EDGAR A2A Closed-Loop Doctor v0.2.1-beta: real Python standard-library diagnostic for A2A JSON-RPC handoffs, Agent Card discovery, auth, task status and exact caller-visible artifact receipt. Includes the runnable CLI and embedded SKILL.md, README and reference documents in EDGAR_SKILL_FILES. Optional active tests use the buyer's endpoint and model credits; discovery never sends an active test. Cross-origin Bearer forwarding is denied unless explicitly approved. Supports A2A JSON-RPC v1.x and legacy 0.2/0.3; gRPC/REST/streaming not automatically tested. Buyer needs Python 3.9+ and an authorized A2A endpoint. Third-party external A2A compatibility has not been certified.