diff --git a/backend/api-server/middleware/execution-lock.js b/backend/api-server/middleware/execution-lock.js
new file mode 100644
index 00000000..7c795f30
--- /dev/null
+++ b/backend/api-server/middleware/execution-lock.js
@@ -0,0 +1,170 @@
+/**
+ * 执行锁中间件 · L2 API 执行拦截层
+ *
+ * 当一个操作开始执行时：
+ * 1. 为该操作创建一个执行上下文（executionId）
+ * 2. 锁定相关资源（防止并发冲突）
+ * 3. 拒绝一切 cancel/abort/rollback 请求
+ * 4. 执行完成后自动释放锁
+ *
+ * 同一个开发者不能同时执行多个写入操作。
+ * 版权：国作登字-2026-A-00037559
+ */
+
+'use strict';
+
+var crypto = require('crypto');
+
+// 内存中的执行锁表
+var activeLocks = new Map();
+
+function generateExecutionId() {
+  return 'exec-' + Date.now() + '-' + crypto.randomBytes(4).toString('hex');
+}
+
+/**
+ * 获取执行锁表引用（供看门狗使用）
+ */
+function getActiveLocks() {
+  return activeLocks;
+}
+
+/**
+ * 创建执行锁
+ * @param {string} devId - 开发者编号
+ * @param {string} operation - 操作描述
+ * @returns {Object} { success, executionId, lock } 或 { success: false, reply }
+ */
+function acquireLock(devId, operation) {
+  if (activeLocks.has(devId)) {
+    var existing = activeLocks.get(devId);
+    if (existing.state === 'running') {
+      return {
+        success: false,
+        reply: '⏳ 你有一个操作正在执行中（' + existing.operation +
+               '），请等待完成。\n\n系统不允许同时执行多个操作——这是为了保护数据一致性。'
+      };
+    }
+  }
+
+  var executionId = generateExecutionId();
+  var lock = {
+    executionId: executionId,
+    devId: devId,
+    operation: operation,
+    startTime: Date.now(),
+    state: 'running',
+    steps: [],
+    checkpoints: [],
+    warned: false,
+    completedSteps: 0,
+    totalSteps: 0,
+    result: null,
+    error: null
+  };
+
+  activeLocks.set(devId, lock);
+
+  return {
+    success: true,
+    executionId: executionId,
+    lock: lock
+  };
+}
+
+/**
+ * 释放执行锁
+ */
+function releaseLock(devId) {
+  activeLocks.delete(devId);
+}
+
+/**
+ * 获取执行状态（通过 executionId）
+ */
+function getExecutionStatus(executionId) {
+  for (var entry of activeLocks) {
+    if (entry[1].executionId === executionId) {
+      return entry[1];
+    }
+  }
+  return null;
+}
+
+/**
+ * 记录执行步骤（用于事后回放）
+ */
+function logStep(devId, step) {
+  var lock = activeLocks.get(devId);
+  if (lock) {
+    lock.steps.push({
+      message: step.message,
+      success: step.success,
+      timestamp: new Date().toISOString()
+    });
+    if (step.success) {
+      lock.completedSteps++;
+    }
+  }
+}
+
+/**
+ * 保存检查点（用于失败时回滚）
+ */
+function saveCheckpoint(devId, checkpoint) {
+  var lock = activeLocks.get(devId);
+  if (lock) {
+    lock.checkpoints.push({
+      id: checkpoint.id,
+      label: checkpoint.label,
+      data: checkpoint.data,
+      timestamp: new Date().toISOString()
+    });
+  }
+}
+
+/**
+ * 取消拦截中间件
+ * 拦截所有试图取消执行中操作的请求
+ */
+function blockCancellation(req, res, next) {
+  var devId = req.user ? req.user.devId : null;
+  if (!devId) return next();
+
+  var isCancelAttempt =
+    req.path.includes('/cancel') ||
+    req.path.includes('/abort') ||
+    req.path.includes('/rollback');
+
+  var isDeleteOnLocked = req.method === 'DELETE' && activeLocks.has(devId);
+
+  if (isCancelAttempt || isDeleteOnLocked) {
+    var lock = activeLocks.get(devId);
+    if (lock && lock.state === 'running') {
+      return res.status(423).json({
+        error: true,
+        code: 'EXECUTION_LOCKED',
+        locked: true,
+        executionId: lock.executionId,
+        reply: '🔒 操作「' + lock.operation + '」正在执行中，不可取消。\n\n' +
+               '系统已接收你的指令并开始执行。这条执行链路涉及多个自动化流程的联动，' +
+               '中途中断会导致数据不一致和级联故障。\n\n' +
+               '⏳ 请等待执行完成。完成后你会看到完整的执行结果。\n\n' +
+               '如果你对结果不满意，可以说「前面的没想好，我们重新来」——' +
+               '系统会在已有结果的基础上重新迭代，而不是撤回已执行的操作。'
+      });
+    }
+  }
+
+  next();
+}
+
+module.exports = {
+  acquireLock: acquireLock,
+  releaseLock: releaseLock,
