fix: use timestamped default filename for session debug exports

.changeset/debug-zip-timestamped-filename.md

@@ -0,0 +1,5 @@
+---
+"@moonshot-ai/kimi-code": patch
+---
+
+Fix `/export-debug-zip` and `kimi export` overwriting the previous ZIP archive when run repeatedly on the same session; the default export filename now includes a timestamp.

packages/agent-core-v2/src/app/sessionExport/sessionExportService.ts

@@ -197,9 +197,10 @@ export async function exportSessionDirectory(input: {
       );
     }
     const bundledWebLog = input.webLog !== undefined;
+    const now = new Date();
     const baseManifest = buildExportManifest({
       summary: input.summary,
-      now: new Date(),
+      now,
       version: input.request.version,
       sessionScan,
       sessionLogPath: stableSessionLog === undefined ? undefined : SESSION_LOG_REL,
@@ -210,7 +211,7 @@ export async function exportSessionDirectory(input: {
     const outputPath =
       input.request.outputPath !== undefined
         ? resolve(input.request.outputPath)
-        : resolve(`${input.summary.id}.zip`);
+        : resolve(defaultExportZipName(input.summary.id, now));
     const extras: ExtraZipEntry[] = [];
     if (input.webLog !== undefined) {
       extras.push({ data: Buffer.from(input.webLog, 'utf8'), target: WEB_LOG_REL });
@@ -252,6 +253,12 @@ export async function exportSessionDirectory(input: {
   }
 }
 
+function defaultExportZipName(sessionId: string, now: Date): string {
+  const shortId = sessionId.slice(0, 8);
+  const timestamp = now.toISOString().replaceAll(/[-:]/g, '').replace(/T/, '-').slice(0, 15);
+  return `kimi-debug-${shortId}-${timestamp}.zip`;
+}
+
 function sessionZipEntryPath(entry: SessionZipEntry): string {
   return typeof entry === 'string' ? entry : entry.path;
 }

packages/agent-core-v2/test/app/sessionExport/sessionExport.test.ts

@@ -8,6 +8,7 @@ import {
   readFile,
   readdir,
   rename,
+  rm,
   stat,
   symlink,
   unlink,
@@ -17,7 +18,7 @@ import { tmpdir } from 'node:os';
 import { Readable } from 'node:stream';
 
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
-import { join } from 'pathe';
+import { basename, dirname, join, resolve } from 'pathe';
 import { open as openZip } from 'yauzl';
 
 import { Disposable, DisposableStore, type IDisposable } from '#/_base/di/lifecycle';
@@ -143,6 +144,54 @@ describe('sessionExport', () => {
     });
   });
 
+  it('uses a timestamped default output path when outputPath is omitted', async () => {
+    const tmp = await mkdtemp(join(tmpdir(), 'session-export-test-'));
+    const sessionDir = join(tmp, 'sessions', 'ws_demo', 'ses_default_output');
+    await mkdir(sessionDir, { recursive: true });
+    await writeFile(join(sessionDir, 'state.json'), '{}\n', 'utf-8');
+
+    const result = await exportSessionDirectory({
+      request: { sessionId: 'ses_default_output', version: '1.0.0-test' },
+      summary: { id: 'ses_default_output', sessionDir },
+    });
+
+    try {
+      expect(dirname(result.zipPath)).toBe(resolve('.'));
+      expect(basename(result.zipPath)).toMatch(/^kimi-debug-ses_defa-\d{8}-\d{6}\.zip$/);
+      await expect(stat(result.zipPath)).resolves.toMatchObject({ size: expect.any(Number) });
+    } finally {
+      await rm(result.zipPath, { force: true });
+    }
+  });
+
+  it('does not overwrite a previous default-path export when run again', async () => {
+    const tmp = await mkdtemp(join(tmpdir(), 'session-export-test-'));
+    const sessionDir = join(tmp, 'sessions', 'ws_demo', 'ses_repeated_export');
+    await mkdir(sessionDir, { recursive: true });
+    await writeFile(join(sessionDir, 'state.json'), '{}\n', 'utf-8');
+    const summary = { id: 'ses_repeated_export', sessionDir };
+
+    const first = await exportSessionDirectory({
+      request: { sessionId: 'ses_repeated_export', version: '1.0.0-test' },
+      summary,
+    });
+    // Cross the next second boundary so the second export gets a distinct timestamp.
+    await new Promise((resolvePromise) => setTimeout(resolvePromise, 1100 - (Date.now() % 1000)));
+    const second = await exportSessionDirectory({
+      request: { sessionId: 'ses_repeated_export', version: '1.0.0-test' },
+      summary,
+    });
+
+    try {
+      expect(second.zipPath).not.toBe(first.zipPath);
+      await expect(stat(first.zipPath)).resolves.toMatchObject({ size: expect.any(Number) });
+      await expect(stat(second.zipPath)).resolves.toMatchObject({ size: expect.any(Number) });
+    } finally {
+      await rm(first.zipPath, { force: true });
+      await rm(second.zipPath, { force: true });
+    }
+  });
+
   it('keeps the session log bound when it rotates as wire scanning starts', async () => {
     const tmp = await mkdtemp(join(tmpdir(), 'session-export-test-'));
     const sessionDir = join(tmp, 'sessions', 'ws_demo', 'ses_rotating_log');

packages/agent-core/src/session/export/session-export.ts

@@ -47,9 +47,10 @@ export async function exportSessionDirectory(input: {
     }
   }
 
