diff --git a/apps/cli/src/ai/chat-command.test.ts b/apps/cli/src/ai/chat-command.test.ts
new file mode 100644
index 00000000..ca6b1a5b
--- /dev/null
+++ b/apps/cli/src/ai/chat-command.test.ts
@@ -0,0 +1,120 @@
+import { describe, it } from 'node:test'
+import assert from 'node:assert/strict'
+import { Writable } from 'node:stream'
+import type { AIChatManager, DatabaseManager } from '@openchatlab/node-runtime'
+import { resolveAIChatTarget, runChatTurn } from './chat-command'
+
+function createDbManager(sessionIds: string[]): DatabaseManager {
+  return {
+    listSessionIds: () => sessionIds,
+    open: (sessionId: string) => (sessionIds.includes(sessionId) ? {} : null),
+  } as unknown as DatabaseManager
+}
+
+function createAIChatManager(existing: Array<{ id: string; sessionId: string }> = []): AIChatManager {
+  const chats = new Map<string, { id: string; sessionId: string; title: string | null; assistantId: string }>(
+    existing.map((chat) => [chat.id, { ...chat, title: null, assistantId: 'general_cn' }])
+  )
+  const messages: Array<{ aiChatId: string; role: string; content: string }> = []
+
+  return {
+    getAIChat: (aiChatId: string) => chats.get(aiChatId) ?? null,
+    createAIChat: (sessionId: string, title: string | undefined, assistantId: string) => {
+      const id = `ai_chat_${chats.size + 1}`
+      const chat = { id, sessionId, title: title ?? null, assistantId }
+      chats.set(id, chat)
+      return chat
+    },
+    addMessage: (aiChatId: string, role: string, content: string) => {
+      messages.push({ aiChatId, role, content })
+      return { id: `msg_${messages.length}`, aiChatId, role, content, timestamp: 1 }
+    },
+    __messages: messages,
+  } as unknown as AIChatManager
+}
+
+class MemoryWritable extends Writable {
+  chunks: string[] = []
+
+  _write(chunk: Buffer | string, _encoding: BufferEncoding, callback: (error?: Error | null) => void): void {
+    this.chunks.push(String(chunk))
+    callback()
+  }
+
+  text(): string {
+    return this.chunks.join('')
+  }
+}
+
+describe('resolveAIChatTarget', () => {
+  it('creates a new AI chat for an explicit session id', () => {
+    const target = resolveAIChatTarget(
+      { sessionId: 'session-1', question: 'hello' },
+      { dbManager: createDbManager(['session-1']), aiChatManager: createAIChatManager() }
+    )
+
+    assert.equal(target.sessionId, 'session-1')
+    assert.equal(target.aiChatId, 'ai_chat_1')
+    assert.equal(target.created, true)
+  })
+
+  it('recovers session id from a globally unique aiChatId', () => {
+    const target = resolveAIChatTarget(
+      { aiChatId: 'ai-chat-1' },
+      {
+        dbManager: createDbManager(['session-1']),
+        aiChatManager: createAIChatManager([{ id: 'ai-chat-1', sessionId: 'session-1' }]),
+      }
+    )
+
+    assert.deepEqual(target, { sessionId: 'session-1', aiChatId: 'ai-chat-1', created: false })
+  })
+
+  it('rejects mismatched explicit session id and aiChatId', () => {
+    assert.throws(
+      () =>
+        resolveAIChatTarget(
+          { sessionId: 'session-2', aiChatId: 'ai-chat-1' },
+          {
+            dbManager: createDbManager(['session-1', 'session-2']),
+            aiChatManager: createAIChatManager([{ id: 'ai-chat-1', sessionId: 'session-1' }]),
+          }
+        ),
+      /belongs to session session-1/
+    )
+  })
+})
+
+describe('runChatTurn', () => {
+  it('collects streamed answer and persists user and assistant messages', async () => {
+    const stdout = new MemoryWritable()
+    const aiChatManager = createAIChatManager()
+    const result = await runChatTurn(
+      { sessionId: 'session-1', question: 'hello', json: true },
+      {
+        dbManager: createDbManager(['session-1']),
+        pathProvider: {} as never,
+        aiChatManager,
+        stdout,
+        createRunAgentStream: () => async (_params, onEvent) => {
+          onEvent({ type: 'content', content: 'hi' })
+          onEvent({
+            type: 'done',
+            isFinished: true,
+            usage: { promptTokens: 1, completionTokens: 1, totalTokens: 2 },
+          })
+        },
+      }
+    )
+
+    assert.equal(result.sessionId, 'session-1')
