feat(core): 实现 Doom Loop 检测和软性 maxSteps 限制

- 新增 doom-loop.ts: 实现 Doom Loop 检测器，检测连续 3 次相同工具调用
- 修改 agent.ts: 集成检测器，添加 onDoomLoop 回调，动态 maxSteps
- 修改 registry.ts: 默认 maxSteps 从 10 改为 50
- 更新 index.ts: 导出新模块

参考 OpenCode/OpenHands 等开源项目的多层防御策略

packages/core/src/agent/registry.ts

@@ -156,8 +156,8 @@ export class AgentRegistry {
    * 应用全局配置到 Agent
    */
   private applyGlobalConfig(agent: AgentInfo): AgentInfo {
-    // 合并 maxSteps
-    const maxSteps = agent.maxSteps ?? this.globalConfig?.maxSteps ?? 10;
+    // 合并 maxSteps（默认 50，提供足够的执行空间）
+    const maxSteps = agent.maxSteps ?? this.globalConfig?.maxSteps ?? 50;
 
     // 合并模型配置
     const model = {

packages/core/src/core/agent.ts

@@ -22,6 +22,11 @@ import { loadVisionConfig } from '../utils/config.js';
 import { getProviderRegistry, resolveApiKey } from '../provider/index.js';
 import { getHookManager } from '../hooks/index.js';
 import { getGitManager } from '../git/index.js';
+import {
+  createDoomLoopDetector,
+  type DoomLoopDetector,
+  DOOM_LOOP_WARNING,
+} from './doom-loop.js';
 
 /**
  * 工具调用开始事件信息
@@ -43,6 +48,14 @@ export interface ToolEndInfo {
   duration?: number;
 }
 
+/**
+ * Doom Loop 检测事件信息
+ */
+export interface DoomLoopInfo {
+  toolName: string;
+  count: number;
+}
+
 /**
  * Agent.chat() 选项
  */
@@ -52,6 +65,8 @@ export interface AgentChatOptions {
   onToolStart?: (info: ToolStartInfo) => void;
   /** 工具执行完成回调 */
   onToolEnd?: (info: ToolEndInfo) => void;
+  /** Doom Loop 检测回调 */
+  onDoomLoop?: (info: DoomLoopInfo) => void;
   abortSignal?: AbortSignal;
 }
 
@@ -72,6 +87,9 @@ export class Agent {
   // 压缩管理器
   private compressionManager: CompressionManager;
 
+  // Doom Loop 检测器
+  private doomLoopDetector: DoomLoopDetector = createDoomLoopDetector();
+
   // 当前 Agent 模式（null 表示默认模式）
   private currentAgentMode: AgentInfo | null = null;
 
@@ -348,10 +366,15 @@ export class Agent {
   async chat(userMessage: string | UserInput, options?: AgentChatOptions | ((text: string) => void)): Promise<ChatResult> {
     // 兼容旧的 onStream 参数
     const opts: AgentChatOptions = typeof options === 'function' ? { onStream: options } : (options || {});
-    const { onStream, onToolStart, onToolEnd, abortSignal } = opts;
+    const { onStream, onToolStart, onToolEnd, onDoomLoop, abortSignal } = opts;
+
+    // 重置 doom loop 检测器（每次对话开始时）
+    this.doomLoopDetector.reset();
 
     // 工具调用时间跟踪
     const toolStartTimes = new Map<string, number>();
+    // Doom loop 检测状态
+    let doomLoopTriggered = false;
     // 处理带图片的消息
     let processedMessage = userMessage;
 
@@ -422,13 +445,16 @@ export class Agent {
 
     if (onStream) {
       // 流式模式
+      // 获取当前 Agent 的 maxSteps 配置（默认 50）
+      const maxSteps = this.currentAgentMode?.maxSteps ?? 50;
+
       const result = streamText({
         model: this.getModel(this.config.model),
         system: this.config.systemPrompt,
         messages: this.conversationHistory,
-        tools: vercelTools,
+        tools: doomLoopTriggered ? {} : vercelTools, // doom loop 时禁用工具
         maxOutputTokens: this.config.maxTokens,
-        stopWhen: stepCountIs(10), // 允许最多 10 轮工具调用
+        stopWhen: stepCountIs(maxSteps),
         abortSignal, // 支持取消
         onChunk: ({ chunk }) => {
           if (chunk.type === 'tool-call') {
@@ -436,6 +462,25 @@ export class Agent {
             const toolCallChunk = chunk as { toolCallId: string; toolName: string; input: unknown };
             const toolCallId = toolCallChunk.toolCallId || `tool-${Date.now()}`;
 
+            // Doom Loop 检测：记录工具调用
+            this.doomLoopDetector.record(
+              toolCallChunk.toolName,
+              toolCallChunk.input
+            );
+
+            // 检查是否触发 doom loop
+            if (this.doomLoopDetector.isTriggered() && !doomLoopTriggered) {
+              doomLoopTriggered = true;
+              const toolName = this.doomLoopDetector.getLastToolName() || toolCallChunk.toolName;
+
+              // 通知回调
+              onDoomLoop?.({ toolName, count: 3 });
+
+              // 输出警告
+              onStream?.(`\n[警告: 检测到 Doom Loop - ${toolName} 被重复调用]\n`);
+              onStream?.(DOOM_LOOP_WARNING);
+            }
+
             // 记录开始时间
             toolStartTimes.set(toolCallId, Date.now());
 
