Some very quick initial thoughts - the json spec has some similarities to mcp: https://google.github.io/A2A/#/documentation?id=agent-card https://google.github.

Some very quick initial thoughts - the json spec has some similarities to mcp: https://google.github.io/A2A/#/documentation?id=agent-card https://google.github.io/A2A/#/documentation?id=agent-card - there's an agent card that describes capabilities that google wants websites to host at https://DOMAIN/.well-known/agent.json https://DOMAIN/.well-known/agent.json according to https://google.github.io/A2A/#/topics/agent_discovery https://google.github.io/A2A/#/topics/agent_discovery so crawlers can scrape to discover agents. The jsonrpc calls look similar-ish to mcp tool calls except the inputs and outputs look closer to the inputs/outputs from calling an LLM (ie messages, artifacts, etc.). The JS server example that they give is interesting https://github.com/google/A2A/tree/main/samples/js/src/server https://github.com/google/A2A/tree/main/samples/js/src/serve... - they're using a generator to send sse events back to the caller - a little weird to expose as the API instead of just doing what express allows you to do after setting up an sse connection (res.send / flush multiple times).