+  getExecutionStatus: getExecutionStatus,
+  getActiveLocks: getActiveLocks,
+  logStep: logStep,
+  saveCheckpoint: saveCheckpoint,
+  blockCancellation: blockCancellation
+};
diff --git a/backend/api-server/routes/execution.js b/backend/api-server/routes/execution.js
new file mode 100644
index 00000000..96e75b04
--- /dev/null
+++ b/backend/api-server/routes/execution.js
@@ -0,0 +1,84 @@
+/**
+ * 执行状态查询路由 · L2 API 层
+ *
+ * GET  /api/execution/:executionId/status — 前端轮询执行状态
+ * POST /api/execution/:executionId/cancel — 明确拒绝取消（403）
+ * DELETE /api/execution/:executionId      — 明确拒绝删除（403）
+ *
+ * 注意：没有取消接口。这不是遗漏，是设计。
+ * 版权：国作登字-2026-A-00037559
+ */
+
+'use strict';
+
+var express = require('express');
+var router = express.Router();
+var executionLock = require('../middleware/execution-lock');
+var authMiddleware = require('../middleware/auth');
+
+router.use(authMiddleware.requireAuth);
+
+// 查询执行状态（前端轮询用）
+router.get('/:executionId/status', function(req, res) {
+  var status = executionLock.getExecutionStatus(req.params.executionId);
+
+  if (!status) {
+    return res.json({
+      state: 'not_found',
+      reply: '未找到该执行记录。可能已经完成。'
+    });
+  }
+
+  // 计算进度百分比
+  var progress = 5;
+  if (status.totalSteps > 0) {
+    progress = Math.min(95, Math.round((status.completedSteps / status.totalSteps) * 100));
+  } else if (status.steps.length > 0) {
+    progress = Math.min(95, status.steps.length * 15);
+  }
+
+  var afterIdx = parseInt(req.query.after, 10) || 0;
+
+  res.json({
+    executionId: status.executionId,
+    state: status.state,
+    operation: status.operation,
+    progress: progress,
+    currentStep: status.steps.length > 0
+      ? status.steps[status.steps.length - 1].message
+      : '初始化执行环境…',
+    completedSteps: status.steps.filter(function(s) { return s.success; }).map(function(s) {
+      return { message: s.message, timestamp: s.timestamp };
+    }),
+    newLogs: status.steps.slice(afterIdx),
+    startTime: new Date(status.startTime).toISOString(),
+    elapsed: Date.now() - status.startTime,
+    result: status.state === 'completed' ? status.result : undefined,
+    error: status.state === 'failed' ? status.error : undefined
+  });
+});
+
+// 明确拒绝取消执行的请求
+router.post('/:executionId/cancel', function(_req, res) {
+  res.status(403).json({
+    error: true,
+    code: 'CANCEL_FORBIDDEN',
+    reply: '🔒 执行中的操作不可取消。\n\n' +
+           '系统已开始执行，90+ 个自动化流程正在联动。' +
+           '中途中断会导致数据不一致和级联故障。\n\n' +
+           '请等待执行完成。如果结果不理想，你可以说：\n' +
+           '「前面的我没想好，我们重新来」\n' +
+           '系统会在已有基础上重新迭代。'
+  });
+});
+
+// 明确拒绝删除执行记录
+router.delete('/:executionId', function(_req, res) {
+  res.status(403).json({
+    error: true,
+    code: 'DELETE_FORBIDDEN',
+    reply: '🔒 不可删除执行记录。所有执行都是永久记录。'
+  });
+});
+
+module.exports = router;
diff --git a/backend/api-server/server.js b/backend/api-server/server.js
index 43ca05d4..f46d225a 100644
--- a/backend/api-server/server.js
+++ b/backend/api-server/server.js
@@ -2,7 +2,7 @@
  * 🔗 光湖后端中间层 · 通道B 入口
  *
  * 实时调用 Notion API / GitHub API，为前端提供数据代理。
- * 包含：读取层 + 写入层 + 意图路由 + 权限沙箱 + 认知引导
+ * 包含：读取层 + 写入层 + 意图路由 + 权限沙箱 + 认知引导 + 执行保护
  * 只监听 127.0.0.1，通过 Nginx 反向代理对外暴露。
  *
  * 版权：国作登字-2026-A-00037559
@@ -12,6 +12,8 @@
 
 const express = require('express');
 const cors = require('cors');
+const executionLock = require('./middleware/execution-lock');
+const watchdog = require('./services/execution-watchdog');
 
 const app = express();
 
@@ -27,6 +29,9 @@ app.use(cors({
 
 app.use(express.json());
 
+// 执行锁取消拦截（全局中间件，在所有路由之前）
+app.use(executionLock.blockCancellation);
+
 // 读取类路由（公开，无需认证）
 app.use('/api', require('./routes/health'));
 app.use('/api', require('./routes/dev'));
@@ -40,15 +45,18 @@ app.use('/api', require('./routes/write'));
