# CycloneStore split (Step 4) — Implementation Plan (Resumed)

> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.

**Goal:** Behaviour-preserving structural split of `backend/src/cyclone/store.py` (2,995 lines) into a `cyclone/store/` subpackage with **14 modules** and a thin facade. Zero public API changes, zero test changes, single atomic commit at the end.

**Architecture:** Module functions for each domain (`batches.add_record`, `inbox.manual_match`, `kpis.dashboard_kpis`, etc.); `CycloneStore` class in `__init__.py` keeps its current method signatures as 1-line delegations. The facade re-exports every currently-importable name (public symbols + 3 private helpers used by tests) so no caller changes.

**Tech Stack:** Python 3.11+, SQLAlchemy 2.x, Pydantic v2, pytest. Existing test infrastructure (no new tests).

**Spec:** [`docs/superpowers/specs/2026-06-21-cyclone-store-split-design.md`](../specs/2026-06-21-cyclone-store-split-design.md) (resumed 2026-06-29).

**Supersedes:** [`docs/superpowers/plans/2026-06-21-cyclone-store-split.md`](2026-06-21-cyclone-store-split.md) — preserved as historical record. The original plan targeted 13 modules / 2,412 LOC / line-number-anchored code copies; the resumed store.py is 583 LOC larger, has 3 new top-level symbols, and uses function-name references rather than line numbers (which drift with every edit).

---

## Delta vs. 2026-06-21 plan

| | 2026-06-21 | 2026-06-29 (this plan) |
|---|---|---|
| `store.py` size | 2,412 LOC | 2,995 LOC |
| Target modules | 13 | **14** (new `kpis.py`) |
| Test baseline | ~712 / ~31 / ~16 | **1,176 / 1 (isolation flake) / 10** |
| Per-task code copies | yes (every function pasted) | no (function-name references; read store.py for the source) |
| New symbols to extract | — | `dashboard_kpis` + `_claim_state_str` → `kpis.py`; `check_matched_pair_drift` → `claim_detail.py` |
| Private-helper re-exports | `_claim_status_from_validation` | + `_persist_835_remit` + `_remittance_835_row` |

**How to use this plan alongside the 2026-06-21 plan:** Treat the 2026-06-21 plan as the historical record of how the pattern was designed. This plan is what to execute today. Tasks 0-13 below correspond to Tasks 0-12 in the original with: (a) `check_matched_pair_drift` folded into Task 8 (claim_detail), (b) a new Task 9 (kpis), (c) original Tasks 9-12 renumbered to 10-13.

---

## File structure (target)

```
backend/src/cyclone/
├── store.py                       ← DELETED in Task 13
└── store/
    ├── __init__.py                ← Task 1 — facade: re-exports + CycloneStore + store + utcnow
    ├── exceptions.py              ← Task 2
    ├── records.py                 ← Task 3
    ├── orm_builders.py            ← Task 4
    ├── ui.py                      ← Task 5
    ├── write.py                   ← Task 6
    ├── batches.py                 ← Task 7
    ├── claim_detail.py            ← Task 8 (now also hosts check_matched_pair_drift)
    ├── kpis.py                    ← Task 9 — NEW: dashboard_kpis + _claim_state_str
    ├── acks.py                    ← Task 10
    ├── backups.py                 ← Task 11
    ├── inbox.py                   ← Task 12
    └── providers.py               ← Task 12
```

Each module has one clear responsibility. Files that change together live together.

---

## Task 0: Pre-flight — capture baseline + audit private-helper leaks

**Goal:** Snapshot the test suite baseline. Find every private-helper import leak (imports of `_`-prefixed names from `cyclone.store`) so the facade re-exports cover all callers.

**Files:**
- Read: `backend/src/cyclone/store.py`
- Write: `/tmp/cyclone-baseline.txt` (test output snapshot)
- Write: `/tmp/cyclone-test-private-imports.txt`
- Write: `/tmp/cyclone-src-private-imports.txt`

- [ ] **Step 1: Capture pytest baseline**

```bash
cd backend && python -m pytest tests/ --tb=line -q 2>&1 | tee /tmp/cyclone-baseline.txt | tail -5
```

Expected: `1 failed, 1176 passed, 10 skipped in <Ns>`. The 1 failure is `tests/test_provider_extended_response.py::test_provider_detail_includes_orphan_remit_received` — known test-isolation flake (passes solo, fails after other tests due to shared state). Record the exact 5-line tail.

