- backend/src/cyclone/parsers/serialize_837.py — full-rebuild 837P serializer.
Emits envelope (ISA/GS/ST/SE/GE/IEA + BHT) + submitter/receiver/billing
provider/subscriber/payer hierarchy + editable segments (CLM/REF*G1/HI)
+ per-service-line LX/SV1/DTP*472/REF*6R — all from canonical
ClaimOutput fields.
Pivoted from spec §3.1 hybrid to full rebuild because ClaimOutput.raw_segments
only captures post-CLM segments (CLM, REF*G1, HI, LX, SV1 pairs) — not the
envelope or hierarchies. A pass-through approach cannot regenerate those
without expanding raw_segments in parse_837.py (out of scope for this SP).
- backend/tests/test_serialize_837.py — 36 tests covering envelope shape,
hierarchy segments, claim-level builders, service-line builders, edited-field
propagation, round-trip, custom sender/receiver IDs, and resubmit helper.
- backend/tests/test_prodfiles_smoke.py::test_claims_prodfile_round_trip —
every file in docs/prodfiles/claims/ (113 files) round-trips through
serialize_837 → parse_837_text with deep-equal ClaimOutput (modulo
validation, which is recomputed by the parser).
- docs/superpowers/plans/2026-06-20-cyclone-serialize-837.md — full plan
with amendment note documenting the Approach A pivot.
Per session convention, plan note about unrelated modifications to
parse_835.py / fixtures stashed separately.
Tyler
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