feat(ai): support editable message branches

apps/cli/src/ai/agent.ts

@@ -32,6 +32,7 @@ export type { AgentStreamChunk }
 export interface RunAgentOptions {
   userMessage: string
   conversationId: string
+  historyLeafMessageId?: string | null
   chatType?: 'group' | 'private'
   locale?: string
   assistantSystemPrompt?: string
@@ -51,6 +52,7 @@ export async function runServerAgent(options: RunAgentOptions): Promise<void> {
   const {
     userMessage,
     conversationId,
+    historyLeafMessageId,
     chatType = 'group',
     locale = 'zh-CN',
     assistantSystemPrompt,
@@ -135,7 +137,7 @@ export async function runServerAgent(options: RunAgentOptions): Promise<void> {
 
   let history: SimpleHistoryMessage[] = []
   try {
-    history = convManager.getHistoryForAgent(conversationId)
+    history = convManager.getHistoryForAgent(conversationId, undefined, historyLeafMessageId)
   } catch {
     // empty history on failure
   }

apps/cli/src/http/routes/ai.ts

@@ -521,6 +521,31 @@ export function registerAiRoutes(
     return convManager.getMessages(request.params.id)
   })
 
+  server.post<{
+    Params: { id: string }
+    Body: {
+      content: string
+      assistantContent: string
+      contentBlocks?: unknown[]
+      tokenUsage?: { promptTokens: number; completionTokens: number; totalTokens: number }
+    }
+  }>('/_web/ai/messages/:id/branches', async (request) => {
+    return convManager.createMessageBranch(
+      request.params.id,
+      request.body.content,
+      request.body.assistantContent,
+      request.body.contentBlocks as any,
+      request.body.tokenUsage
+    )
+  })
+
+  server.post<{
+    Params: { id: string }
+    Body: { messageId: string }
+  }>('/_web/ai/conversations/:id/branches/switch', async (request) => {
+    return convManager.switchMessageBranch(request.params.id, request.body.messageId)
+  })
+
   server.get<{ Params: { id: string } }>('/_web/ai/conversations/:id/token-usage', async (request) => {
     return convManager.getConversationTokenUsage(request.params.id)
   })
@@ -533,6 +558,7 @@ export function registerAiRoutes(
     Body: {
       userMessage: string
       conversationId: string
+      historyLeafMessageId?: string | null
       sessionId: string
       chatType?: 'group' | 'private'
       locale?: string
@@ -550,6 +576,7 @@ export function registerAiRoutes(
     const {
       userMessage,
       conversationId,
+      historyLeafMessageId,
       sessionId,
       chatType,
       locale,
@@ -660,6 +687,7 @@ export function registerAiRoutes(
       await runServerAgent({
         userMessage,
         conversationId,
+        historyLeafMessageId,
         chatType,
         locale,
         assistantSystemPrompt,

apps/desktop/main/ai/agent/index.ts

@@ -279,7 +279,7 @@ export class Agent {
       return []
     }
     try {
-      return getHistoryForAgent(conversationId)
+      return getHistoryForAgent(conversationId, undefined, this.context.historyLeafMessageId)
     } catch (error) {
       aiLogger.warn('Agent', 'Failed to load history from DB, using empty history', { conversationId, error })
       return []

apps/desktop/main/ai/conversations.ts

@@ -9,7 +9,14 @@ import { AIConversationManager } from '@openchatlab/node-runtime'
 import { getPathProvider } from '../path-context'
 import { aiLogger } from './logger'
 
-export type { AIConversation, AIMessage, AIMessageRole, ContentBlock, TokenUsageData } from '@openchatlab/node-runtime'
+export type {
+  AIConversation,
+  AIMessage,
+  AIMessageRole,
+  ContentBlock,
+  TokenUsageData,
+  MessageBranchResult,
+} from '@openchatlab/node-runtime'
 
 let manager: AIConversationManager | null = null
 
@@ -93,6 +100,26 @@ export function deleteMessage(messageId: string) {
   return getManager().deleteMessage(messageId)
 }
 
+export function createMessageBranch(
+  originalUserMessageId: string,
+  newUserContent: string,
+  assistantContent: string,
+  contentBlocks?: import('@openchatlab/node-runtime').ContentBlock[],
+  tokenUsage?: import('@openchatlab/node-runtime').TokenUsageData
+) {
+  return getManager().createMessageBranch(
+    originalUserMessageId,
+    newUserContent,
+    assistantContent,
+    contentBlocks,
+    tokenUsage
+  )
+}
+
+export function switchMessageBranch(conversationId: string, messageId: string) {
+  return getManager().switchMessageBranch(conversationId, messageId)
+}
+
 export function setPendingDebugContext(conversationId: string, debugContext: string) {
   return getManager().setPendingDebugContext(conversationId, debugContext)
 }
@@ -109,8 +136,8 @@ export function getConversationTokenUsage(conversationId: string) {
   return getManager().getConversationTokenUsage(conversationId)
 }
 
-export function getHistoryForAgent(conversationId: string, maxMessages?: number) {
+export function getHistoryForAgent(conversationId: string, maxMessages?: number, leafMessageId?: string | null) {
-  return getManager().getHistoryForAgent(conversationId, maxMessages)
+  return getManager().getHistoryForAgent(conversationId, maxMessages, leafMessageId)
 }
 
 export function addSummaryMessage(

apps/desktop/main/ai/tools/types.ts

@@ -37,6 +37,8 @@ export interface ToolContext {
   sessionId: string
   /** 当前 AI 对话 ID（用于上下文管理隔离） */
   conversationId?: string
+  /** 读取 Agent 历史时使用的叶子消息；编辑重答时指向被编辑消息的父节点 */
+  historyLeafMessageId?: string | null
   /** 当前聊天数据库快照（仅用于提示模型当前数据范围，不能替代工具检索结果） */
   dataSnapshot?: DataSnapshot
   /** 时间过滤器 */

apps/desktop/main/ipc/ai.ts

@@ -284,6 +284,40 @@ export function registerAIHandlers({ win }: IpcContext): void {
     }
   })
 
+  ipcMain.handle(
+    'ai:createMessageBranch',
+    async (
+      _,
+      originalUserMessageId: string,
+      newUserContent: string,
+      assistantContent: string,
+      contentBlocks?: aiConversations.ContentBlock[],
+      tokenUsage?: aiConversations.TokenUsageData
+    ) => {
+      try {
+        return aiConversations.createMessageBranch(
+          originalUserMessageId,
+          newUserContent,
+          assistantContent,
+          contentBlocks,
+          tokenUsage
+        )
+      } catch (error) {
+        console.error('Failed to create AI message branch:', error)
+        throw error
+      }
+    }
+  )
+
+  ipcMain.handle('ai:switchMessageBranch', async (_, conversationId: string, messageId: string) => {
+    try {
+      return aiConversations.switchMessageBranch(conversationId, messageId)
+    } catch (error) {
+      console.error('Failed to switch AI message branch:', error)
+      throw error
+    }
+  })
+
   // ==================== 脱敏规则 ====================
 
   ipcMain.handle('ai:getDefaultDesensitizeRules', (_, locale: string) => {

apps/desktop/preload/apis/ai.ts

@@ -27,6 +27,7 @@ export interface AIConversation {
   sessionId: string
   title: string | null
   assistantId: string
+  activeMessageId?: string | null
   createdAt: number
   updatedAt: number
 }
@@ -34,6 +35,7 @@ export interface AIConversation {
 // 内容块类型（用于 AI 消息的混合渲染）
 export type ContentBlock =
   | { type: 'text'; text: string }
+  | { type: 'think'; tag: string; text: string; durationMs?: number }
   | {
       type: 'tool'
       tool: {
@@ -44,6 +46,8 @@ export type ContentBlock =
       }
     }
   | { type: 'skill'; skillId: string; skillName: string }
+  | { type: 'error'; error: SerializedErrorInfo }
+  | { type: 'summary_meta'; bufferBoundaryTimestamp: number; compressedMessageCount: number }
 
 export type AIMessageRole = 'user' | 'assistant' | 'summary'
 
@@ -59,12 +63,26 @@ export interface AIMessage {
   role: AIMessageRole
   content: string
   timestamp: number
+  parentId?: string | null
+  siblingGroupId?: string
+  branchIndex?: number
+  branch?: {
+    index: number
+    total: number
+    prevMessageId: string | null
+    nextMessageId: string | null
+  }
   dataKeywords?: string[]
   dataMessageCount?: number
   contentBlocks?: ContentBlock[]
   tokenUsage?: TokenUsageData
 }
 
+export interface MessageBranchResult {
+  userMessage: AIMessage
+  assistantMessage: AIMessage
+}
+
 // LLM API 类型
 export interface LLMProvider {
   id: string
@@ -171,6 +189,7 @@ export interface PreprocessConfig {
 export interface ToolContext {
   sessionId: string
   conversationId?: string
+  historyLeafMessageId?: string | null
   timeFilter?: { startTs: number; endTs: number }
   maxMessagesLimit?: number
   ownerInfo?: { platformId: string; displayName: string }
@@ -496,6 +515,27 @@ export const aiApi = {
     )
   },
 
+  createMessageBranch: (
+    originalUserMessageId: string,
+    newUserContent: string,
+    assistantContent: string,
+    contentBlocks?: ContentBlock[],
+    tokenUsage?: TokenUsageData
+  ): Promise<MessageBranchResult> => {
+    return ipcRenderer.invoke(
+      'ai:createMessageBranch',
+      originalUserMessageId,
+      newUserContent,
+      assistantContent,
+      contentBlocks,
+      tokenUsage
+    )
+  },
+
+  switchMessageBranch: (conversationId: string, messageId: string): Promise<AIMessage[]> => {
+    return ipcRenderer.invoke('ai:switchMessageBranch', conversationId, messageId)
+  },
+
   /**
    * 获取 AI 对话的所有消息
    */
@@ -1014,6 +1054,7 @@ export const agentApi = {
     const sanitizedContext: ToolContext = {
       sessionId: context.sessionId,
       conversationId: context.conversationId,
+      historyLeafMessageId: context.historyLeafMessageId,
       timeFilter: context.timeFilter
         ? {
             startTs: context.timeFilter.startTs,

apps/desktop/preload/index.d.ts

@@ -304,6 +304,7 @@ interface AIConversation {
   sessionId: string
   title: string | null
   assistantId: string
+  activeMessageId?: string | null
   createdAt: number
   updatedAt: number
 }
@@ -311,6 +312,7 @@ interface AIConversation {
 // 内容块类型（用于 AI 消息的混合渲染）
 type AIContentBlock =
   | { type: 'text'; text: string }
+  | { type: 'think'; tag: string; text: string; durationMs?: number }
   | {
       type: 'tool'
       tool: {
@@ -321,6 +323,7 @@ type AIContentBlock =
       }
     }
   | { type: 'skill'; skillId: string; skillName: string }
+  | { type: 'error'; error: SerializedErrorInfo }
   | {
       type: 'summary_meta'
       bufferBoundaryTimestamp: number
@@ -341,12 +344,26 @@ interface AIMessage {
   role: AIMessageRole
   content: string
   timestamp: number
+  parentId?: string | null
+  siblingGroupId?: string
+  branchIndex?: number
+  branch?: {
+    index: number
+    total: number
+    prevMessageId: string | null
+    nextMessageId: string | null
+  }
   dataKeywords?: string[]
   dataMessageCount?: number
   contentBlocks?: AIContentBlock[]
   tokenUsage?: AITokenUsageData
 }
 