- [ ] **Step 2: Audit private-helper imports in tests**

```bash
grep -rn "from cyclone.store import _" backend/tests/ | tee /tmp/cyclone-test-private-imports.txt
```

Expected (verified 2026-06-29):

```
backend/tests/test_service_line_payments.py:23:from cyclone.store import _persist_835_remit, _remittance_835_row
backend/tests/test_api_line_reconciliation.py:21:from cyclone.store import _persist_835_remit, _remittance_835_row
backend/tests/test_reconcile_line_level.py:25:from cyclone.store import _persist_835_remit, _remittance_835_row
backend/tests/test_inbox_endpoints_sp7.py:22:from cyclone.store import _persist_835_remit, _remittance_835_row
```

Both `_persist_835_remit` and `_remittance_835_row` must be re-exported from the facade (in addition to `_claim_status_from_validation` from the original audit).

- [ ] **Step 3: Audit private-helper imports in source**

```bash
grep -rn "from cyclone.store import _" backend/src/ | tee /tmp/cyclone-src-private-imports.txt
```

Expected (verified 2026-06-29):

```
backend/src/cyclone/batch_diff.py:32:from cyclone.store import BatchRecord, BatchRecord835, BatchRecord837, _claim_status_from_validation
```

`_claim_status_from_validation` must be re-exported from the facade (already documented in original spec).

- [ ] **Step 4: Verify package discovery on the current tree**

```bash
cd backend && pip install -e . --quiet 2>&1 | tail -3
python -c "import cyclone.store; print('OK:', cyclone.store.__file__)"
```

Expected: prints the absolute path to `backend/src/cyclone/store.py`.

- [ ] **Step 5: Verify no `store*` subpackage exists yet**

```bash
find backend/src/cyclone -maxdepth 1 -name "store*"
```

Expected: only `backend/src/cyclone/store.py` (no `store/` directory).

No commit. Pre-flight only.

---

## Task 1: Create the package skeleton (atomic move, no commit yet)

The trick: copy `store.py` content into `store/__init__.py`, delete `store.py`, verify everything still works via the package. The CycloneStore class and `store` singleton live in `__init__.py` for now; they'll be delegated to module functions in Tasks 2-12. The working tree stays dirty through Tasks 2-12 — the single atomic commit happens at the end of Task 13.

**Files:**
- Create: `backend/src/cyclone/store/__init__.py` (verbatim copy of store.py with updated docstring)
- Delete: `backend/src/cyclone/store.py`

- [ ] **Step 1: Read the current store.py**

```bash
wc -l backend/src/cyclone/store.py
```

Expected: `2995`.

- [ ] **Step 2: Create the package directory and copy**

```bash
mkdir -p backend/src/cyclone/store
cp backend/src/cyclone/store.py backend/src/cyclone/store/__init__.py
```

- [ ] **Step 3: Update the module docstring**

Read the first ~30 lines of `backend/src/cyclone/store/__init__.py` (the existing docstring). Replace the existing module docstring with this updated text that names all 14 sibling modules and notes the 3 private-helper re-exports:

```python
"""SQLAlchemy-backed batch store for parsed X12 files.

The package exposes a single ``CycloneStore`` class and a module-level
singleton (``store``). All persistence flows through SQLAlchemy
sessions via ``db.SessionLocal()()`` (the double-paren function-style
accessor).

This ``__init__.py`` is the facade — it re-exports every public name
plus the 3 private helpers imported by tests (``_claim_status_from_validation``,
``_persist_835_remit``, ``_remittance_835_row``) from the sibling modules:

    exceptions      AlreadyMatchedError, NotMatchedError, InvalidStateError
    records         BatchKind, BatchRecord, BatchRecord837, BatchRecord835
    orm_builders    ORM row builders + the 3 private-helper re-exports
    ui              UI serializers (to_ui_*)
    write           add_record + private event/reconcile helpers
    batches         Batch reads + _BatchesShim (test-cleanup shim)
    claim_detail    Single-claim reads + matched-pair drift audit
    kpis            Dashboard aggregation
    acks            999 / TA1 / 277CA ACK persistence
    backups         Backup-pending marker inserts
    inbox           Manual match/unmatch + lane listing
    providers       Provider/payer/clearhouse config

The ``CycloneStore`` class below keeps its current method signatures as
thin delegations for back-compat with existing callers and tests.

Public API (preserved verbatim):
    CycloneStore, store, BatchRecord, BatchRecord837, BatchRecord835,
    BatchKind, AlreadyMatchedError, NotMatchedError, InvalidStateError,
    utcnow, dashboard_kpis, check_matched_pair_drift

Backward-compat shims for tests:
    ``_lock`` — a threading.RLock used by 7 test files for cleanup.
    ``_batches.clear()`` — wipes all rows from the DB tables; the
        ``_BatchesShim`` class lives in ``batches.py``.
"""
```

