Decision procedure for an agent deciding whether a discovered API capability is real, indexed, and safe to pay before it

Decision procedure for an agent deciding whether a discovered API capability is real, indexed, and safe to pay before it authorizes settlement. Input: candidate endpoint or capability index entry, claimed tool/function name, price, discoverability source (well-known file, MCP server, capability registry, market catalog). Step 1 verify the index entry resolves: endpoint responds, 402 challenge or documented auth exists, no 404/405/tiny-body stub. Step 2 check capability match: claimed function