+interface MessageBranchResult {
+  userMessage: AIMessage
+  assistantMessage: AIMessage
+}
+
 interface AiApi {
   searchMessages: (
     sessionId: string,
@@ -408,7 +425,14 @@ interface AiApi {
     contentBlocks?: AIContentBlock[],
     tokenUsage?: AITokenUsageData
   ) => Promise<AIMessage>
-  getMessages: (conversationId: string) => Promise<AIMessage[]>
+  createMessageBranch: (
+    originalUserMessageId: string,
+    newUserContent: string,
+    assistantContent: string,
+    contentBlocks?: AIContentBlock[],
+    tokenUsage?: AITokenUsageData
+  ) => Promise<MessageBranchResult>
+  switchMessageBranch: (conversationId: string, messageId: string) => Promise<AIMessage[]>
   getMessages: (conversationId: string) => Promise<AIMessage[]>
   getConversationTokenUsage: (conversationId: string) => Promise<AITokenUsageData>
   deleteMessage: (messageId: string) => Promise<boolean>
@@ -744,6 +768,7 @@ interface PreprocessConfig {
 interface ToolContext {
   sessionId: string
   conversationId?: string
+  historyLeafMessageId?: string | null
   timeFilter?: { startTs: number; endTs: number }
   /** 用户配置：每次发送给 AI 的最大消息条数 */
   maxMessagesLimit?: number
@@ -1225,6 +1250,7 @@ export {
   SearchMessageResult,
   AIConversation,
   AIMessage,
+  MessageBranchResult,
   LLMProviderInfo,
   AIServiceConfigDisplay,
   LLMChatMessage,

apps/desktop/tsconfig.node.json

@@ -11,6 +11,7 @@
     "../../packages/node-runtime/**/*",
     "../../packages/config/**/*",
     "../../packages/parser/**/*",
+    "../../packages/mcp-server/**/*",
     "../../apps/cli/**/*",
     "../../packages/tools/**/*",
     "../../packages/sync/**/*"
@@ -23,7 +24,8 @@
     "paths": {
       "@/*": ["../../src/*"],
       "@electron/*": ["./*"],
-      "@openchatlab/*": ["../../packages/*"]
+      "@openchatlab/*": ["../../packages/*"],
+      "chatlab-mcp": ["../../packages/mcp-server/src"]
     }
   }
 }

packages/node-runtime/src/ai/__tests__/conversations.test.ts

@@ -0,0 +1,205 @@
+import { describe, it } from 'node:test'
+import assert from 'node:assert/strict'
+import { mkdtempSync, rmSync } from 'node:fs'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import Database from 'better-sqlite3'
+import { AIConversationManager } from '../conversations'
+
+const sqliteNativeBinding = process.env.CHATLAB_TEST_SQLITE_NATIVE_BINDING
+
+function createTempDir(): string {
+  return mkdtempSync(join(tmpdir(), 'chatlab-ai-conv-'))
+}
+
+function createTestDatabase(filename: string): Database.Database {
+  return sqliteNativeBinding ? new Database(filename, { nativeBinding: sqliteNativeBinding }) : new Database(filename)
+}
+
+function createManager(dir: string): AIConversationManager {
+  return sqliteNativeBinding
+    ? new AIConversationManager(dir, { nativeBinding: sqliteNativeBinding })
+    : new AIConversationManager(dir)
+}
+
+function cleanup(dir: string): void {
+  try {
+    rmSync(dir, { recursive: true, force: true, maxRetries: 5, retryDelay: 50 })
+  } catch {
+    // Windows can hold SQLite WAL handles briefly after close; temp cleanup is best-effort.
+  }
+}
+
+describe('AIConversationManager message branches', () => {
+  it('migrates legacy flat messages into an active path', () => {
+    const dir = createTempDir()
+    try {
+      const db = createTestDatabase(join(dir, 'conversations.db'))
+      db.exec(`
+        CREATE TABLE ai_conversation (
+          id TEXT PRIMARY KEY,
+          session_id TEXT NOT NULL,
+          title TEXT,
+          created_at INTEGER NOT NULL,
+          updated_at INTEGER NOT NULL
+        );
+        CREATE TABLE ai_message (
+          id TEXT PRIMARY KEY,
+          conversation_id TEXT NOT NULL,
+          role TEXT NOT NULL,
+          content TEXT NOT NULL,
+          timestamp INTEGER NOT NULL,
+          data_keywords TEXT,
+          data_message_count INTEGER,
+          content_blocks TEXT
+        );
+      `)
+      db.prepare('INSERT INTO ai_conversation VALUES (?, ?, ?, ?, ?)').run('conv-1', 'session-1', 'Legacy', 1, 4)
+      db.prepare('INSERT INTO ai_message VALUES (?, ?, ?, ?, ?, NULL, NULL, NULL)').run(
+        'm1',
+        'conv-1',
+        'user',
+        'one',
+        1
+      )
+      db.prepare('INSERT INTO ai_message VALUES (?, ?, ?, ?, ?, NULL, NULL, NULL)').run(
+        'm2',
+        'conv-1',
+        'assistant',
+        'two',
+        2
+      )
+      db.close()
+
+      const manager = createManager(dir)
+      const messages = manager.getMessages('conv-1')
+      assert.deepEqual(
+        messages.map((message) => message.content),
+        ['one', 'two']
+      )
+      assert.equal(messages[0]?.parentId, null)
+      assert.equal(messages[1]?.parentId, 'm1')
+      assert.equal(manager.getConversation('conv-1')?.activeMessageId, 'm2')
+      manager.close()
+    } finally {
+      cleanup(dir)
+    }
+  })
+
+  it('does not rerun legacy backfill over existing root branches', () => {
+    const dir = createTempDir()
+    try {
+      let manager = createManager(dir)
+      const conversation = manager.createConversation('session-1', 'Root branch', 'general_cn')
+      const root = manager.addMessage(conversation.id, 'user', 'original root')
+      manager.addMessage(conversation.id, 'assistant', 'original answer')
+      const branch = manager.createMessageBranch(root.id, 'edited root', 'edited answer')
+      assert.equal(branch.userMessage.parentId, null)
+      manager.close()
+
+      manager = createManager(dir)
+      const messages = manager.getMessages(conversation.id)
+      assert.deepEqual(
+        messages.map((message) => message.content),
+        ['edited root', 'edited answer']
+      )
+      assert.equal(messages[0]?.parentId, null)
+      assert.equal(manager.getConversation(conversation.id)?.activeMessageId, branch.assistantMessage.id)
+      manager.close()
+    } finally {
+      cleanup(dir)
+    }
+  })
+
+  it('creates editable branches without losing the original path', () => {
+    const dir = createTempDir()
+    try {
+      const manager = createManager(dir)
+      const conversation = manager.createConversation('session-1', 'Branch', 'general_cn')
+      const user1 = manager.addMessage(conversation.id, 'user', 'original question')
+      manager.addMessage(conversation.id, 'assistant', 'original answer', undefined, undefined, undefined, {
+        promptTokens: 1,
+        completionTokens: 2,
+        totalTokens: 3,
+      })
+      manager.addMessage(conversation.id, 'user', 'follow up')
+      const oldLeaf = manager.addMessage(
+        conversation.id,
+        'assistant',
+        'follow answer',
+        undefined,
+        undefined,
+        undefined,
+        {
+          promptTokens: 4,
+          completionTokens: 5,
+          totalTokens: 9,
+        }
+      )
+
+      const branch = manager.createMessageBranch('' + user1.id, 'edited question', 'edited answer', undefined, {
+        promptTokens: 10,
+        completionTokens: 11,
+        totalTokens: 21,
+      })
+
+      assert.deepEqual(
+        manager.getMessages(conversation.id).map((message) => message.content),
+        ['edited question', 'edited answer']
+      )
+      assert.equal(branch.userMessage.branch?.total, 2)
+      assert.equal(manager.getHistoryForAgent(conversation.id, undefined, branch.userMessage.parentId).length, 0)
+      assert.deepEqual(manager.getConversationTokenUsage(conversation.id), {
+        promptTokens: 10,
+        completionTokens: 11,
+        totalTokens: 21,
+      })
+
+      manager.switchMessageBranch(conversation.id, user1.id)
+      assert.deepEqual(
+        manager.getMessages(conversation.id).map((message) => message.content),
+        ['original question', 'original answer', 'follow up', 'follow answer']
+      )
+      assert.equal(manager.getConversation(conversation.id)?.activeMessageId, oldLeaf.id)
+      assert.deepEqual(manager.getConversationTokenUsage(conversation.id), {
+        promptTokens: 5,
+        completionTokens: 7,
+        totalTokens: 12,
+      })
+      manager.close()
+    } finally {
+      cleanup(dir)
+    }
+  })
+
+  it('keeps summaries on inactive branches when adding a new summary', () => {
+    const dir = createTempDir()
+    try {
+      const manager = createManager(dir)
+      const conversation = manager.createConversation('session-1', 'Summary branch', 'general_cn')
+      manager.addMessage(conversation.id, 'user', 'intro')
+      manager.addMessage(conversation.id, 'assistant', 'answer')
+      manager.addSummaryMessage(conversation.id, 'original summary', {
+        bufferBoundaryTimestamp: 2,
+        compressedMessageCount: 2,
+      })
+      const followUp = manager.addMessage(conversation.id, 'user', 'follow up')
+      manager.addMessage(conversation.id, 'assistant', 'follow answer')
+
+      manager.createMessageBranch(followUp.id, 'edited follow up', 'edited follow answer')
+      manager.addSummaryMessage(conversation.id, 'edited summary', {
+        bufferBoundaryTimestamp: 4,
+        compressedMessageCount: 2,
+      })
+      manager.switchMessageBranch(conversation.id, followUp.id)
+
+      assert.deepEqual(
+        manager.getMessages(conversation.id).map((message) => message.content),
+        ['intro', 'answer', 'original summary', 'follow up', 'follow answer']
+      )
+      manager.close()
+    } finally {
+      cleanup(dir)
+    }
+  })
+})

packages/node-runtime/src/ai/conversations.ts

@@ -18,6 +18,7 @@ export interface AIConversation {
   sessionId: string
   title: string | null
   assistantId: string
+  activeMessageId?: string | null
   createdAt: number
   updatedAt: number
 }
@@ -54,12 +55,41 @@ export interface AIMessage {
   role: AIMessageRole
   content: string
   timestamp: number
+  parentId?: string | null
+  siblingGroupId?: string
+  branchIndex?: number
+  branch?: {
+    index: number
+    total: number
+    prevMessageId: string | null
+    nextMessageId: string | null
+  }
   dataKeywords?: string[]
   dataMessageCount?: number
   contentBlocks?: ContentBlock[]
   tokenUsage?: TokenUsageData
 }
 
