diff --git a/packages/node-runtime/src/data-dir-compat.test.ts b/packages/node-runtime/src/data-dir-compat.test.ts
new file mode 100644
index 00000000..41d8e414
--- /dev/null
+++ b/packages/node-runtime/src/data-dir-compat.test.ts
@@ -0,0 +1,198 @@
+import assert from 'node:assert/strict'
+import fs from 'node:fs'
+import os from 'node:os'
+import path from 'node:path'
+import test from 'node:test'
+import type { PathProvider } from '@openchatlab/core'
+import {
+  assertDataDirCompatible,
+  DataDirCompatibilityError,
+  raiseDataDirMinRuntimeVersion,
+  readDataDirCompatibilityMeta,
+} from './data-dir-compat'
+
+function makeTempDir(): string {
+  const baseDir = fs.existsSync('/private/tmp') ? '/private/tmp' : os.tmpdir()
+  return fs.mkdtempSync(path.join(baseDir, 'chatlab-data-compat-'))
+}
+
+function makePathProvider(userDataDir: string): PathProvider {
+  return {
+    getSystemDir: () => path.join(userDataDir, '..', 'system'),
+    getUserDataDir: () => userDataDir,
+    getDatabaseDir: () => path.join(userDataDir, 'databases'),
+    getAiDataDir: () => path.join(userDataDir, '..', 'system', 'ai'),
+    getSettingsDir: () => path.join(userDataDir, '..', 'system', 'settings'),
+    getCacheDir: () => path.join(userDataDir, '..', 'system', 'cache'),
+    getTempDir: () => path.join(userDataDir, '..', 'system', 'temp'),
+    getLogsDir: () => path.join(userDataDir, '..', 'system', 'logs'),
+    getDownloadsDir: () => path.join(userDataDir, '..', 'downloads'),
+  }
+}
+
+function writeMeta(userDataDir: string, meta: unknown): void {
+  fs.mkdirSync(userDataDir, { recursive: true })
+  fs.writeFileSync(path.join(userDataDir, '.chatlab-meta.json'), JSON.stringify(meta, null, 2), 'utf-8')
+}
+
+function withOverride<T>(value: string | undefined, fn: () => T): T {
+  const previous = process.env.CHATLAB_ALLOW_INCOMPATIBLE_DATA_DIR
+  if (value === undefined) {
+    delete process.env.CHATLAB_ALLOW_INCOMPATIBLE_DATA_DIR
+  } else {
+    process.env.CHATLAB_ALLOW_INCOMPATIBLE_DATA_DIR = value
+  }
+
+  try {
+    return fn()
+  } finally {
+    if (previous === undefined) {
+      delete process.env.CHATLAB_ALLOW_INCOMPATIBLE_DATA_DIR
+    } else {
+      process.env.CHATLAB_ALLOW_INCOMPATIBLE_DATA_DIR = previous
+    }
+  }
+}
+
+test('missing data dir compatibility meta is compatible', () => {
+  const userDataDir = makeTempDir()
+  const provider = makePathProvider(userDataDir)
+
+  assert.equal(readDataDirCompatibilityMeta(userDataDir), null)
+  assert.doesNotThrow(() => {
+    assertDataDirCompatible(provider, { version: '0.25.1', kind: 'cli' })
+  })
+})
+
+test('current runtime satisfying minRuntimeVersion is compatible', () => {
+  const userDataDir = makeTempDir()
+  writeMeta(userDataDir, {
+    formatVersion: 1,
+    minRuntimeVersion: '0.25.1',
+    dataCompatibilityVersion: 1,
+    reasons: ['segment-schema'],
+    updatedBy: { runtime: 'cli', module: 'chat-db-migration', version: '0.25.1' },
+    updatedAt: 1780830000,
+  })
+
+  assert.doesNotThrow(() => {
+    assertDataDirCompatible(makePathProvider(userDataDir), { version: '0.25.1', kind: 'desktop' })
+  })
+})
+
+test('current runtime below minRuntimeVersion is blocked', () => {
+  const userDataDir = makeTempDir()
+  writeMeta(userDataDir, {
+    formatVersion: 1,
+    minRuntimeVersion: '0.25.1',
+    dataCompatibilityVersion: 1,
+    reasons: ['segment-schema'],