+    assert.equal(result.aiChatId, 'ai_chat_1')
+    assert.equal(result.answer, 'hi')
+    assert.equal(result.usage.tokenUsage?.totalTokens, 2)
+    assert.equal(stdout.text(), '')
+    assert.deepEqual((aiChatManager as unknown as { __messages: unknown[] }).__messages, [
+      { aiChatId: 'ai_chat_1', role: 'user', content: 'hello' },
+      { aiChatId: 'ai_chat_1', role: 'assistant', content: 'hi' },
+    ])
+  })
+})
diff --git a/apps/cli/src/ai/chat-command.ts b/apps/cli/src/ai/chat-command.ts
new file mode 100644
index 00000000..750fb917
--- /dev/null
+++ b/apps/cli/src/ai/chat-command.ts
@@ -0,0 +1,184 @@
+import { createInterface } from 'node:readline/promises'
+import type { Readable, Writable } from 'node:stream'
+import type { DatabaseManager, AIChatManager, AgentStreamChunk, TokenUsageData } from '@openchatlab/node-runtime'
+import type { PathProvider } from '@openchatlab/core'
+import { createCliRunAgentStream } from './agent-stream-runner'
+
+export interface ChatCommandOptions {
+  sessionId?: string
+  aiChatId?: string
+  question?: string
+  json?: boolean
+  stream?: boolean
+  locale?: string
+}
+
+export interface ChatCommandDeps {
+  dbManager: DatabaseManager
+  pathProvider: PathProvider
+  aiChatManager: AIChatManager
+  stdout?: Pick<Writable, 'write'>
+  stderr?: Pick<Writable, 'write'>
+  stdin?: Readable
+  createRunAgentStream?: typeof createCliRunAgentStream
+}
+
+export interface ResolvedAIChatTarget {
+  sessionId: string
+  aiChatId: string
+  created: boolean
+}
+
+export interface ChatTurnResult {
+  sessionId: string
+  aiChatId: string
+  question: string
+  answer: string
+  usage: {
+    durationMs: number
+    tokenUsage: TokenUsageData | null
+  }
+}
+
+function write(stream: Pick<Writable, 'write'>, text: string): void {
+  stream.write(text)
+}
+
+function buildTitle(question?: string): string {
+  const trimmed = question?.trim()
+  if (!trimmed) return 'CLI Chat'
+  return trimmed.length > 50 ? `${trimmed.slice(0, 50)}...` : trimmed
+}
+
+function resolveSingleSessionId(dbManager: DatabaseManager): string {
+  const sessionIds = dbManager.listSessionIds()
+  if (sessionIds.length === 1) return sessionIds[0]!
+  if (sessionIds.length === 0) {
+    throw new Error('No chat sessions found. Import data first or run `chatlab sessions` to verify available sessions.')
+  }
+  throw new Error('Missing --session-id. Run `chatlab sessions` to choose a session ID.')
+}
+
+function assertSessionExists(dbManager: DatabaseManager, sessionId: string): void {
+  const db = dbManager.open(sessionId)
+  if (!db) {
+    throw new Error(`Session ${sessionId} not found`)
+  }
+}
+
+export function resolveAIChatTarget(
+  options: Pick<ChatCommandOptions, 'sessionId' | 'aiChatId' | 'question'>,
+  deps: Pick<ChatCommandDeps, 'dbManager' | 'aiChatManager'>
+): ResolvedAIChatTarget {
+  if (options.aiChatId) {
+    const aiChat = deps.aiChatManager.getAIChat(options.aiChatId)
+    if (!aiChat) {
+      throw new Error(`AI chat ${options.aiChatId} not found`)
+    }
+    if (options.sessionId && options.sessionId !== aiChat.sessionId) {
+      throw new Error(`AI chat ${options.aiChatId} belongs to session ${aiChat.sessionId}, not ${options.sessionId}`)
+    }
+    assertSessionExists(deps.dbManager, aiChat.sessionId)
+    return { sessionId: aiChat.sessionId, aiChatId: aiChat.id, created: false }
+  }
+
+  const sessionId = options.sessionId ?? resolveSingleSessionId(deps.dbManager)
+  assertSessionExists(deps.dbManager, sessionId)
+  const aiChat = deps.aiChatManager.createAIChat(sessionId, buildTitle(options.question), 'general_cn')
+  return { sessionId, aiChatId: aiChat.id, created: true }
+}
+
+export async function runChatTurn(
+  options: Required<Pick<ChatCommandOptions, 'question'>> &
+    Pick<ChatCommandOptions, 'sessionId' | 'aiChatId' | 'json' | 'stream' | 'locale'>,
+  deps: ChatCommandDeps
+): Promise<ChatTurnResult> {
+  const stdout = deps.stdout ?? process.stdout
+  const target = resolveAIChatTarget(options, deps)
+  const startedAt = Date.now()
+  let answer = ''
+  let tokenUsage: TokenUsageData | null = null
+
+  const runAgentStream = (deps.createRunAgentStream ?? createCliRunAgentStream)(deps.dbManager, deps.aiChatManager)