+interface AIMessageRow {
+  id: string
+  conversationId: string
+  role: string
+  content: string
+  timestamp: number
+  parentId: string | null
+  siblingGroupId: string | null
+  branchIndex: number | null
+  dataKeywords: string | null
+  dataMessageCount: number | null
+  contentBlocks: string | null
+  tokenUsage: string | null
+}
+
+export interface MessageBranchResult {
+  userMessage: AIMessage
+  assistantMessage: AIMessage
+}
+
 export interface ConversationManagerLogger {
   warn(category: string, message: string, extra?: Record<string, unknown>): void
 }
@@ -104,6 +134,7 @@ export class AIConversationManager {
         id TEXT PRIMARY KEY,
         session_id TEXT NOT NULL,
         title TEXT,
+        active_message_id TEXT,
         created_at INTEGER NOT NULL,
         updated_at INTEGER NOT NULL
       );
@@ -117,6 +148,9 @@ export class AIConversationManager {
         data_keywords TEXT,
         data_message_count INTEGER,
         content_blocks TEXT,
+        parent_id TEXT,
+        sibling_group_id TEXT,
+        branch_index INTEGER DEFAULT 0,
         FOREIGN KEY(conversation_id) REFERENCES ai_conversation(id) ON DELETE CASCADE
       );
 
@@ -133,6 +167,11 @@ export class AIConversationManager {
       const messageTableInfo = db.pragma('table_info(ai_message)') as Array<{ name: string }>
       const messageColumns = messageTableInfo.map((col) => col.name)
 
+      const needsMessageTreeBackfill =
+        !messageColumns.includes('parent_id') ||
+        !messageColumns.includes('sibling_group_id') ||
+        !messageColumns.includes('branch_index')
+
       if (!messageColumns.includes('content_blocks')) {
         db.exec('ALTER TABLE ai_message ADD COLUMN content_blocks TEXT')
       }
@@ -142,22 +181,204 @@ export class AIConversationManager {
       if (!messageColumns.includes('debug_context')) {
         db.exec('ALTER TABLE ai_message ADD COLUMN debug_context TEXT')
       }
+      if (!messageColumns.includes('parent_id')) {
+        db.exec('ALTER TABLE ai_message ADD COLUMN parent_id TEXT')
+      }
+      if (!messageColumns.includes('sibling_group_id')) {
+        db.exec('ALTER TABLE ai_message ADD COLUMN sibling_group_id TEXT')
+      }
+      if (!messageColumns.includes('branch_index')) {
+        db.exec('ALTER TABLE ai_message ADD COLUMN branch_index INTEGER DEFAULT 0')
+      }
 
       const convTableInfo = db.pragma('table_info(ai_conversation)') as Array<{ name: string }>
       const convColumns = convTableInfo.map((col) => col.name)
+      const needsConversationBackfill = !convColumns.includes('active_message_id')
 
       if (!convColumns.includes('assistant_id')) {
         db.exec(`ALTER TABLE ai_conversation ADD COLUMN assistant_id TEXT DEFAULT '${DEFAULT_GENERAL_ID}'`)
       }
+      if (!convColumns.includes('active_message_id')) {
+        db.exec('ALTER TABLE ai_conversation ADD COLUMN active_message_id TEXT')
+      }
+
+      if (needsMessageTreeBackfill || needsConversationBackfill) {
+        this.backfillMessageTree(db)
+      }
+
+      db.exec(`
+        CREATE INDEX IF NOT EXISTS idx_ai_message_parent ON ai_message(parent_id);
+        CREATE INDEX IF NOT EXISTS idx_ai_message_sibling ON ai_message(sibling_group_id);
+      `)
     } catch (error) {
       console.error('[AI DB Migration] Migration failed:', error)
     }
   }
 
+  private backfillMessageTree(db: Database.Database): void {
+    const conversations = db.prepare('SELECT id FROM ai_conversation').all() as Array<{ id: string }>
+    const updateMessage = db.prepare(
+      'UPDATE ai_message SET parent_id = ?, sibling_group_id = COALESCE(sibling_group_id, ?), branch_index = COALESCE(branch_index, 0) WHERE id = ?'
+    )
+    const updateConversation = db.prepare('UPDATE ai_conversation SET active_message_id = ? WHERE id = ?')
+
+    const tx = db.transaction(() => {
+      for (const conversation of conversations) {
+        const messages = db
+          .prepare(
+            `SELECT id, parent_id as parentId, sibling_group_id as siblingGroupId
+             FROM ai_message WHERE conversation_id = ? ORDER BY timestamp ASC, id ASC`
+          )
+          .all(conversation.id) as Array<{ id: string; parentId: string | null; siblingGroupId: string | null }>
+
+        let previousId: string | null = null
+        for (const message of messages) {
+          const parentId = message.parentId === undefined ? previousId : (message.parentId ?? previousId)
+          updateMessage.run(parentId, message.siblingGroupId ?? message.id, message.id)
+          previousId = message.id
+        }
+
+        const conversationRow = db
+          .prepare('SELECT active_message_id as activeMessageId FROM ai_conversation WHERE id = ?')
+          .get(conversation.id) as { activeMessageId: string | null } | undefined
+        if (!conversationRow?.activeMessageId && previousId) {
+          updateConversation.run(previousId, conversation.id)
+        }
+      }
+    })
+
+    tx()
+  }
+
   private generateId(prefix: string): string {
     return `${prefix}_${Date.now()}_${Math.random().toString(36).slice(2, 8)}`
   }
 
+  private parseMessageRow(row: AIMessageRow, branch?: AIMessage['branch']): AIMessage {
+    return {
+      id: row.id,
+      conversationId: row.conversationId,
+      role: row.role as AIMessageRole,
+      content: row.content,
+      timestamp: row.timestamp,
+      parentId: row.parentId ?? null,
+      siblingGroupId: row.siblingGroupId ?? row.id,
+      branchIndex: row.branchIndex ?? 0,
+      branch,
+      dataKeywords: row.dataKeywords ? JSON.parse(row.dataKeywords) : undefined,
+      dataMessageCount: row.dataMessageCount ?? undefined,
+      contentBlocks: row.contentBlocks ? JSON.parse(row.contentBlocks) : undefined,
+      tokenUsage: row.tokenUsage ? JSON.parse(row.tokenUsage) : undefined,
+    }
+  }
+
+  private getMessageRow(messageId: string): AIMessageRow | null {
+    const db = this.getDb()
+    const row = db
+      .prepare(
+        `SELECT id, conversation_id as conversationId, role, content, timestamp,
+                parent_id as parentId, sibling_group_id as siblingGroupId, branch_index as branchIndex,
+                data_keywords as dataKeywords, data_message_count as dataMessageCount,
+                content_blocks as contentBlocks, token_usage as tokenUsage
+         FROM ai_message WHERE id = ?`
+      )
+      .get(messageId) as AIMessageRow | undefined
+    return row ?? null
+  }
+
+  private getActiveMessageId(conversationId: string): string | null {
+    const db = this.getDb()
+    const row = db
+      .prepare('SELECT active_message_id as activeMessageId FROM ai_conversation WHERE id = ?')
+      .get(conversationId) as { activeMessageId: string | null } | undefined
+    if (row?.activeMessageId) {
+      const activeExists = db.prepare('SELECT 1 FROM ai_message WHERE id = ?').get(row.activeMessageId)
+      if (activeExists) return row.activeMessageId
+    }
+
+    const fallback = db
+      .prepare('SELECT id FROM ai_message WHERE conversation_id = ? ORDER BY timestamp DESC, id DESC LIMIT 1')
+      .get(conversationId) as { id: string } | undefined
+    if (fallback?.id) {
+      db.prepare('UPDATE ai_conversation SET active_message_id = ? WHERE id = ?').run(fallback.id, conversationId)
+      return fallback.id
+    }
+    return null
+  }
+
+  private getActivePathRows(conversationId: string, leafMessageId?: string | null): AIMessageRow[] {
+    const db = this.getDb()
+    if (leafMessageId === null) return []
+    let currentId = leafMessageId ?? this.getActiveMessageId(conversationId)
+    const rows: AIMessageRow[] = []
+    const seen = new Set<string>()
+
+    while (currentId && !seen.has(currentId)) {
+      seen.add(currentId)
+      const row = this.getMessageRow(currentId)
+      if (!row || row.conversationId !== conversationId) break
+      rows.push(row)
+      currentId = row.parentId
+    }
+
+    if (rows.length === 0) {
+      return db
+        .prepare(
+          `SELECT id, conversation_id as conversationId, role, content, timestamp,
+                  parent_id as parentId, sibling_group_id as siblingGroupId, branch_index as branchIndex,
+                  data_keywords as dataKeywords, data_message_count as dataMessageCount,
+                  content_blocks as contentBlocks, token_usage as tokenUsage
+           FROM ai_message WHERE conversation_id = ? ORDER BY timestamp ASC, id ASC`
+        )
+        .all(conversationId) as AIMessageRow[]
+    }
+
+    return rows.reverse()
+  }
+
+  private getBranchMeta(row: AIMessageRow): AIMessage['branch'] | undefined {
+    const groupId = row.siblingGroupId ?? row.id
+    const siblings = this.getDb()
+      .prepare(
+        `SELECT id FROM ai_message
+         WHERE conversation_id = ? AND sibling_group_id = ?
+         ORDER BY branch_index ASC, timestamp ASC, id ASC`
+      )
+      .all(row.conversationId, groupId) as Array<{ id: string }>
+
+    if (siblings.length <= 1) return undefined
+    const index = siblings.findIndex((item) => item.id === row.id)
+    const safeIndex = index >= 0 ? index : 0
+    return {
+      index: safeIndex,
+      total: siblings.length,
+      prevMessageId: safeIndex > 0 ? siblings[safeIndex - 1]!.id : null,
+      nextMessageId: safeIndex < siblings.length - 1 ? siblings[safeIndex + 1]!.id : null,
+    }
+  }
+
+  private getDeepestLeafId(messageId: string): string {
+    const db = this.getDb()
+    let currentId = messageId
+    const seen = new Set<string>()
+
+    while (!seen.has(currentId)) {
+      seen.add(currentId)
+      const child = db
+        .prepare(
+          `SELECT id FROM ai_message
+           WHERE parent_id = ?
+           ORDER BY branch_index DESC, timestamp DESC, id DESC
+           LIMIT 1`
+        )
+        .get(currentId) as { id: string } | undefined
+      if (!child?.id) break
+      currentId = child.id
+    }
+
+    return currentId
+  }
+
   // ==================== 生命周期 ====================
 
   close(): void {
@@ -246,7 +467,7 @@ export class AIConversationManager {
        VALUES (?, ?, ?, ?, ?, ?)`
     ).run(id, sessionId, title || null, assistantId, now, now)
 
