RFC 9457 Problem Details Author

Use this skill when the user asks to:

• return API errors over HTTP (or similar) in a structured way
• define a problem-details schema/payload
• map internal errors to HTTP status codes
• standardize error responses across handlers/services

Mandatory references (read in order)

1. references/nonnegotiables.md
2. references/doterr.md
3. references/clearpath.md (production code only)
4. references/go-dt-paths.md (only if paths/files appear in metadata)
5. references/rfc9457-package-notes.md (go-rfc9457 catalog notes)