- [ ] **Step 4: Delete the old store.py**

```bash
rm backend/src/cyclone/store.py
```

- [ ] **Step 5: Verify imports still work**

```bash
python -c "
from cyclone.store import (
    CycloneStore, store, BatchRecord, BatchRecord837, BatchRecord835, BatchKind,
    AlreadyMatchedError, NotMatchedError, InvalidStateError, utcnow,
    dashboard_kpis, check_matched_pair_drift,
    _claim_status_from_validation, _persist_835_remit, _remittance_835_row,
)
print('all imports OK')
"
```

Expected: `all imports OK`.

- [ ] **Step 6: Verify test suite matches baseline**

```bash
cd backend && python -m pytest tests/ --tb=line -q 2>&1 | tail -5
```

Expected: identical 5-line tail to `/tmp/cyclone-baseline.txt`. Any deviation is a regression — halt and investigate before continuing.

**No commit yet.** The final atomic commit happens in Task 13.

---

## Task 2: Extract `exceptions.py`

**Files:**
- Create: `backend/src/cyclone/store/exceptions.py`
- Modify: `backend/src/cyclone/store/__init__.py`

- [ ] **Step 1: Create `exceptions.py`**

Read the 3 exception class definitions in `backend/src/cyclone/store/__init__.py` (the 3 classes with names starting at column 0: `AlreadyMatchedError`, `NotMatchedError`, `InvalidStateError`). Copy them verbatim into `backend/src/cyclone/store/exceptions.py` with this module docstring:

```python
"""Exception types raised by CycloneStore and its domain modules.

These are part of the public API — callers (API endpoints) catch them
and translate to HTTP 409 Conflict responses.
"""
```

- [ ] **Step 2: Update `__init__.py` to re-export**

Remove the 3 class definitions from `__init__.py`. Add at the top of `__init__.py` (after `from cyclone import db`):

```python
from .exceptions import AlreadyMatchedError, NotMatchedError, InvalidStateError
```

- [ ] **Step 3: Verify tests still pass**

```bash
cd backend && python -m pytest tests/ --tb=line -q 2>&1 | tail -5
```

Expected: identical to baseline.

---

## Task 3: Extract `records.py`

**Files:**
- Create: `backend/src/cyclone/store/records.py`
- Modify: `backend/src/cyclone/store/__init__.py`

- [ ] **Step 1: Create `records.py`**

Read the Pydantic-model block in `__init__.py` (the 4 definitions: `BatchKind = Literal[...]`, `class BatchRecord`, `class BatchRecord837`, `class BatchRecord835`). Copy them verbatim into `backend/src/cyclone/store/records.py` with this module docstring:

```python
"""Pydantic models for parsed-batch records.

``BatchRecord`` is the union type; ``BatchRecord837`` and ``BatchRecord835``
narrow ``result`` to the parser-specific output types. Construction of
``BatchRecord(kind="837p", ...)`` dispatches to ``BatchRecord837`` via
``__new__`` so isinstance checks downstream narrow ``result`` correctly.
"""
```

- [ ] **Step 2: Update `__init__.py`**

Remove the 4 definitions from `__init__.py`. Add to imports:

```python
from .records import BatchKind, BatchRecord, BatchRecord837, BatchRecord835
```

- [ ] **Step 3: Verify tests still pass**

```bash
cd backend && python -m pytest tests/ --tb=line -q 2>&1 | tail -5
```

Expected: identical to baseline.

