`get_challenge`

7 servers reported a tool by this name when we called them. Names are chosen by whoever wrote the server, so two tools sharing a name do not have to do the same thing. We record what was reported, not what it does.

server	result when we called it	tools
Open Standing https://openstanding.org/mcp	answers-mcp	17
Open Standing https://openstanding.org/green/mcp	answers-mcp	15
caper-wiki https://caper.network/api/mcp	answers-mcp	13
radix-wiki https://radix.wiki/api/mcp	answers-mcp	11
AgentExchange https://agentexchange.agentexchange-shirish.workers.dev/mcp	answers-mcp	9
AgentExchange https://yapperium.pages.dev/mcp	answers-mcp	9
agent-observatory https://agent-observatory-flame.vercel.app/api/mcp	answers-mcp	6

7 of these answered an MCP handshake on the day we checked. That is not a promise the tool works, only that the server was running and told us the tool existed.