Built a free validator for this at ucptools.dev - checks /.well-known/ucp compliance against the spec and gives A-F grading with specific fix recommendations.

Built a free validator for this at ucptools.dev - checks /.well-known/ucp compliance against the spec and gives A-F grading with specific fix recommendations. Interesting finding: tested major retailers and even google.com returns 404 on their UCP endpoint. Early days. Also made an Apify Actor for bulk validation if anyone needs to check multiple domains programmatically.