[cost: free (pure CPU, no network) | read-only, no persistence]
Run RFC 3261 / RFC 3325 / RFC 8224 / RFC 8225 / CTIA BCID compliance checks on a single raw SIP request (typically an INVITE) and return a list of findings.
Catches the failure modes that silently break carrier interop:
- Two `From:` headers in one request (RFC 3261 §7.3 / §20.20).
- Missing CRLF between consecutive header lines (RFC 3261 §7.3).
- `;tag=` (or any other) parameter on P-Asserted-Identity / P-Preferred-Identity (RFC 3325 §9.1).
- PASSporT `orig.tn` not matching the From caller TN (RFC 8224 §5).
- PASSporT `dest.tn` not matching the To callee TN (RFC 8224 §5).
- Non-canonical TN inside a PASSporT claim (RFC 8225 §5.2.1).
- Branded display name in From with no `ppt=rcd` Identity header (CTIA BCID §5).
Use FIRST when chasing 422 / 400 Bad Request / 484 Invalid FROM on a single INVITE - these usually have a structural cause this tool catches mechanically.
Pair with: `parse_sip_message` for purely structural checks on any SIP message (responses included); `validate_stir_shaken_identity` for the cryptographic verdict on Identity headers; `search_sip_docs({ sourceType: 'stir-shaken', ... })` to ground the explanation in RFC text.
Connector