Add stores to ARC's free, open agent-commerce directory (CC-BY dataset). Pass url for one store or hosts for up to 50. Each new host is validated (live HTTPS, not parked, not redirecting to another brand); accepted hosts are queued for ARC's plain-HTTP rails checks (UCP, WebMCP, MCP, policies, product data) and appear in the dataset with source=submitted. No model calls, no login. Rate limited per caller.