A phone number your agent can actually read

Point your client at it

The server speaks the Model Context Protocol over HTTP. Add it to any MCP client that can send an Authorization header. Create the key in your workspace settings, where it's shown once.

{
  "mcpServers": {
    "cleat": {
      "type": "http",
      "url": "https://cleat.so/api/mcp",
      "headers": { "Authorization": "Bearer clt_your_api_key" }
    }
  }
}

The key decides what the agent can reach. Left open, that is its own workspace's lines and nothing else. Narrow it when you create it — to named lines, and to a date it stops working — and the agent reaches only the line you meant: anything else answers 404, and after the date the key answers 401 with code key_expired. Revoke it and the agent is locked out on the next call. No password or session is affected.

The four tools

Waiting beats polling

wait_for_code only counts texts that arrive after the call starts. A code left over from an earlier sign-in is never mistaken for this one. Call it immediately before the step that triggers the text, then submit the form. The tool is already listening.

curl https://cleat.so/api/mcp \
  -H "Authorization: Bearer $CLEAT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/call",
    "params": {
      "name": "wait_for_code",
      "arguments": { "lineId": "8f14e45f-ceea-4b6b-9d3c-2a1f0e7c5b10", "timeoutSeconds": 45 }
    }
  }'

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "structuredContent": {
      "found": true,
      "id": "c9a7e0d2-5b1f-4e8a-9f3c-6d2b1a0e4f77",
      "line": { "id": "8f14e45f-ceea-4b6b-9d3c-2a1f0e7c5b10", "phone": "13055550100", "label": "Agent line" },
      "from": "55512",
      "body": "Your verification code is 704 118",
      "code": "704118",
      "receivedAt": "2026-09-11T10:02:41.000Z",
      "service": null,
      "contact": null,
      "label": null
    },
    "content": [{ "type": "text", "text": "…the same JSON again, for the model to read" }]
  }
}

If nothing arrives in time it returns found: false with timedOut: true. That is an ordinary result the agent can retry, not an error.

Why the number has to outlast the sign-up

Most numbers sold for agent work are rented by the minute or the week and then returned to a pool. That fits one sign-up and fails an account the agent keeps. Even vendors selling the disposable kind make the argument against it: “If your agent creates an account and keeps operating it, a one-time number is a problem, because platforms periodically re-verify, and if the number is gone the account locks out.” And: “A dedicated number stays assigned to that agent's account, holds its verification history, and receives the new code whenever a platform re-checks” (GeeLark, 16 September 2026).

A Cleat line is the durable kind by construction. One number on a subscription, no rental clock, and no endpoint that rotates it. A re-check three months later lands on the same line, and a signed webhook can wake a process that isn't running to catch it. What Cleat doesn't sell is the other half of that pitch: pools of fresh numbers for provisioning accounts at volume. One line per subscription, one verified owner, for accounts that owner is entitled to hold.

What this is, and what it isn't

• Receive only. Cleat Line receives texts. It cannot send them, and there is no tool that tries. It cannot place or answer a call either.
• A code phoned in still lands. When a service reads a code out over an automated call, the call is transcribed. The transcript arrives as an ordinary message, code extracted, with the number that called in from. No field marks it as a call.
• One number per subscription. Each line is $24.99 a month. Cleat isn't a pool of throwaway numbers, and there's no endpoint that rotates them.
• A verified human owns every line. Identity is checked once, for the account, before any number is issued. An agent can't sign itself up.
• 120 requests a minute per key. A wait_for_code that's waiting isn't spending requests.
• A line on hold can't be read. If a subscription lapses, the number is held and its texts stay locked until it resumes.

If you'd rather not use MCP

The same data is a plain REST API with signed webhooks. It suits a long-running service better than an agent session: see Cleat for developers. To share codes with people instead of programs, use the team inbox. A real mobile line receives codes that an internet number never gets: see non-VoIP numbers and Google Voice and verification codes.