diff --git a/docs/serve/api.md b/docs/serve/api.md
index 1c049145d..f0a837a61 100644
--- a/docs/serve/api.md
+++ b/docs/serve/api.md
@@ -513,29 +513,48 @@ data: {"type":"server.heartbeat","ts":1713001234567}
 
 ## 6. Question
 
-csc 通过 `control_request { subtype: "elicitation" }` 实现 MCP elicitation 交互，映射为 question 端点。
+csc 的 question API 兼容 opencode 格式，同时支持两种底层来源：
+
+1. **MCP Elicitation** — 通过 `control_request { subtype: "elicitation" }` 实现的 MCP 服务器用户输入请求
+2. **AskUserQuestionTool** — 内置工具的多选题交互，通过 `can_use_tool` permission 流程暴露为 question
 
 ### `GET /question`
 
-列出所有待处理的问题请求。
+列出所有待处理的问题请求，返回 opencode 格式的数组。
 
 **Response 200:**
 
 ```json
-{
-  "questions": [
-    {
-      "request_id": "req-2",
-      "session_id": "uuid-1",
-      "mcp_server_name": "my-server",
-      "message": "Please provide your API key",
-      "mode": "form",
-      "requested_schema": { "type": "object", "properties": { "key": { "type": "string" } } }
-    }
-  ]
-}
+[
+  {
+    "id": "req-2",
+    "sessionID": "uuid-1",
+    "questions": [
+      {
+        "question": "Which library should we use?",
+        "header": "Library",
+        "options": [
+          { "label": "date-fns", "description": "Lightweight, tree-shakeable" },
+          { "label": "moment", "description": "Legacy, mutable" }
+        ],
+        "multiple": false,
+        "custom": false
+      }
+    ]
+  }
+]
 ```
 
+字段说明：
+- `id` — 请求唯一标识
+- `sessionID` — 所属会话 ID
+- `questions` — 问题数组（1-4 个）
+  - `question` — 问题文本
+  - `header` — 短标签（≤30 字符）
+  - `options` — 选项列表，每项含 `label` 和 `description`
+  - `multiple` — 是否允许多选
+  - `custom` — 是否允许自定义输入
+
 ### `POST /question/:requestID/reply`
 
 回复问题请求。
@@ -544,11 +563,15 @@ csc 通过 `control_request { subtype: "elicitation" }` 实现 MCP elicitation 
 
 ```json
 {
-  "action": "accept",
-  "content": { "key": "sk-xxx" }
+  "answers": [
+    ["date-fns"],
+    ["option1", "option2"]
+  ]
 }
 ```
 
+`answers` 是二维数组，外层索引对应 `questions` 数组顺序，内层是每个问题选中的 `label` 列表。
+
 **Response 200:**
 
 ```json
@@ -557,15 +580,7 @@ csc 通过 `control_request { subtype: "elicitation" }` 实现 MCP elicitation 
 
 ### `POST /question/:requestID/reject`
 
-拒绝问题请求。
-
-**Request Body:**
-
-```json
-{
-  "action": "decline"
-}
-```
+拒绝问题请求。无需请求体。
 
 **Response 200:**
 
diff --git a/src/cli/print.ts b/src/cli/print.ts
index 5d3a1ed3c..b7d652869 100644
--- a/src/cli/print.ts
+++ b/src/cli/print.ts
@@ -2743,7 +2743,7 @@ function runHeadlessStreaming(
           uuid: randomUUID(),
         })
         void run()
-      } else {
+      } else if (!process.env.CSC_SERVE_MODE) {
         // Wait for any in-flight push suggestion before closing the output stream.
         if (suggestionState.inflightPromise) {
           await Promise.race([suggestionState.inflightPromise, sleep(5000)])
@@ -4296,7 +4296,7 @@ function runHeadlessStreaming(
     }
     inputClosed = true
     cronScheduler?.stop()
-    if (!running) {
+    if (!running && !process.env.CSC_SERVE_MODE) {
       // If a push-suggestion is in-flight, wait for it to emit before closing
       // the output stream (5 s safety timeout to prevent hanging).