---

## Task 4: Extract `orm_builders.py`

**Files:**
- Create: `backend/src/cyclone/store/orm_builders.py`
- Modify: `backend/src/cyclone/store/__init__.py`

- [ ] **Step 1: Create `orm_builders.py`**

Read the ORM row-builder block in `__init__.py` (the 6 module-level helpers named with leading underscore: `_service_dates_from_claim`, `_claim_837_row`, `_remittance_835_row`, `_cas_adjustment_row`, `_persist_835_remit`, `_claim_status_from_validation`). Copy them verbatim into `backend/src/cyclone/store/orm_builders.py` with this module docstring:

```python
"""ORM row builders — convert parser output into SQLAlchemy ORM rows.

Each function returns an unsaved ORM object (or inserts related rows
within an existing session). They never commit or close the session —
the caller (``write.add_record``, ``acks.add_ack``, etc.) owns the
transaction boundary.
"""
```

- [ ] **Step 2: Update `__init__.py`**

Remove the 6 helpers from `__init__.py`. Add to imports — re-export the 3 private helpers that tests + `batch_diff.py` import:

```python
from .orm_builders import (
    _claim_status_from_validation,
    _persist_835_remit,
    _remittance_835_row,
)
```

The other 3 (`_service_dates_from_claim`, `_claim_837_row`, `_cas_adjustment_row`) are module-private; siblings import them directly via `from .orm_builders import ...`.

- [ ] **Step 3: Verify tests still pass**

```bash
cd backend && python -m pytest tests/test_service_line_payments.py tests/test_api_line_reconciliation.py tests/test_reconcile_line_level.py tests/test_inbox_endpoints_sp7.py tests/test_batch_diff.py tests/ --tb=line -q 2>&1 | tail -5
```

Expected: identical to baseline. (The 4 files importing the private helpers will fail loud if the re-export is wrong.)

---

## Task 5: Extract `ui.py`

**Files:**
- Create: `backend/src/cyclone/store/ui.py`
- Modify: `backend/src/cyclone/store/__init__.py`

- [ ] **Step 1: Create `ui.py`**

Read the UI-serializer block in `__init__.py`: every top-level function whose name starts with `to_ui_` or `_iso_z` / `_address_to_ui` / `_validation_issues_to_ui` / `_svc_to_wire_dict` / `_date_in_bounds` / `_provider_orm_to_dict` / `_payer_orm_to_dict`, plus the constant `CLAIM_DETAIL_HISTORY_LIMIT`. Also include the `utcnow()` function. Copy them verbatim into `backend/src/cyclone/store/ui.py` with this module docstring:

```python
"""UI serialization helpers — convert ORM rows to API-shaped dicts.

These are the boundary between the persistence layer and the wire format
consumed by the React frontend. Keep them stable: any rename or
shape change ripples to every API consumer.

Also hosts ``utcnow()`` (the tz-aware UTC now) because it's a small
free function that several modules want and there's no better home.
"""
```

- [ ] **Step 2: Update `__init__.py`**

Remove the UI serializer functions AND `utcnow()` from `__init__.py`. Add to imports:

```python
from .ui import utcnow
```

`utcnow` is the only one re-exported (for `api_helpers.py` docstring reference and any external use).

- [ ] **Step 3: Verify tests still pass**

```bash
cd backend && python -m pytest tests/ --tb=line -q 2>&1 | tail -5
```

Expected: identical to baseline.

---

## Task 6: Extract `write.py`

**Files:**
- Create: `backend/src/cyclone/store/write.py`
- Modify: `backend/src/cyclone/store/__init__.py`

- [ ] **Step 1: Create `write.py`**

Read the `CycloneStore.add` method body, plus the 3 private methods `_publish_events_sync`, `_sync_publish`, `_run_reconcile` in `__init__.py`. Copy them into `backend/src/cyclone/store/write.py` as module functions with these renames:

| Class method | Module function |
|---|---|
| `CycloneStore.add` | `add_record(record, *, event_bus=None)` |
| `CycloneStore._publish_events_sync` | `publish_events_sync(event_bus, record, claim_ids, remit_ids)` |
| `CycloneStore._sync_publish` | `_sync_publish(event_bus, kind, payload)` |
| `CycloneStore._run_reconcile` | `run_reconcile(batch_id)` |

In each function body:
- Strip the `self.` prefix from all attribute accesses (but no other refactoring).
- `self._publish_events_sync(...)` → `publish_events_sync(...)`
- `self._run_reconcile(...)` → `run_reconcile(...)`
- `self._sync_publish(...)` → `_sync_publish(...)`

