# Sub-project 39 — 2010BB NM109 byte defect fix: Design Spec

**Date:** 2026-07-07
**Status:** Draft, awaiting user sign-off
**Branch:** `sp39-2010bb-nm109-fix`
**Aesthetic direction:** No new UI; one serializer normalization helper + regression tests + regen script.

## 1. Scope

On 2026-07-07, an audit of Cyclone's outbound 837P files surfaced a byte-level
defect in loop 2010BB (payer): the `NM1*PR*2*<name>*****PI*<id>` segment was
being emitted with `NM109 = "SKCO0"` (and `NM103 = "COHCPF"`) for CO Medicaid
claims, where Gainwell's MOVEit Transfer SFTP requires `NM109 = "CO_TXIX"`
or `"CO_BHA"`. The payer rejected four batches at the SET level with
`"2010BB NM109 must equal CO_TXIX or CO_BHA"`. SP33 already corrected the
canonical `PayerConfig.co_medicaid()` payer id going forward, but the
serializer's `_build_payer_block` still emits whatever `claim.payer.id` it
is handed — so any pre-SP33 `ClaimOutput` rows in the DB whose `raw_json`
captured `payer.id = "SKCO0"` will round-trip the defect on re-serialize.

A 363-file pre-correction set already exists at
`ingest/corrected/batch-*/` (regenerated earlier with an upstream
`raw['payer']['id']` workaround in `regen_837s.py`), plus four original
outbound 837s at `ingest/tp11525703-837P-20260701*.txt` that retain the
defect. The SP-N lands a defense-in-depth fix inside the serializer
itself so the workaround can be removed and so any future caller that
hands the serializer a stale `SKCO0` (or empty) payer id still emits a
byte that Gainwell accepts.

**In scope:**

- A new private helper `_normalize_payer_id(payer)` in
  `backend/src/cyclone/parsers/serialize_837.py` that substitutes
  `"CO_TXIX"` for `payer.id` whenever the value is empty,
  `"SKCO0"`, or `"CO_BHA"`. The substitution also aligns
  `payer.name` to `"CO_TXIX"` when the original `payer.name` was
  the legacy `"COHCPF"`, `"CO_BHA"`, or empty, so the regenerated
  `NM103` stays consistent with the substituted `NM109`. Foreign
  payer IDs (anything not in the substitution set) are emitted
  verbatim — the helper only normalizes CO Medicaid-shape values.
- A WARNING log emitted by `_build_payer_block` whenever the
  helper substitutes a value, carrying the substituted-from and
  substituted-to strings (one log per affected call; the
  serializer is invoked once per claim so the volume is bounded
  by batch size).
- Hardening `_build_payer_block` to call the helper before
  delegating to `_build_nm1`.
- A regression test in `backend/tests/test_serialize_837.py`
  asserting: `SKCO0` → `CO_TXIX` in NM109 + NM103; empty payer id
  → `CO_TXIX` in NM109; `CO_BHA` → `CO_TXIX` in NM109 + NM103;
  a foreign-payer id (e.g. `"OTHER_PAYER"`) preserved unchanged.
- An idempotent regen script
  `unbilled-july2026/scripts/regen_corrected_files.py` (alongside
  the analysis scripts in the sibling project folder) that walks
  the 363 corrected `ingest/corrected/batch-*/` files,
  re-parses each one through `parse_837.parse_837_text`, and
  re-serializes through `serialize_837_for_resubmit`. Output goes
  to `ingest/corrected-v2/<batch-id>-<N>-claims/` with a single
  global counter for unique timestamps. Each emitted file is
  re-validated with `parse_837_text` + a content check that
  asserts `PI*CO_TXIX` is present and neither `PI*SKCO0` nor
  `*COHCPF****` appear.
- A new `resubmissions` table
  (`claim_id`, `batch_id`, `resubmitted_at`, `source_corrected_path`,
  `interchange_control_number`, `group_control_number`) plus a
  matching SQLAlchemy migration under `backend/migrations/0013_*.py`.
  The table is populated by the existing `cyclone resubmit-rejected-claims`
  CLI when the operator pushes a corrected file (one row per claim
  per resubmission; idempotent on `(claim_id, interchange_control_number)`).
- A new CLI `cyclone resubmissions status [--batch-id=<id>]`
  that joins `resubmissions` → `claims` → `claim_acks` (via the
  existing SP28/31 ack-claim auto-link) → `remittances` (via the
  existing CLP→claim auto-link) and prints a per-claim row:
  `claim_id | patient | resubmitted_at | 999_status | 277ca_status |
  payment_status`. Statuses are derived as: `pending_999` if no
  ack row exists yet, `999_accepted` if a 999 with accept code
  exists, `999_rejected` if a 999 with reject code exists,
  `277ca_accepted` / `277ca_rejected` once 277CA arrives,
  `paid` once a remittance CLP links, `denied_again` if a 277CA
  reject exists post-resubmission.
- A note in `docs/RUNBOOK.md` under "Manual SFTP mode" pointing
  the operator at the new `corrected-v2/` tree + the new
  `cyclone resubmissions status` CLI after this SP merges, and
  an inline TODO comment in
  `submission/core.py:EXPECTED_PAYER_ID` block referencing the
  future follow-up that will trace where `ClaimOutput.payer.id`
  gets set to `"SKCO0"` upstream.