+  const now = new Date();
   const manifest = buildExportManifest({
     summary: input.summary,
-    now: new Date(),
+    now,
     version: input.request.version,
     sessionScan,
     sessionLogPath: hasSessionLog ? SESSION_LOG_REL : undefined,
@@ -61,7 +62,7 @@ export async function exportSessionDirectory(input: {
   const outputPath =
     input.request.outputPath !== undefined
       ? resolve(input.request.outputPath)
-      : resolve(`${input.summary.id}.zip`);
+      : resolve(defaultExportZipName(input.summary.id, now));
 
   const entries = await writeExportZip({
     outputPath,
@@ -79,6 +80,12 @@ export async function exportSessionDirectory(input: {
   };
 }
 
+function defaultExportZipName(sessionId: string, now: Date): string {
+  const shortId = sessionId.slice(0, 8);
+  const timestamp = now.toISOString().replaceAll(/[-:]/g, '').replace(/T/, '-').slice(0, 15);
+  return `kimi-debug-${shortId}-${timestamp}.zip`;
+}
+
 async function readOptionalFile(path: string): Promise<Buffer | undefined> {
   try {
     return await readFile(path);

packages/node-sdk/test/export-session.test.ts

@@ -1,7 +1,7 @@
 import { existsSync } from 'node:fs';
 import { mkdir, mkdtemp, readFile, rm, writeFile } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join, resolve } from 'node:path';
+import { join, resolve, basename, dirname } from 'node:path';
 import * as zlib from 'node:zlib';
 
 import { afterEach, describe, expect, it } from 'vitest';
@@ -169,7 +169,7 @@ describe('exportSessionDirectory', () => {
     expect(manifest.workspaceDir).toBe(workDir);
   });
 
-  it('uses the default output path when outputPath is omitted', async () => {
+  it('uses a timestamped default output path when outputPath is omitted', async () => {
     const tmp = await makeTempDir();
     const sid = 'session_default_output';
     const sessionDir = join(tmp, 'sessions', sid);
@@ -181,10 +181,39 @@ describe('exportSessionDirectory', () => {
       summary: makeSummary({ id: sid, sessionDir, workDir: tmp }),
     });
 
-    const expectedPath = resolve(`${sid}.zip`);
-    expect(result.zipPath).toBe(toPosix(expectedPath));
+    expect(dirname(result.zipPath)).toBe(toPosix(resolve('.')));
+    expect(basename(result.zipPath)).toMatch(/^kimi-debug-session_-\d{8}-\d{6}\.zip$/);
     expect(existsSync(result.zipPath)).toBe(true);
-    await rm(expectedPath, { force: true });
+    await rm(result.zipPath, { force: true });
+  });
+
+  it('does not overwrite a previous default-path export when run again', async () => {
+    const tmp = await makeTempDir();
+    const sid = 'session_repeated_export';
+    const sessionDir = join(tmp, 'sessions', sid);
+    await mkdir(sessionDir, { recursive: true });
+    await writeFile(join(sessionDir, 'state.json'), '{}', 'utf-8');
+    const summary = makeSummary({ id: sid, sessionDir, workDir: tmp });
+
+    const first = await exportSessionDirectory({
+      request: { sessionId: sid, version: '1.0.0-test' },
+      summary,
+    });
+    // Cross the next second boundary so the second export gets a distinct timestamp.
+    await new Promise((resolvePromise) => setTimeout(resolvePromise, 1100 - (Date.now() % 1000)));
+    const second = await exportSessionDirectory({
+      request: { sessionId: sid, version: '1.0.0-test' },
+      summary,
+    });
+
+    try {
+      expect(second.zipPath).not.toBe(first.zipPath);
+      expect(existsSync(first.zipPath)).toBe(true);
+      expect(existsSync(second.zipPath)).toBe(true);
+    } finally {
+      await rm(first.zipPath, { force: true });
+      await rm(second.zipPath, { force: true });
+    }
   });
 
   it('omits global log manifest path when the global log cannot be bundled', async () => {
@@ -245,7 +274,7 @@ describe('exportSessionDirectory', () => {
 
     expect(result.manifest.sessionFirstActivity).toBeUndefined();
     expect(result.manifest.sessionLastActivity).toBeUndefined();
-    await rm(resolve(`${sid}.zip`), { force: true });
+    await rm(result.zipPath, { force: true });
   });
 
   it('rejects empty or missing session directories', async () => {