@@ -534,13 +579,16 @@ export class Agent {
       }
     } else {
       // 非流式模式
+      // 获取当前 Agent 的 maxSteps 配置（默认 50）
+      const maxSteps = this.currentAgentMode?.maxSteps ?? 50;
+
       const result = await generateText({
         model: this.getModel(this.config.model),
         system: this.config.systemPrompt,
         messages: this.conversationHistory,
         tools: vercelTools,
         maxOutputTokens: this.config.maxTokens,
-        stopWhen: stepCountIs(10), // 允许最多 10 轮工具调用
+        stopWhen: stepCountIs(maxSteps),
         abortSignal, // 支持取消
       });
 

packages/core/src/core/doom-loop.ts

@@ -0,0 +1,136 @@
+/**
+ * Doom Loop 检测器
+ *
+ * 检测模型是否陷入重复工具调用的死循环。
+ * 参考 OpenCode 和 OpenHands 的实现。
+ */
+
+import { createHash } from 'crypto';
+
+/**
+ * 工具调用记录
+ */
+export interface ToolCallRecord {
+  toolName: string;
+  inputHash: string;
+}
+
+/**
+ * Doom Loop 检测器接口
+ */
+export interface DoomLoopDetector {
+  /** 记录工具调用 */
+  record(toolName: string, input: unknown): void;
+  /** 检测是否触发 doom loop */
+  isTriggered(): boolean;
+  /** 重置记录（新对话时调用） */
+  reset(): void;
+  /** 获取当前状态描述（用于日志） */
+  getStatus(): string;
+  /** 获取最后重复的工具名称（触发时使用） */
+  getLastToolName(): string | null;
+}
+
+/**
+ * Doom Loop 检测阈值
+ * 连续 N 次相同的工具调用（相同工具名 + 相同参数）触发检测
+ */
+export const DOOM_LOOP_THRESHOLD = 3;
+
+/**
+ * 计算输入参数的哈希值
+ */
+function hashInput(input: unknown): string {
+  const str = JSON.stringify(input, Object.keys(input as object).sort());
+  return createHash('md5').update(str).digest('hex').slice(0, 16);
+}
+
+/**
+ * 创建 Doom Loop 检测器
+ */
+export function createDoomLoopDetector(threshold = DOOM_LOOP_THRESHOLD): DoomLoopDetector {
+  const history: ToolCallRecord[] = [];
+  let triggered = false;
+  let lastToolName: string | null = null;
+
+  return {
+    record(toolName: string, input: unknown): void {
+      const inputHash = hashInput(input);
+      history.push({ toolName, inputHash });
+
+      // 只保留最近 threshold 条记录
+      if (history.length > threshold) {
+        history.shift();
+      }
+
+      // 检测是否触发
+      if (history.length >= threshold) {
+        const lastN = history.slice(-threshold);
+        const first = lastN[0];
+        const allSame = lastN.every(
+          (call) => call.toolName === first.toolName && call.inputHash === first.inputHash
+        );
+
+        if (allSame) {
+          triggered = true;
+          lastToolName = first.toolName;
+        }
+      }
+    },
+
+    isTriggered(): boolean {
+      return triggered;
+    },
+
+    reset(): void {
+      history.length = 0;
+      triggered = false;
+      lastToolName = null;
+    },
+
+    getStatus(): string {
+      if (triggered) {
+        return `Doom loop detected: ${lastToolName} called ${threshold} times with same input`;
+      }
+      return `Normal: ${history.length} calls recorded`;
+    },
+
+    getLastToolName(): string | null {
+      return lastToolName;
+    },
+  };
+}
+
+/**
+ * MAX_STEPS 达到时的警告提示
+ * 注入到 system prompt 中，让模型输出总结
+ */
+export const MAX_STEPS_WARNING = `
+CRITICAL - MAXIMUM STEPS REACHED
+
+The maximum number of steps allowed for this task has been reached. Tools are disabled until next user input. Respond with text only.
+
+STRICT REQUIREMENTS:
+1. Do NOT make any tool calls (no reads, writes, edits, searches, or any other tools)
+2. MUST provide a text response summarizing work done so far
+3. This constraint overrides ALL other instructions
+
+Please summarize:
+1. What has been completed
+2. What remains to be done
+3. Any recommendations for next steps
+`;
+
+/**
+ * Doom Loop 触发时的警告提示
+ */
+export const DOOM_LOOP_WARNING = `
+WARNING - DOOM LOOP DETECTED
+
+The same tool call has been repeated multiple times with identical inputs, indicating a potential infinite loop. Tools are temporarily disabled.
+
+Please:
+1. Explain what you were trying to accomplish
+2. Describe why the repeated calls might not be working
+3. Suggest an alternative approach
+`;

packages/core/src/index.ts

@@ -1,5 +1,14 @@
 export { Agent } from './core/agent.js';
-export type { AgentChatOptions, ToolStartInfo, ToolEndInfo } from './core/agent.js';
+export type { AgentChatOptions, ToolStartInfo, ToolEndInfo, DoomLoopInfo } from './core/agent.js';
+
+// Doom Loop Detection
+export {
+  createDoomLoopDetector,
+  DOOM_LOOP_THRESHOLD,
+  DOOM_LOOP_WARNING,
+  MAX_STEPS_WARNING,
+} from './core/doom-loop.js';
+export type { DoomLoopDetector } from './core/doom-loop.js';
 export { toolRegistry, todoManager, initTaskContext, updateTaskDescription, updateSkillDescription } from './tools/index.js';
 export { loadConfig, saveConfig, getConfig, loadVisionConfig, ConfigurationError } from './utils/config.js';
 export type { VisionConfig } from './utils/config.js';