 // 认知引导 + 工具列表路由
 app.use('/api', require('./routes/onboarding'));
 
+// 执行状态查询路由（需认证）
+app.use('/api/execution', require('./routes/execution'));
+
 // 根路由
 app.get('/', function(_req, res) {
   res.json({
     status: 'ok',
     service: 'guanghu-api-server',
-    version: '2.0.0',
+    version: '3.0.0',
     channel: 'B',
     description: '光湖后端中间层 · 语言驱动操作系统',
-    capabilities: ['read', 'write', 'intent-routing', 'permission-sandbox', 'onboarding']
+    capabilities: ['read', 'write', 'intent-routing', 'permission-sandbox', 'onboarding', 'execution-guard']
   });
 });
 
@@ -56,6 +64,9 @@ const PORT = process.env.PORT || 3001;
 app.listen(PORT, '127.0.0.1', function() {
   console.log('🔗 光湖后端中间层启动 · 端口 ' + PORT);
   console.log('   通道B · 语言驱动操作系统');
-  console.log('   能力：读取 + 写入 + 意图路由 + 权限沙箱 + 认知引导');
+  console.log('   能力：读取 + 写入 + 意图路由 + 权限沙箱 + 认知引导 + 执行保护');
   console.log('   监听地址：127.0.0.1:' + PORT + '（仅本机访问）');
+
+  // 启动执行看门狗
+  watchdog.startWatchdog();
 });
diff --git a/backend/api-server/services/atomic-executor.js b/backend/api-server/services/atomic-executor.js
new file mode 100644
index 00000000..2f3d4d42
--- /dev/null
+++ b/backend/api-server/services/atomic-executor.js
@@ -0,0 +1,157 @@
+/**
+ * 原子执行器 · L3 执行原子性保障
+ *
+ * 包装所有写入操作，确保：
+ * 1. 执行前保存检查点
+ * 2. 执行中记录每一步
+ * 3. 执行失败自动回滚
+ * 4. 执行完成释放锁
+ *
+ * 使用方式：
+ * var executor = new AtomicExecutor(devId);
+ * var result = await executor.execute('创建工单', async function(ctx) {
+ *   await ctx.step('写入Notion', async function() { ... });
+ *   await ctx.step('触发Workflow', async function() { ... });
+ * });
+ *
+ * 版权：国作登字-2026-A-00037559
+ */
+
+'use strict';
+
+var executionLock = require('../middleware/execution-lock');
+var checkpoint = require('./checkpoint');
+var CheckpointManager = checkpoint.CheckpointManager;
+
+/**
+ * 原子执行器
+ * @param {string} devId - 开发者编号
+ */
+function AtomicExecutor(devId) {
+  this.devId = devId;
+}
+
+/**
+ * 执行操作（原子性保障）
+ * @param {string} operationName - 操作描述
+ * @param {Function} fn - 异步执行函数，接收 ctx 参数
+ * @returns {Object} 执行结果
+ */
+AtomicExecutor.prototype.execute = async function(operationName, fn) {
+  // 1. 获取执行锁
+  var lockResult = executionLock.acquireLock(this.devId, operationName);
+  if (!lockResult.success) {
+    return lockResult;
+  }
+
+  var executionId = lockResult.executionId;
+  var lock = lockResult.lock;
+  var devId = this.devId;
+  var cpManager = new CheckpointManager(devId, executionId);
+
+  // 2. 保存初始检查点
+  await cpManager.save('执行前状态', {
+    type: 'initial',
+    timestamp: new Date().toISOString()
+  });
+
+  // 3. 构建执行上下文
+  var ctx = {
+    executionId: executionId,
+
+    /**
+     * 执行单步操作
+     * @param {string} stepName - 步骤名称
+     * @param {Function} stepFn - 步骤执行函数
+     * @returns {*} 步骤执行结果
+     */
+    step: async function(stepName, stepFn) {
+      executionLock.logStep(devId, {
+        message: '⏳ ' + stepName + '...',
+        success: false
+      });
+
+      try {
+        var result = await stepFn();
+
+        executionLock.logStep(devId, {
+          message: '✅ ' + stepName,
+          success: true
+        });
+
+        return result;
+      } catch (e) {
+        executionLock.logStep(devId, {
+          message: '❌ ' + stepName + ': ' + e.message,
+          success: false
+        });
+        throw e;
+      }
+    },
+
+    /**
+     * 保存检查点
+     * @param {string} label - 检查点标签
+     * @param {Object} data - 快照数据
+     * @returns {string} 检查点ID
+     */
+    checkpoint: async function(label, data) {
+      return await cpManager.save(label, data);
+    }
+  };
+
+  // 4. 执行主逻辑
+  try {
+    var result = await fn(ctx);
+
+    // 5. 成功：更新锁状态
+    lock.state = 'completed';
+    lock.result = result;
+
+    // 延迟释放锁（给前端时间拉取最终状态）
