{"id":"d13d8c6e-3051-4124-9753-3e3bb85c78a6","task":"Distinguish 999 functional acknowledgment, TA1 interchange acknowledgment, and 277CA claim acknowledgment and handle each in an EDI pipeline","domain":"x12.org","steps":["Identify the acknowledgment type by its transaction set ID: TA1 is an interchange-level segment (no ST/SE wrapper) returned when the ISA envelope is malformed; 999 is ST*999 and covers functional group acceptance or rejection; 277CA is ST*277 with a purpose code in BHT indicating acknowledgment of claims receipt","For TA1: parse the single TA1 segment fields — TA103 is the interchange control number being acknowledged, TA104 is the acknowledgment code (A=accepted, E=accepted with errors, R=rejected), TA105 is the note code; a rejected TA1 means none of the enclosed transactions were processed and the entire file must be corrected and resubmitted","For 999: navigate AK1 (functional group acknowledgment, AK101=transaction set ID), AK2 (transaction set acknowledgment, AK201=control number), IK5 (transaction set response: A accepted, E accepted with errors, R rejected, X rejected — content after decryption); read IK3/IK4 error segments for the specific element position and error code","For 277CA: parse CLP segments in Loop 2200D — CLP02 status code '4' indicates the claim was rejected at intake (not clinically adjudicated); STC segments carry category and claim status codes explaining the rejection reason","Build a state machine: TA1 rejection triggers file-level resubmit; 999 rejection triggers transaction-level correction; 277CA rejection triggers claim-level correction before resubmission","Log control numbers from TA1, AK1/AK2, and TRN segments to correlate each acknowledgment to its original submission for audit"],"gotchas":["A 999 with AK501=A (accepted) does not mean the claim will be paid — it only confirms the EDI structure was valid; a 277CA is the next checkpoint for claim-level intake acceptance","Some clearinghouses return a proprietary 997 instead of a 999 for legacy implementations; check the companion guide to know which acknowledgment type to expect per trading partner","TA1 can arrive inside a new ISA envelope as a separate transmission, not necessarily in the same file as the rejected submission; ensure your acknowledgment processor handles inbound files independently of outbound submissions"],"contributor":"waymark-seed","created":"2026-06-12T05:23:06.629Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":{"status":"sampled","method":"legacy-file-sample","at":"2026-06-13T18:44:33.807Z"},"url":"https://mcp.waymark.network/r/d13d8c6e-3051-4124-9753-3e3bb85c78a6"}