       if (suggestionState.inflightPromise) {
diff --git a/src/server/__tests__/questionRoutes.test.ts b/src/server/__tests__/questionRoutes.test.ts
new file mode 100644
index 000000000..41de99310
--- /dev/null
+++ b/src/server/__tests__/questionRoutes.test.ts
@@ -0,0 +1,287 @@
+import { describe, expect, test, mock } from 'bun:test'
+import { Hono } from 'hono'
+import { createQuestionRoutes } from '../routes/question.js'
+import { errorHandler } from '../errors.js'
+import type { SessionManager } from '../sessionManager.js'
+import type { SessionHandle } from '../sessionHandle.js'
+
+function createMockSessionManager(opts: {
+  questions?: Array<{
+    requestId: string
+    sessionId: string
+    mcpServerName: string
+    message: string
+    mode: string
+    requestedSchema: Record<string, unknown>
+  }>
+  permissions?: Array<{
+    requestId: string
+    sessionId: string
+    toolName: string
+    toolUseId: string
+    input: Record<string, unknown>
+    title: string
+    description: string
+    suggestions: Record<string, unknown>[]
+  }>
+  findQuestion?: { handle: SessionHandle; question: unknown } | null
+  findPermission?: { handle: SessionHandle; perm: unknown } | null
+}): SessionManager {
+  return {
+    getAllPendingQuestions: () => opts.questions ?? [],
+    getAllPendingPermissions: () =>
+      opts.permissions?.map((p) => ({
+        requestId: p.requestId,
+        sessionId: p.sessionId,
+        toolName: p.toolName,
+        toolUseId: p.toolUseId,
+        input: p.input,
+        title: p.title,
+        description: p.description,
+        suggestions: p.suggestions,
+      })) ?? [],
+    findQuestionAcrossSessions: () => opts.findQuestion ?? null,
+    findPermissionAcrossSessions: () => opts.findPermission ?? null,
+  } as unknown as SessionManager
+}
+
+function createMockHandle(): SessionHandle {
+  return {
+    replyQuestion: mock(() => {}),
+    replyPermission: mock(() => {}),
+  } as unknown as SessionHandle
+}
+
+describe('createQuestionRoutes', () => {
+  describe('GET /question', () => {
+    test('returns empty array when no questions', async () => {
+      const mgr = createMockSessionManager({})
+      const app = createQuestionRoutes(mgr)
+      app.onError(errorHandler)
+      const res = await app.request('/question')
+      expect(res.status).toBe(200)
+      const body = await res.json()
+      expect(body).toEqual([])
+    })
+
+    test('returns elicitation questions in opencode format', async () => {
+      const mgr = createMockSessionManager({
+        questions: [
+          {
+            requestId: 'req-1',
+            sessionId: 'sess-1',
+            mcpServerName: 'my-server',
+            message: 'Please provide API key',
+            mode: 'form',
+            requestedSchema: {
+              type: 'object',
+              properties: { key: { type: 'string' } },
+            },
+          },
+        ],
+      })
+      const app = createQuestionRoutes(mgr)
+      app.onError(errorHandler)
+      const res = await app.request('/question')
+      expect(res.status).toBe(200)
+      const body = await res.json()
+      expect(body).toHaveLength(1)
+      expect(body[0].id).toBe('req-1')
+      expect(body[0].sessionID).toBe('sess-1')
+      expect(body[0].questions[0].question).toBe('Please provide API key')
+      expect(body[0].questions[0].header).toBe('my-server')
+      expect(body[0].questions[0].custom).toBe(true)
+    })
+
+    test('returns AskUserQuestionTool permissions as questions', async () => {
+      const mgr = createMockSessionManager({
+        permissions: [
+          {
+            requestId: 'perm-1',
+            sessionId: 'sess-1',
+            toolName: 'AskUserQuestionTool',
+            toolUseId: 'tu-1',
+            input: {
+              questions: [
+                {
+                  question: 'Which library?',
+                  header: 'Library',
+                  options: [
+                    { label: 'A', description: 'Option A' },
+                    { label: 'B', description: 'Option B' },
+                  ],
+                  multiSelect: false,
+                },
+              ],
+            },
+            title: 'AskUserQuestionTool',
+            description: '',
+            suggestions: [],
+          },
+        ],
+      })
+      const app = createQuestionRoutes(mgr)
+      app.onError(errorHandler)
+      const res = await app.request('/question')
+      expect(res.status).toBe(200)
+      const body = await res.json()
+      expect(body).toHaveLength(1)
+      expect(body[0].id).toBe('perm-1')
+      expect(body[0].questions[0].question).toBe('Which library?')