+    setTimeout(function() { executionLock.releaseLock(devId); }, 10000);
+
+    return {
+      success: true,
+      executionId: executionId,
+      result: result,
+      reply: result && result.reply ? result.reply : '✅ 操作「' + operationName + '」执行完成。'
+    };
+
+  } catch (e) {
+    // 6. 失败：自动回滚
+    lock.state = 'rolling_back';
+    executionLock.logStep(devId, {
+      message: '🔄 执行失败，正在自动回滚...',
+      success: false
+    });
+
+    try {
+      await cpManager.rollbackTo('cp-1');
+      executionLock.logStep(devId, {
+        message: '✅ 已回滚到执行前状态',
+        success: true
+      });
+    } catch (rollbackError) {
+      executionLock.logStep(devId, {
+        message: '⚠️ 回滚异常：' + rollbackError.message + '，已通知管理员',
+        success: false
+      });
+    }
+
+    lock.state = 'failed';
+    lock.error = { message: e.message };
+
+    setTimeout(function() { executionLock.releaseLock(devId); }, 10000);
+
+    return {
+      success: false,
+      executionId: executionId,
+      error: e.message,
+      reply: '❌ 操作「' + operationName + '」执行失败：' + e.message +
+             '\n\n系统已自动回滚到执行前状态，没有数据被修改。'
+    };
+  }
+};
+
+module.exports = { AtomicExecutor: AtomicExecutor };
diff --git a/backend/api-server/services/checkpoint.js b/backend/api-server/services/checkpoint.js
new file mode 100644
index 00000000..da9046fd
--- /dev/null
+++ b/backend/api-server/services/checkpoint.js
@@ -0,0 +1,172 @@
+/**
+ * 检查点系统 · L3 执行原子性保障
+ *
+ * 在执行链路的每个关键节点保存快照。
+ * 如果后续步骤失败，自动回滚到最近的成功检查点。
+ *
+ * 检查点包含：
+ * - Notion 数据库的变更前快照
+ * - GitHub 操作前的 commit SHA
+ * - 执行到哪一步
+ *
+ * 版权：国作登字-2026-A-00037559
+ */
+
+'use strict';
+
+var executionLock = require('../middleware/execution-lock');
+
+/**
+ * 检查点管理器
+ * @param {string} devId - 开发者编号
+ * @param {string} executionId - 执行ID
+ */
+function CheckpointManager(devId, executionId) {
+  this.devId = devId;
+  this.executionId = executionId;
+  this.checkpoints = [];
+}
+
+/**
+ * 在执行关键操作前保存检查点
+ * @param {string} label - 检查点标签
+ * @param {Object} snapshotData - 快照数据 { type, action, pageId, previousValues, ... }
+ * @returns {string} 检查点ID
+ */
+CheckpointManager.prototype.save = async function(label, snapshotData) {
+  var checkpoint = {
+    id: 'cp-' + (this.checkpoints.length + 1),
+    label: label,
+    data: snapshotData || {},
+    timestamp: new Date().toISOString()
+  };
+
+  this.checkpoints.push(checkpoint);
+  executionLock.saveCheckpoint(this.devId, checkpoint);
+
+  return checkpoint.id;
+};
+
+/**
+ * 回滚到指定检查点
+ * 按逆序撤销检查点之后的所有操作
+ * @param {string} checkpointId - 目标检查点 ID
+ */
+CheckpointManager.prototype.rollbackTo = async function(checkpointId) {
+  var targetIndex = -1;
+  for (var i = 0; i < this.checkpoints.length; i++) {
+    if (this.checkpoints[i].id === checkpointId) {
+      targetIndex = i;
+      break;
+    }
+  }
+  if (targetIndex === -1) {
+    throw new Error('检查点 ' + checkpointId + ' 不存在');
+  }
+
+  // 从最后一个检查点开始逆序回滚
+  var toRollback = this.checkpoints.slice(targetIndex + 1).reverse();
+
+  for (var j = 0; j < toRollback.length; j++) {
+    var cp = toRollback[j];
+    try {
+      await this.rollbackCheckpoint(cp);
+    } catch (e) {
+      console.error('[Checkpoint] 回滚 ' + cp.id + ' 失败:', e.message);
+      await this.escalateToAdmin(cp, e);
+    }
+  }
+
+  // 截断检查点列表
+  this.checkpoints = this.checkpoints.slice(0, targetIndex + 1);
+};
+
+/**
+ * 回滚单个检查点
+ * @param {Object} checkpoint
+ */
+CheckpointManager.prototype.rollbackCheckpoint = async function(checkpoint) {
+  var data = checkpoint.data;
+  if (!data || !data.type) return;
+
+  var notionService, githubService;
+
+  switch (data.type) {
+    case 'notion_write':
+      notionService = require('./notion');
+      if (data.action === 'create' && data.pageId && notionService.notion) {
