, ToolResultMessage, UserMessage } from '@deepseek-ai/dsh-llm'
 export { isJsonValue, snapshotJsonValue } from './json.ts'
 export type { JsonValue } from './json.ts'
-export { interruptedTurnClosers, lastActivityTime, TOOL_NOT_STARTED, TOOL_OUTCOME_UNKNOWN } from './repair.ts'
+export { interruptedTurnClosers, TOOL_NOT_STARTED, TOOL_OUTCOME_UNKNOWN } from './repair.ts'
 export { decodeStorageRecord, packChunkRuns } from './chunk-rows.ts'
 export type { ChunkRow, StorageRecord } from './chunk-rows.ts'
 export type { SessionSurface, SurfaceFoldReplacement, SurfaceFoldResult } from './surface.ts'

packages/core/session/src/repair.ts

@@ -1,10 +1,7 @@
 /**
  * Crash-recovery repair for an interrupted session log. It preserves a fully
  * written final turn and supplies the missing tool, step, and turn boundaries
- * needed to resume with a provider-valid transcript, plus the activity-time
- * read that must skip the end-seed boundary — which this module does
- * not write (`Session`'s constructor does) but whose synthetic closers can
- * inherit that boundary's timestamp, the one real coupling between the two.
+ * needed to resume with a provider-valid transcript.
  * @module @deepseek-ai/dsh-session/repair
  */
 
@@ -12,22 +9,6 @@ import { MessageId, freezeMessage, type CallId } from '@deepseek-ai/dsh-llm'
 import type { ToolResultMessage } from '@deepseek-ai/dsh-llm'
 import type { SessionEvent } from './types.ts'
 
-/**
- * The `time` of the log's last event representing actual work, skipping the
- * `session/end-seed` boundary — picking a session up is not activity, so
- * activity ordering must exclude it.
- *
- * Excluded by type, so a pickup time still leaks when a boundary is the last
- * event of an open turn: {@link interruptedTurnClosers} copies it onto the
- * synthetic `turn/end`, which this counts as work. Reachable only by seeding an
- * unbalanced log directly — `load()` balances first.
- * @param events - the log to scan, in seq order.
- * @returns the latest non-boundary event's `time`, or undefined when there is none.
- */
-export function lastActivityTime(events: readonly SessionEvent[]): number | undefined {
-  return events.findLast(event => event.type !== 'session/end-seed')?.time
-}
-
 /** Recovery code for an assistant tool request that never reached a recorded call start. */
 export const TOOL_NOT_STARTED = 'TOOL_NOT_STARTED'
 

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

@@ -1,6 +1,6 @@
 import { describe, expect, it } from 'vitest'
 import { CallId , createMessage, createToolResultMessage } from '@deepseek-ai/dsh-llm'
-import { interruptedTurnClosers, lastActivityTime, TOOL_NOT_STARTED, TOOL_OUTCOME_UNKNOWN } from '../src/index.ts'
+import { interruptedTurnClosers, TOOL_NOT_STARTED, TOOL_OUTCOME_UNKNOWN } from '../src/index.ts'
 import type { SessionEvent, SurfaceEvent } from '../src/index.ts'
 
 /**
@@ -273,44 +273,3 @@ describe('interruptedTurnClosers', () => {
     expect(closers.map(e => e.type)).toEqual(['step/end', 'turn/end'])
   })
 })
-
-describe('lastActivityTime', () => {
-  const endSeedAt = (seq: number, time: number): SessionEvent =>
-    ({ type: 'session/end-seed', seq, time, data: {} })
-
-  it('has no answer for an empty log', () => {
-    expect(lastActivityTime([])).toBeUndefined()
-  })
-
-  it('reports the log tail when no boundary is present', () => {
-    const events: SessionEvent[] = [
-      userTurnStart(1, 0),
-      { type: 'turn/end', seq: 1, time: 500, data: { turn: 1, reason: { kind: 'completed' } } },
-    ]
-    expect(lastActivityTime(events)).toBe(500)
-  })
-
-  it('skips a trailing boundary in favour of the last real work', () => {
-    const events: SessionEvent[] = [
-      userTurnStart(1, 0),
-      { type: 'turn/end', seq: 1, time: 500, data: { turn: 1, reason: { kind: 'completed' } } },
-      endSeedAt(2, 9_000),
-    ]
-    // Resumed long after the work, but never worked in again.
-    expect(lastActivityTime(events)).toBe(500)
-  })
-
-  it('reports work appended after end-seed', () => {
-    const events: SessionEvent[] = [
-      userTurnStart(1, 0),
-      endSeedAt(1, 9_000),
-      { type: 'turn/end', seq: 2, time: 9_500, data: { turn: 1, reason: { kind: 'completed' } } },
-    ]
-    expect(lastActivityTime(events)).toBe(9_500)
-  })
-
-  it('has no answer for a log of nothing but boundaries', () => {
-    // Unreachable via the constructor, but the projection is a pure function.
-    expect(lastActivityTime([endSeedAt(0, 1), endSeedAt(1, 2)])).toBeUndefined()
-  })
-})