A2A

A2A is the agent-to-agent protocol Google introduced at Cloud Next in April 2025 (and donated to the Linux Foundation that June). Where MCP targets the LLM-to-tool link, A2A targets the agent-to-agent link — one agent delegating work to another vendor's agent and consuming the result.

For marketers it sketches a near-future shape: a user's shopping agent talking directly to a brand's customer-service agent to check stock or negotiate price. That handoff is the canonical A2A example in industry talks.

MCP, A2A and UCP all landed in a short window, which makes the standards landscape feel crowded. The current read is that they live at different layers rather than competing head-on, but it will probably take through late 2026 to see which survive.