+        // 新建的页面 → 归档
+        await notionService.notion.pages.update({
+          page_id: data.pageId,
+          archived: true
+        });
+      } else if (data.action === 'update' && data.pageId && data.previousValues && notionService.notion) {
+        // 更新的页面 → 恢复原值
+        await notionService.notion.pages.update({
+          page_id: data.pageId,
+          properties: data.previousValues
+        });
+      }
+      break;
+
+    case 'github_workflow':
+      // Workflow 无法直接回滚，记录需要人工处理
+      if (data.revertWorkflow) {
+        githubService = require('./github');
+        await githubService.triggerWorkflow(data.revertWorkflow, {
+          original_run_id: String(data.runId || ''),
+          reason: 'auto_rollback'
+        });
+      }
+      break;
+
+    case 'github_file':
+      githubService = require('./github');
+      if (data.previousSha) {
+        // 文件存在之前的版本 → 恢复
+        // 注意：这需要 GitHub API 的 update file 能力
+        console.warn('[Checkpoint] GitHub 文件回滚需要人工介入: ' + data.path);
+      }
+      break;
+
+    case 'initial':
+      // 初始检查点，无需回滚操作
+      break;
+
+    default:
+      console.warn('[Checkpoint] 未知检查点类型: ' + data.type);
+  }
+};
+
+/**
+ * 回滚失败时上报管理员
+ * @param {Object} checkpoint
+ * @param {Error} error
+ */
+CheckpointManager.prototype.escalateToAdmin = async function(checkpoint, error) {
+  try {
+    var notionService = require('./notion');
+    var dbConfig = require('../config/databases');
+
+    if (dbConfig.maintenanceLog && notionService.notion) {
+      await notionService.writeToDB(dbConfig.maintenanceLog, {
+        '标题': {
+          title: [{ text: { content: '[紧急] 自动回滚失败 · ' + this.executionId } }]
+        },
+        '类型': { select: { name: '系统异常' } },
+        '操作者': {
+          rich_text: [{
+            text: {
+              content: '检查点 ' + checkpoint.id + ' (' + checkpoint.label +
+                       ') 回滚失败: ' + error.message + '。需要冰朔人工介入。'
+            }
+          }]
+        }
+      });
+    }
+  } catch (e) {
+    console.error('[Checkpoint] 上报管理员失败:', e.message);
+  }
+};
+
+module.exports = { CheckpointManager: CheckpointManager };
diff --git a/backend/api-server/services/execution-watchdog.js b/backend/api-server/services/execution-watchdog.js
new file mode 100644
index 00000000..4327bc1e
--- /dev/null
+++ b/backend/api-server/services/execution-watchdog.js
@@ -0,0 +1,100 @@
+/**
+ * 执行看门狗 · 超时保护 + 死锁防护
+ *
+ * 定期检查执行锁是否超时。
+ * 如果一个操作执行超过 MAX_EXECUTION_TIME，标记为超时并释放锁。
+ * 这是防止死锁的兜底机制。
+ *
+ * 版权：国作登字-2026-A-00037559
+ */
+
+'use strict';
+
+var executionLock = require('../middleware/execution-lock');
+
+// 最大执行时间：15 分钟
+var MAX_EXECUTION_TIME = 15 * 60 * 1000;
+
+// 警告时间：10 分钟
+var WARN_TIME = 10 * 60 * 1000;
+
+// 检查间隔：30 秒
+var CHECK_INTERVAL = 30 * 1000;
+
+var watchdogTimer = null;
+
+/**
+ * 启动看门狗
+ * 定期扫描活跃锁表，检测超时操作
+ */
+function startWatchdog() {
+  if (watchdogTimer) return;
+
+  watchdogTimer = setInterval(function() {
+    var activeLocks = executionLock.getActiveLocks();
+    var now = Date.now();
+
+    for (var entry of activeLocks) {
+      var devId = entry[0];
+      var lock = entry[1];
+
+      if (lock.state !== 'running') continue;
+
+      var elapsed = now - lock.startTime;
+
+      // 超时：强制释放
+      if (elapsed > MAX_EXECUTION_TIME) {
+        console.error(
+          '[WATCHDOG] 执行超时: ' + lock.executionId +
+          ' (' + lock.operation + ') - ' + Math.round(elapsed / 1000) + 's'
+        );
+
+        lock.state = 'timeout';
+        lock.error = {
+          message: '执行超时（超过 ' + Math.round(MAX_EXECUTION_TIME / 60000) + ' 分钟）'
+        };
+
+        executionLock.logStep(devId, {
+          message: '⏰ 执行超时，看门狗已强制释放锁',
+          success: false
+        });
