# An unknown /.well-known address answers 404

- Date: 2026-10-28
- Type: New
- Surface: Developer portal and CLI
- What you need to do: Nothing.
- Address: https://developers.rivr.io/changelog/2026-10-28-unknown-well-known-is-404

An address under /.well-known that the portal does not serve, such as /.well-known/skills/index.json or /.well-known/openapi.json, answered the portal's start page with status 200, so a tool or an agent that looked for it could not tell that it does not exist. It now answers 404 with a JSON body (`error` not_found) that names the two documents the portal does serve there: /.well-known/security.txt and the agent skill registry /.well-known/agent-skills/index.json.