+
+  await runAgentStream(
+    {
+      userMessage: options.question,
+      sessionId: target.sessionId,
+      aiChatId: target.aiChatId,
+      chatType: 'group',
+      locale: options.locale ?? 'zh-CN',
+    },
+    (chunk: AgentStreamChunk) => {
+      if (chunk.type === 'content' && chunk.content) {
+        answer += chunk.content
+        if (!options.json && options.stream !== false) write(stdout, chunk.content)
+      }
+      if (chunk.type === 'done' && chunk.usage) {
+        tokenUsage = chunk.usage
+      }
+    },
+    new AbortController().signal
+  )
+
+  if (!options.json && options.stream !== false && answer && !answer.endsWith('\n')) {
+    write(stdout, '\n')
+  }
+
+  deps.aiChatManager.addMessage(target.aiChatId, 'user', options.question)
+  deps.aiChatManager.addMessage(
+    target.aiChatId,
+    'assistant',
+    answer,
+    undefined,
+    undefined,
+    undefined,
+    tokenUsage ?? undefined
+  )
+
+  return {
+    sessionId: target.sessionId,
+    aiChatId: target.aiChatId,
+    question: options.question,
+    answer,
+    usage: {
+      durationMs: Date.now() - startedAt,
+      tokenUsage,
+    },
+  }
+}
+
+export async function runChatCommand(options: ChatCommandOptions, deps: ChatCommandDeps): Promise<void> {
+  const stdout = deps.stdout ?? process.stdout
+  const stderr = deps.stderr ?? process.stderr
+
+  if (options.question?.trim()) {
+    const result = await runChatTurn({ ...options, question: options.question.trim() }, deps)
+    if (options.json) {
+      write(stdout, `${JSON.stringify(result, null, 2)}\n`)
+    } else if (options.stream === false) {
+      write(stdout, `${result.answer}\n`)
+    }
+    return
+  }
+
+  const rl = createInterface({
+    input: deps.stdin ?? process.stdin,
+    output: stdout as Writable,
+  })
+
+  try {
+    let aiChatId = options.aiChatId
+    while (true) {
+      const question = (await rl.question('chatlab> ')).trim()
+      if (!question || question === 'exit' || question === 'quit') break
+      const result = await runChatTurn({ ...options, aiChatId, question, json: false, stream: true }, deps)
+      aiChatId = result.aiChatId
+    }
+  } catch (error) {
+    write(stderr, `${error instanceof Error ? error.message : String(error)}\n`)
+    throw error
+  } finally {
+    rl.close()
+  }
+}
diff --git a/apps/cli/src/cli.ts b/apps/cli/src/cli.ts
index 62f1b568..e9153cad 100644
--- a/apps/cli/src/cli.ts
+++ b/apps/cli/src/cli.ts
@@ -11,6 +11,7 @@ import { DEFAULT_API_PORT, loadConfig, getConfigPath } from '@openchatlab/config
 import {
   NodePathProvider,
   DatabaseManager,
+  AIChatManager,
   applyPendingNodeDataDirMigrationIfNeeded,
   hasPendingElectronDataWarning,
   verifyCliDataPath,
@@ -299,6 +300,41 @@ program
     await startCliMcpServer()
   })
 
+program
+  .command('chat')
+  .description('Ask ChatLab AI about an imported chat session')
+  .option('--session-id <id>', 'Source chat session ID')
+  .option('--ai-chat-id <id>', 'Existing AI chat ID to continue')
+  .option('-q, --question <text>', 'Question to ask')
+  .option('--json', 'Output structured JSON')
+  .option('--no-stream', 'Disable streaming output')
+  .option('--locale <locale>', 'AI response locale', 'zh-CN')
+  .action(async (options) => {
+    const { runChatCommand } = await import('./ai/chat-command')
+    const { dbManager, pathProvider } = initRuntime()
+    const aiChatManager = new AIChatManager(pathProvider.getAiDataDir(), { nativeBinding: resolveNativeBinding() })
+
+    try {
+      await runChatCommand(
+        {
+          sessionId: options.sessionId,
+          aiChatId: options.aiChatId,
+          question: options.question,
+          json: !!options.json,
+          stream: options.stream,
+          locale: options.locale,
+        },
+        { dbManager, pathProvider, aiChatManager }
+      )
+    } catch (error) {
+      console.error(error instanceof Error ? error.message : String(error))
+      process.exitCode = 1
+    } finally {
+      aiChatManager.close()
+      dbManager.closeAll()
+    }
+  })
+
 program
   .command('start')
   .description('Start ChatLab (HTTP API + Web UI)')