+
+        // 延迟释放（给前端时间获取超时状态）
+        (function(id) {
+          setTimeout(function() { executionLock.releaseLock(id); }, 30000);
+        })(devId);
+      }
+      // 警告
+      else if (elapsed > WARN_TIME && !lock.warned) {
+        console.warn(
+          '[WATCHDOG] 执行时间较长: ' + lock.executionId +
+          ' (' + lock.operation + ') - ' + Math.round(elapsed / 1000) + 's'
+        );
+        lock.warned = true;
+      }
+    }
+  }, CHECK_INTERVAL);
+
+  // 不阻止 Node.js 进程退出
+  if (watchdogTimer.unref) {
+    watchdogTimer.unref();
+  }
+
+  console.log('[WATCHDOG] 执行看门狗已启动 · 检查间隔 ' + (CHECK_INTERVAL / 1000) + 's · 超时阈值 ' + (MAX_EXECUTION_TIME / 60000) + 'min');
+}
+
+/**
+ * 停止看门狗
+ */
+function stopWatchdog() {
+  if (watchdogTimer) {
+    clearInterval(watchdogTimer);
+    watchdogTimer = null;
+  }
+}
+
+module.exports = {
+  startWatchdog: startWatchdog,
+  stopWatchdog: stopWatchdog,
+  MAX_EXECUTION_TIME: MAX_EXECUTION_TIME
+};
diff --git a/docs/css/execution-guard.css b/docs/css/execution-guard.css
new file mode 100644
index 00000000..27ed1681
--- /dev/null
+++ b/docs/css/execution-guard.css
@@ -0,0 +1,125 @@
+/**
+ * 执行保护样式 · L1 前端隔离
+ *
+ * 注意：没有 .cancel-button 类。这不是遗漏，是设计。
+ * 版权：国作登字-2026-A-00037559
+ */
+
+/* 执行中状态 · 输入框锁定 */
+.chat-input.execution-locked,
+#chat-input.execution-locked {
+  opacity: 0.5;
+  pointer-events: none;
+  background: #2a2a3a;
+  border-color: #444;
+}
+
+.chat-input.execution-locked::placeholder,
+#chat-input.execution-locked::placeholder {
+  color: #888;
+}
+
+/* 执行状态条 */
+.execution-status-bar {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 8px;
+  padding: 12px 16px;
+  border-radius: 8px;
+  margin: 8px 0;
+  font-size: 14px;
+  animation: pulse-gentle 2s infinite;
+}
+
+.execution-status-bar .exec-icon {
+  flex-shrink: 0;
+  font-size: 1.1em;
+}
+
+.execution-status-bar .exec-text {
+  flex: 1;
+}
+
+.execution-status-bar.blue {
+  background: rgba(35, 131, 226, 0.08);
+  color: #64c8ff;
+}
+
+.execution-status-bar.green {
+  background: rgba(15, 123, 108, 0.08);
+  color: #0F7B6C;
+  animation: none;
+}
+
+.execution-status-bar.red {
+  background: rgba(212, 76, 71, 0.08);
+  color: #D44C47;
+  animation: none;
+}
+
+/* 执行进度条 */
+.execution-progress {
+  width: 100%;
+  height: 3px;
+  background: rgba(255, 255, 255, 0.1);
+  border-radius: 2px;
+  margin-top: 4px;
+  overflow: hidden;
+}
+
+.execution-progress-fill {
+  height: 100%;
+  background: #64c8ff;
+  border-radius: 2px;
+  transition: width 0.5s ease;
+}
+
+.execution-status-bar.green .execution-progress-fill {
+  background: #0F7B6C;
+}
+
+.execution-status-bar.red .execution-progress-fill {
+  background: #D44C47;
+}
+
+/* 执行日志容器 */
+.execution-log-container {
+  max-height: 200px;
+  overflow-y: auto;
+  padding: 4px 8px;
+  margin: 4px 0 12px;
+  font-size: 13px;
+}
+
+/* 执行日志条目 */
+.execution-log-entry {
+  display: flex;
+  align-items: flex-start;
+  gap: 8px;
+  padding: 3px 0;
+  color: #b0b0c0;
+}
+
+.execution-log-entry .log-icon {
+  flex-shrink: 0;
+  font-size: 0.9em;
+}
+
+.execution-log-entry .log-msg {
+  flex: 1;
+}
+
+.execution-log-entry .log-time {
+  flex-shrink: 0;
+  color: #666;
+  font-size: 12px;
+}
+
+/* 温和脉冲动画 */
+@keyframes pulse-gentle {
+  0%, 100% { opacity: 1; }
+  50% { opacity: 0.7; }
+}
+
+/* 注意：没有 .cancel-button 类。这不是遗漏。 */
diff --git a/docs/js/execution-guard.js b/docs/js/execution-guard.js
new file mode 100644
index 00000000..23a0fbaa
--- /dev/null
+++ b/docs/js/execution-guard.js
@@ -0,0 +1,247 @@
+/**
+ * 执行保护 · 前端隔离层 (L1)
+ *
+ * 当开发者发出一条会触发系统操作的指令后：
+ * 1. 输入框立即禁用（不能发新指令）
+ * 2. 取消/撤回按钮不存在（从未渲染过，不是隐藏）
+ * 3. 界面进入「执行回放」模式
+ * 4. 执行完成后才解锁输入框
+ *
+ * 版权：国作登字-2026-A-00037559
+ */
+
+/* global HOLOLAKE_ENV */
+
+(function(window) {
