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.

The proxy works in standalone mode — if Reactotron is not open, the app connection is kept alive and all messages are still captured. When Reactotron is opened later, the proxy reconnects automatically (with exponential backoff). This means you don't need to have Reactotron running before starting your app.

Requirements

• Your app pointed at the proxy port (default 9091) instead of Reactotron directly
• Reactotron desktop app (optional — for the visual UI)

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 (log/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, HTTP method, status code, minimum duration, and limit.
get_timeline	Full chronological timeline of all Reactotron messages.
get_state_actions	View completed Redux or MobX-State-Tree actions. Filter by action type substring and limit.
get_state_changes	View state mutation events. Filter by state path substring and limit.
get_benchmarks	View performance benchmark reports with per-step timings. Filter by title and limit.
get_displays	Read custom display messages sent via reactotron.display(). Filter by name/preview text and limit.
get_errors	Consolidated view of error-level logs and failed network requests (4xx/5xx) in one call.
get_images	Retrieve images logged via reactotron.image(), rendered inline as native MCP image content.
get_app_info	Show connected app metadata from the Reactotron handshake: name, version, platform, React/RN versions.
get_connection_status	Check whether an app is connected, including app name, platform, and proxy port.
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.
clear_messages	Clear captured messages from the in-memory buffer. Clears all buffers or a specific message type.
list_custom_commands	List all custom commands currently registered by the connected app.

Resources

Resources expose the same data as tools but as readable URIs, useful for attaching live context directly to a conversation.

Resource	URI	Description
Logs	reactotron://logs	Latest 50 log messages
Network	reactotron://network	Latest 50 network requests
Timeline	reactotron://timeline	Latest 100 messages across all types
State	reactotron://state{/path*}	App state at a given path (e.g. reactotron://state/user/profile)
State Actions	reactotron://state-actions	Latest 50 Redux/MST actions
State Changes	reactotron://state-changes	Latest 50 state mutations
Benchmarks	reactotron://benchmarks	Latest 50 benchmark reports
Display Messages	reactotron://displays	Latest 50 reactotron.display() messages
Custom Commands	reactotron://custom-commands	All registered custom commands
Connection	reactotron://connection	Connection status and app info
Images	reactotron://images	Metadata list of captured images (use get_images tool to view inline)

Prompts

Prompts are reusable templates that guide the AI through common debugging workflows. Invoke them via your AI assistant's prompt/slash-command interface.

Prompt	Description
debug_app	Get a comprehensive debug snapshot — checks connection, logs, network, state, and recent actions.
trace_action	Trace a specific Redux/MST action through its payload, state changes, logs, and network side effects. Takes an action argument (e.g. AUTH/LOGIN_SUCCESS).
diagnose_network	Identify and analyse failed or errored API requests, spot patterns, and check related state.
debug_performance	Analyse benchmark reports and slow network requests to identify performance bottlenecks.
debug_errors	Triage all errors — error logs, failed requests, important display messages, and error state.

Development

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