feat(agent-core-v2): drop the experimental gate from turn-level file history

.changeset/file-history-always-on.md

@@ -0,0 +1,5 @@
+---
+"@moonshot-ai/kimi-code": minor
+---
+
+Turn-level file history is now always on; the experimental file-history flag has been removed.

packages/agent-core-v2/src/features/fileHistory/fileHistory.ts

@@ -42,7 +42,6 @@ export interface FileHistoryContent {
 export interface IAgentFileHistoryService {
   readonly _serviceBrand: undefined;
 
-  enabled(): boolean;
   history(): FileHistoryState;
   settled(): Promise<void>;
   captureForActiveTurn(path: string): Promise<void>;

packages/agent-core-v2/src/features/fileHistory/fileHistoryFeature.ts

@@ -1,7 +1,6 @@
 import { Feature } from '#/features/feature';
 import { registerFeature } from '#/features/featureRegistry';
 
-import './flag';
 import { IAgentFileHistoryService } from './fileHistory';
 import { AgentFileHistoryService } from './fileHistoryService';
 

packages/agent-core-v2/src/features/fileHistory/fileHistoryService.ts

@@ -15,7 +15,6 @@ import { IHostFileSystem } from '#/os/interface/hostFileSystem';
 import { IAtomicDocumentStore } from '#/persistence/interface/atomicDocumentStore';
 import { TurnEnded } from '#/agent/loop/turnOps';
 import { IEventBus } from '#/app/event/eventBus';
-import { IFlagService } from '#/app/flag/flag';
 import { IBlobStore } from '#/persistence/interface/blobStore';
 import { IAgentLifecycleService, MAIN_AGENT_ID } from '#/session/agentLifecycle/agentLifecycle';
 import { ISessionWorkspaceContext } from '#/session/workspaceContext/workspaceContext';
@@ -40,7 +39,6 @@ import {
   fileHistoryKey,
 } from './fileHistoryOps';
 import { touchFileHistorySession } from './fileHistoryRetention';
-import { FILE_HISTORY_FLAG_ID } from './flag';
 
 export const FILE_HISTORY_MAX_FILE_BYTES = 4 * 1024 * 1024;
 export { FILE_HISTORY_BLOB_PREFIX } from './fileHistory';
@@ -58,7 +56,6 @@ export class AgentFileHistoryService extends Service implements IAgentFileHistor
     @IAgentToolExecutorService toolExecutor: IAgentToolExecutorService,
     @IEventBus eventBus: IEventBus,
     @IEventDispatcher private readonly dispatcher: IEventDispatcher,
-    @IFlagService private readonly flags: IFlagService,
     @IAgentRuntimeService private readonly runtime: IAgentRuntimeService,
     @IBlobStore private readonly blobs: IBlobStore,
     @ISessionWorkspaceContext private readonly workspaceCtx: ISessionWorkspaceContext,
@@ -89,17 +86,12 @@ export class AgentFileHistoryService extends Service implements IAgentFileHistor
       eventBus.subscribe(TurnEnded, (event) => {
         if (event.agentId !== this.agentCtx.agentId) return;
         if (this.activeTurnId === event.turnId) this.activeTurnId = undefined;
-        if (!this.enabled()) return;
         void this.enqueue(() => this.endCheckpoint(event.turnId));
       }),
     );
     this.effect(() => () => this.queue, 'fileHistory:drain');
   }
 
-  enabled(): boolean {
-    return this.flags.enabled(FILE_HISTORY_FLAG_ID);
-  }
-
   history(): FileHistoryState {
     return this.agentState.get(fileHistoryKey);
   }
@@ -109,12 +101,10 @@ export class AgentFileHistoryService extends Service implements IAgentFileHistor
   }
 
   changes(turnId: number): Promise<FileHistoryChange[]> {
-    if (!this.enabled()) return Promise.resolve([]);
     return this.enqueueValue(() => this.readChanges(turnId));
   }
 
