SimpleMCP

A lightweight MCP-like alternative (Model Context Protocol) server that lets you bolt on tool "kits" without touching the core. Drop a new _kit.py file in kits/, slap a @tool decorator on your functions, and the server picks them up automatically. No manual imports, no config files, no fuss.

How it works

• Server (server.py): Three operating modes (see below). Auto-discovers all kits at startup.

• Kits (kits/): Each kit is a Python file with @tool-decorated functions. The kits/__init__.py auto-discovers and imports every kit at startup.

• Registry (utils/registry.py): The @tool decorator registers functions into a global dict. extract_parameters scrapes type hints to build JSON Schema for the tool's I/O.

• Config (config.py): MCP_MODE flag (default False). Set MCP_MODE=true via env var or edit the file directly.

• Client (client.py): Streamlit frontend that talks to the server and routes tool calls through Groq.

Kits included

• sqlite_kit — List tables, list columns, preview rows from a SQLite database.

• web_kit — Web search, page extraction, crawling, and mapping via the Tavily API.

Adding a new kit

1. Create a file in kits/, e.g. kits/my_kit.py

2. Import the decorator: from utils import tool

3. Write your functions with type hints and docstrings:

from utils import tool

@tool
def do_something(query: str, limit: int = 10):
    """Does something cool with a query."""
    # your logic here
    return {"result": "stuff"}

4. That's it. Restart the server and it's live.

Setup

python -m venv .venv
source .venv/bin/activate
pip install fastapi uvicorn tavily streamlit requests groq

Set your API keys:

export TAVILY_API_KEY="your-tavily-key"
export GROQ_API_KEY="your-groq-key"

Run the server:

HTTP mode (for Streamlit client / browser debugging):

uvicorn server:app --host 0.0.0.0 --port 8000

MCP HTTP mode (standard MCP endpoints over HTTP — for any MCP-compatible HTTP client):

MCP_MODE=true uvicorn server:app --host 0.0.0.0 --port 8000

Exposes a single MCP endpoint at /mcp:

• POST /mcp — JSON-RPC 2.0 dispatch (initialize, tools/list, tools/call); responds as SSE or JSON depending on client Accept header

• GET /mcp — SSE stream for server-initiated messages / keepalive

MCP stdio mode (for Claude Desktop and any MCP-compatible host):

python server.py

Run the client:

streamlit run client.py

Connecting to Claude Desktop

Add this to your claude_desktop_config.json:

{
  "mcpServers": {
    "SimpleMCP": {
      "command": "/absolute/path/to/SimpleMCP/venv/python.exe",
      "args": ["/absolute/path/to/server.py"],
      "env": {"TAVILY_API_KEY": "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"}
    }
  }
}

Claude Desktop will spawn server.py as a child process and communicate over stdin/stdout using MCP JSON-RPC 2.0.