**Out of scope:**

- Tracing and patching the upstream setter that populates
  `ClaimOutput.payer.id = "SKCO0"` (a separate future ticket; this
  SP only defense-in-depths the serializer). The
  `_normalize_payer_id` helper masks the upstream bug for any path
  that goes through `serialize_837` / `serialize_837_for_resubmit`,
  but does not touch the `claims` table.
- Re-ingesting the four rejected `ingest/tp11525703-837P-*.txt`
  files. They are historical artifacts of the rejected
  submission and remain in `ingest/` for audit only; the operator
  does not resubmit them. The 363 corrected files in
  `ingest/corrected/batch-*/` are the resubmission payload, not
  these four.
- Auto-resubmitting `ingest/corrected-v2/` via
  `cyclone resubmit-rejected-claims`. That CLI is the operator's
  workflow (per RUNBOOK §"Manual SFTP mode") and remains
  operator-invoked only. This SP only regenerates the corrected
  files; the operator chooses when to push them.
- Any change to `PayerConfig.co_medicaid()` (SP33 already
  canonicalized it) or to the `submission/core.py` validation
  gate at `EXPECTED_PAYER_ID`. The gate continues to enforce
  CO_TXIX at submit time and is not relaxed by this SP.
- A frontend surface for resubmission status. The CLI report is
  the only operator-facing view; a future UI increment (likely a
  new Inbox lane or Dashboard KPI) can render the same joined
  data once the workflow is proven.
- Touching the existing 999/277CA/remit auto-link code paths.
  The resubmission status CLI consumes the same joined tables
  the auto-link already populates; this SP does not modify the
  auto-link logic itself.

## 2. Decisions (locked during brainstorming)

**D1: Substitute both legacy values — `SKCO0` and `CO_BHA` —
plus empty — to `CO_TXIX`.**

The operator's policy is "every claim is CO_TXIX". The companion
guide technically accepts `CO_BHA` for behavioral-health claims,
but Cyclone is not configured to distinguish BHA claims at
submission time and the operator's existing manual workflow
treats `CO_TXIX` as the canonical value for all CO Medicaid
submits. `CO_BHA` therefore gets normalized the same way `SKCO0`
does. Foreign payer IDs (any value not in `{empty, "SKCO0",
"CO_BHA"}`) are emitted verbatim — the helper only normalizes
CO Medicaid-shape values and must not corrupt a non-CO submit.

**D2: The helper also fixes `payer.name` to match.**

When the helper substitutes `payer.id` to `CO_TXIX`, it also
substitutes `payer.name` from `"COHCPF"`, `"CO_BHA"`, or empty
to `"CO_TXIX"`. This keeps NM103 consistent with NM109 and
matches the byte the operator's manual-mode workflow already
uses in the corrected files.

**D3: WARNING log per substitution, not per batch.**

`_build_payer_block` is invoked once per claim. One log line per
substitution is bounded by batch size (≤ 145 lines for the Jun 24
batches) and is the minimum signal the operator needs to detect
"this batch still has upstream contamination". Per-batch
aggregation would hide multi-payer batches (if any are ever
supported).

**D4: Regression tests live in `test_serialize_837.py`, not a
new file.**

The existing file already covers NM1 segment shape; appending
three tests for the helper is the minimal-surface change.
Matching the `cyclone-tests` convention (sibling test file per
module).

