ChatGPT App MCP Backend for Mofei's Blog

This repository hosts the Cloudflare Workers MCP server that powers the blog app from the article “How to Build a ChatGPT App From Scratch: MCP Integration, Custom Widgets, and Real API Examples”. It exposes Mofei's blog APIs as MCP tools so ChatGPT (and any MCP client) can browse posts, fetch details, and surface recommendations.

What’s inside

• Cloudflare Worker + Durable Object MCP server (src/index.ts) with SSE endpoints at /sse and /mcp.
• Four blog-focused MCP tools: list-blog-posts, get-blog-article, get-comment-list, and get-recommend-blog.
• Wrangler configuration (wrangler.jsonc) ready for local dev and production deploy.

Quick start (local)

1. Install dependencies: npm install
2. Start the dev server: npm run dev
3. The MCP endpoints are available at http://localhost:8787/sse (SSE) and http://localhost:8787/mcp.

If you need to expose local dev to ChatGPT, run ngrok http 8787 (or your tunneling tool) and append /sse to the public URL.

Deploy to Cloudflare Workers

1. Configure your Cloudflare account with Wrangler (npm create cloudflare@latest if you need an account setup).
2. Deploy: npm run deploy
3. Your public MCP endpoint will be https://<worker-name>.<your-account>.workers.dev/sse.

Connect from ChatGPT (Apps Developer Mode)

1. In ChatGPT: Settings → Apps & Connectors → Advanced settings → Enable “Developer mode”.
2. Create a connection and set “MCP Server URL” to your endpoint:
   • Cloudflare: https://<worker-name>.<your-account>.workers.dev/sse
   • Local via ngrok: https://<random>.ngrok.io/sse
   • Keep the trailing /sse.
3. Test the connection to confirm tools and resources are detected, then save.
4. Try a prompt such as: “Show me the latest posts from Mofei’s blog in English.”

Available tools

• list-blog-posts — Paginated blog list. Params: page (number), lang (en/zh).
• get-blog-article — Fetch a specific article by id and lang.
• get-comment-list — Retrieve comments with page and pageSize.
• get-recommend-blog — Related articles for a given id and lang.

Responses return the underlying JSON from https://api.mofei.life. For UI widgets, pair this server with the single-file widget bundle described in the blog post (structured content for the model + _meta for the widget data).

Useful scripts

• npm run dev — Local dev server on port 8787.
• npm run deploy — Deploy to Cloudflare Workers.
• npm run format / npm run lint:fix — Biome formatting and linting.

More resources

• Full article: https://www.mofei.life/en/blog/article/chatgpt-app
• ChatGPT Apps SDK docs: https://developers.openai.com/apps-sdk
• MCP spec: https://modelcontextprotocol.io/