-    return { id, sessionId, title: title || null, assistantId, createdAt: now, updatedAt: now }
+    return { id, sessionId, title: title || null, assistantId, activeMessageId: null, createdAt: now, updatedAt: now }
   }
 
   getConversationCountsBySession(): Map<string, number> {
@@ -270,6 +491,7 @@ export class AIConversationManager {
     return db
       .prepare(
         `SELECT id, session_id as sessionId, title, assistant_id as assistantId,
+                active_message_id as activeMessageId,
                 created_at as createdAt, updated_at as updatedAt
          FROM ai_conversation WHERE session_id = ? ORDER BY updated_at DESC`
       )
@@ -281,6 +503,7 @@ export class AIConversationManager {
     const row = db
       .prepare(
         `SELECT id, session_id as sessionId, title, assistant_id as assistantId,
+                active_message_id as activeMessageId,
                 created_at as createdAt, updated_at as updatedAt
          FROM ai_conversation WHERE id = ?`
       )
@@ -318,6 +541,9 @@ export class AIConversationManager {
     const db = this.getDb()
     const now = Math.floor(Date.now() / 1000)
     const id = this.generateId('msg')
+    const parentId = this.getActiveMessageId(conversationId)
+    const siblingGroupId = id
+    const branchIndex = 0
 
     const pendingDebug = role === 'assistant' ? this.pendingDebugContextMap.get(conversationId) : undefined
     if (pendingDebug) {
@@ -325,8 +551,11 @@ export class AIConversationManager {
     }
 
     db.prepare(
-      `INSERT INTO ai_message (id, conversation_id, role, content, timestamp, data_keywords, data_message_count, content_blocks, token_usage, debug_context)
+      `INSERT INTO ai_message (
-       VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`
+         id, conversation_id, role, content, timestamp, data_keywords, data_message_count,
+         content_blocks, token_usage, debug_context, parent_id, sibling_group_id, branch_index
+       )
+       VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`
     ).run(
       id,
       conversationId,
@@ -337,10 +566,17 @@ export class AIConversationManager {
       dataMessageCount ?? null,
       contentBlocks ? JSON.stringify(contentBlocks) : null,
       tokenUsage ? JSON.stringify(tokenUsage) : null,
-      pendingDebug ?? null
+      pendingDebug ?? null,
+      parentId,
+      siblingGroupId,
+      branchIndex
     )
 
-    db.prepare('UPDATE ai_conversation SET updated_at = ? WHERE id = ?').run(now, conversationId)
+    db.prepare('UPDATE ai_conversation SET active_message_id = ?, updated_at = ? WHERE id = ?').run(
+      id,
+      now,
+      conversationId
+    )
 
     return {
       id,
@@ -348,6 +584,9 @@ export class AIConversationManager {
       role,
       content,
       timestamp: now,
+      parentId,
+      siblingGroupId,
+      branchIndex,
       dataKeywords,
       dataMessageCount,
       contentBlocks,
@@ -356,37 +595,8 @@ export class AIConversationManager {
   }
 
   getMessages(conversationId: string): AIMessage[] {
-    const db = this.getDb()
+    const rows = this.getActivePathRows(conversationId)
-    const rows = db
+    return rows.map((row) => this.parseMessageRow(row, this.getBranchMeta(row)))
-      .prepare(
-        `SELECT id, conversation_id as conversationId, role, content, timestamp,
-                data_keywords as dataKeywords, data_message_count as dataMessageCount,
-                content_blocks as contentBlocks, token_usage as tokenUsage
-         FROM ai_message WHERE conversation_id = ? ORDER BY timestamp ASC`
-      )
-      .all(conversationId) as Array<{
-      id: string
-      conversationId: string
-      role: string
-      content: string
-      timestamp: number
-      dataKeywords: string | null
-      dataMessageCount: number | null
-      contentBlocks: string | null
-      tokenUsage: string | null
-    }>
-
-    return rows.map((row) => ({
-      id: row.id,
-      conversationId: row.conversationId,
-      role: row.role as AIMessageRole,
-      content: row.content,
-      timestamp: row.timestamp,
-      dataKeywords: row.dataKeywords ? JSON.parse(row.dataKeywords) : undefined,
-      dataMessageCount: row.dataMessageCount ?? undefined,
-      contentBlocks: row.contentBlocks ? JSON.parse(row.contentBlocks) : undefined,
-      tokenUsage: row.tokenUsage ? JSON.parse(row.tokenUsage) : undefined,
-    }))
   }
 
   deleteMessage(messageId: string): boolean {
@@ -395,18 +605,115 @@ export class AIConversationManager {
     return result.changes > 0
   }
 
-  getConversationTokenUsage(conversationId: string): TokenUsageData {
+  createMessageBranch(
+    originalUserMessageId: string,
+    newUserContent: string,
+    assistantContent: string,
+    contentBlocks?: ContentBlock[],
+    tokenUsage?: TokenUsageData
+  ): MessageBranchResult {
     const db = this.getDb()
-    const row = db
+    const original = this.getMessageRow(originalUserMessageId)
+    if (!original || original.role !== 'user') {
+      throw new Error('Original user message not found')
+    }
+
+    const now = Math.floor(Date.now() / 1000)
+    const userMessageId = this.generateId('msg')
+    const assistantMessageId = this.generateId('msg')
+    const siblingGroupId = original.siblingGroupId ?? original.id
+    const branchRow = db
       .prepare(
-        `SELECT
+        `SELECT COALESCE(MAX(branch_index), -1) + 1 as branchIndex
-           COALESCE(SUM(json_extract(token_usage, '$.promptTokens')), 0) as promptTokens,
+         FROM ai_message WHERE conversation_id = ? AND sibling_group_id = ?`
-           COALESCE(SUM(json_extract(token_usage, '$.completionTokens')), 0) as completionTokens,
-           COALESCE(SUM(json_extract(token_usage, '$.totalTokens')), 0) as totalTokens
-         FROM ai_message WHERE conversation_id = ? AND token_usage IS NOT NULL`
       )
-      .get(conversationId) as { promptTokens: number; completionTokens: number; totalTokens: number }
+      .get(original.conversationId, siblingGroupId) as { branchIndex: number }
-    return { promptTokens: row.promptTokens, completionTokens: row.completionTokens, totalTokens: row.totalTokens }
+
+    const pendingDebug = this.pendingDebugContextMap.get(original.conversationId)
+    if (pendingDebug) {
+      this.pendingDebugContextMap.delete(original.conversationId)
+    }
+
+    const tx = db.transaction(() => {
+      db.prepare(
+        `INSERT INTO ai_message (
+           id, conversation_id, role, content, timestamp, data_keywords, data_message_count,
+           content_blocks, token_usage, debug_context, parent_id, sibling_group_id, branch_index
+         )
+         VALUES (?, ?, 'user', ?, ?, NULL, NULL, NULL, NULL, NULL, ?, ?, ?)`
+      ).run(
+        userMessageId,
+        original.conversationId,
+        newUserContent,
+        now,
+        original.parentId,
+        siblingGroupId,
+        branchRow.branchIndex
+      )
+
+      db.prepare(
+        `INSERT INTO ai_message (
+           id, conversation_id, role, content, timestamp, data_keywords, data_message_count,
+           content_blocks, token_usage, debug_context, parent_id, sibling_group_id, branch_index
+         )
+         VALUES (?, ?, 'assistant', ?, ?, NULL, NULL, ?, ?, ?, ?, ?, 0)`
+      ).run(
+        assistantMessageId,
+        original.conversationId,
+        assistantContent,
+        now,
+        contentBlocks ? JSON.stringify(contentBlocks) : null,
+        tokenUsage ? JSON.stringify(tokenUsage) : null,
+        pendingDebug ?? null,
+        userMessageId,
+        assistantMessageId
+      )
+
+      db.prepare('UPDATE ai_conversation SET active_message_id = ?, updated_at = ? WHERE id = ?').run(
+        assistantMessageId,
+        now,
+        original.conversationId
+      )
+    })
+
+    tx()
+
+    const userRow = this.getMessageRow(userMessageId)!
+    const assistantRow = this.getMessageRow(assistantMessageId)!
+    return {
+      userMessage: this.parseMessageRow(userRow, this.getBranchMeta(userRow)),
+      assistantMessage: this.parseMessageRow(assistantRow, this.getBranchMeta(assistantRow)),
+    }
+  }
+
+  switchMessageBranch(conversationId: string, messageId: string): AIMessage[] {
+    const target = this.getMessageRow(messageId)
+    if (!target || target.conversationId !== conversationId) {
+      throw new Error('Message branch not found')
+    }
+
+    const leafId = this.getDeepestLeafId(messageId)
+    const now = Math.floor(Date.now() / 1000)
+    this.getDb()
+      .prepare('UPDATE ai_conversation SET active_message_id = ?, updated_at = ? WHERE id = ?')
+      .run(leafId, now, conversationId)
+
+    return this.getMessages(conversationId)
+  }
+
+  getConversationTokenUsage(conversationId: string): TokenUsageData {
+    const messages = this.getMessages(conversationId)
+    return messages.reduce<TokenUsageData>(
+      (total, message) => {
+        if (message.tokenUsage) {
+          total.promptTokens += message.tokenUsage.promptTokens
+          total.completionTokens += message.tokenUsage.completionTokens
+          total.totalTokens += message.tokenUsage.totalTokens
+        }
+        return total
+      },
+      { promptTokens: 0, completionTokens: 0, totalTokens: 0 }
+    )
   }
 
   // ==================== Debug context ====================
@@ -430,9 +737,10 @@ export class AIConversationManager {
 
   getHistoryForAgent(
     conversationId: string,
-    maxMessages?: number
+    maxMessages?: number,
+    leafMessageId?: string | null
   ): Array<{ role: 'user' | 'assistant' | 'summary'; content: string }> {
-    const messages = this.getMessages(conversationId)
+    const messages = this.getActivePathRows(conversationId, leafMessageId).map((row) => this.parseMessageRow(row))
     const validMessages = messages.filter(
       (m) => (m.role === 'user' || m.role === 'assistant' || m.role === 'summary') && m.content?.trim()
     )
@@ -490,9 +798,6 @@ export class AIConversationManager {
     content: string,
     meta: { bufferBoundaryTimestamp: number; compressedMessageCount: number }
   ): AIMessage {
-    const db = this.getDb()
-    db.prepare("DELETE FROM ai_message WHERE conversation_id = ? AND role = 'summary'").run(conversationId)
-
     const contentBlocks: ContentBlock[] = [
       {
         type: 'summary_meta',
@@ -505,78 +810,32 @@ export class AIConversationManager {
   }
 
   getLatestSummary(conversationId: string): AIMessage | null {
-    const db = this.getDb()
+    const row = [...this.getActivePathRows(conversationId)].reverse().find((message) => message.role === 'summary')
-    const row = db
+    return row ? this.parseMessageRow(row) : null
-      .prepare(
-        `SELECT id, conversation_id as conversationId, role, content, timestamp,
-                data_keywords as dataKeywords, data_message_count as dataMessageCount,
-                content_blocks as contentBlocks
-         FROM ai_message WHERE conversation_id = ? AND role = 'summary'
-         ORDER BY timestamp DESC LIMIT 1`
-      )
-      .get(conversationId) as
-      | {
-          id: string
-          conversationId: string
-          role: string
-          content: string
-          timestamp: number
-          dataKeywords: string | null
-          dataMessageCount: number | null
-          contentBlocks: string | null
-        }
-      | undefined
-
-    if (!row) return null
-    return {
-      id: row.id,
-      conversationId: row.conversationId,
-      role: row.role as AIMessageRole,
-      content: row.content,
-      timestamp: row.timestamp,
-      dataKeywords: row.dataKeywords ? JSON.parse(row.dataKeywords) : undefined,
-      dataMessageCount: row.dataMessageCount ?? undefined,
-      contentBlocks: row.contentBlocks ? JSON.parse(row.contentBlocks) : undefined,
-    }
   }
 