**D5: Regen script lives in the unbilled-july2026 sibling
project.**

The 363 files + the four `ingest/tp11525703-837P-*.txt` originals
are part of the unbilled-july2026 recovery work, not the Cyclone
core codebase. The sibling project folder already houses the
analysis scripts; the regen script follows the same convention.
The script reads `ingest/corrected/batch-*/` (relative to
Cyclone's repo root, since `ingest/` is shared with the
production SFTP workflow) and writes to `ingest/corrected-v2/`.

**D6: Re-run into `ingest/corrected-v2/`, not clobber the
original `batch-*/` tree.**

The 363 corrected files are the postmortem anchor for SP33-era
SKCO0 contamination. Preserving them under `batch-*/` lets a
future contributor diff pre-SP39 and post-SP39 outputs and
confirms the helper is a byte-faithful transformation on every
input that was already correct. The `corrected-v2/` tree is the
new submission payload.

**D7: File a follow-up note (in RUNBOOK), don't patch the
upstream `ClaimOutput.payer.id` setter in this SP.**

The operator picked hard-fix the serializer (Approach 1) over
trace to root cause (Approach 3). The follow-up ticket belongs
in a future SP; this SP captures the need via a TODO comment in
`submission/core.py` and a RUNBOOK entry pointing at the new
corrected-v2/ tree.

**D8: `resubmissions` is a write-once audit table, not a
state-machine.**

The table records "this claim was pushed to SFTP at this time
from this local file" — one row per claim per push. The CLI
derives status (`pending_999` / `999_accepted` / `paid` / etc.)
at read-time by joining against `claim_acks` + `remittances`
+ the existing auto-link tables. We do not denormalize status
onto the `resubmissions` row, because that would create a
write-coordination problem between the SFTP push and the
inbound 999/277CA ingestion.

**D9: Post-submission tracking joins reuse the existing
auto-link data, no new matching logic.**

The 999 ack auto-link (SP28/31) already maps an inbound CLP
segment back to a `claim_id` via CLP01 + charge + service date.
Because the corrected-v2 regen preserves the original `claim_id`
from `raw_json.claim.claim_id`, the 999 ack for a resubmitted
file auto-links to the original claim row — and the new status
CLI just joins `resubmissions.claim_id` against `claim_acks.claim_id`
to surface the result. No new matching code is needed; this SP
adds the read-side join and the CLI surface, not a new matcher.

**D10: The `resubmit-rejected-claims` CLI inserts `resubmissions`
rows; we do not add a new push CLI.**

The existing `cyclone resubmit-rejected-claims` (per
`backend/src/cyclone/cli.py` and the SP33 followup work) is
the operator's only entry point for pushing corrected files via
SFTP. We instrument it to insert one `resubmissions` row per
claim per push (matching the same idempotency key as the SFTP
upload). No new CLI command for the push side.

## 3. Open questions

None. The operator confirmed the design via the brainstorming
Q&A on 2026-07-07: hard-fix the serializer with empty/SKCO0/CO_BHA
substitution to CO_TXIX (no CO_BHA preservation), regen into
corrected-v2/, add a post-submission tracking table + status CLI
(joined against existing auto-link data, no new matcher), file
a follow-up note for upstream tracing, no UI, no auto-resubmit.

## 4. Test impact

Per `cyclone-tests` (autouse conftest at `backend/tests/conftest.py`):

