Connecting Serena MCP Server to ChatGPT via MCPO & Cloudflare Tunnel

Connecting Serena MCP Server to ChatGPT via MCPO & Cloudflare Tunnel#

This guide explains how to expose a locally running Serena MCP server (powered by MCPO) to the internet using Cloudflare Tunnel, and how to connect it to ChatGPT as a Custom GPT with tool access.

Once configured, ChatGPT becomes a powerful coding agent with direct access to your codebase, shell, and file system — so read the security notes carefully.

Prerequisites#

Make sure you have uv and cloudflared installed.

1. Start the Serena MCP Server via MCPO#

Run the following command to launch Serena as http server (assuming port 8000):

uvx mcpo --port 8000 --api-key <YOUR_SECRET_KEY> -- \
  uvx --from git+https://github.com/oraios/serena \
  serena start-mcp-server --context chatgpt --project $(pwd)

  • --api-key is required to secure the server.

  • --project should point to the root of your codebase.

You can also use other options, and you don’t have to pass --project if you want to work on multiple projects or want to activate it later. See

uvx --from git+https://github.com/oraios/serena serena start-mcp-server --help

2. Expose the Server Using Cloudflare Tunnel#

Run:

cloudflared tunnel --url http://localhost:8000

This will give you a public HTTPS URL like:

https://serena-agent-tunnel.trycloudflare.com

Your server is now securely exposed to the internet.

3. Connect It to ChatGPT (Custom GPT)#

Steps:#

  1. Go to ChatGPT → Explore GPTs → Create

  2. During setup, click “Add APIs”

  3. Set up API Key authentication with the auth type as Bearer and enter the api key you used to start the MCPO server.

  4. In the Schema section, click on import from URL and paste <cloudflared_url>/openapi.json with the URL you got from the previous step.

  5. Add the following line to the top of the imported JSON schema:

     "servers": ["url": "<cloudflared_url>"],

    Important: don’t include a trailing slash at the end of the URL!

ChatGPT will read the schema and create functions automatically.

Security Warning — Read Carefully#

Depending on your configuration and enabled tools, Serena’s MCP server may:

  • Execute arbitrary shell commands

  • Read, write, and modify files in your codebase

This gives ChatGPT the same powers as a remote developer on your machine.

⚠️ Key Rules:#

  • NEVER expose your API key

  • Only expose this server when needed, and monitor its use.

In your project’s .serena/project.yml or global config, you can disable tools like:

excluded_tools:
  - execute_shell_command
  - ...
read_only: true

This is strongly recommended if you want a read-only or safer agent.

Final Thoughts#

With this setup, ChatGPT becomes a coding assistant running on your local code — able to index, search, edit, and even run shell commands depending on your configuration.

Use responsibly, and keep security in mind.

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