   getMessagesAfterSummary(
     conversationId: string,
     summaryTimestamp: number
   ): Array<{ role: AIMessageRole; content: string; timestamp: number }> {
-    const db = this.getDb()
+    return this.getActivePathRows(conversationId)
-    const rows = db
+      .filter((row) => row.timestamp > summaryTimestamp && (row.role === 'user' || row.role === 'assistant'))
-      .prepare(
+      .map((row) => ({ role: row.role as AIMessageRole, content: row.content, timestamp: row.timestamp }))
-        `SELECT role, content, timestamp FROM ai_message
-         WHERE conversation_id = ? AND timestamp > ? AND role IN ('user', 'assistant')
-         ORDER BY timestamp ASC`
-      )
-      .all(conversationId, summaryTimestamp) as Array<{ role: string; content: string; timestamp: number }>
-    return rows.map((r) => ({ role: r.role as AIMessageRole, content: r.content, timestamp: r.timestamp }))
   }
 
   getAllUserAssistantMessages(
     conversationId: string
   ): Array<{ role: AIMessageRole; content: string; timestamp: number }> {
-    const db = this.getDb()
+    return this.getActivePathRows(conversationId)
-    const rows = db
+      .filter((row) => row.role === 'user' || row.role === 'assistant')
-      .prepare(
+      .map((row) => ({ role: row.role as AIMessageRole, content: row.content, timestamp: row.timestamp }))
-        `SELECT role, content, timestamp FROM ai_message
-         WHERE conversation_id = ? AND role IN ('user', 'assistant')
-         ORDER BY timestamp ASC`
-      )
-      .all(conversationId) as Array<{ role: string; content: string; timestamp: number }>
-    return rows.map((r) => ({ role: r.role as AIMessageRole, content: r.content, timestamp: r.timestamp }))
   }
 
   getMessageCountAfterSummary(conversationId: string): number {
     const summary = this.getLatestSummary(conversationId)
     if (!summary) {
-      const db = this.getDb()
+      return this.getActivePathRows(conversationId).filter((row) => row.role === 'user' || row.role === 'assistant')
-      const row = db
+        .length
-        .prepare("SELECT COUNT(*) as count FROM ai_message WHERE conversation_id = ? AND role IN ('user', 'assistant')")
-        .get(conversationId) as { count: number }
-      return row.count
     }
 
     const metaBlock = summary.contentBlocks?.find(
@@ -584,12 +843,8 @@ export class AIConversationManager {
     )
     const boundary = metaBlock?.bufferBoundaryTimestamp ?? summary.timestamp
 
-    const db = this.getDb()
+    return this.getActivePathRows(conversationId).filter(
-    const row = db
+      (row) => row.timestamp >= boundary && (row.role === 'user' || row.role === 'assistant')
-      .prepare(
+    ).length
-        "SELECT COUNT(*) as count FROM ai_message WHERE conversation_id = ? AND timestamp >= ? AND role IN ('user', 'assistant')"
-      )
-      .get(conversationId, boundary) as { count: number }
-    return row.count
   }
 }

packages/node-runtime/src/ai/index.ts

@@ -32,6 +32,7 @@ export type {
   ContentBlock,
   TokenUsageData,
   ConversationManagerLogger,
+  MessageBranchResult,
 } from './conversations'
 
 // Tokenizer

packages/node-runtime/src/index.ts

@@ -79,7 +79,7 @@ export {
 } from './nlp'
 
 // AI 助手/技能解析器 + 对话管理
-export type { AssistantConfig, AssistantSummary, SkillDef, SkillSummary } from './ai'
+export type { AssistantConfig, AssistantSummary, SkillDef, SkillSummary, MessageBranchResult } from './ai'
 export { parseAssistantFile, serializeAssistant, parseSkillFile, extractSkillId } from './ai'
 export { AIConversationManager } from './ai'
 export { countTokens, countMessagesTokens } from './ai'

src/components/AIChat/ChatExplorer.vue

@@ -54,6 +54,8 @@ const {
   agentStatus,
   selectedAssistantId,
   sendMessage,
+  editMessageAndRegenerate,
+  switchMessageBranch,
   loadConversation,
   startNewConversation,
   loadMoreSourceMessages,
@@ -244,6 +246,28 @@ async function handleSend(payload: { content: string; mentionedMembers: Mentione
   conversationListRef.value?.refresh()
 }
 
+async function handleEditMessage(payload: { messageId: string; content: string }) {
+  const result = await editMessageAndRegenerate(payload.messageId, payload.content)
+  if (!result.success) {
+    if (result.reason === 'busy') {
+      showRunningTaskToast()
+    }
+    return
+  }
+  scrollToBottom(true)
+  conversationListRef.value?.refresh()
+}
+
+async function handleSwitchMessageBranch(messageId: string | null) {
+  if (!messageId) return
+  const ok = await switchMessageBranch(messageId)
+  if (!ok) {
+    showLockedActionToast()
+    return
+  }
+  scrollToBottom(true)
+}
+
 // 切换数据源面板
 function toggleSourcePanel() {
   isSourcePanelCollapsed.value = !isSourcePanelCollapsed.value
@@ -413,10 +437,16 @@ watch(
                   <ChatMessage
                     v-if="pair.user && (pair.user.role === 'user' || pair.user.content)"
                     :role="pair.user.role"
+                    :message-id="pair.user.id"
                     :content="pair.user.content"
                     :timestamp="pair.user.timestamp"
                     :is-streaming="pair.user.isStreaming"
                     :content-blocks="pair.user.contentBlocks"
+                    :branch="pair.user.branch"
+                    :editable="!isAIThinking"
+                    @edit="handleEditMessage"
+                    @branch-prev="handleSwitchMessageBranch"
+                    @branch-next="handleSwitchMessageBranch"
                   />
                   <!-- AI 回复 -->
                   <ChatMessage

src/components/AIChat/chat/ChatMessage.vue

@@ -1,5 +1,5 @@
 <script setup lang="ts">
-import { computed } from 'vue'
+import { computed, ref, watch, nextTick } from 'vue'
 import { useI18n } from 'vue-i18n'
 import dayjs from 'dayjs'
 import MarkdownIt from 'markdown-it'
@@ -13,6 +13,7 @@ const toast = useToast()
 
 // Props
 const props = defineProps<{
+  messageId?: string
   role: 'user' | 'assistant' | 'summary'
   content: string
   timestamp: number
@@ -21,6 +22,19 @@ const props = defineProps<{
   contentBlocks?: ContentBlock[]
   /** 是否显示截屏按钮（仅 AI 回复） */
   showCaptureButton?: boolean
+  editable?: boolean
+  branch?: {
+    index: number
+    total: number
+    prevMessageId: string | null
+    nextMessageId: string | null
+  }
+}>()
+
+const emit = defineEmits<{
+  edit: [payload: { messageId: string; content: string }]
+  branchPrev: [messageId: string | null]
+  branchNext: [messageId: string | null]
 }>()
 
 // 格式化时间
@@ -31,6 +45,11 @@ const formattedTime = computed(() => {
 // 是否是用户消息
 const isUser = computed(() => props.role === 'user')
 const isSummary = computed(() => props.role === 'summary')
+const isEditing = ref(false)
+const editContent = ref(props.content)
+const editTextareaRef = ref<HTMLTextAreaElement | null>(null)
+const canEdit = computed(() => isUser.value && props.editable && !props.isStreaming && !!props.messageId)
+const hasBranchSwitcher = computed(() => isUser.value && !!props.branch && props.branch.total > 1)
 
 // 创建 markdown-it 实例
 const md = new MarkdownIt({
@@ -77,6 +96,37 @@ const renderedContent = computed(() => {
   return md.render(props.content)
 })
 
+watch(
+  () => props.content,
+  (content) => {
+    if (!isEditing.value) editContent.value = content
+  }
+)
+
+async function startEditing() {
+  if (!canEdit.value) return
+  editContent.value = props.content
+  isEditing.value = true
+  await nextTick()
+  editTextareaRef.value?.focus()
+}
+
+function cancelEditing() {
+  isEditing.value = false
+  editContent.value = props.content
+}
+
+function submitEditing() {
+  if (!props.messageId) return
+  const content = editContent.value.trim()
+  if (!content || content === props.content.trim()) {
+    cancelEditing()
+    return
+  }
+  isEditing.value = false
+  emit('edit', { messageId: props.messageId, content })
+}
+
 // 过滤无内容的文本/思考块，避免显示空气泡
 const visibleBlocks = computed(() => {
   const blocks = props.contentBlocks || []
@@ -331,7 +381,28 @@ async function handleCopyMarkdown() {
 
       <!-- 用户消息：简单气泡 -->
       <template v-else-if="isUser">
-        <div class="rounded-3xl bg-primary-50 px-5 py-3 text-gray-900 dark:bg-primary-500/50 dark:text-gray-100">
+        <div
+          v-if="isEditing"
+          class="rounded-2xl bg-primary-50 p-3 text-gray-900 dark:bg-primary-500/50 dark:text-gray-100"
+        >
+          <textarea
+            ref="editTextareaRef"
+            v-model="editContent"
+            class="max-h-64 min-h-28 w-full resize-y rounded-xl border border-primary-200 bg-white/90 px-3 py-2 text-sm leading-relaxed outline-none focus:border-primary-400 dark:border-primary-400/40 dark:bg-gray-900/70"
+            @keydown.esc.prevent="cancelEditing"
+            @keydown.ctrl.enter.prevent="submitEditing"
+            @keydown.meta.enter.prevent="submitEditing"
+          />
+          <div class="mt-2 flex justify-end gap-2">
+            <UButton size="xs" variant="ghost" color="gray" @click="cancelEditing">
+              {{ t('common.cancel') }}
+            </UButton>
+            <UButton size="xs" color="primary" @click="submitEditing">
+              {{ t('ai.chat.message.edit.submit') }}
+            </UButton>
+          </div>
+        </div>
+        <div v-else class="rounded-3xl bg-primary-50 px-5 py-3 text-gray-900 dark:bg-primary-500/50 dark:text-gray-100">
           <div class="prose prose-sm dark:prose-invert max-w-none leading-relaxed" v-html="renderedContent" />
         </div>
       </template>
@@ -480,6 +551,31 @@ async function handleCopyMarkdown() {
             @click="handleCopyMarkdown"
           />
         </UTooltip>
+        <UTooltip v-if="canEdit" :text="t('ai.chat.message.edit.tooltip')" class="no-capture">
+          <UButton icon="i-heroicons-pencil-square" variant="ghost" color="primary" size="xs" @click="startEditing" />
+        </UTooltip>
+        <div
+          v-if="hasBranchSwitcher"
+          class="no-capture flex items-center gap-1 rounded-full bg-gray-100 px-1 py-0.5 text-[11px] text-gray-500 dark:bg-gray-800 dark:text-gray-400"
+        >
+          <UButton
+            icon="i-heroicons-chevron-left"
+            variant="ghost"
+            color="gray"
+            size="xs"
+            :disabled="!branch?.prevMessageId"
+            @click="emit('branchPrev', branch?.prevMessageId ?? null)"
+          />
+          <span class="min-w-8 text-center">{{ (branch?.index ?? 0) + 1 }} / {{ branch?.total ?? 1 }}</span>
+          <UButton
+            icon="i-heroicons-chevron-right"
+            variant="ghost"
+            color="gray"
+            size="xs"
+            :disabled="!branch?.nextMessageId"
+            @click="emit('branchNext', branch?.nextMessageId ?? null)"
+          />
+        </div>
         <!-- 截屏按钮（仅 AI 回复显示） -->
         <CaptureButton
           v-if="showCaptureButton && !isUser && !isStreaming"

