localhost-mcp

MCP server that inspects, manages, and kills local dev servers. Stop guessing what's on :3000.

Pairs with terminal-history-mcp — together they give your AI agent full memory of your dev environment: what you ran, what's running.

Why

Every dev hits these daily:

• Error: listen EADDRINUSE :::3000 — what's holding the port?
• 5 forgotten node / vite / next PIDs from last week eating RAM
• Switching projects → no idea which dev servers still running
• lsof -i :3000, kill -9 <pid>, repeat

localhost-mcp makes it one tool call.

Install

npm install -g localhost-mcp

Wire into Claude Code:

claude mcp add --scope user localhost -- localhost-mcp

Or any MCP-compatible client. The command runs as a stdio MCP server.

Tools

| Tool | Purpose | |------|---------| | list_dev_servers | All listening dev servers w/ port, pid, framework, project, uptime, mem, cpu | | port_info | Inspect single port — who holds it | | kill_server | Kill by pid or port. Dry-run by default; pass confirm=true to execute | | find_zombies | Detect long-running, idle, memory-heavy dev servers | | port_conflict | Why is port X busy + 5 free alternatives nearby |

Sample output

{
  "port": 3000,
  "pid": 48211,
  "process": "node",
  "cmdline": "next dev",
  "cwd": "/Users/me/code/myapp",
  "project_name": "myapp",
  "framework": "next.js",
  "uptime_seconds": 14523,
  "memory_mb": 412,
  "cpu_pct": 0.3,
  "user": "me"
}

Safety

• kill_server defaults to dry-run. Must pass confirm=true.
• Refuses to kill PIDs < 1000 (system processes).
• Refuses processes outside the dev whitelist (node, python, ruby, go, deno, bun, php, java, rails, vite, next, etc).
• SIGTERM first, escalates to SIGKILL after 5s timeout.

Frameworks detected

next.js, vite, nuxt, remix, astro, webpack-dev-server, esbuild, create-react-app, express, fastify, koa, hono, rails, django, flask, fastapi, uvicorn, gunicorn, deno, bun, php-builtin, jekyll, hugo.

Falls back to package.json sniffing when the cmdline is generic (node server.js).

Platform support

• macOS — full support (uses lsof)
• Linux — full support (uses lsof + /proc)
• Windows — basic port scan only (uses netstat); cwd / framework detection limited

CLI usage

localhost-mcp list      # JSON list of all dev servers
localhost-mcp zombies   # JSON list of zombie candidates
localhost-mcp           # Start MCP stdio server

Build from source

git clone https://github.com/hasanjahidul/localhost-mcp.git
cd localhost-mcp
npm install
npm run build
node dist/cli.js list

License

MIT