SimAgentPlg 0.1.2

A lightweight multi-agent framework with ReAct reasoning, tool dispatch, and MCP integration

SimAgentPlg

A lightweight multi-agent framework with ReAct reasoning, tool dispatch, and MCP integration.

Features

• ReAct Agent — ReAct (Reasoning + Acting) loop with multi-turn tool calling
• Chat Agent — simple conversational agent with multi-turn history support
• Tool Dispatch — convention-over-configuration: define do_{tool_name} methods, auto-routed via reflection
• MCP Integration — pluggable MCP server manager for external tool providers
• Skill System — skill-based prompt injection for domain-specific behaviors
• Built-in Bash Executor — async sandboxed bash execution with timeout, output truncation, and blacklist filtering
• Stateless Execution — each runtime() call starts with a clean context; history is caller-managed
• OpenAI-compatible — works with any OpenAI-compatible API (DeepSeek, etc.)

Installation

pip install simagentplg

Or with uv:

uv pip install simagentplg

Quick Start

Set up your environment variables (.env):

CHAT_MODEL=deepseek-chat
MODEL_API_KEY=sk-xxxxxxxx
MODEL_URL=https://api.deepseek.com
LLM_TIMEOUT=30

Chat Agent

from simagentplg import ChatLoop

loop = ChatLoop()
result = await loop.runtime(task="介绍一下你自己")

# With multi-turn history
history = [
    {"role": "user", "content": "今天天气不错"},
    {"role": "assistant", "content": "是啊，适合出去走走"},
]
result = await loop.runtime(task="我们去哪", history=history)

ReAct Agent

from simagentplg import ReactLoop

loop = ReactLoop()
result = await loop.runtime(task="帮我写一个Python脚本打印当前时间")

The ReAct agent supports built-in tools (like bash_run) and any MCP tools configured in mcp_config.json.

MCP Configuration

Place an mcp_config.json alongside your ReactLoop:

{
  "mcpServers": {
    "playwright": {
      "command": "npx",
      "args": ["-y", "@anthropic/mcp-playwright"]
    }
  }
}

Architecture

LLMConfig (BaseHandler, ABC)
├── ChatLoop         — stateless conversational agent
├── ReactLoop        — ReAct reasoning + tool dispatch
│   ├── MCP tools    — external tools via MCP protocol
│   ├── Skill system — domain-specific prompt injection
│   └── Local tools  — built-in bash_run, extensible
└── (future) PlanLoop / ExecuteLoop

Tool Dispatch Flow

LLM calls "bash_run"
    → BaseHandler.dispatch("bash_run", args)
        → hasattr(self, "do_bash_run")?  YES
            → await self.do_bash_run(args)  ← local tool
        → NO
            → "未知工具" → MCP fallback  ← external tool

Adding a Local Tool

1. Define the tool schema in tool_schema.py:

LOCAL_TOOLS = [
    {
        "type": "function",
        "function": {
            "name": "calculator",
            "description": "Evaluate a math expression",
            "parameters": {
                "type": "object",
                "properties": {
                    "expression": {"type": "string", "description": "Math expression"}
                },
                "required": ["expression"]
            }
        }
    }
]

2. Add the do_calculator method in LLMConfig:

async def do_calculator(self, args: dict) -> StepOutcome:
    result = eval(args["expression"])
    return StepOutcome(data=result, next_prompt="\n")

All agents automatically inherit the new tool.

API

ChatLoop

loop = ChatLoop(temperature=0.7)
await loop.runtime(*, task, system_prompt=None, history=None) -> str | None

ReactLoop

loop = ReactLoop()
await loop.runtime(*, task, system_prompt=None, history=None) -> str | None

StepOutcome

@dataclass
class StepOutcome:
    data: Any              # tool return value
    next_prompt: str | None  # None = task complete
    should_exit: bool      # True = force exit

Requirements

• Python >= 3.12
• fastmcp >= 3.4.2
• openai >= 2.41.0
• python-dotenv >= 1.2.2

License

MIT