Mern-Chat-App MCP Server

This is a standalone Model Context Protocol server generated for the Mern-Chat-App repository. It exposes two kinds of tools:

Code-reading tools (bundled repo source + Claude's architecture notes):

• list_files(pattern?) — list bundled files, optionally filtered by glob (e.g. *.py)

• read_file(path) — read a file's contents

• search_code(query, regex?, max_results?) — search across the bundled source

• get_repo_overview() — the Claude-generated architecture overview

• get_file_summary(path) — the Claude-generated summary for one file

API-calling tools (auto-generated, see server.py for the actual list — search for @mcp.tool()) — one per endpoint Claude found this app's own frontend actually calling. These call the real, already-deployed instance of this app's backend — they don't run any code from this repo themselves. They do nothing until you set API_BASE_URL (see below) to point at where you've deployed the actual application.

This server has no dependency on Claude, Anthropic, or any external API at runtime — it only needs the mcp package (which pulls in httpx for the API-calling tools), and works with any MCP-compatible client (Claude Desktop, Claude Code, or any other agent that can launch a stdio MCP server).

Run it

pip install -r requirements.txt   # or: pip install "mcp[cli]"
python server.py

Use it from Claude Desktop / Claude Code

Add to your MCP client config (e.g. claude_desktop_config.json):

{
  "mcpServers": {
    "mern-chat-app": {
      "command": "python",
      "args": ["/absolute/path/to/mern-chat-app-mcp-server/server.py"]
    }
  }
}

Or with the Claude Code CLI:

claude mcp add mern-chat-app -- python /absolute/path/to/mern-chat-app-mcp-server/server.py

Any other MCP-compatible agent that can launch a stdio child process can use this the same way.

Try it standalone

mcp dev server.py

This opens the MCP Inspector so you can call the tools manually before wiring it into an agent.

Connecting the API-calling tools to your real app

The generated API-calling tools are proxies — they need to know where your actual app is running and (if it requires login) how to authenticate. Two environment variables:

AUTH_MODE=service (default) — one shared credential for every call:

AUTH_MODE=service
TARGET_API_TOKEN=<a token your app accepts, e.g. from its own login endpoint>

Every tool call sends Authorization: Bearer <TARGET_API_TOKEN> to your app. Simple, but every call acts as this one identity — right for single-operator/admin use, not for an app with many separate end users. If the token expires, update the TARGET_API_TOKEN env var (a fast restart, not a rebuild, on hosts like Render) — no redeploy needed.

AUTH_MODE=passthrough — for apps with many end users, each with their own login:

AUTH_MODE=passthrough

No credential is stored here at all. Whatever Authorization header arrives on this server's own incoming request is forwarded as-is to your app's API — each caller acts as themselves. This means whatever calls this MCP server on a given user's behalf must already hold that user's own valid token for your app and pass it through — the same way your own app's frontend already does today. This server never stores, inspects, or manages those tokens; it's a pure relay.

Deploy remotely (e.g. Render)

⚠️ This bundles your entire repository's source code, and (once configured above) can call your real app's API. Deployed with no auth, read_file/search_code would let anyone with the URL read your whole repo (including any secrets accidentally committed to it), and the API-calling tools would be usable by anyone with the URL too. Don't deploy without the token check below.

By default this server runs over stdio (a local subprocess, no network exposure). To run it as a remote HTTP server instead, set:

On Render: this project includes a render.yaml blueprint. In the Render dashboard, choose New → Blueprint, point it at a git repo containing these files, and Render will create the service, install requirements.txt, run python server.py, and auto-generate MCP_AUTH_TOKEN for you (visible in the service's Environment tab afterward). Render assigns the port automatically — the server reads it from the PORT env var Render sets (defaults to 10000 if unset, matching Render's own convention).

Calling the deployed server: MCP clients that support remote servers connect to https://<your-service>.onrender.com/mcp and must include the header:

Authorization: Bearer <the MCP_AUTH_TOKEN value>

Requests missing or mismatching that header get HTTP 401 — the repository source is never served without it.