RCO-A2A MCP - streamable HTTP JSON-RPC at POST /mcp

get_receipt    - the signed receipt of a gate decision on a GSC hub, by decision_id
write_receipt  - hubs only (x-hub-key)

Human: https://rco-a2a.ai/  ·  a receipt page per id at https://rco-a2a.ai/receipts/{decision_id}