A2A and MCP: complementary, not competing
MCP connects agents to tools; Agent2Agent connects agents to each other. Together they turn single agents into systems, and raise the governance stakes.
MCP and A2A solve different problems, and the debate over which one wins misses that. Google Cloud Next 2025 brought the Agent2Agent protocol, the Agent Development Kit and MCP support together. Google's own A2A announcement described it as complementing MCP: MCP gives an agent access to tools and data, while A2A lets agents discover and work with each other.
A2A's modality-agnostic design is the part I find most interesting. Agents can collaborate in whatever form suits the task, including text, audio or video streaming, rather than being forced through a single chat format.
Standards are making AI less of a solo act. Interoperability is what turns individual agents into enterprise systems. But it also raises the governance stakes considerably. When one agent can call tools and also delegate to other agents, you need identity, authorization and audit across both protocols. A permission boundary that holds for a single agent can leak once it starts handing work to others.
If your agents can talk to each other, can you trace who asked whom to do what?
Cite this: Bommiah, M. (2025, May 1). A2A and MCP: complementary, not competing. muthub.org. https://muthub.org/writing/a2a-and-mcp
Adapted from my LinkedIn posts of April 10 and April 30, 2025. Views are my own and do not represent my employer.