diff --git a/.changeset/fix-migration-legacy-shared-slugify.md b/.changeset/fix-migration-legacy-shared-slugify.md
new file mode 100644
index 000000000..a9d69fcb1
--- /dev/null
+++ b/.changeset/fix-migration-legacy-shared-slugify.md
@@ -0,0 +1,14 @@
+---
+"@moonshot-ai/agent-core": patch
+"@moonshot-ai/kimi-code": patch
+"@moonshot-ai/migration-legacy": patch
+---
+
+fix(migration-legacy): use shared slugifyWorkDirName from agent-core
+
+Exports `slugifyWorkDirName` from `@moonshot-ai/agent-core` and removes the
+duplicate local implementation in `packages/migration-legacy/src/sessions/workdir-bucket.ts`.
+
+No user-visible behavior change. The migrator now imports the canonical
+slugifier, so migrated bucket names stay byte-identical to agent-core
+without manual sync.
diff --git a/packages/agent-core/src/index.ts b/packages/agent-core/src/index.ts
index 8c28740f3..5153d8dd2 100644
--- a/packages/agent-core/src/index.ts
+++ b/packages/agent-core/src/index.ts
@@ -15,6 +15,7 @@ export {
   resolveGlobalLogPath,
 } from './logging/logger';
 export { resolveLoggingConfig } from './logging/resolve-config';
+export { slugifyWorkDirName } from './utils/workdir-slug';
 export type { ResolveLoggingInput } from './logging/resolve-config';
 export type {
   LogContext,
diff --git a/packages/migration-legacy/src/sessions/workdir-bucket.ts b/packages/migration-legacy/src/sessions/workdir-bucket.ts
index 7a8222a7a..fe1cd1a7e 100644
--- a/packages/migration-legacy/src/sessions/workdir-bucket.ts
+++ b/packages/migration-legacy/src/sessions/workdir-bucket.ts
@@ -1,26 +1,22 @@
 import { basename, resolve } from 'node:path';
 import { createHash } from 'node:crypto';
 
+import { slugifyWorkDirName } from '@moonshot-ai/agent-core';
+
 const WORKDIR_KEY_PREFIX = 'wd_';
 const HASH_LENGTH = 12;
 
 /**
  * Compute the v2 bucket directory name `wd_<slug>_<hash12>` for a workdir
- * path. Hash function and slug rules mirror
- * `packages/kimi-core/src/utils/workdir-slug.ts` and
- * `packages/kimi-core/src/harness/session-manager/workdir-key.ts:13–18`.
+ * path. Slug rules use `slugifyWorkDirName` from `@moonshot-ai/agent-core`
+ * (file: `packages/agent-core/src/utils/workdir-slug.ts`); hash and resolve
+ * logic mirror `packages/agent-core/src/harness/session-manager/workdir-key.ts`.
  *
  * IMPORTANT: agent-core's `encodeWorkDirKey` runs `resolve()` on the workdir
  * before hashing/slugifying, and the session picker locates sessions purely
  * by `readdir(encodeWorkDirKey(...))` — it never consults `session_index.jsonl`.
  * We MUST apply the same `resolve()` here or migrated sessions become
  * invisible in the picker.
- *
- * TODO: The canonical slugifier is `slugifyWorkDirName` in
- * `@moonshot-ai/agent-core` (file: `src/utils/workdir-slug.ts`). It is not part
- * of that package's public export surface today. When/if it becomes public,
- * delete the local duplicate below and import it from agent-core directly so
- * buckets stay byte-identical between the running app and this migrator.
  */
 export function computeWorkdirBucket(workdirPath: string): string {
   const normalized = resolve(workdirPath);
@@ -34,18 +30,4 @@ export function oldMd5BucketName(workdirPath: string): string {
   return createHash('md5').update(workdirPath).digest('hex');
 }
 
-const MAX_WORKDIR_SLUG_LENGTH = 40;
 
-/**
- * Local copy of kimi-core's `slugifyWorkDirName`. Keep byte-identical to the
- * canonical implementation in `packages/kimi-core/src/utils/workdir-slug.ts`.
- */
-function slugifyWorkDirName(name: string): string {
-  const slug = name
-    .toLowerCase()
-    .replaceAll(/[^a-z0-9._-]+/g, '-')
-    .replaceAll(/^-+|-+$/g, '')
-    .slice(0, MAX_WORKDIR_SLUG_LENGTH)
-    .replaceAll(/^-+|-+$/g, '');
-  return slug === '' || slug === '.' || slug === '..' ? 'workspace' : slug;
-}