# captionrich auth.md

How AI agents and developers authenticate with captionrich.

## Public data needs no credentials

These are public and read-only. Call them without a token, key, or registration:

- MCP server: https://captionrich.com/api/mcp (Streamable HTTP, JSON-RPC over POST)
- Public JSON API: https://captionrich.com/api/public/v1 (OpenAPI: https://captionrich.com/openapi.json)
- https://captionrich.com/llms.txt, https://captionrich.com/llms-full.txt, and every marketing page, also as Markdown with `Accept: text/markdown`

## User accounts

- People sign in with Google, in a web browser, at https://captionrich.com/login. There is no password login, no API key, and no OAuth client registration for third-party agents.
- There is no agent registration or provisioning endpoint. Agents cannot create accounts or obtain credentials for a user.
- The editor at https://captionrich.com/edit uses the signed-in browser session. An agent working in the user's own browser uses that session after the user signs in.

## Contact

Questions about agent access: support@captionrich.com