src/composables/useAIChat.ts

@@ -66,6 +66,9 @@ export function useAIChat(
     selectedAssistantId: toRef(state, 'selectedAssistantId'),
     sendMessage: (content: string, options?: { mentionedMembers?: MentionedMemberContext[] }) =>
       aiChatStore.sendMessage(chatKey, content, options),
+    editMessageAndRegenerate: (messageId: string, content: string) =>
+      aiChatStore.editMessageAndRegenerate(chatKey, messageId, content),
+    switchMessageBranch: (messageId: string) => aiChatStore.switchMessageBranch(chatKey, messageId),
     loadConversation: (conversationId: string) => aiChatStore.loadConversation(chatKey, conversationId),
     startNewConversation: (welcomeMessage?: string) => aiChatStore.startNewConversation(chatKey, welcomeMessage),
     loadMoreSourceMessages: () => aiChatStore.loadMoreSourceMessages(),

src/i18n/locales/en-US/ai.json

@@ -53,6 +53,10 @@
         "success": "Markdown copied to clipboard",
         "failed": "Failed to copy Markdown"
       },
+      "edit": {
+        "tooltip": "Edit and regenerate",
+        "submit": "Send"
+      },
       "tools": {
         "get_chat_overview": "Get Chat Overview",
         "search_messages": "Search Messages",

src/i18n/locales/ja-JP/ai.json

@@ -53,6 +53,10 @@
         "success": "Markdown をクリップボードにコピーしました",
         "failed": "Markdown のコピーに失敗しました"
       },
+      "edit": {
+        "tooltip": "編集して再生成",
+        "submit": "送信"
+      },
       "tools": {
         "get_chat_overview": "チャット概要を取得",
         "search_messages": "チャット履歴を検索",

src/i18n/locales/zh-CN/ai.json

@@ -53,6 +53,10 @@
         "success": "Markdown 已复制到剪贴板",
         "failed": "复制 Markdown 失败"
       },
+      "edit": {
+        "tooltip": "编辑并重新生成",
+        "submit": "发送"
+      },
       "tools": {
         "get_chat_overview": "获取聊天概览",
         "search_messages": "搜索聊天记录",

src/i18n/locales/zh-TW/ai.json

@@ -53,6 +53,10 @@
         "success": "Markdown 已複製到剪貼簿",
         "failed": "複製 Markdown 失敗"
       },
+      "edit": {
+        "tooltip": "編輯並重新生成",
+        "submit": "送出"
+      },
       "tools": {
         "get_chat_overview": "取得聊天概覽",
         "search_messages": "搜尋聊天紀錄",

src/services/ai/electron.ts

@@ -5,6 +5,7 @@ import type {
   AIMessageRole,
   ContentBlock,
   TokenUsageData,
+  MessageBranchResult,
   FilterResultWithPagination,
   ExportFilterParams,
   ExportProgress,
@@ -63,6 +64,26 @@ export class ElectronAIAdapter implements AIAdapter {
     ) as Promise<AIMessage>
   }
 
+  async createMessageBranch(
+    originalUserMessageId: string,
+    newUserContent: string,
+    assistantContent: string,
+    contentBlocks?: ContentBlock[],
+    tokenUsage?: TokenUsageData
+  ): Promise<MessageBranchResult> {
+    return window.aiApi.createMessageBranch(
+      originalUserMessageId,
+      newUserContent,
+      assistantContent,
+      contentBlocks as any,
+      tokenUsage
+    ) as Promise<MessageBranchResult>
+  }
+
+  async switchMessageBranch(conversationId: string, messageId: string): Promise<AIMessage[]> {
+    return window.aiApi.switchMessageBranch(conversationId, messageId) as Promise<AIMessage[]>
+  }
+
   async getConversationTokenUsage(conversationId: string): Promise<TokenUsageData> {
     return window.aiApi.getConversationTokenUsage(conversationId)
   }

src/services/ai/fetch.ts

@@ -12,6 +12,7 @@ import type {
   AIMessageRole,
   ContentBlock,
   TokenUsageData,
+  MessageBranchResult,
   FilterResultWithPagination,
   ExportFilterParams,
   ExportProgress,
@@ -76,6 +77,25 @@ export class FetchAIAdapter implements AIAdapter {
     })
   }
 
+  async createMessageBranch(
+    originalUserMessageId: string,
+    newUserContent: string,
+    assistantContent: string,
+    contentBlocks?: ContentBlock[],
+    tokenUsage?: TokenUsageData
+  ): Promise<MessageBranchResult> {
+    return post<MessageBranchResult>(`/ai/messages/${originalUserMessageId}/branches`, {
+      content: newUserContent,
+      assistantContent,
+      contentBlocks,
+      tokenUsage,
+    })
+  }
+
+  async switchMessageBranch(conversationId: string, messageId: string): Promise<AIMessage[]> {
+    return post<AIMessage[]>(`/ai/conversations/${conversationId}/branches/switch`, { messageId })
+  }
+
   async getConversationTokenUsage(conversationId: string): Promise<TokenUsageData> {
     return get<TokenUsageData>(`/ai/conversations/${conversationId}/token-usage`)
   }

src/services/ai/types.ts

@@ -5,12 +5,14 @@ export interface AIConversation {
   sessionId: string
   title: string | null
   assistantId: string
+  activeMessageId?: string | null
   createdAt: number
   updatedAt: number
 }
 
 export type ContentBlock =
   | { type: 'text'; text: string }
+  | { type: 'think'; tag: string; text: string; durationMs?: number }
   | {
       type: 'tool'
       tool: {
@@ -21,6 +23,8 @@ export type ContentBlock =
       }
     }
   | { type: 'skill'; skillId: string; skillName: string }
+  | { type: 'error'; error: { name: string | null; message: string; stack?: string | null } }
+  | { type: 'summary_meta'; bufferBoundaryTimestamp: number; compressedMessageCount: number }
 
 export type AIMessageRole = 'user' | 'assistant' | 'summary'
 
@@ -36,12 +40,26 @@ export interface AIMessage {
   role: AIMessageRole
   content: string
   timestamp: number
+  parentId?: string | null
+  siblingGroupId?: string
+  branchIndex?: number
+  branch?: {
+    index: number
+    total: number
+    prevMessageId: string | null
+    nextMessageId: string | null
+  }
   dataKeywords?: string[]
   dataMessageCount?: number
   contentBlocks?: ContentBlock[]
   tokenUsage?: TokenUsageData
 }
 
+export interface MessageBranchResult {
+  userMessage: AIMessage
+  assistantMessage: AIMessage
+}
+
 export interface DesensitizeRule {
   id: string
   label: string
@@ -162,6 +180,14 @@ export interface AIAdapter {
     contentBlocks?: ContentBlock[],
     tokenUsage?: TokenUsageData
   ): Promise<AIMessage>
+  createMessageBranch(
+    originalUserMessageId: string,
+    newUserContent: string,
+    assistantContent: string,
+    contentBlocks?: ContentBlock[],
+    tokenUsage?: TokenUsageData
+  ): Promise<MessageBranchResult>
+  switchMessageBranch(conversationId: string, messageId: string): Promise<AIMessage[]>
   getConversationTokenUsage(conversationId: string): Promise<TokenUsageData>
   estimateContextTokens(
     conversationId: string

src/services/ai/web.ts

@@ -5,6 +5,7 @@ import type {
   AIMessageRole,
   ContentBlock,
   TokenUsageData,
+  MessageBranchResult,
   FilterResultWithPagination,
   ExportFilterParams,
   ExportProgress,
@@ -65,6 +66,20 @@ export class WebAIAdapter implements AIAdapter {
     throw new Error(NOT_AVAILABLE)
   }
 
+  async createMessageBranch(
+    _originalUserMessageId: string,
+    _newUserContent: string,
+    _assistantContent: string,
+    _contentBlocks?: ContentBlock[],
+    _tokenUsage?: TokenUsageData
+  ): Promise<MessageBranchResult> {
+    throw new Error('AI message branching is not available in static web mode')
+  }
+
+  async switchMessageBranch(_conversationId: string, _messageId: string): Promise<AIMessage[]> {
+    throw new Error('AI message branching is not available in static web mode')
+  }
+
   async getConversationTokenUsage(_conversationId: string): Promise<TokenUsageData> {
     return { promptTokens: 0, completionTokens: 0, totalTokens: 0 }
   }

src/services/registry.ts

@@ -314,6 +314,7 @@ async function installAiApiShims(): Promise<void> {
           body: {
             userMessage,
             conversationId: context.conversationId,
+            historyLeafMessageId: context.historyLeafMessageId,
             sessionId: context.sessionId,
             chatType: chatType || 'group',
             locale: locale || 'zh-CN',

src/stores/aiChat.ts

@@ -11,6 +11,7 @@ import { usePromptStore } from '@/stores/prompt'
 import { useSessionStore } from '@/stores/session'
 import { useSettingsStore } from '@/stores/settings'
 import { useDataService, useAIService } from '@/services'
+import type { AIMessage as PersistedAIMessage } from '@/services/ai/types'
 import { useAssistantStore } from '@/stores/assistant'
 import { useSkillStore } from '@/stores/skill'
 import type { TokenUsage, AgentRuntimeStatus, SerializedErrorInfo } from '@electron/shared/types'
@@ -63,6 +64,15 @@ export interface ChatMessage {
   role: 'user' | 'assistant' | 'summary'
   content: string
   timestamp: number
+  parentId?: string | null
+  siblingGroupId?: string
+  branchIndex?: number
+  branch?: {
+    index: number
+    total: number
+    prevMessageId: string | null
+    nextMessageId: string | null
+  }
   dataSource?: {
     toolsUsed: string[]
     toolRounds: number
@@ -184,6 +194,20 @@ function createEmptyTokenUsage(): TokenUsage {
   return { promptTokens: 0, completionTokens: 0, totalTokens: 0 }
 }
 
