A2A protocol
Also known as: agent-to-agent protocol, A2A, inter-agent protocol
Agent-to-agent (A2A) is an emerging open standard for inter-agent communication, originally proposed by Google in 2025 and adopted by working groups across multiple vendors. It defines how one agent advertises its capabilities, accepts delegations, returns structured results, and reports failures to another agent — across vendor and infrastructure boundaries.
A2A is at deployment-grade stability for narrow use cases (vendor-to-vendor capability advertisement) but not yet for production-critical multi-agent coordination as of Q2 2026. The protocol's adoption trajectory affects how multi-agent architectures evolve; widespread A2A would shift the 2026 default pattern toward broker-mediated by reducing the implementation cost. CIOs evaluating multi-agent platforms should ask which A2A version (if any) the vendor implements and where the implementation falls short.
Related frameworks
Articles that analyse this term
Primary sources
- Google Cloud. A2A — A new era of agent interoperability
- Linux Foundation. Agent2Agent project