We have got at least three discovery mechanisms now. A2A well-known endpoints, MCP server listings, and agents.txt (which is an IETF draft that expires April 10, and nobody seems to be renewing it). Each assumes agents will discover peers through its own channel. None of them interoperate.
I have been building a cross-protocol registry that indexes agents across all three, so a tool like m2a could query "show me agents that do X" instead of requiring the exact URL upfront. The split between these protocols is only going to widen as more agents ship.
Are you thinking about adding any discovery layer, or staying focused on the "I already have the URL" use case?
A2A don't seem to define a protocol for discovery yet - at least I couldn't find one. Happy to engage further and discuss if you want on what are you building.
One of our goals is to accelerate adoption of A2A protocols so anything that is happening on that domain is of our interest!
rafael@mantyx.io if you want to reach out and I agree that doing something like `m2a REGISTRY_URL` might be better generally or any other discovery mechanism.