+function toRuntimeMessage(msg: PersistedAIMessage): ChatMessage {
+  return {
+    id: msg.id,
+    role: msg.role,
+    content: msg.content,
+    timestamp: msg.timestamp * 1000,
+    parentId: msg.parentId,
+    siblingGroupId: msg.siblingGroupId,
+    branchIndex: msg.branchIndex,
+    branch: msg.branch,
+    contentBlocks: msg.contentBlocks as ContentBlock[] | undefined,
+  }
+}
+
 function createConversationBuffer(assistantId: string | null = null): ConversationBuffer {
   return {
     messages: [],
@@ -455,17 +479,7 @@ export const useAIChatStore = defineStore('aiChatRuntime', () => {
           useAIService().getMessages(conversationId),
           useAIService().getConversationTokenUsage(conversationId),
         ])
-        buffer.messages.splice(
+        buffer.messages.splice(0, buffer.messages.length, ...history.map((msg) => toRuntimeMessage(msg)))
-          0,
-          buffer.messages.length,
-          ...history.map((msg) => ({
-            id: msg.id,
-            role: msg.role,
-            content: msg.content,
-            timestamp: msg.timestamp * 1000,
-            contentBlocks: msg.contentBlocks as ContentBlock[] | undefined,
-          }))
-        )
         buffer.sourceMessages.splice(0, buffer.sourceMessages.length)
         buffer.currentKeywords.splice(0, buffer.currentKeywords.length)
         buffer.sessionTokenUsage = tokenUsage
@@ -954,12 +968,20 @@ export const useAIChatStore = defineStore('aiChatRuntime', () => {
           isStreaming: false,
         }
 
-        await saveConversation(
+        const savedMessages = await saveConversation(
           resolvedConversationId,
           userMessage,
           targetBuffer.messages[aiMessageIndex],
           lastDoneUsage
         )
+        if (savedMessages) {
+          Object.assign(userMessage, savedMessages.userMessage)
+          targetBuffer.messages[aiMessageIndex] = {
+            ...targetBuffer.messages[aiMessageIndex],
+            ...savedMessages.assistantMessage,
+            isStreaming: false,
+          }
+        }
       } else if (!hasStreamError) {
         const blocks = targetBuffer.messages[aiMessageIndex].contentBlocks || []
         blocks.push({
@@ -971,19 +993,35 @@ export const useAIChatStore = defineStore('aiChatRuntime', () => {
           contentBlocks: [...blocks],
           isStreaming: false,
         }
-        await saveConversation(
+        const savedMessages = await saveConversation(
           resolvedConversationId,
           userMessage,
           targetBuffer.messages[aiMessageIndex],
           lastDoneUsage
         )
+        if (savedMessages) {
+          Object.assign(userMessage, savedMessages.userMessage)
+          targetBuffer.messages[aiMessageIndex] = {
+            ...targetBuffer.messages[aiMessageIndex],
+            ...savedMessages.assistantMessage,
+            isStreaming: false,
+          }
+        }
       } else {
-        await saveConversation(
+        const savedMessages = await saveConversation(
           resolvedConversationId,
           userMessage,
           targetBuffer.messages[aiMessageIndex],
           lastDoneUsage
         )
+        if (savedMessages) {
+          Object.assign(userMessage, savedMessages.userMessage)
+          targetBuffer.messages[aiMessageIndex] = {
+            ...targetBuffer.messages[aiMessageIndex],
+            ...savedMessages.assistantMessage,
+            isStreaming: false,
+          }
+        }
       }
 
       return { success: true }
@@ -1027,17 +1065,17 @@ export const useAIChatStore = defineStore('aiChatRuntime', () => {
     userMsg: ChatMessage,
     aiMsg: ChatMessage,
     tokenUsage?: TokenUsage
-  ): Promise<void> {
+  ): Promise<{ userMessage: ChatMessage; assistantMessage: ChatMessage } | null> {
     try {
       if (!conversationId) {
-        return
+        return null
       }
 