+      expect(body[0].questions[0].options).toHaveLength(2)
+      expect(body[0].questions[0].multiple).toBe(false)
+      expect(body[0].questions[0].custom).toBe(false)
+    })
+
+    test('converts enum schema to options', async () => {
+      const mgr = createMockSessionManager({
+        questions: [
+          {
+            requestId: 'req-1',
+            sessionId: 'sess-1',
+            mcpServerName: 'my-server',
+            message: 'Pick region',
+            mode: 'form',
+            requestedSchema: {
+              type: 'object',
+              properties: {
+                region: {
+                  type: 'string',
+                  enum: ['us-east-1', 'us-west-2'],
+                },
+              },
+            },
+          },
+        ],
+      })
+      const app = createQuestionRoutes(mgr)
+      app.onError(errorHandler)
+      const res = await app.request('/question')
+      const body = await res.json()
+      expect(body[0].questions[0].options).toEqual([
+        { label: 'us-east-1', description: '' },
+        { label: 'us-west-2', description: '' },
+      ])
+      expect(body[0].questions[0].custom).toBe(false)
+    })
+  })
+
+  describe('POST /question/:id/reply', () => {
+    test('replies to elicitation with parsed content', async () => {
+      const handle = createMockHandle()
+      const mgr = createMockSessionManager({
+        findQuestion: {
+          handle,
+          question: {
+            requestId: 'req-1',
+            sessionId: 'sess-1',
+            mcpServerName: 'my-server',
+            message: 'Please provide API key',
+            mode: 'form',
+            requestedSchema: {
+              type: 'object',
+              properties: { key: { type: 'string' } },
+            },
+          },
+        },
+      })
+      const app = createQuestionRoutes(mgr)
+      app.onError(errorHandler)
+      const res = await app.request('/question/req-1/reply', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ answers: [['my-api-key']] }),
+      })
+      expect(res.status).toBe(200)
+      expect(handle.replyQuestion).toHaveBeenCalledWith(
+        'req-1',
+        'accept',
+        { key: 'my-api-key' },
+      )
+    })
+
+    test('replies to AskUserQuestionTool permission', async () => {
+      const handle = createMockHandle()
+      const mgr = createMockSessionManager({
+        findPermission: {
+          handle,
+          perm: {
+            requestId: 'perm-1',
+            sessionId: 'sess-1',
+            toolName: 'AskUserQuestionTool',
+            toolUseId: 'tu-1',
+            input: {
+              questions: [
+                { question: 'Which library?', header: 'Library', options: [{ label: 'A', description: '' }] },
+              ],
+            },
+          },
+        },
+      })
+      const app = createQuestionRoutes(mgr)
+      app.onError(errorHandler)
+      const res = await app.request('/question/perm-1/reply', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ answers: [['A']] }),
+      })
+      expect(res.status).toBe(200)
+      expect(handle.replyPermission).toHaveBeenCalledWith(
+        'perm-1',
+        'allow',
+        {
+          updatedInput: expect.objectContaining({
+            answers: { 'Which library?': 'A' },
+          }),
+        },
+      )
+    })
+
+    test('returns 404 for unknown request', async () => {
+      const mgr = createMockSessionManager({})
+      const app = createQuestionRoutes(mgr)
+      app.onError(errorHandler)
+      const res = await app.request('/question/unknown/reply', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ answers: [[]] }),
+      })
+      expect(res.status).toBe(404)
+    })
+  })
+
+  describe('POST /question/:id/reject', () => {
+    test('rejects elicitation', async () => {
+      const handle = createMockHandle()
+      const mgr = createMockSessionManager({
+        findQuestion: {
+          handle,
+          question: { requestId: 'req-1' },
+        },
+      })
+      const app = createQuestionRoutes(mgr)
+      app.onError(errorHandler)
+      const res = await app.request('/question/req-1/reject', { method: 'POST' })
+      expect(res.status).toBe(200)