- `backend/tests/test_serialize_837.py` — append three tests
  targeting `_build_payer_block` via the public
  `serialize_837_for_resubmit` entry point. Each test constructs
  a minimal `ClaimOutput` whose `payer.id` is set to the value
  under test, calls `serialize_837_for_resubmit`, and asserts the
  emitted `NM1*PR` segment. Tests:
    - `test_2010bb_normalizes_skco0_to_co_txix` — asserts
      `SKCO0` → `CO_TXIX` in NM109 and `COHCPF` → `CO_TXIX` in
      NM103.
    - `test_2010bb_normalizes_empty_payer_id_to_co_txix` —
      asserts empty `payer.id` → `CO_TXIX` and empty `payer.name`
      → `CO_TXIX`.
    - `test_2010bb_normalizes_co_bha_to_co_txix` — asserts
      `CO_BHA` (with name `CO_BHA`) → `CO_TXIX` in both NM109
      and NM103. Plus a fourth assertion that a foreign payer id
      (e.g. `"OTHER_PAYER"` with name `"OTHER PAYER NAME"`) is
      emitted verbatim — the helper must not corrupt non-CO
      submits.
- `backend/tests/test_resubmissions_cli.py` — new, tests the
  `cyclone resubmissions status` CLI via `click.testing.CliRunner`.
  Seeds the `resubmissions` table + `claim_acks` (via the
  existing fixture pattern) and asserts:
    - `pending_999` when no ack exists yet.
    - `999_accepted` after a 999 ack with accept code is linked.
    - `paid` after a remittance CLP links.
    - Exit code 0 with empty `resubmissions` table prints
      "no resubmissions recorded" and exits 0.
- `backend/tests/test_resubmissions_table.py` — new, tests the
  SQLAlchemy model + idempotency of `(claim_id, interchange_control_number)`.
  Asserts schema columns, asserts a second insert with the same
  key is a no-op (raises IntegrityError or ON CONFLICT DO NOTHING,
  matching the convention in the rest of `db.py`).
- `unbilled-july2026/scripts/test_regen_corrected_files.py` —
  new, sibling test in the unbilled-july2026 project. Uses a
  fixture of three fake-corrected files (one already correct,
  one with SKCO0 from a degenerate raw_json, one with CO_BHA)
  and asserts the regen script emits all three with the expected
  normalization.
- Migration test impact: append to
  `backend/tests/test_db_migrate.py` (or equivalent) a check
  that migration 0013 creates the `resubmissions` table with
  the documented columns + idempotency unique constraint.
- No frontend test impact.

## 5. Files expected to change

- `backend/src/cyclone/parsers/serialize_837.py` — add
  `_normalize_payer_id(payer)`, call it from `_build_payer_block`,
  emit WARNING log on substitution.
- `backend/src/cyclone/db.py` — add `Resubmission` SQLAlchemy
  model.
- `backend/migrations/0013_resubmissions.py` — new migration
  creating the `resubmissions` table.
- `backend/src/cyclone/cli.py` — instrument
  `resubmit-rejected-claims` to insert one `Resubmission` row
  per claim per push (idempotent on
  `(claim_id, interchange_control_number)`); add the
  `cyclone resubmissions status` subcommand.
- `backend/src/cyclone/store/__init__.py` — add
  `CycloneStore.record_resubmission(...)` and
  `CycloneStore.find_resubmission_status(...)` helpers; re-export
  through the facade.
- `backend/tests/test_serialize_837.py` — append the three
  regression tests.
- `backend/tests/test_resubmissions_cli.py` — new CLI tests.
- `backend/tests/test_resubmissions_table.py` — new model +
  idempotency tests.
- `backend/tests/test_db_migrate.py` — append migration test
  for 0013.
- `unbilled-july2026/scripts/regen_corrected_files.py` — new
  sibling-project regen script.
- `unbilled-july2026/scripts/test_regen_corrected_files.py` —
  new sibling-project test.
- `docs/RUNBOOK.md` — append "After SP39 lands" entry under
  "Manual SFTP mode" pointing the operator at `corrected-v2/`,
  the new `cyclone resubmissions status` CLI, and the workflow
  to push via `cyclone resubmit-rejected-claims`.
- `backend/src/cyclone/submission/core.py` — append TODO comment
  above `EXPECTED_PAYER_ID` referencing the future upstream-
  trace ticket.
- `docs/superpowers/plans/2026-07-07-cyclone-2010bb-nm109-fix.md`
  — the implementation plan, written after this spec is signed
  off.

## 6. Auth boundary

The auth boundary is HTTP (login required, bcrypt + HttpOnly
session cookie); file-system threats remain the local-only threat
model (SQLCipher at rest, macOS Keychain). The serializer helper
is invoked server-side by both `serialize_837` (tested via
`cyclone submit-batch` / `POST /api/submit-batch`, both behind
HTTP auth) and `serialize_837_for_resubmit` (called by the
operator's regen workflow and by `/api/inbox/rejected/resubmit`,
also behind HTTP auth). The sibling-project regen script is
operator-invoked only and runs against a local file tree; it does
not touch the HTTP surface or the DB. No change to the threat
model.