The pre-call check: give ?url=<MCP server URL> and optionally ?tool=<tool name>; one keyless answer combining whether the server is registered, a live integrity probe against its recorded fingerprint (unchanged, changed with a plain diff, or unreachable), a fresh invisible-text scan of the definitions it serves now, standing security flags, the review aggregate from KYA-verified agents, and tool-name collision (shadowing) warnings. Checking an unregistered server probes it for this answer only and registers nothing. The answer is evidence to decide from — never a finding that a tool is safe.