+      expect(handle.replyQuestion).toHaveBeenCalledWith('req-1', 'decline')
+    })
+
+    test('rejects AskUserQuestionTool permission', async () => {
+      const handle = createMockHandle()
+      const mgr = createMockSessionManager({
+        findPermission: {
+          handle,
+          perm: {
+            requestId: 'perm-1',
+            toolName: 'AskUserQuestionTool',
+          },
+        },
+      })
+      const app = createQuestionRoutes(mgr)
+      app.onError(errorHandler)
+      const res = await app.request('/question/perm-1/reject', { method: 'POST' })
+      expect(res.status).toBe(200)
+      expect(handle.replyPermission).toHaveBeenCalledWith('perm-1', 'deny')
+    })
+  })
+})
diff --git a/src/server/routes/question.ts b/src/server/routes/question.ts
index 75af140f9..e116bdd2e 100644
--- a/src/server/routes/question.ts
+++ b/src/server/routes/question.ts
@@ -2,31 +2,219 @@ import { Hono } from 'hono'
 import type { SessionManager } from '../sessionManager.js'
 import { notFound } from '../errors.js'
 
+// ============================================================================
+// Opencode-compatible Question Types
+// ============================================================================
+
+type QuestionOption = {
+  label: string
+  description: string
+}
+
+type QuestionInfo = {
+  question: string
+  header: string
+  options: QuestionOption[]
+  multiple?: boolean
+  custom?: boolean
+}
+
+type QuestionRequest = {
+  id: string
+  sessionID: string
+  questions: QuestionInfo[]
+}
+
+type QuestionReplyBody = {
+  answers: string[][]
+}
+
+// ============================================================================
+// Conversion helpers
+// ============================================================================
+
+function convertAskUserQuestionToOpencode(
+  requestId: string,
+  sessionId: string,
+  input: Record<string, unknown>,
+): QuestionRequest {
+  const questions = (input.questions as Array<{
+    question: string
+    header: string
+    options: Array<{ label: string; description: string }>
+    multiSelect?: boolean
+  }>) ?? []
+
+  return {
+    id: requestId,
+    sessionID: sessionId,
+    questions: questions.map(q => ({
+      question: q.question,
+      header: q.header,
+      options: q.options.map(o => ({
+        label: o.label,
+        description: o.description,
+      })),
+      multiple: q.multiSelect ?? false,
+      custom: false,
+    })),
+  }
+}
+
+function convertElicitationToOpencode(
+  requestId: string,
+  sessionId: string,
+  message: string,
+  mcpServerName: string,
+  requestedSchema: Record<string, unknown>,
+): QuestionRequest {
+  // Try to extract enum options from schema properties for better UX
+  const properties = requestedSchema.properties as Record<string, { enum?: string[]; type?: string }> | undefined
+  let options: QuestionOption[] = []
+  let custom = true
+
+  if (properties && Object.keys(properties).length === 1) {
+    const singleProp = Object.values(properties)[0]
+    if (singleProp.enum && singleProp.enum.length > 0) {
+      options = singleProp.enum.map(label => ({ label, description: '' }))
+      custom = false
+    }
+  }
+
+  return {
+    id: requestId,
+    sessionID: sessionId,
+    questions: [{
+      question: message,
+      header: mcpServerName || 'MCP',
+      options,
+      multiple: false,
+      custom,
+    }],
+  }
+}
+
+function buildElicitationContent(
+  requestedSchema: Record<string, unknown>,
+  answers: string[][],
+): Record<string, unknown> {
+  const answerText = answers[0]?.[0] ?? ''
+  if (!answerText) return {}
+
+  const properties = requestedSchema.properties as Record<string, { type?: string; enum?: string[] }> | undefined
+  if (properties && Object.keys(properties).length === 1) {
+    const key = Object.keys(properties)[0]
+    const prop = properties[key]
+    if (prop.type === 'string' && prop.enum && prop.enum.includes(answerText)) {
+      return { [key]: answerText }
+    }
+    if (prop.type === 'boolean' && (answerText === 'true' || answerText === 'false')) {
+      return { [key]: answerText === 'true' }
+    }
+    if (prop.type === 'number') {
+      const num = Number(answerText)