+    updatedBy: { runtime: 'desktop', module: 'chat-db-migration', version: '0.25.1' },
+    updatedAt: 1780830000,
+  })
+
+  assert.throws(
+    () => {
+      assertDataDirCompatible(makePathProvider(userDataDir), { version: '0.25.0', kind: 'cli' })
+    },
+    (error) =>
+      error instanceof DataDirCompatibilityError &&
+      error.code === 'DATA_DIR_REQUIRES_NEWER_RUNTIME' &&
+      error.minRuntimeVersion === '0.25.1' &&
+      error.currentVersion === '0.25.0' &&
+      error.userDataDir === userDataDir
+  )
+})
+
+test('override bypasses only version insufficiency and emits a warning', () => {
+  const userDataDir = makeTempDir()
+  const warnings: string[] = []
+  writeMeta(userDataDir, {
+    formatVersion: 1,
+    minRuntimeVersion: '0.25.1',
+    dataCompatibilityVersion: 1,
+    reasons: ['segment-schema'],
+    updatedBy: { runtime: 'desktop', module: 'chat-db-migration', version: '0.25.1' },
+    updatedAt: 1780830000,
+  })
+
+  withOverride('1', () => {
+    assert.doesNotThrow(() => {
+      assertDataDirCompatible(
+        makePathProvider(userDataDir),
+        { version: '0.25.0', kind: 'cli' },
+        {
+          warn: (message) => warnings.push(message),
+        }
+      )
+    })
+  })
+
+  assert.equal(warnings.length, 1)
+  assert.match(warnings[0], /CHATLAB_ALLOW_INCOMPATIBLE_DATA_DIR=1/)
+  assert.match(warnings[0], /0\.25\.0/)
+  assert.match(warnings[0], /0\.25\.1/)
+  assert.match(warnings[0], new RegExp(userDataDir.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')))
+})
+
+test('broken JSON and invalid meta are blocked even with override', () => {
+  const brokenDir = makeTempDir()
+  fs.writeFileSync(path.join(brokenDir, '.chatlab-meta.json'), '{ broken', 'utf-8')
+
+  withOverride('1', () => {
+    assert.throws(
+      () => assertDataDirCompatible(makePathProvider(brokenDir), { version: '0.25.0', kind: 'cli' }),
+      (error) => error instanceof DataDirCompatibilityError && error.code === 'DATA_DIR_COMPATIBILITY_META_INVALID'
+    )
+  })
+
+  const invalidDir = makeTempDir()
+  writeMeta(invalidDir, {
+    formatVersion: 1,
+    minRuntimeVersion: '0.25.1-beta.0',
+    dataCompatibilityVersion: 1,
+    reasons: ['segment-schema'],
+    updatedBy: { runtime: 'cli', module: 'chat-db-migration', version: '0.25.1' },
+    updatedAt: 1780830000,
+  })
+
+  withOverride('1', () => {
+    assert.throws(
+      () => assertDataDirCompatible(makePathProvider(invalidDir), { version: '0.25.0', kind: 'cli' }),
+      (error) => error instanceof DataDirCompatibilityError && error.code === 'DATA_DIR_COMPATIBILITY_META_INVALID'
+    )
+  })
+})
+
+test('raising minRuntimeVersion writes atomically and never lowers existing requirements', () => {
+  const userDataDir = makeTempDir()
+  const provider = makePathProvider(userDataDir)
+
+  raiseDataDirMinRuntimeVersion(provider, {
+    minRuntimeVersion: '0.26.0',
+    dataCompatibilityVersion: 2,
+    reason: 'future-schema',
+    runtime: { version: '0.26.0', kind: 'desktop' },
+    module: 'future-migration',
+    now: () => 1780830000,
+  })
+
+  raiseDataDirMinRuntimeVersion(provider, {
+    minRuntimeVersion: '0.25.1',
+    dataCompatibilityVersion: 1,
+    reason: 'segment-schema',
+    runtime: { version: '0.25.1', kind: 'cli' },
+    module: 'chat-db-migration',
+    now: () => 1780830001,
+  })
+
+  const meta = readDataDirCompatibilityMeta(userDataDir)
+