+  'use strict';
+
+  var API_BASE = (typeof HOLOLAKE_ENV !== 'undefined' && HOLOLAKE_ENV === 'production')
+    ? 'https://guanghulab.com/api' : '';
+
+  /**
+   * ExecutionGuard 构造函数
+   * @param {Object} chatInterface - 聊天界面接口对象
+   */
+  function ExecutionGuard(chatInterface) {
+    this.chat = chatInterface || {};
+    this.locked = false;
+    this.executionId = null;
+    this._pollTimer = null;
+    this._logIndex = 0;
+  }
+
+  /**
+   * 进入执行保护状态
+   */
+  ExecutionGuard.prototype.lockExecution = function(executionId) {
+    this.locked = true;
+    this.executionId = executionId;
+    this._logIndex = 0;
+
+    // 1. 禁用输入框
+    var input = this.chat.inputField || document.getElementById('chat-input');
+    var sendBtn = this.chat.sendButton || document.getElementById('send-btn');
+
+    if (input) {
+      input.disabled = true;
+      input.placeholder = '⏳ 系统执行中…请等待完成';
+      input.classList.add('execution-locked');
+    }
+    if (sendBtn) {
+      sendBtn.disabled = true;
+    }
+
+    // 2. 显示执行状态条
+    this._showStatusBar('🔄', '指令已接收，系统正在执行…', 'blue');
+
+    // 3. 开始轮询执行状态
+    this._pollExecutionStatus(executionId);
+  };
+
+  /**
+   * 轮询执行状态
+   */
+  ExecutionGuard.prototype._pollExecutionStatus = function(executionId) {
+    var self = this;
+
+    var poll = function() {
+      if (!self.locked) return;
+      if (!API_BASE) {
+        // 无后端时模拟完成
+        setTimeout(function() { self.unlockExecution({ reply: '（本地模式：执行模拟完成）' }); }, 2000);
+        return;
+      }
+
+      var ctrl = new AbortController();
+      var tid = setTimeout(function() { ctrl.abort(); }, 10000);
+
+      fetch(API_BASE + '/execution/' + executionId + '/status?after=' + self._logIndex, {
+        signal: ctrl.signal
+      })
+      .then(function(res) { clearTimeout(tid); return res.json(); })
+      .then(function(status) {
+        // 更新进度
+        self._updateProgressBar(status.progress || 0);
+
+        // 展示新日志
+        if (status.newLogs && status.newLogs.length > 0) {
+          for (var i = 0; i < status.newLogs.length; i++) {
+            self._appendLogEntry(status.newLogs[i]);
+          }
+          self._logIndex += status.newLogs.length;
+        }
+
+        if (status.state === 'completed') {
+          self.unlockExecution(status.result || {});
+        } else if (status.state === 'failed' || status.state === 'timeout') {
+          self.handleExecutionFailure(status.error || { message: '执行失败' });
+        } else {
+          self._pollTimer = setTimeout(poll, 2000);
+        }
+      })
+      .catch(function() {
+        clearTimeout(tid);
+        // 网络错误不中断执行，继续轮询
+        self._pollTimer = setTimeout(poll, 5000);
+      });
+    };
+
+    poll();
+  };
+
+  /**
+   * 执行完成，解锁界面
+   */
+  ExecutionGuard.prototype.unlockExecution = function(result) {
+    this.locked = false;
+    this.executionId = null;
+    if (this._pollTimer) { clearTimeout(this._pollTimer); this._pollTimer = null; }
+
+    // 恢复输入框
+    var input = this.chat.inputField || document.getElementById('chat-input');
+    var sendBtn = this.chat.sendButton || document.getElementById('send-btn');
+
+    if (input) {
+      input.disabled = false;
+      input.placeholder = '和铸渊说话…';
+      input.classList.remove('execution-locked');
+    }
+    if (sendBtn) {
+      sendBtn.disabled = false;
+    }
+
+    // 更新状态条
+    this._showStatusBar('✅', '执行完成', 'green');
+    var self = this;
+    setTimeout(function() { self._hideStatusBar(); }, 5000);
+
+    // 展示结果
+    if (result && result.reply && this.chat.appendMessage) {
+      this.chat.appendMessage({ role: 'assistant', content: result.reply });
+    }
+  };
+
+  /**
+   * 执行失败处理
+   */
+  ExecutionGuard.prototype.handleExecutionFailure = function(error) {
