NumberBroom MCP Server

A remote MCP server that lets AI agents (Claude, ChatGPT, and other MCP-compatible clients) verify US phone numbers through the NumberBroom API: carrier-level line type, carrier name, an activity score, and TCPA litigator status.

This server is a thin, stateless proxy. It has no database and runs no OAuth flow — it forwards your NumberBroom API key straight through to https://numberbroom.com/api/v1, which already owns authentication, rate limiting, billing, and abuse protection. See numberbroom.com/developers for the underlying REST API this wraps.

Tools

Tool	Description	Cost
verify_phone_number	Line type, carrier, activity score, TCPA litigator flag for one US number.	$0.20/call, charged to your NumberBroom credit balance. Unparseable numbers are not charged.
get_credit_balance	Remaining pre-paid credit balance on your NumberBroom account.	Free.

Get an API key

1. Sign up at numberbroom.com and add credit to your account.
2. Generate an API key at numberbroom.com/settings.

Connect a client

Add this server as a remote MCP connection using its deployed URL, https://numberbroom.com/mcp, with your NumberBroom API key as a Bearer token in the Authorization header:

Authorization: Bearer nb_live_YOUR_KEY

Exactly how you set that header depends on the client — most MCP-capable apps that support remote servers let you add a custom header per connection.

Local development

npm install
npm run dev

This starts the server at http://localhost:8787/mcp via wrangler dev.

Deploy

npm run deploy

Deploys to Cloudflare Workers as numberbroom-mcp. Requires a Cloudflare account authenticated via wrangler login.

Why a proxy, not a rewrite

Every tool call here is a direct, unmodified pass-through to NumberBroom's own /api/v1 endpoints. That means:

• Auth, rate limiting (5,000 lookups/key/day), the circuit breaker, and billing are all enforced exactly once, by NumberBroom's own API — this server does not duplicate or second-guess any of it.
• A number that fails to parse costs nothing, same as calling the REST API directly.
• This server never sees or stores your API key beyond the lifetime of a single request; each MCP tool call constructs an isolated server instance with no shared state between callers.

License

MIT