+  assert.equal(meta?.formatVersion, 1)
+  assert.equal(meta?.minRuntimeVersion, '0.26.0')
+  assert.equal(meta?.dataCompatibilityVersion, 2)
+  assert.deepEqual(meta?.reasons, ['future-schema', 'segment-schema'])
+  assert.deepEqual(meta?.updatedBy, { runtime: 'cli', module: 'chat-db-migration', version: '0.25.1' })
+  assert.equal(meta?.updatedAt, 1780830001)
+  assert.equal(fs.existsSync(path.join(userDataDir, '.chatlab-meta.json')), true)
+})
diff --git a/packages/node-runtime/src/data-dir-compat.ts b/packages/node-runtime/src/data-dir-compat.ts
new file mode 100644
index 00000000..61afc38f
--- /dev/null
+++ b/packages/node-runtime/src/data-dir-compat.ts
@@ -0,0 +1,285 @@
+import fs from 'node:fs'
+import path from 'node:path'
+import type { PathProvider } from '@openchatlab/core'
+
+export type RuntimeKind = 'cli' | 'desktop' | 'mcp' | 'unknown'
+
+export interface RuntimeIdentity {
+  version: string
+  kind: RuntimeKind
+}
+
+export interface DataDirCompatibilityMeta {
+  formatVersion: 1
+  minRuntimeVersion: string
+  dataCompatibilityVersion: number
+  reasons: string[]
+  updatedBy: {
+    runtime: RuntimeKind
+    module: string
+    version: string
+  }
+  updatedAt: number
+}
+
+export interface RaiseDataDirCompatibilityInput {
+  minRuntimeVersion: string
+  dataCompatibilityVersion: number
+  reason: string
+  runtime: RuntimeIdentity
+  module: string
+  now?: () => number
+}
+
+export interface AssertDataDirCompatibilityOptions {
+  warn?: (message: string) => void
+  env?: Pick<NodeJS.ProcessEnv, 'CHATLAB_ALLOW_INCOMPATIBLE_DATA_DIR'>
+}
+
+type DataDirCompatibilityErrorCode = 'DATA_DIR_REQUIRES_NEWER_RUNTIME' | 'DATA_DIR_COMPATIBILITY_META_INVALID'
+
+export class DataDirCompatibilityError extends Error {
+  readonly code: DataDirCompatibilityErrorCode
+  readonly userDataDir: string
+  readonly metaPath: string
+  readonly currentVersion?: string
+  readonly minRuntimeVersion?: string
+  readonly statusCode = 409
+
+  constructor(
+    code: DataDirCompatibilityErrorCode,
+    message: string,
+    options: {
+      userDataDir: string
+      metaPath: string
+      currentVersion?: string
+      minRuntimeVersion?: string
+      cause?: unknown
+    }
+  ) {
+    super(message, { cause: options.cause })
+    this.name = 'DataDirCompatibilityError'
+    this.code = code
+    this.userDataDir = options.userDataDir
+    this.metaPath = options.metaPath
+    this.currentVersion = options.currentVersion
+    this.minRuntimeVersion = options.minRuntimeVersion
+  }
+}
+
+export function readDataDirCompatibilityMeta(userDataDir: string): DataDirCompatibilityMeta | null {
+  const metaPath = getMetaPath(userDataDir)
+  if (!fs.existsSync(metaPath)) return null
+
+  let parsed: unknown
+  try {
+    parsed = JSON.parse(fs.readFileSync(metaPath, 'utf-8'))
+  } catch (error) {
+    throw createInvalidMetaError(userDataDir, metaPath, 'Invalid data directory compatibility meta JSON.', error)
+  }
+
+  return validateDataDirCompatibilityMeta(parsed, userDataDir, metaPath)
+}
+
+export function assertDataDirCompatible(
+  pathProvider: PathProvider,
+  runtime: RuntimeIdentity,
+  options: AssertDataDirCompatibilityOptions = {}
+): void {
+  const userDataDir = pathProvider.getUserDataDir()
+  const meta = readDataDirCompatibilityMeta(userDataDir)
+  if (!meta) return
+
+  if (!isStableSemver(runtime.version) || compareStableSemver(runtime.version, meta.minRuntimeVersion) < 0) {