Module docstring:

```python
"""Write path for parsed batches — insert, reconcile, publish.

The single entry point is ``add_record(record, *, event_bus=None)``,
which replaces the body of the previous ``CycloneStore.add`` method.
It owns its own SQLAlchemy session, runs idempotency checks, persists
the batch + child rows, then (for 835 batches) triggers reconciliation
and (if ``event_bus`` is provided) publishes live-tail events.

Reconciliation runs OUTSIDE the persistence session, fail-soft: errors
are logged but do not roll back the persisted batch.
"""
```

- [ ] **Step 2: Update `__init__.py` CycloneStore class**

Add import:

```python
from . import write
```

Replace the 4 method bodies with 1-line delegations:

```python
    def add(self, record, *, event_bus=None):
        """Persist a parsed batch (837P or 835)."""
        return write.add_record(record, event_bus=event_bus)

    def _publish_events_sync(self, event_bus, record, claim_ids, remit_ids):
        return write.publish_events_sync(event_bus, record, claim_ids, remit_ids)

    def _run_reconcile(self, batch_id):
        return write.run_reconcile(batch_id)

    @staticmethod
    def _sync_publish(event_bus, kind, payload):
        return write._sync_publish(event_bus, kind, payload)
```

- [ ] **Step 3: Verify hot-path tests pass**

```bash
cd backend && python -m pytest tests/test_parse_999.py tests/test_parse_277ca.py tests/test_api_999.py tests/test_api_277ca.py tests/test_reconcile.py tests/test_reconcile_line_level.py tests/test_api_line_reconciliation.py --tb=short -q
```

Expected: 100% pass on these 7 files.

- [ ] **Step 4: Verify full suite matches baseline**

```bash
cd backend && python -m pytest tests/ --tb=line -q 2>&1 | tail -5
```

Expected: identical to baseline.

---

## Task 7: Extract `batches.py`

**Files:**
- Create: `backend/src/cyclone/store/batches.py`
- Modify: `backend/src/cyclone/store/__init__.py`

- [ ] **Step 1: Create `batches.py`**

Read in `__init__.py`:
- The `_BatchesShim` class definition (verbatim — the test-cleanup shim)
- The `_row_to_record` helper
- The 5 `CycloneStore` methods: `get_batch`, `get`, `list`, `all`, `load_two_for_diff`

Copy into `backend/src/cyclone/store/batches.py` as module functions with these renames:

| Class method | Module function |
|---|---|
| `CycloneStore.get_batch` | `get_batch(batch_id)` |
| `CycloneStore.get` | `get_record(batch_id)` (rename avoids builtin shadow) |
| `CycloneStore.list` | `list_batches(*, limit=100)` |
| `CycloneStore.all` | `all_batches()` |
| `CycloneStore.load_two_for_diff` | `load_two_for_diff(batch_ids)` |

Strip `self` from each. Module docstring:

```python
"""Batch read APIs and the legacy _BatchesShim.

The ``_BatchesShim`` class is retained for back-compat with the
``with store._lock: store._batches.clear()`` test-cleanup idiom used
in 7 test files. Its ``clear()`` method wipes all rows from the DB
tables so tests that depended on a fresh in-memory list per-test get
a fresh DB state per-test.
"""
```

- [ ] **Step 2: Update `__init__.py` CycloneStore class**

Add import:

```python
from .batches import (
    _BatchesShim, _row_to_record,
    get_batch, get_record, list_batches, all_batches, load_two_for_diff,
)
```

Replace the 5 method bodies with 1-line delegations. (Note: `get_batch` is a top-level function in `batches.py`; the class method also called `get_batch` is a thin wrapper — Python scope resolves correctly.)

```python
    def get_batch(self, batch_id):
        return get_batch(batch_id)

    def get(self, batch_id):
        return get_record(batch_id)

    def list(self, *, limit=100):
        return list_batches(limit=limit)

    def all(self):
        return all_batches()

    def load_two_for_diff(self, batch_ids):
        return load_two_for_diff(batch_ids)
```

- [ ] **Step 3: Verify tests pass**

```bash
cd backend && python -m pytest tests/test_api_gets.py tests/test_api_parse_persists.py tests/test_api_parse_persists_ack.py tests/test_api_claim_detail.py tests/test_api_999.py tests/test_api_ta1.py tests/test_store.py --tb=short -q
```

Expected: 100% pass on these 7 files.

