Localhost MCP MCP Server

MCP server: inspect, manage, kill local dev servers. Stop guessing what's on :3000.

Local serverstdioPython

What is the Localhost MCP MCP server?

MCP server: inspect, manage, kill local dev servers. Stop guessing what's on :3000. The localhost mcp mcp server wraps that behind the Model Context Protocol, so an assistant can use it through 5 defined tools rather than through you.

What it actually does

  • 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 , repeat

Its toolset

Everything the assistant can do here goes through one of these:

  • 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

Adding it to your client

localhost-mcp on npm is all you need. Most clients run it directly, so configuration is a few lines and a restart.

When to reach for it

This sits in the knowledge and memory group, where several servers overlap in what they claim to do but differ sharply once you actually set them up. Localhost MCP's toolset — list_dev_servers, port_info, kill_server and 2 more — is a fair guide to whether it matches your workflow. It is maintained by HasanJahidul; worth a glance at recent repository activity before you build anything load-bearing on it.

We check each listing at SyncDev against the project's documentation before it goes live — if something here drifts out of date, it is a bug worth reporting.

Caveats

  • It runs with your machine's permissions. That is convenient and also the reason to think about what you point it at before you approve a tool call.
  • MCP clients confirm each tool call by default. Leave that on until you have watched what the localhost mcp mcp server does with a few real requests.

Available tools

ToolWhat it does
list_dev_serversAll listening dev servers w/ port, pid, framework, project, uptime, mem, cpu
port_infoInspect single port — who holds it
kill_serverKill by pid or port. Dry-run by default; pass confirm=true to execute
find_zombiesDetect long-running, idle, memory-heavy dev servers
port_conflictWhy is port X busy + 5 free alternatives nearby

How to install the Localhost MCP MCP server

{
  "mcpServers": {
    "localhost": {
      "command": "npx",
      "args": ["-y", "localhost-mcp"]
    }
  }
}

Add to claude_desktop_config.json, then restart Claude Desktop.

Example prompts to try

  • Use Localhost MCP to list dev servers.
  • Use Localhost MCP to port info.
  • Use Localhost MCP to kill server.

Frequently asked questions

macOS and Linux have full support (using `lsof` and `/proc`). Windows support is basic (port scan only via `netstat`; cwd and framework detection are limited).