OpenA2A This document defines ai-safety.txt, a plain-text declaration format that a domain publishes at a well-known location to communicate its AI-safety posture to autonomous agents and agent-driven browsers. Modeled on the robots.txt convention, an ai-safety.txt file lets a domain assert, in a machine-readable form, whether its content is safe for autonomous agent consumption, whether that content is hardened against prompt injection, and whether it is rendered consistently to human and agent user agents. The file also carries a security contact, a link to an external verification record, and the date the declaration was last verified. The declarations in an ai-safety.txt file are self-asserted by the publishing domain. This document specifies the file format and its well-known location, and it is explicit that a consuming agent treats a declaration as a hint rather than as proof, verifying it against independent evidence where such evidence is available.