+    const env = options.env ?? process.env
+    if (env.CHATLAB_ALLOW_INCOMPATIBLE_DATA_DIR === '1') {
+      const warn = options.warn ?? console.warn
+      warn(
+        [
+          'CHATLAB_ALLOW_INCOMPATIBLE_DATA_DIR=1 is set. ChatLab will bypass the data directory runtime version gate.',
+          `Current runtime ${runtime.kind}@${runtime.version} is below required version ${meta.minRuntimeVersion}.`,
+          `Data directory: ${userDataDir}. Continuing may risk data corruption.`,
+        ].join(' ')
+      )
+      return
+    }
+
+    throw new DataDirCompatibilityError(
+      'DATA_DIR_REQUIRES_NEWER_RUNTIME',
+      `ChatLab data directory requires runtime version ${meta.minRuntimeVersion} or newer; current version is ${runtime.version}.`,
+      {
+        userDataDir,
+        metaPath: getMetaPath(userDataDir),
+        currentVersion: runtime.version,
+        minRuntimeVersion: meta.minRuntimeVersion,
+      }
+    )
+  }
+}
+
+export function raiseDataDirMinRuntimeVersion(
+  pathProvider: PathProvider,
+  input: RaiseDataDirCompatibilityInput
+): DataDirCompatibilityMeta {
+  const userDataDir = pathProvider.getUserDataDir()
+  const metaPath = getMetaPath(userDataDir)
+
+  assertStableVersion(input.minRuntimeVersion, userDataDir, metaPath, 'Invalid minRuntimeVersion.')
+  assertStableVersion(input.runtime.version, userDataDir, metaPath, 'Invalid runtime version.')
+  if (!isRuntimeKind(input.runtime.kind)) {
+    throw createInvalidMetaError(userDataDir, metaPath, 'Invalid runtime kind.')
+  }
+  if (!isNonEmptyString(input.module) || !isNonEmptyString(input.reason)) {
+    throw createInvalidMetaError(userDataDir, metaPath, 'Invalid compatibility raise metadata.')
+  }
+  if (!Number.isInteger(input.dataCompatibilityVersion) || input.dataCompatibilityVersion < 0) {
+    throw createInvalidMetaError(userDataDir, metaPath, 'Invalid dataCompatibilityVersion.')
+  }
+
+  const existing = readDataDirCompatibilityMeta(userDataDir)
+  const minRuntimeVersion =
+    existing && compareStableSemver(existing.minRuntimeVersion, input.minRuntimeVersion) > 0
+      ? existing.minRuntimeVersion
+      : input.minRuntimeVersion
+  const dataCompatibilityVersion = Math.max(existing?.dataCompatibilityVersion ?? 0, input.dataCompatibilityVersion)
+  const reasons = mergeReasons(existing?.reasons ?? [], input.reason)
+  const now = input.now ?? (() => Math.floor(Date.now() / 1000))
+
+  const nextMeta: DataDirCompatibilityMeta = {
+    formatVersion: 1,
+    minRuntimeVersion,
+    dataCompatibilityVersion,
+    reasons,
+    updatedBy: {
+      runtime: input.runtime.kind,
+      module: input.module,
+      version: input.runtime.version,
+    },
+    updatedAt: now(),
+  }
+
+  writeMetaAtomic(userDataDir, metaPath, nextMeta)
+  return nextMeta
+}
+
+function getMetaPath(userDataDir: string): string {
+  return path.join(userDataDir, '.chatlab-meta.json')
+}
+
+function validateDataDirCompatibilityMeta(
+  value: unknown,
+  userDataDir: string,
+  metaPath: string
+): DataDirCompatibilityMeta {
+  if (!isRecord(value)) {
+    throw createInvalidMetaError(userDataDir, metaPath, 'Data directory compatibility meta must be an object.')
+  }
+
+  if (value.formatVersion !== 1) {
+    throw createInvalidMetaError(userDataDir, metaPath, 'Unsupported data directory compatibility meta format.')