   turnRecorded(turnId: number): Promise<boolean> {
-    if (!this.enabled()) return Promise.resolve(false);
     return this.enqueueValue(async () => {
       const state = this.history();
       const index = state.checkpoints.findIndex(
@@ -129,10 +119,17 @@ export class AgentFileHistoryService extends Service implements IAgentFileHistor
         index === state.checkpoints.length - 1 &&
         this.activeTurnId === turnId;
       if (end === undefined && !live) return false;
-      const entries = { ...state.checkpoints[index]!.entries, ...end?.entries };
-      const keyed = Object.values(entries).find((entry) => entry.key !== null);
-      if (keyed?.key === null || keyed?.key === undefined) return true;
-      return this.blobs.has(this.agentCtx.scope(), keyed.key);
+      const keys = new Set<string>();
+      for (const entry of [
+        ...Object.values(state.checkpoints[index]!.entries),
+        ...Object.values(end?.entries ?? {}),
+      ]) {
+        if (entry.key !== null) keys.add(entry.key);
+      }
+      for (const key of keys) {
+        if (!(await this.blobs.has(this.agentCtx.scope(), key))) return false;
+      }
+      return true;
     });
   }
 
@@ -219,7 +216,6 @@ export class AgentFileHistoryService extends Service implements IAgentFileHistor
     path: string,
     phase: FileHistoryCheckpointPhase = 'start',
   ): Promise<FileHistoryContent | undefined> {
-    if (!this.enabled()) return Promise.resolve(undefined);
     return this.enqueueValue(() => this.readContentAt(turnId, path, phase));
   }
 
@@ -255,14 +251,12 @@ export class AgentFileHistoryService extends Service implements IAgentFileHistor
   }
 
   private onWillExecuteTool(event: WillExecuteToolEvent): void {
-    if (!this.enabled()) return;
     const path = editTargetPath(event.execution.display);
     if (path === undefined) return;
     event.waitUntil(this.enqueue(() => this.capture(path, event.turnId)));
   }
 
   private onSubagentWillExecuteTool(event: WillExecuteToolEvent): void {
-    if (!this.enabled()) return;
     const path = editTargetPath(event.execution.display);
     if (path === undefined) return;
     const main = this.agentLifecycle.handleOf(MAIN_AGENT_ID);
@@ -272,7 +266,7 @@ export class AgentFileHistoryService extends Service implements IAgentFileHistor
 
   captureForActiveTurn(path: string): Promise<void> {
     const turnId = this.activeTurnId;
-    if (!this.enabled() || turnId === undefined) return Promise.resolve();
+    if (turnId === undefined) return Promise.resolve();
     return this.enqueue(() => this.capture(path, turnId));
   }
 

packages/agent-core-v2/src/index.ts

@@ -330,7 +330,6 @@ import '#/features/plan/planFeature';
 export * from '#/features/fileHistory/fileHistory';
 export * from '#/features/fileHistory/fileHistoryOps';
 export * from '#/features/fileHistory/fileHistoryService';
-export * from '#/features/fileHistory/flag';
 import '#/features/fileHistory/fileHistoryFeature';
 export * from '#/features/externalHooks/configSection';
 export * from '#/features/externalHooks/app/externalHooksRunner';

packages/agent-core-v2/src/persistence/backends/node-fs/blobStoreService.ts

@@ -26,8 +26,7 @@ export class BlobStoreService implements IBlobStore {
   }
 
   async has(scope: string, key: string): Promise<boolean> {
-    const keys = await this.storage.list(scope, key);
-    return keys.includes(key);
+    return (await this.storage.size(scope, key)) !== undefined;
   }
 