+      if (!Number.isNaN(num)) return { [key]: num }
+    }
+    return { [key]: answerText }
+  }
+
+  // Fallback: try to parse as JSON for complex schemas
+  try {
+    return JSON.parse(answerText) as Record<string, unknown>
+  } catch {
+    return { answer: answerText }
+  }
+}
+
+// ============================================================================
+// Routes
+// ============================================================================
+
 export function createQuestionRoutes(sessionManager: SessionManager): Hono {
   return new Hono()
     .get('/question', c => {
-      const questions = sessionManager.getAllPendingQuestions()
-      return c.json({ questions })
+      const result: QuestionRequest[] = []
+
+      // 1. Elicitation questions (MCP)
+      for (const q of sessionManager.getAllPendingQuestions()) {
+        result.push(convertElicitationToOpencode(
+          q.requestId,
+          q.sessionId,
+          q.message,
+          q.mcpServerName,
+          q.requestedSchema,
+        ))
+      }
+
+      // 2. AskUserQuestionTool permissions exposed as questions
+      for (const p of sessionManager.getAllPendingPermissions()) {
+        if (p.toolName === 'AskUserQuestionTool') {
+          result.push(convertAskUserQuestionToOpencode(
+            p.requestId,
+            p.sessionId,
+            p.input,
+          ))
+        }
+      }
+
+      return c.json(result)
     })
     .post('/question/:requestID/reply', async c => {
       const requestId = c.req.param('requestID')
-      const found = sessionManager.findQuestionAcrossSessions(requestId)
-      if (!found) throw notFound('question request not found')
 
-      const body = await c.req.json<{
-        action: 'accept'
-        content?: Record<string, unknown>
-      }>()
+      // 1. Try elicitation question first
+      const qFound = sessionManager.findQuestionAcrossSessions(requestId)
+      if (qFound) {
+        const body = await c.req.json<QuestionReplyBody>()
+        const content = buildElicitationContent(qFound.question.requestedSchema, body.answers)
+        qFound.handle.replyQuestion(requestId, 'accept', content)
+        return c.json({ resolved: true })
+      }
 
-      found.handle.replyQuestion(requestId, body.action, body.content)
-      return c.json({ resolved: true })
+      // 2. Try AskUserQuestionTool permission
+      const pFound = sessionManager.findPermissionAcrossSessions(requestId)
+      if (pFound && pFound.perm.toolName === 'AskUserQuestionTool') {
+        const body = await c.req.json<QuestionReplyBody>()
+        const input = pFound.perm.input as {
+          questions: Array<{ question: string }>
+          answers?: Record<string, string>
+          annotations?: Record<string, unknown>
+        }
+
+        const answers: Record<string, string> = {}
+        for (let i = 0; i < input.questions.length; i++) {
+          const ansLabels = body.answers[i] ?? []
+          answers[input.questions[i].question] = ansLabels.join(', ')
+        }
+
+        pFound.handle.replyPermission(requestId, 'allow', {
+          updatedInput: {
+            ...pFound.perm.input,
+            answers,
+          },
+        })
+        return c.json({ resolved: true })
+      }
+
+      throw notFound('question request not found')
     })
     .post('/question/:requestID/reject', async c => {
       const requestId = c.req.param('requestID')
-      const found = sessionManager.findQuestionAcrossSessions(requestId)
-      if (!found) throw notFound('question request not found')
 
-      found.handle.replyQuestion(requestId, 'decline')
-      return c.json({ resolved: true })
+      // 1. Try elicitation question first
+      const qFound = sessionManager.findQuestionAcrossSessions(requestId)
+      if (qFound) {
+        qFound.handle.replyQuestion(requestId, 'decline')
+        return c.json({ resolved: true })
+      }
+
+      // 2. Try AskUserQuestionTool permission
+      const pFound = sessionManager.findPermissionAcrossSessions(requestId)
+      if (pFound && pFound.perm.toolName === 'AskUserQuestionTool') {
+        pFound.handle.replyPermission(requestId, 'deny')
+        return c.json({ resolved: true })
+      }
+