+    this.locked = false;
+    this.executionId = null;
+    if (this._pollTimer) { clearTimeout(this._pollTimer); this._pollTimer = null; }
+
+    var input = this.chat.inputField || document.getElementById('chat-input');
+    var sendBtn = this.chat.sendButton || document.getElementById('send-btn');
+
+    if (input) {
+      input.disabled = false;
+      input.placeholder = '和铸渊说话…';
+      input.classList.remove('execution-locked');
+    }
+    if (sendBtn) {
+      sendBtn.disabled = false;
+    }
+
+    this._showStatusBar('❌', '执行失败 · 系统已自动回滚到执行前状态', 'red');
+    var self = this;
+    setTimeout(function() { self._hideStatusBar(); }, 10000);
+
+    var msg = error && error.message ? error.message : '未知错误';
+    if (this.chat.appendMessage) {
+      this.chat.appendMessage({
+        role: 'assistant',
+        content: '❌ 操作执行失败：' + msg +
+                 '\n\n系统已自动回滚到执行前的状态。没有任何数据被修改。\n' +
+                 '你可以重新描述你想做的事，或者说「发生了什么」来查看详细日志。'
+      });
+    }
+  };
+
+  /**
+   * 拦截浏览器关闭/刷新
+   */
+  ExecutionGuard.prototype.setupBrowserGuard = function() {
+    var self = this;
+    window.addEventListener('beforeunload', function(e) {
+      if (self.locked) {
+        e.preventDefault();
+        e.returnValue = '⚠️ 系统正在执行操作，关闭页面不会中断执行，但你将无法看到执行结果。';
+        return e.returnValue;
+      }
+    });
+  };
+
+  // ====== 内部 UI 辅助方法 ======
+
+  ExecutionGuard.prototype._showStatusBar = function(icon, text, color) {
+    var bar = document.getElementById('execution-status-bar');
+    if (!bar) {
+      bar = document.createElement('div');
+      bar.id = 'execution-status-bar';
+      bar.className = 'execution-status-bar';
+      var chatArea = document.querySelector('.chat-messages') || document.querySelector('.chat-container') || document.body;
+      chatArea.appendChild(bar);
+    }
+    bar.className = 'execution-status-bar ' + (color || 'blue');
+    bar.innerHTML = '<span class="exec-icon">' + icon + '</span> <span class="exec-text">' + text + '</span>' +
+                    '<div class="execution-progress"><div class="execution-progress-fill" id="exec-progress-fill" style="width:5%"></div></div>';
+    bar.style.display = 'flex';
+    // 注意：没有取消按钮。这不是遗漏，是设计。
+  };
+
+  ExecutionGuard.prototype._hideStatusBar = function() {
+    var bar = document.getElementById('execution-status-bar');
+    if (bar) bar.style.display = 'none';
+  };
+
+  ExecutionGuard.prototype._updateProgressBar = function(percent) {
+    var fill = document.getElementById('exec-progress-fill');
+    if (fill) fill.style.width = Math.max(5, Math.min(100, percent)) + '%';
+  };
+
+  ExecutionGuard.prototype._appendLogEntry = function(log) {
+    var container = document.getElementById('execution-log-container');
+    if (!container) {
+      container = document.createElement('div');
+      container.id = 'execution-log-container';
+      container.className = 'execution-log-container';
+      var bar = document.getElementById('execution-status-bar');
+      if (bar && bar.parentNode) {
+        bar.parentNode.insertBefore(container, bar.nextSibling);
+      } else {
+        (document.querySelector('.chat-messages') || document.body).appendChild(container);
+      }
+    }
+    var entry = document.createElement('div');
+    entry.className = 'execution-log-entry';
+    var icon = log.success ? '✅' : '⏳';
+    var time = log.timestamp ? new Date(log.timestamp).toLocaleTimeString('zh-CN') : '';
+    entry.innerHTML = '<span class="log-icon">' + icon + '</span>' +
+                      '<span class="log-msg">' + (log.message || '') + '</span>' +
+                      '<span class="log-time">' + time + '</span>';
+    container.appendChild(entry);
+  };
+
+  // 导出到全局
+  window.ExecutionGuard = ExecutionGuard;
+
+})(window);