graph TB
    subgraph "Agent 运行时"
        PI[Pi Agent Runner<br/>核心推理引擎]

        subgraph "模型集成"
            MC[Model Catalog<br/>模型目录]
            AP[Auth Profiles<br/>凭证管理]
            FB[Fallback Chains<br/>模型降级链]
            TH[Thinking Mode<br/>思考/推理模式]
        end

        subgraph "工具系统"
            TC[Tool Catalog]
            T1[web_search 网络搜索]
            T2[browser_tool 浏览器]
            T3[system.run 终端执行]
            T4[system.spawn_acp 子Agent]
            T5[channel actions 通道操作]
        end

        subgraph "技能系统"
            SL[Skill Loader<br/>jiti 动态导入]
            SF[skill.json 元数据]
            SH[skill.ts 运行时处理器]
        end

        subgraph "子 Agent"
            SR[Subagent Registry]
            SP[Spawn ACP<br/>隔离会话派生]
        end
    end

    PI --> MC --> AP --> FB
    PI --> TC --> T1 & T2 & T3 & T4 & T5
    PI --> SL --> SF & SH
    PI --> SR --> SP
    MC --> TH

    subgraph "LLM 提供商"
        L1[Anthropic Claude]
        L2[OpenAI GPT]
        L3[Google Gemini]
        L4[Qwen 通义千问]
        L5[Ollama 本地]
        L6[Groq / Grok / Azure / Minimax / 火山引擎]
    end

    FB --> L1 & L2 & L3 & L4 & L5 & L6