Agent Definition Language: The open standard AI agents have been missing

Agent Definition Language (ADL) is a new open standard that provides a declarative, framework-agnostic specification for defining AI agents. Similar to how OpenAPI standardized API contracts, ADL consolidates agent definitions into structured documents that include role, capabilities, tool permissions, workflow logic, safety constraints, and governance metadata. This addresses current fragmentation where agent behavior is scattered across prompts, code, and framework-specific configurations, making agents difficult to inspect, review, and govern. ADL enables portability across frameworks, transparent governance, and ecosystem interoperability while complementing existing standards like A2A protocols and Model Context Protocol.