dummy-mcp

A toy MCP server with two mocked PostHog-style tools (get_trends, get_funnel) for experimenting with the MCP Streamable HTTP transport and the @posthog/mcp analytics SDK.

Setup

npm install

Open index.js and replace the placeholder apiKey: "phc_....." inside track(server, { ... }) with a real project API key (the phc_… value from PostHog → Project Settings → Project API Key). Personal API keys (phx_…) will be rejected with 401 personal_api_key.

Adjust host in the same block if you're not pointing at a local PostHog (http://localhost:8010 is the default). Use https://us.i.posthog.com or https://eu.i.posthog.com for cloud.

Run

node index.js

You should see:

server.ready http://localhost:3000/mcp

Override the port with PORT=4000 node index.js if needed.

All tool-call logs (get_trends called …, etc.) go to stderr in this terminal. Leave it running.

Connect from Claude Desktop

Claude Desktop speaks stdio MCP, so we bridge to the HTTP server with the mcp-remote proxy.

Edit ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "dummy-mcp": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "http://localhost:3000/mcp", "--transport", "http-only"]
    }
  }
}

Then restart Claude Desktop. Ask it to invoke get_trends or get_funnel and watch the live logs in the terminal running node index.js.

Tools

• get_trends(event, days=7, interval="day") — mocked daily time series
• get_funnel(steps[], days=7) — mocked funnel breakdown with conversion rates