   async delete(scope: string, key: string): Promise<void> {

packages/agent-core-v2/test/features/fileHistory/fileHistory.test.ts

@@ -15,12 +15,10 @@ import { TurnEnded } from '#/agent/loop/turnOps';
 import { USER_PROMPT_ORIGIN } from '#/agent/contextMemory/types';
 import { IEventBus, type ISessionEventBus } from '#/app/event/eventBus';
 import { EventBusService } from '#/app/event/eventBusService';
-import type { IFlagService } from '#/app/flag/flag';
 import { IAgentFileHistoryService } from '#/features/fileHistory/fileHistory';
 import { AgentFileHistoryService, countLineDiff } from '#/features/fileHistory/fileHistoryService';
 import { displacedCheckpoints } from '#/features/fileHistory/fileHistoryOps';
 import type { IAgentLifecycleService } from '#/session/agentLifecycle/agentLifecycle';
-import { FILE_HISTORY_FLAG_ENV } from '#/features/fileHistory/flag';
 import type { ToolCall } from '#/kosong/contract/message';
 import type { IAgentRuntimeService } from '#/agent/runtimeBinding/agentRuntime';
 import type { IHostFileSystem } from '#/os/interface/hostFileSystem';
@@ -39,7 +37,7 @@ import type { RunnableToolExecution } from '#/tool/toolContract';
 import { createFakeHostFs } from '../../tools/fixtures/fake-exec';
 import { stubToolExecutorEvents, type ToolExecutorEventStubs } from '../../agent/toolExecutor/stubs';
 import { registerTestAgentWire, registerTestEventDispatcher, testWireScope } from '../../wire/stubs';
-import { createTestAgent } from '../../harness';
+import { createTestAgent, homeDirServices } from '../../harness';
 
 const SCOPE = 'wire';
 const KEY = 'file-history-test';
@@ -56,7 +54,6 @@ describe('AgentFileHistoryService', () => {
   let blobs: IBlobStore;
   let scopeCtx: IAgentScopeContext;
   let files: Map<string, Uint8Array>;
-  let flagEnabled: boolean;
 
   beforeEach(() => {
     disposables = new DisposableStore();
@@ -79,7 +76,6 @@ describe('AgentFileHistoryService', () => {
     executorEvents = stubToolExecutorEvents();
     blobs = new BlobStoreService(new InMemoryStorageService());
     files = new Map();
-    flagEnabled = true;
   });
 
   afterEach(() => {
@@ -119,7 +115,6 @@ describe('AgentFileHistoryService', () => {
       agentId === scopeCtx.agentId
         ? scopeCtx
         : makeAgentScopeContext({ agentId, agentScope: testWireScope(SCOPE, KEY) });
-    const flags = { enabled: () => flagEnabled } as unknown as IFlagService;
     const workspace = {
       workDir: WORK_DIR,
       additionalDirs: [],
@@ -138,7 +133,6 @@ describe('AgentFileHistoryService', () => {
         executorEvents.executor,
         eventBus,
         ix.get(IEventDispatcher),
-        flags,
         stubRuntime(),
             blobs,
           workspace,
@@ -312,19 +306,6 @@ describe('AgentFileHistoryService', () => {
     ]);
   });
 
-  it('does nothing while the flag is off', async () => {
-    flagEnabled = false;
-    const service = createService();
-    setFile('/ws/a.txt', 'content\n');
-
-    startTurn(1);
-    await fireEdit(service, '/ws/a.txt', 1);
-    await service.settled();
-
-    const state = service.history();
-    expect(state.checkpoints).toEqual([]);
-    expect(state.tracked).toEqual([]);
-  });
 
   it('excludes user edits between turns via the end-of-turn checkpoint', async () => {
     const service = createService();
@@ -349,25 +330,6 @@ describe('AgentFileHistoryService', () => {
     expect(await service.contentAt(2, 'a.txt')).toBeUndefined();
   });
 
-  it('guards reads once the flag is turned off after data was recorded', async () => {
-    const service = createService();
-    setFile('/ws/a.txt', 'content\n');
-
-    startTurn(1);
-    await fireEdit(service, '/ws/a.txt', 1);
-    setFile('/ws/a.txt', 'changed\n');
-    endTurn(1);
-    startTurn(2);
-    await service.settled();
-    expect(await service.changes(1)).toEqual([
-      { path: 'a.txt', status: 'modified', additions: 1, deletions: 1 },
-    ]);
-    expect((await service.contentAt(1, 'a.txt'))?.content).toBe('content\n');
-
-    flagEnabled = false;
-    expect(await service.changes(1)).toEqual([]);
-    expect(await service.contentAt(1, 'a.txt')).toBeUndefined();
-  });
 
   it('reports an over-budget modified file as oversize with no counts', async () => {
     const service = createService();
@@ -472,6 +434,28 @@ describe('AgentFileHistoryService', () => {
     expect(await service.turnRecorded(3)).toBe(false);
   });
 
