Protocol Buffer Schema System For Typed Message Serialization And Cross Language Communication

via “protocol buffers-based canonical data model definition for agent interoperability”

Agent2Agent (A2A) is an open protocol enabling communication and interoperability between opaque agentic applications.

Unique: Uses Protocol Buffers as the canonical specification source rather than JSON Schema or OpenAPI, enabling efficient binary serialization and strong typing guarantees across all protocol bindings while maintaining a single source of truth that generates language-specific SDKs

vs others: More efficient than JSON Schema-based approaches (smaller wire size, faster serialization) and more language-agnostic than REST-only specifications, enabling true polyglot agent ecosystems without vendor lock-in