Add a Claude phone connector

Add a Claude phone connector by pasting one URL: https://api.ringkit.com/mcp/oauth. That is the custom-connector address in RingKit's MCP OAuth notes. Claude then runs the OAuth sign-in. You approve one business. Claude does not become the receptionist. RingKit's AI still answers the phone line. The connector lets Claude use the tools that token is allowed to call.

This page does not invent Claude's buttons. If a menu name is not in the notes below, it is not a step you should take from this article. The notes are docs/mcp-oauth.md in the RingKit repo, read for this post on November 10, 2026.

The URL you paste

For a Claude custom connector, the URL to paste is https://api.ringkit.com/mcp/oauth.

That path exists because the main MCP URL behaves differently. https://api.ringkit.com/mcp stays open to anonymous clients so an agent can create a business with no key. It answers 401 only when a token is present and bad. Claude starts OAuth when a server answers 401 with no token at all. /mcp/oauth is the same server, but it always returns 401 and a WWW-Authenticate header when there is no token. That is the signal Claude is built to follow.

Do not paste an API key into that URL. API-key clients use https://api.ringkit.com/mcp with Authorization: Bearer rk_.... That is a different connection. The public docs still show that key-based JSON for Claude Desktop, and a claude mcp add command for Claude Code. Those are not this connector. If you follow the key example, you are not in the OAuth flow this page describes.

What the connector is actually doing

The OAuth shape is the one in those notes, which point at the protected-resource metadata format in RFC 9728. In short, the client discovers where to send you, you sign in, and you approve a scope.

The documented sequence is:

1. The client looks up protected-resource metadata at /.well-known/oauth-protected-resource/mcp (also at the root well-known path), or reads WWW-Authenticate on a 401.
2. It reads authorization-server metadata at /.well-known/oauth-authorization-server.
3. It registers with POST /oauth/register. Public clients send token_endpoint_auth_method: "none". Other clients get a client_secret once. Redirect URIs are https, loopback http, or a native app scheme.
4. It sends you to GET /oauth/authorize with an authorization code and PKCE S256. The resource is https://api.ringkit.com/mcp. The scope is ringkit.read, or ringkit.manage (manage includes read). The default is read.
5. You sign in on app.ringkit.com if you are not already signed in. The consent screen names the client, the redirect host, the permissions, and a business picker. Only an owner can approve.
6. POST /oauth/token returns a 1-hour access token and a 90-day refresh token. Refresh tokens rotate on every use. Sending an already-rotated refresh token again revokes the whole grant, and the client must connect again.

You do not type those paths into Claude. You paste the connector URL. Claude is supposed to do the discovery. If it asks you for a different host than api.ringkit.com, stop.

Three credentials, and they do not mix

Three credentials exist, and they are not substitutes. No credential is for an agent creating a new business with ringkit_create_business, on /mcp only. An rk_... API key is for scripts and for agents that already have a key, on /mcp and on the REST API. An rko_at_... OAuth access token is what a linked MCP client uses, on /mcp or /mcp/oauth, and it does not work as a REST API key. Google Connected Apps is a separate resource at /mcp/google. A token from that resource does not work on /mcp, and a token from this connector does not work there.

Registration has limits the notes state. A client may register 10 times per IP per minute. The client secret, when there is one, is shown once, and only a SHA-256 hash is stored. A registration that never receives a code or a grant is deleted after 24 hours. If Claude asks you to connect again the next day, that can be a new registration, not a broken phone line.

One business, and the tools you will not see

A linked session acts for exactly one business. The tools that create a business, manage API keys, or invite an owner are hidden. That is deliberate. The connector is for the business you picked on the consent screen, not for opening new companies.

A read-only token that calls a write tool gets insufficient_scope, with a step-up challenge. If you need changes, approve ringkit.manage when you connect, or connect again. Do not paste an API key beside the OAuth token and hope both apply.

POST /oauth/revoke and the /oauth/connections page disconnect the grant. After a revoke, the connector has no business until you approve one again.

What this does not do

The connector does not answer calls. The receptionist does, on the number you forward or publish. It says it is an AI, uses the brief, transfers to your own team or takes a message, and leaves a summary. That behavior is described in what an AI receptionist does.

The connector does not file an LLC or book a calendar. The public docs say to use the API or MCP directly.

It also does not replace the carrier forward. Connecting Claude does not point your existing number at RingKit. A person still sets that up with the carrier.

If DISABLE_MCP_OAUTH=1 is set on the server, this flow is off. API keys still work. That flag is an operator setting, not a switch in Claude.

If the docs page and this page disagree

The public docs page, as published with the site, tells Claude Desktop to send a bearer API key to https://api.ringkit.com/mcp. That is the key path. This article is the OAuth path, and the URL is /mcp/oauth.

Use the OAuth URL when you want Claude's connector sign-in and a consent screen. Use the key path when you already have an rk_ key and a config file. Do not mix them in one connection and expect the hidden tools to reappear. A linked OAuth session will still hide business creation, API keys, and owner invites.

Prices for the phone line are on the pricing page: $1.99 a month per number and $0.20 a minute for the AI receptionist, with the first 10 seconds of each call free. The connector does not change that. Reading a setting from Claude is not phone time, and it does not start the monthly number fee by itself.