-      await useAIService().addMessage(conversationId, 'user', userMsg.content)
+      const savedUserMessage = await useAIService().addMessage(conversationId, 'user', userMsg.content)
       const serializableContentBlocks = aiMsg.contentBlocks
         ? JSON.parse(JSON.stringify(aiMsg.contentBlocks))
         : undefined
-      await useAIService().addMessage(
+      const savedAssistantMessage = await useAIService().addMessage(
         conversationId,
         'assistant',
         aiMsg.content,
@@ -1046,8 +1084,441 @@ export const useAIChatStore = defineStore('aiChatRuntime', () => {
         serializableContentBlocks,
         tokenUsage
       )
+      return {
+        userMessage: toRuntimeMessage(savedUserMessage),
+        assistantMessage: toRuntimeMessage(savedAssistantMessage),
+      }
     } catch (error) {
       console.error('[AI] 保存对话失败：', error)
+      return null
+    }
+  }
+
+  function buildSerializablePreprocessConfig() {
+    const preprocessConfig = settingsStore.aiPreprocessConfig
+    const hasPreprocess =
+      preprocessConfig.dataCleaning ||
+      preprocessConfig.mergeConsecutive ||
+      preprocessConfig.blacklistKeywords.length > 0 ||
+      preprocessConfig.denoise ||
+      preprocessConfig.desensitize ||
+      preprocessConfig.anonymizeNames
+
+    if (!hasPreprocess) return undefined
+    return {
+      dataCleaning: preprocessConfig.dataCleaning,
+      mergeConsecutive: preprocessConfig.mergeConsecutive,
+      mergeWindowSeconds: preprocessConfig.mergeWindowSeconds,
+      blacklistKeywords: [...preprocessConfig.blacklistKeywords],
+      denoise: preprocessConfig.denoise,
+      desensitize: preprocessConfig.desensitize,
+      desensitizeRules: preprocessConfig.desensitizeRules.map((rule) => ({
+        ...rule,
+        locales: [...rule.locales],
+      })),
+      anonymizeNames: preprocessConfig.anonymizeNames,
+    }
+  }
+
+  function normalizeMentionLookupText(value: string): string {
+    return value
+      .trim()
+      .replace(/^[\s"'“”‘’([{<]+|[\s"'“”‘’)\]}>.,!?;:，。！？；：、]+$/g, '')
+      .toLocaleLowerCase()
+  }
+
+  async function resolveMentionedMembersFromContent(
+    state: AIChatSessionState,
+    content: string
+  ): Promise<MentionedMemberContext[]> {
+    const mentionTokens = new Set<string>()
+    for (const match of content.matchAll(/@([^\s@]+)/g)) {
+      const token = normalizeMentionLookupText(match[1] ?? '')
+      if (token) {
+        mentionTokens.add(token)
+      }
+    }
+
+    if (mentionTokens.size === 0) {
+      return []
+    }
+
+    try {
+      const members = await useDataService().getMembers(state.sessionId)
+      const displayNameCounts = new Map<string, number>()
+      members.forEach((member) => {
+        const displayName = member.groupNickname || member.accountName || member.platformId
+        displayNameCounts.set(displayName, (displayNameCounts.get(displayName) ?? 0) + 1)
+      })
+
+      const candidates = members.map((member) => {
+        const displayName = member.groupNickname || member.accountName || member.platformId
+        const insertName =
+          (displayNameCounts.get(displayName) ?? 0) > 1 ? `${displayName}·${member.platformId}` : displayName
+        const aliases = [...member.aliases]
+        const lookupValues = [
+          displayName,
+          member.groupNickname || '',
+          member.accountName || '',
+          member.platformId,
+          insertName,
+          ...aliases,
+        ]
+          .map(normalizeMentionLookupText)
+          .filter(Boolean)
+
+        return {
+          memberId: member.id,
+          platformId: member.platformId,
+          displayName,
+          aliases,
+          mentionText: `@${insertName}`,
+          lookupValues,
+        }
+      })
+
+      const selected: MentionedMemberContext[] = []
+      const selectedIds = new Set<number>()
+      for (const token of mentionTokens) {
+        const candidate = candidates.find(
+          (item) => !selectedIds.has(item.memberId) && item.lookupValues.includes(token)
+        )
+        if (!candidate) continue
+
+        selectedIds.add(candidate.memberId)
+        selected.push({
+          memberId: candidate.memberId,
+          platformId: candidate.platformId,
+          displayName: candidate.displayName,
+          aliases: candidate.aliases,
+          mentionText: candidate.mentionText,
+        })
+      }
+
+      return selected
+    } catch (error) {
+      console.error('[AI] Failed to resolve mentioned members for edited message:', error)
+      return []
+    }
+  }
+
+  async function editMessageAndRegenerate(
+    chatKey: string,
+    messageId: string,
+    newContent: string
+  ): Promise<SendMessageResult> {
+    const state = getSessionState(chatKey)
+    const content = newContent.trim()
+    if (!state || !state.currentConversationId) return { success: false, reason: 'error' }
+    if (!content) return { success: false, reason: 'empty' }
+    if (state.isAIThinking || activeTask.value) {
+      return { success: false, reason: 'busy', activeTask: activeTask.value }
+    }
+
+    const targetBuffer = getOrCreateBuffer(state, state.currentConversationId, state.selectedAssistantId)
+    const editIndex = targetBuffer.messages.findIndex((message) => message.id === messageId)
+    const originalMessage = targetBuffer.messages[editIndex]
+    if (!originalMessage || originalMessage.role !== 'user' || originalMessage.isStreaming) {
+      return { success: false, reason: 'error' }
+    }
+    if (originalMessage.content.trim() === content) {
+      return { success: false, reason: 'empty' }
+    }
+
+    const thisRequestId = generateId('req')
+    let lastDoneUsage: TokenUsage | undefined
+    let hasStreamError = false
+
+    setActiveTaskMeta(chatKey, content, thisRequestId, state.currentConversationId)
+    applySessionAssistantSelection(chatKey)
+    void ensureOwnerInfo(chatKey)
+
+    state.isAIThinking = true
+    state.isLoadingSource = true
+    state.currentToolStatus = null
+    state.toolsUsedInCurrentRound = []
+    state.agentStatus = null
+    state.isAborted = false
+    state.currentRequestId = thisRequestId
+    state.currentAgentRequestId = ''
+
+    const userMessage: ChatMessage = {
+      id: generateId('user'),
+      role: 'user',
+      content,
+      timestamp: Date.now(),
+      parentId: originalMessage.parentId ?? null,
+      toolCalls: [],
+    }
+    const aiMessage: ChatMessage = {
+      id: generateId('ai'),
+      role: 'assistant',
+      content: '',
+      timestamp: Date.now(),
+      isStreaming: true,
+      contentBlocks: [],
+    }
+
+    const currentSkillId = skillStore.activeSkillId
+    const currentSkillName = skillStore.activeSkill?.name
+    if (currentSkillId && currentSkillName) {
+      aiMessage.contentBlocks!.push({ type: 'skill', skillId: currentSkillId, skillName: currentSkillName })
+    }
+
+    const previousTail = targetBuffer.messages.slice(editIndex)
+    targetBuffer.messages.splice(editIndex, targetBuffer.messages.length - editIndex, userMessage, aiMessage)
+    const aiMessageIndex = editIndex + 1
+    const restorePreviousTail = () => {
+      targetBuffer.messages.splice(editIndex, targetBuffer.messages.length - editIndex, ...previousTail)
+    }
+
+    const updateAIMessage = (updates: Partial<ChatMessage>) => {
+      targetBuffer.messages[aiMessageIndex] = {
+        ...targetBuffer.messages[aiMessageIndex],
+        ...updates,
+      }
+    }
+
+    const appendTextToBlocks = (text: string) => {
+      if (!text) return
+      const blocks = targetBuffer.messages[aiMessageIndex].contentBlocks || []
+      const lastBlock = blocks[blocks.length - 1]
+      if (text.trim().length === 0 && (!lastBlock || lastBlock.type !== 'text')) return
+      if (lastBlock && lastBlock.type === 'text') {
+        lastBlock.text += text
+      } else {
+        blocks.push({ type: 'text', text })
+      }
+      updateAIMessage({
+        contentBlocks: [...blocks],
+        content: targetBuffer.messages[aiMessageIndex].content + text,
+      })
+    }
+
+    const appendThinkToBlocks = (text: string, tag?: string, durationMs?: number) => {
+      if (!text && durationMs === undefined) return
+      const blocks = targetBuffer.messages[aiMessageIndex].contentBlocks || []
+      const thinkTag = tag || 'think'
+      const lastBlock = blocks[blocks.length - 1]
+      let targetBlock: ContentBlock | undefined = lastBlock
+      if (lastBlock && lastBlock.type === 'think' && lastBlock.tag === thinkTag) {
+        lastBlock.text += text
+      } else if (text.trim().length > 0) {
+        targetBlock = { type: 'think', tag: thinkTag, text }
+        blocks.push(targetBlock)
+      } else if (durationMs !== undefined) {
+        targetBlock = [...blocks].reverse().find((block) => block.type === 'think' && block.tag === thinkTag)
+      }
+      if (durationMs !== undefined && targetBlock && targetBlock.type === 'think') {
+        targetBlock.durationMs = durationMs
+      }
+      updateAIMessage({ contentBlocks: [...blocks] })
+    }
+
+    const addToolBlock = (toolName: string, params?: Record<string, unknown>) => {
+      const blocks = targetBuffer.messages[aiMessageIndex].contentBlocks || []
+      blocks.push({
+        type: 'tool',
+        tool: { name: toolName, displayName: toolName, status: 'running', params },
+      })
+      updateAIMessage({ contentBlocks: [...blocks] })
+    }
+
+    const updateToolBlockStatus = (toolName: string, status: 'done' | 'error') => {
+      const blocks = targetBuffer.messages[aiMessageIndex].contentBlocks || []
+      for (let index = blocks.length - 1; index >= 0; index--) {
+        const block = blocks[index]
+        if (block.type === 'tool' && block.tool.name === toolName && block.tool.status === 'running') {
+          block.tool.status = status
+          break
+        }
+      }
+      updateAIMessage({ contentBlocks: [...blocks] })
+    }
+
+    try {
+      const hasConfig = await window.llmApi.hasConfig()
+      if (!hasConfig) {
+        restorePreviousTail()
+        clearActiveTask(chatKey, thisRequestId)
+        return { success: false, reason: 'no_config' }
+      }
+
+      const currentAssistantId = targetBuffer.assistantId ?? getDefaultGeneralAssistantId(state.locale)
+      const currentMentionedMembers = await resolveMentionedMembersFromContent(state, content)
+      if (state.isAborted) {
+        restorePreviousTail()
+        clearActiveTask(chatKey, thisRequestId)
+        return { success: false, reason: 'aborted' }
+      }
+      if (thisRequestId !== state.currentRequestId) {
+        restorePreviousTail()
+        clearActiveTask(chatKey, thisRequestId)
+        return { success: false, reason: 'busy', activeTask: activeTask.value }
+      }
+
+      const context = {
+        sessionId: state.sessionId,
+        conversationId: state.currentConversationId,
+        historyLeafMessageId: originalMessage.parentId ?? null,
+        timeFilter: state.timeFilter ? { startTs: state.timeFilter.startTs, endTs: state.timeFilter.endTs } : undefined,
+        maxMessagesLimit: aiGlobalSettings.value.maxMessagesPerRequest,
+        ownerInfo: state.ownerInfo
+          ? { platformId: state.ownerInfo.platformId, displayName: state.ownerInfo.displayName }
+          : undefined,
+        mentionedMembers: currentMentionedMembers.length > 0 ? currentMentionedMembers : undefined,
+        preprocessConfig: buildSerializablePreprocessConfig(),
+        searchContextBefore: aiGlobalSettings.value.searchContextBefore,
+        searchContextAfter: aiGlobalSettings.value.searchContextAfter,
+      }
+
+      const { requestId: agentReqId, promise: agentPromise } = window.agentApi.runStream(
+        content,
+        context,
+        (chunk) => {
+          if (state.isAborted || thisRequestId !== state.currentRequestId) return
+          switch (chunk.type) {
+            case 'content':
+              state.currentToolStatus = null
+              appendTextToBlocks(chunk.content || '')
+              break
+            case 'think':
+              if (chunk.content) appendThinkToBlocks(chunk.content, chunk.thinkTag)
+              else if (chunk.thinkDurationMs !== undefined)
+                appendThinkToBlocks('', chunk.thinkTag, chunk.thinkDurationMs)
+              break
+            case 'tool_start':
+              if (chunk.toolName) {
+                state.currentToolStatus = { name: chunk.toolName, displayName: chunk.toolName, status: 'running' }
+                state.toolsUsedInCurrentRound.push(chunk.toolName)
+                addToolBlock(chunk.toolName, chunk.toolParams as Record<string, unknown> | undefined)
+              }
+              break
+            case 'tool_result':
+              if (chunk.toolName) updateToolBlockStatus(chunk.toolName, 'done')
+              state.currentToolStatus = null
+              state.isLoadingSource = false
+              break
+            case 'status':
+              if (chunk.status && (!state.agentStatus || chunk.status.updatedAt >= state.agentStatus.updatedAt)) {
+                state.agentStatus = chunk.status
+              }
+              break
+            case 'done':
+              state.currentToolStatus = null
+              if (chunk.usage) lastDoneUsage = { ...chunk.usage }
+              setAgentPhase(state, 'completed', chunk.usage ? { totalUsage: chunk.usage } : undefined)
+              break
+            case 'error': {
+              hasStreamError = true
+              if (state.currentToolStatus) updateToolBlockStatus(state.currentToolStatus.name, 'error')
+              const blocks = targetBuffer.messages[aiMessageIndex].contentBlocks || []
+              blocks.push({ type: 'error', error: chunk.error || { name: null, message: '未知错误', stack: null } })
+              updateAIMessage({ contentBlocks: [...blocks], isStreaming: false })
+              setAgentPhase(state, 'error')
+              break
+            }
+          }
+        },
+        state.chatType,
+        state.locale,
+        currentAssistantId,
+        currentSkillId,
+        !currentSkillId ? (aiGlobalSettings.value.enableAutoSkill ?? true) : undefined,
+        { enabled: false, tokenThresholdPercent: 75, bufferSizePercent: 20 }
+      )
+
+      state.currentAgentRequestId = agentReqId
+      setActiveTaskMeta(chatKey, content, agentReqId, state.currentConversationId)
+
+      const result = await agentPromise
+      if (state.isAborted) {
+        restorePreviousTail()
+        clearActiveTask(chatKey, agentReqId)
+        return { success: false, reason: 'aborted' }
+      }
+      if (thisRequestId !== state.currentRequestId) {
+        restorePreviousTail()
+        clearActiveTask(chatKey, agentReqId)
+        return { success: false, reason: 'busy', activeTask: activeTask.value }
+      }
+
+      if (result.success && result.result) {
+        updateAIMessage({
+          dataSource: { toolsUsed: result.result.toolsUsed, toolRounds: result.result.toolRounds },
+          isStreaming: false,
+        })
+      } else if (!hasStreamError) {
+        const blocks = targetBuffer.messages[aiMessageIndex].contentBlocks || []
+        blocks.push({ type: 'error', error: result.error || { name: null, message: '未知错误', stack: null } })
+        updateAIMessage({ contentBlocks: [...blocks], isStreaming: false })
+      }
+
+      const serializableContentBlocks = targetBuffer.messages[aiMessageIndex].contentBlocks
+        ? JSON.parse(JSON.stringify(targetBuffer.messages[aiMessageIndex].contentBlocks))
+        : undefined
+      const branch = await useAIService().createMessageBranch(
+        messageId,
+        userMessage.content,
+        targetBuffer.messages[aiMessageIndex].content,
+        serializableContentBlocks,
+        lastDoneUsage
+      )
+      targetBuffer.messages.splice(
+        editIndex,
+        targetBuffer.messages.length - editIndex,
+        toRuntimeMessage(branch.userMessage),
+        {
+          ...toRuntimeMessage(branch.assistantMessage),
+          dataSource: targetBuffer.messages[aiMessageIndex].dataSource,
+          isStreaming: false,
+        }
+      )
+      targetBuffer.sessionTokenUsage = await useAIService().getConversationTokenUsage(state.currentConversationId)
+      state.sessionTokenUsage = { ...targetBuffer.sessionTokenUsage }
+      return { success: true }
+    } catch (error) {
+      if (state.isAborted) {
+        restorePreviousTail()
+        return { success: false, reason: 'aborted' }
+      }
+      console.error('[AI] 编辑并重新生成失败：', error)
+      const blocks = targetBuffer.messages[aiMessageIndex].contentBlocks || []
+      blocks.push({
+        type: 'error',
+        error: {
+          name: error instanceof Error ? error.name : null,
+          message: error instanceof Error ? error.message : String(error),
+          stack: error instanceof Error ? (error.stack ?? null) : null,
+        },
+      })
+      updateAIMessage({ contentBlocks: [...blocks], isStreaming: false })
+      return { success: false, reason: 'error' }
+    } finally {
+      state.isAIThinking = false
+      state.isLoadingSource = false
+      state.currentToolStatus = null
+      state.isAborted = false
+      state.currentRequestId = ''
+      state.currentAgentRequestId = ''
+      clearActiveTask(chatKey)
+    }
+  }
+
+  async function switchMessageBranch(chatKey: string, messageId: string): Promise<boolean> {
+    const state = getSessionState(chatKey)
+    if (!state?.currentConversationId || state.isAIThinking || activeTask.value) return false
+    const buffer = getOrCreateBuffer(state, state.currentConversationId, state.selectedAssistantId)
+    try {
+      const messages = await useAIService().switchMessageBranch(state.currentConversationId, messageId)
+      const tokenUsage = await useAIService().getConversationTokenUsage(state.currentConversationId)
+      buffer.messages.splice(0, buffer.messages.length, ...messages.map((message) => toRuntimeMessage(message)))
+      buffer.sessionTokenUsage = tokenUsage
+      state.sessionTokenUsage = { ...tokenUsage }
+      return true
+    } catch (error) {
+      console.error('[AI] 切换消息分支失败：', error)
+      return false
     }
   }
 
@@ -1108,6 +1579,8 @@ export const useAIChatStore = defineStore('aiChatRuntime', () => {
     loadMoreSourceMessages,
     updateMaxMessages,
     sendMessage,
+    editMessageAndRegenerate,
+    switchMessageBranch,
     stopGeneration,
     stopActiveTask,
   }