+  }
+
+  const minRuntimeVersion = value.minRuntimeVersion
+  const dataCompatibilityVersion = value.dataCompatibilityVersion
+  const reasons = value.reasons
+  const updatedBy = value.updatedBy
+  const updatedAt = value.updatedAt
+
+  if (
+    !isStableSemver(minRuntimeVersion) ||
+    typeof dataCompatibilityVersion !== 'number' ||
+    !Number.isInteger(dataCompatibilityVersion) ||
+    dataCompatibilityVersion < 0 ||
+    !Array.isArray(reasons) ||
+    !reasons.every(isNonEmptyString) ||
+    !isRecord(updatedBy) ||
+    !isRuntimeKind(updatedBy.runtime) ||
+    !isNonEmptyString(updatedBy.module) ||
+    !isStableSemver(updatedBy.version) ||
+    typeof updatedAt !== 'number' ||
+    !Number.isInteger(updatedAt) ||
+    updatedAt < 0
+  ) {
+    throw createInvalidMetaError(userDataDir, metaPath, 'Invalid data directory compatibility meta fields.')
+  }
+
+  return {
+    formatVersion: 1,
+    minRuntimeVersion,
+    dataCompatibilityVersion,
+    reasons: [...reasons],
+    updatedBy: {
+      runtime: updatedBy.runtime,
+      module: updatedBy.module,
+      version: updatedBy.version,
+    },
+    updatedAt,
+  }
+}
+
+function createInvalidMetaError(
+  userDataDir: string,
+  metaPath: string,
+  message: string,
+  cause?: unknown
+): DataDirCompatibilityError {
+  return new DataDirCompatibilityError('DATA_DIR_COMPATIBILITY_META_INVALID', message, {
+    userDataDir,
+    metaPath,
+    cause,
+  })
+}
+
+function assertStableVersion(version: string, userDataDir: string, metaPath: string, message: string): void {
+  if (!isStableSemver(version)) {
+    throw createInvalidMetaError(userDataDir, metaPath, message)
+  }
+}
+
+function isStableSemver(version: unknown): version is string {
+  return typeof version === 'string' && /^\d+\.\d+\.\d+$/.test(version)
+}
+
+function compareStableSemver(left: string, right: string): number {
+  const leftParts = left.split('.').map(Number)
+  const rightParts = right.split('.').map(Number)
+
+  for (let i = 0; i < 3; i += 1) {
+    if (leftParts[i] > rightParts[i]) return 1
+    if (leftParts[i] < rightParts[i]) return -1
+  }
+
+  return 0
+}
+
+function mergeReasons(existing: string[], next: string): string[] {
+  return [...new Set([...existing, next])]
+}
+
+function writeMetaAtomic(userDataDir: string, metaPath: string, meta: DataDirCompatibilityMeta): void {
+  fs.mkdirSync(userDataDir, { recursive: true })
+  const tempPath = path.join(userDataDir, `.chatlab-meta.json.${process.pid}.${Date.now()}.tmp`)
+  try {
+    fs.writeFileSync(tempPath, `${JSON.stringify(meta, null, 2)}\n`, 'utf-8')
+    fs.renameSync(tempPath, metaPath)
+  } catch (error) {
+    try {
+      if (fs.existsSync(tempPath)) fs.unlinkSync(tempPath)
+    } catch {
+      // Ignore cleanup failures so callers see the original write/rename error.
+    }
+    throw error
+  }
+}
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === 'object' && value !== null && !Array.isArray(value)
+}
+
+function isNonEmptyString(value: unknown): value is string {
+  return typeof value === 'string' && value.trim().length > 0
+}
+
+function isRuntimeKind(value: unknown): value is RuntimeKind {
+  return value === 'cli' || value === 'desktop' || value === 'mcp' || value === 'unknown'
+}
diff --git a/packages/node-runtime/src/index.ts b/packages/node-runtime/src/index.ts
index eb6a3589..5e564fd8 100644
--- a/packages/node-runtime/src/index.ts
+++ b/packages/node-runtime/src/index.ts
@@ -80,6 +80,19 @@ export type {
   RunPendingDataDirMigrationDeps,
   RunPendingDataDirMigrationResult,
 } from './data-dir-switch'
+export {
+  assertDataDirCompatible,
+  DataDirCompatibilityError,
+  raiseDataDirMinRuntimeVersion,
+  readDataDirCompatibilityMeta,
+} from './data-dir-compat'
+export type {
+  AssertDataDirCompatibilityOptions,
+  DataDirCompatibilityMeta,
+  RaiseDataDirCompatibilityInput,
+  RuntimeIdentity,
+  RuntimeKind,
+} from './data-dir-compat'
 
 // NLP 分词引擎、词频统计、词库管理
 export {