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Install the MCP

Reactor runs a remote MCP server at https://reactor.tools/api/mcp, authenticated with a Bearer token: your Reactor API key, which scopes every call to your workspace.

First, generate a key (see Authentication). Then connect a client.

The @reactor-tools/mcp package detects your client and wires everything up:

npx @reactor-tools/mcp install --key YOUR_API_KEY

It auto-detects installed clients (Claude Code, Cursor, Claude Desktop, Windsurf). Restart the client, then ask it to "list the Reactor tools".

Target a specific client, or all of them:

npx @reactor-tools/mcp install --key YOUR_API_KEY --client cursor
npx @reactor-tools/mcp install --key YOUR_API_KEY --client all

Options: --client claude-code|cursor|claude-desktop|windsurf|vscode|all, --project (write project-scoped config in the current directory), --no-save.

Config snippet​

If you'd rather edit your client's config by hand, add the reactor entry. The package acts as a branded bridge, so the endpoint stays out of your config:

{
  "mcpServers": {
    "reactor": {
      "command": "npx",
      "args": ["-y", "@reactor-tools/mcp"],
      "env": { "REACTOR_API_KEY": "YOUR_API_KEY" }
    }
  }
}
  • Claude Desktop: Settings → Developer → Edit Config (claude_desktop_config.json), add the entry, then restart.
  • Cursor: Settings → MCP → Add new MCP server, add the entry to mcp.json.
  • VS Code: use a .vscode/mcp.json with a top-level servers block (npx @reactor-tools/mcp install --client vscode --project writes it for you).

REACTOR_MCP_URL overrides the endpoint if you point the package at a self-hosted deployment.

Without the package​

The package wraps mcp-remote, which bridges the remote HTTP server to clients that speak local (stdio) MCP. You can call it directly:

npx -y mcp-remote https://reactor.tools/api/mcp --header "Authorization: Bearer YOUR_API_KEY"

Clients that support remote HTTP MCP natively can skip the bridge entirely. In Claude Code:

claude mcp add reactor --transport http https://reactor.tools/api/mcp --header "Authorization: Bearer YOUR_API_KEY"

Verify​

Ask your client to list the Reactor tools, or call get_engine_config. The server is self-describing; your client reads each tool's description and input schema over the protocol.