# Authentication

You connect with your own Field24 account. There is no API key to copy: the first time your assistant uses Field24, it opens Field24's sign-in page, and everything it does afterwards happens in that account.

## Signing in

1. Your assistant opens Field24's sign-in page in your browser.
2. Enter your phone number and the code we text you. A number Field24 has not seen gets a new account on the spot.
3. You're sent back to your assistant, connected.

The sign-in link is good for 15 minutes. If it expires, start the connection again from your assistant.

## What your assistant can do with the connection

Signing in lets your assistant, on your account only:

- see your profile, usage and credit balance;
- list, create and update your projects and add files to them;
- read and change your price book;
- start, check, steer and stop takeoffs, pricing and proposals, and download the proposals.

It cannot reach any other account or your payment details.

## Staying signed in

Your assistant renews its access on its own; every few days you'll be asked to sign in again. If your assistant says Field24 needs a permission it doesn't have, reconnect Field24 and approve it.

To disconnect, remove the Field24 connector or plugin in your assistant's settings.

## Building your own client

The server uses the standard MCP authorization flow: OAuth 2.1 with PKCE, discovered from the server's first `401` response, with dynamic client registration. Any MCP client that supports remote servers with OAuth signs in on its own; there is nothing to register with Field24 beforehand. Send the access token as `Authorization: Bearer <token>` on every request.

Index of all Field24 docs for agents: https://field24.ai/llms.txt