reactotron-mcp

An MCP (Model Context Protocol) server for Reactotron, enabling AI assistants to read logs, inspect app state, monitor network requests, and trigger custom commands in your React or React Native app.

How it works

The MCP server runs a WebSocket proxy between your app and the Reactotron desktop app:

App ──► MCP Proxy (port 9091) ──► Reactotron (port 9090)
               │
          captures everything
               │
          MCP tools (Claude/Cursor etc.)

Your app connects to the proxy instead of directly to Reactotron. The proxy forwards all traffic to Reactotron (so the desktop UI works normally) and captures every message for the MCP tools.

Requirements

• Reactotron desktop app running
• Your app pointed at the proxy port (default 9091) instead of Reactotron directly

Installation

Claude Code

claude mcp add reactotron-mcp npx reactotron-mcp

Or with Bun:

claude mcp add reactotron-mcp bunx reactotron-mcp

npx (Node)

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

bunx (Bun)

{
  "mcpServers": {
    "reactotron": {
      "command": "bunx",
      "args": ["reactotron-mcp"]
    }
  }
}

Custom port

If Reactotron is running on a non-default port, set REACTOTRON_PORT:

{
  "mcpServers": {
    "reactotron": {
      "command": "npx",
      "args": ["-y", "reactotron-mcp"],
      "env": {
        "REACTOTRON_PORT": "9090"
      }
    }
  }
}

App setup

Point your app's Reactotron config at the proxy port instead of the default:

// Before
Reactotron.configure({ host: 'localhost' }).connect()

// After
Reactotron.configure({ host: 'localhost', port: 9091 }).connect()

Configuration

Environment variable	Default	Description
REACTOTRON_PROXY_PORT	9091	Port the MCP proxy listens on (apps connect here)
REACTOTRON_PORT	9090	Port the Reactotron desktop app is running on
REACTOTRON_TIMEOUT	5000	Timeout in ms for state queries

Tools

Tool	Description
get_logs	Read captured log messages. Filter by level (debug/warn/error), text search, and limit.
get_state	Query the app's state tree. Browse keys at a path or read the value.
get_network	View captured API requests and responses. Filter by URL, status code, and limit.
get_timeline	Full chronological timeline of all Reactotron messages.
run_custom_command	List or trigger custom commands registered by the app.
dispatch_action	Dispatch a Redux or MobX-State-Tree action to the app.

Development

bun install
bun run dev       # run from source
bun run build     # bundle for distribution
bun run typecheck # type-check without building