What is A2A? Agent discovery and cross-system task collaboration
Understand Agent2Agent through delegated research, including discovery, task state, artifacts, differences from MCP, and limits of trust and authorization.
Understand the concept
Agent2Agent is an open protocol for requests and task results across agent systems, including discovery and task interactions without exposing all internal implementation. It differs in focus from MCP and can complement it. Protocol use does not establish trust, correctness, or inherited user authorization.
Capability descriptions aid discovery but require verification
A research assistant can discover a remote service for public-source retrieval and delegate a scoped task. Agent Cards describe capabilities and access, but are provider statements rather than proof of evidence quality or expertise.
Use supported authentication and authorization, sending only permitted task data rather than unrelated private material. This is a public-research example without connecting remote agents or performing cross-system business actions.
Read task state separately from final artifacts
Remote tasks may take time or need more input; receiving a response does not imply completion. Handle state and inspect artifacts for coverage. A2A defines tasks and messages, while actual interaction support depends on both implementations.
Cited answers still require source checks. A claim of verification without traceable material remains insufficient. Cross-system transfer and agent agreement do not turn unsupported assertions into facts.
Distinguish MCP and local multi-agent orchestration
MCP focuses on applications connecting to tools and context services; A2A focuses on collaboration between agents. A remote agent can use MCP internally and return work through A2A. They are complementary choices based on the interaction needed.
Local roles can be coordinated without a cross-system protocol. A2A integrations still need failure, cancellation, and duplicate handling. This explanation uses specification and ADK sources without interoperability tests or blanket cross-vendor compatibility claims.
Checked sources
These sources support the concepts and methods described here. Examples and test scope are labeled separately; check the version of the tools you use.