SMS codes for AI agents: read verification codes through MCP

Connect your agent

Sign-in is OAuth 2.1 with dynamic client registration: point the client at the URL, a browser window opens, you confirm with a code sent to your email (or to the phone on your account) and press Allow. There is no client ID or secret to paste.

claude mcp add --transport http busysms https://busysms.net/mcp

codex mcp add busysms --url https://busysms.net/mcp

[mcp_servers.busysms]
url = "https://busysms.net/mcp"

In the Claude app, open Customize → Connectors → + Add → Add custom connector, name it BusySMS and paste https://busysms.net/mcp. Other MCP clients, Grok included, add it as a remote HTTP server with the same URL. A client that cannot do OAuth can send a bsk_live_ API key as a Bearer token instead.

A typical agent flow

1. 1

   Start the sign-in

   The agent fills in the login form or calls the service, and the service texts a code to your number.

2. 2

   Wait for the code

   It calls wait_for_code straight away, passing phone or sender when you have several numbers.

3. 3

   Use the code

   It types the code in and carries on. If nothing arrives, it gets nothing back and can retry or ask you, instead of guessing.

A prompt as plain as this works with any connected agent:

Sign in to staging.example.com as +44 7700 900123.
When the site asks for the SMS code, call BusySMS wait_for_code
with phone 447700900123, enter the code, and tell me when you are in.

Several numbers, shared numbers, and when codes do not come

With more than one number on your account, or a number a teammate has shared with you, "the next code" is ambiguous. Pass phone with the receiving number so a code for another sign-in on another number is not returned, or sender with part of the sender's name. Shared numbers work like your own: once you accept a share, the code tools include its new codes.

If codes are not arriving at all, ask the agent to run diagnose_my_gateway: it compares what is enrolled, verified and online and suggests the next step. test_my_gateway goes further and proves the whole path end to end. Let the agent ask you first, because it sends a real SMS to your number.

Safety built into the tools

• Your phones only. Every tool is scoped to your account and to numbers shared with you. An agent cannot read anyone else's messages.
• No secret in the transcript. create_api_key makes a REST key but never returns it: you get a one-time link, valid for 15 minutes, that you open yourself. SMS text can carry instructions written by a stranger, so a long-lived key must never enter the agent's context.
• Changes need a signed-in session. Tools that change things, such as testing your gateway, sharing a number or revoking a key, cannot be used with an API key at all.
• Messages to yourself only. send_sms_to_me and send_email_to_me have no recipient argument; they can only reach the number and address on your own account.

What the agent needs on your side

• A phone with the SIM: Android with the BusySMS app, or an iPhone with a Shortcuts automation.
• The number verified in BusySMS.
• An active trial or subscription. Without one, code-reading tools return a billing error, while list_devices keeps working so the agent can tell you why.

No account yet?

The public tools answer product questions without signing in (pricing, setup steps, device requirements, troubleshooting), so an assistant can tell you accurately what BusySMS does before you sign up. Reading codes needs an account: $5 per verified number per month after a 7-day free trial.

FAQ

Frequently asked questions