+  it('reports a deletion turn unrecorded once its baseline blob is gone', async () => {
+    const service = createService();
+    setFile('/ws/d.txt', 'gone\n');
+
+    startTurn(1);
+    await fireEdit(service, '/ws/d.txt', 1);
+    files.delete('/ws/d.txt');
+    endTurn(1);
+    await service.settled();
+
+    expect(await service.changes(1)).toEqual([
+      { path: 'd.txt', status: 'deleted', additions: 0, deletions: 1 },
+    ]);
+    expect(await service.turnRecorded(1)).toBe(true);
+
+    const keyed = Object.values(
+      service.history().checkpoints.find((c) => c.turnId === 1 && c.phase !== 'end')!.entries,
+    ).find((entry) => entry.key !== null);
+    await blobs.delete(scopeCtx.scope(), keyed!.key!);
+    expect(await service.turnRecorded(1)).toBe(false);
+  });
+
   it('keeps a shared baseline blob alive until its last window reference leaves', async () => {
     const service = createService();
     setFile('/ws/s.txt', 'base\n');
@@ -522,19 +506,12 @@ describe('AgentFileHistoryService', () => {
 });
 
 describe('file history through real scripted turns', () => {
-  beforeEach(() => {
-    process.env[FILE_HISTORY_FLAG_ENV] = '1';
-  });
-
-  afterEach(() => {
-    delete process.env[FILE_HISTORY_FLAG_ENV];
-  });
-
   it('checkpoints edits across turns and serves exact per-turn changes', async () => {
     const dir = await mkdtemp(join(tmpdir(), 'file-history-e2e-'));
+    const home = await mkdtemp(join(tmpdir(), 'file-history-home-'));
     const file = join(dir, 'notes.txt');
     await writeFile(file, 'alpha\nbeta\n');
-    const ctx = createTestAgent();
+    const ctx = createTestAgent(homeDirServices(home));
     try {
       await ctx.rpc.setPermission({ mode: 'yolo' });
 
@@ -582,9 +559,14 @@ describe('file history through real scripted turns', () => {
         { path: file, status: 'modified', additions: 1, deletions: 1 },
       ]);
       expect(await service.changes(1)).toEqual([]);
+
+      expect(await service.turnRecorded(0)).toBe(true);
+      expect(await service.turnRecorded(1)).toBe(false);
+      expect(await service.turnRecorded(99)).toBe(false);
     } finally {
       await ctx.dispose();
       await rm(dir, { recursive: true, force: true });
+      await rm(home, { recursive: true, force: true });
     }
   });
 

packages/kap-server/src/protocol/rest-file-history.ts

@@ -24,7 +24,6 @@ export type WireFileHistoryChange = z.infer<typeof fileHistoryChangeSchema>;
 
 export const fileHistoryChangesResponseSchema = z.object({
   changes: z.array(fileHistoryChangeSchema),
-  enabled: z.boolean(),
   recorded: z.boolean(),
 });
 export type FileHistoryChangesResponse = z.infer<typeof fileHistoryChangesResponseSchema>;

packages/kap-server/src/routes/fileHistory.ts

@@ -60,7 +60,6 @@ export function registerFileHistoryRoutes(app: FileHistoryRouteHost, core: Scope
         okEnvelope(
           {
             changes: await history.changes(req.query.turn_id),
-            enabled: history.enabled(),
             recorded: await history.turnRecorded(req.query.turn_id),
           },
           req.id,

packages/kap-server/test/fileHistory.test.ts

@@ -92,7 +92,6 @@ describe('file history routes', () => {
     expect(changes.statusCode).toBe(200);
     expect((changes.json() as Envelope<{ changes: unknown[] }>).data).toEqual({
       changes: [],
-      enabled: false,
       recorded: false,
     });