Let Agents from Different Frameworks and Vendors Work Together
The Agent2Agent (A2A) Protocol: an open standard for agent communication
Agents declare capabilities in an Agent Card and deliver work through Messages and Tasks, without exposing their internals.
Three protocol bindings: JSON-RPC, gRPC, and HTTP+JSON. Official SDKs are available in six languages.
Publish an Agent
Declare interfaces, capabilities, skills, and security schemes, then validate and sign an Agent Card you can publish.
Debug Cross-Binding Interoperability
Compare JSON-RPC, gRPC, and HTTP+JSON behavior and the wire differences between v0.3 and v1.0.1 to find out why two implementations do not connect.
Run Tasks and Recover
Pick a delivery mode, learn what each state allows, check the event stream, and handle dropped streams and v0.3 migration traps.
Prepare for Production
Check before release: discovery preflight, authentication and task isolation, streaming and push behavior, observable evidence, and a rollback plan.
Error Codes and Field Numbers
How the nine A2A-specific errors map across the three bindings, and how Agent Card field numbers changed between v0.3.0 and v1.0.1.
Understand A2A First
The problems A2A solves, how it divides the work with MCP, and the full life of a request.
Official Sources and Related Resources
A2A Official Documentation
The protocol originals and release notes, for checking the version.
Official Sources and Resources
Entry to the specification copies, official blog posts, SDKs, and the samples repository.
A2A on GitHub
The official repository for the specification, the proto, and the SDKs.
Model Context Protocol
A2A connects agents to each other; MCP connects an agent to its tools and data.