Homelab MCP starter

A minimal, working Model Context Protocol server over Streamable HTTP. It ships with a few demo tools and one resource so you can verify the whole path — client → Cloudflare Tunnel → this server — before you write anything of your own.

What's here

• server.py — the server: four demo tools (ping, echo, add, server_info), one resource, a /health route, and optional bearer-token auth.
• requirements.txt, Dockerfile, docker-compose.yml — containerised, with an optional Cloudflare Tunnel sidecar.
• .env.example — every config knob.

1. Run it locally

python -m venv .venv && source .venv/bin/activate
pip install -r requirements.txt
cp .env.example .env          # set MCP_AUTH_TOKEN to a random value
export $(grep -v '^#' .env | xargs)
python server.py

Verify in another terminal:

# Health (no auth required)
curl -s http://127.0.0.1:8000/health        # -> ok

# MCP handshake (auth required)
curl -s -X POST http://127.0.0.1:8000/mcp \
  -H "Authorization: Bearer $MCP_AUTH_TOKEN" \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"curl","version":"0"}}}'

For an interactive view of the tools, point the MCP Inspector at it:

npx @modelcontextprotocol/inspector
# Transport: Streamable HTTP, URL: http://127.0.0.1:8000/mcp
# Add an Authorization header: Bearer <your token>

2. Run it in Docker

cp .env.example .env          # fill in MCP_AUTH_TOKEN (and TUNNEL_TOKEN later)
docker compose up -d --build mcp

3. Expose it with Cloudflare Tunnel

Both Claude and ChatGPT connect to your server from their cloud, so it needs a public HTTPS URL. A tunnel gives you that without opening any inbound ports.

1. In the Cloudflare dashboard: Zero Trust → Networks → Tunnels → Create a tunnel. Choose the token install method and copy the tunnel token.

2. Put it in .env as TUNNEL_TOKEN=....

3. In the tunnel's Public Hostname config, add e.g. mcp.yourdomain.com and set the service to http://mcp:8000 (the compose service name).

4. Start the sidecar:

   docker compose up -d
   

Your endpoint is now https://mcp.yourdomain.com/mcp.

4. Connect it to Claude and ChatGPT

Same URL in both.

• Claude (Pro/Max/Team/Enterprise): Settings → Connectors → Add custom connector → paste https://mcp.yourdomain.com/mcp.
• ChatGPT (Plus/Pro/Business/Enterprise/Edu): Settings → Apps → Advanced settings → Developer mode → add the same URL.

5. A note on auth

The bearer token here is real protection and is perfect for curl, the MCP Inspector, and any code you write. The catch: the consumer connector UIs don't reliably let you set a custom Authorization header, so for Claude/ChatGPT specifically you have two clean production options:

• Cloudflare Access in front of the public hostname (simplest for a homelab): gate the hostname with an Access policy. Good for connectors you drive yourself.
• OAuth — the path the connector "Connect" button is built for. FastMCP ships providers (GitHub, Google, Azure, Auth0, Keycloak, …) under fastmcp.server.auth.providers; wire one in to replace the bearer middleware.

Until you add one of those, keep MCP_AUTH_TOKEN set and treat the URL as a secret. Never run with auth disabled on a public hostname.

6. Add your own tools

Replace the demo functions in server.py. The pattern is just a decorated function — type hints become the input schema, and the docstring is what the model reads to decide when to call it:

@mcp.tool
def restart_service(name: str) -> str:
    """Restart a systemd service by name on the host. Returns the new status."""
    ...

Keep descriptions concrete about when to use the tool, validate every input (these run with whatever privileges the container has), and prefer read-only tools until you trust the setup.

Security checklist

• [ ] MCP_AUTH_TOKEN set to a random 32-byte value, .env git-ignored.
• [ ] Public hostname gated by Cloudflare Access or OAuth before exposing write tools.
• [ ] Container runs least-privilege (no host Docker socket, scoped mounts only).
• [ ] Tools validate inputs and avoid shelling out with unsanitised arguments.