+      throw notFound('question request not found')
     })
 }
diff --git a/src/server/routes/session.ts b/src/server/routes/session.ts
index 719fa7157..c9c6949c0 100644
--- a/src/server/routes/session.ts
+++ b/src/server/routes/session.ts
@@ -11,6 +11,33 @@ import {
 } from '../errors.js'
 import { listSessionsImpl } from '../../utils/listSessionsImpl.js'
 
+async function getOrCreateSession(
+  sessionManager: SessionManager,
+  id: string,
+): Promise<import('../sessionHandle.js').SessionHandle> {
+  const existing = sessionManager.getSession(id)
+  if (existing) return existing
+
+  try {
+    const handle = await sessionManager.createSession({
+      resumeSessionId: id,
+      execPath: process.execPath,
+      scriptArgs: getScriptArgsForChild(),
+    })
+    await handle.start()
+    return handle
+  } catch (err) {
+    const msg = err instanceof Error ? err.message : 'Failed to create session'
+    if (msg.includes('Maximum concurrent')) {
+      throw tooManySessions(msg)
+    }
+    if (msg.includes('Working directory does not exist')) {
+      throw sessionError(msg)
+    }
+    throw notFound('session not found')
+  }
+}
+
 function ssePrompt(
   handle: import('../sessionHandle.js').SessionHandle,
   id: string,
@@ -355,8 +382,7 @@ export function createSessionRoutes(
     })
     .post('/session/:sessionID/prompt', async c => {
       const id = c.req.param('sessionID')
-      const handle = sessionManager.getSession(id)
-      if (!handle) throw notFound('session not found')
+      const handle = await getOrCreateSession(sessionManager, id)
 
       const body = await c.req.json<{
         content?: string
@@ -382,10 +408,7 @@ export function createSessionRoutes(
     .post('/session/:sessionID/prompt_async', async c => {
       const id = c.req.param('sessionID')
 
-      const handle = sessionManager.getSession(id)
-      if (!handle) {
-        throw notFound('session not found')
-      }
+      const handle = await getOrCreateSession(sessionManager, id)
 
       const body = await c.req.json<{
         content?: string
@@ -422,15 +445,13 @@ export function createSessionRoutes(
     })
     .post('/session/:sessionID/abort', async c => {
       const id = c.req.param('sessionID')
-      const handle = sessionManager.getSession(id)
-      if (!handle) throw notFound('session not found')
+      const handle = await getOrCreateSession(sessionManager, id)
       await handle.abort()
       return c.json({ aborted: true })
     })
     .post('/session/:sessionID/shell', async c => {
       const id = c.req.param('sessionID')
-      const handle = sessionManager.getSession(id)
-      if (!handle) throw notFound('session not found')
+      const handle = await getOrCreateSession(sessionManager, id)
 
       const body = await c.req.json<{ command: string }>()
       if (!body.command) throw badRequest('command is required')
@@ -438,8 +459,7 @@ export function createSessionRoutes(
     })
     .post('/session/:sessionID/command', async c => {
       const id = c.req.param('sessionID')
-      const handle = sessionManager.getSession(id)
-      if (!handle) throw notFound('session not found')
+      const handle = await getOrCreateSession(sessionManager, id)
 
       const body = await c.req.json<{ command: string }>()
       if (!body.command) throw badRequest('command is required')
@@ -447,8 +467,7 @@ export function createSessionRoutes(
     })
     .post('/session/:sessionID/command_async', async c => {
       const id = c.req.param('sessionID')
-      const handle = sessionManager.getSession(id)
-      if (!handle) throw notFound('session not found')
+      const handle = await getOrCreateSession(sessionManager, id)
 
       const body = await c.req.json<{ command: string }>()
       if (!body.command) throw badRequest('command is required')
diff --git a/src/server/sessionHandle.ts b/src/server/sessionHandle.ts
index 9482894b6..6bec386f7 100644
--- a/src/server/sessionHandle.ts
+++ b/src/server/sessionHandle.ts
@@ -252,6 +252,7 @@ export class SessionHandle {
     const env: NodeJS.ProcessEnv = {
       ...process.env,
       CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC: '1',
+      CSC_SERVE_MODE: '1',
     }
 
     if (this.opts.systemPrompt) {