---

## Task 8: Extract `claim_detail.py` (also hosts `check_matched_pair_drift`)

**Files:**
- Create: `backend/src/cyclone/store/claim_detail.py`
- Modify: `backend/src/cyclone/store/__init__.py`

- [ ] **Step 1: Create `claim_detail.py`**

Read in `__init__.py`:
- The 6 `CycloneStore` methods: `get_remittance`, `get_claim_detail`, `iter_claims`, `iter_remittances`, `distinct_providers`, `recent_activity`
- The module-level function `check_matched_pair_drift()` (added by SP27; ~110 LOC, returns `int` count of drifted pairs)

Copy into `backend/src/cyclone/store/claim_detail.py` as module functions:

| Class method / function | Module function |
|---|---|
| `CycloneStore.get_remittance` | `get_remittance(remittance_id)` |
| `CycloneStore.get_claim_detail` | `get_claim_detail(claim_id)` |
| `CycloneStore.iter_claims` | `iter_claims(...)` (preserve generator pattern) |
| `CycloneStore.iter_remittances` | `iter_remittances(...)` (preserve generator pattern) |
| `CycloneStore.distinct_providers` | `distinct_providers()` |
| `CycloneStore.recent_activity` | `recent_activity(*, limit=200)` |
| module-level `check_matched_pair_drift` | `check_matched_pair_drift()` (no rename) |

For the 2 generators (`iter_claims`, `iter_remittances`), each must open its own `with db.SessionLocal()() as s:` and `yield` inside; the session lifetime tracks the generator's. Preserve the existing pattern verbatim.

Module docstring:

```python
"""Claim- and remittance-detail read APIs.

Includes the only large non-write query in the store:
``get_claim_detail`` which joins Claim + CasAdjustment + ActivityEvent
history for the right-drawer UI.

Also hosts ``check_matched_pair_drift()`` — the SP27 startup invariant
audit that returns the count of Claim↔Remit pairs where
``matched_remittance_id`` doesn't agree with the FK in ``remittances.claim_id``.
It lives here (not in its own module) because it reads the same pair of
tables as ``get_claim_detail``'s matched-remittance summary.
"""
```

- [ ] **Step 2: Update `__init__.py` CycloneStore class**

Add import:

```python
from .claim_detail import (
    get_remittance, get_claim_detail,
    iter_claims, iter_remittances,
    distinct_providers, recent_activity,
    check_matched_pair_drift,
)
```

Replace the 6 method bodies with 1-line delegations:

```python
    def get_remittance(self, remittance_id):
        return get_remittance(remittance_id)

    def get_claim_detail(self, claim_id):
        return get_claim_detail(claim_id)

    def iter_claims(self, *args, **kwargs):
        return iter_claims(*args, **kwargs)

    def iter_remittances(self, *args, **kwargs):
        return iter_remittances(*args, **kwargs)

    def distinct_providers(self):
        return distinct_providers()

    def recent_activity(self, *, limit=200):
        return recent_activity(limit=limit)
```

- [ ] **Step 3: Verify tests pass**

```bash
cd backend && python -m pytest tests/test_api_claim_detail.py tests/test_store_claim_detail.py tests/test_store_match_invariant.py --tb=short -q
```

Expected: 100% pass on these 3 files (the drift-audit tests live in `test_store_match_invariant.py`).

---

## Task 9: Extract `kpis.py` (NEW MODULE from SP27)

**Files:**
- Create: `backend/src/cyclone/store/kpis.py`
- Modify: `backend/src/cyclone/store/__init__.py`

- [ ] **Step 1: Create `kpis.py`**

Read in `__init__.py`:
- The module-level function `dashboard_kpis()` (~150 LOC, returns a dict with `claims_total`, `remittances_total`, `matched_total`, `unmatched_total`, `paid_total_cents`, `adjustments_total_cents`, `recent_activity`)
- The module-level helper `_claim_state_str()` (used internally by `dashboard_kpis`)

Copy them verbatim into `backend/src/cyclone/store/kpis.py`. Module docstring:

```python
"""Dashboard KPI aggregation — cross-table reads consumed by /api/dashboard/kpis.

``dashboard_kpis()`` returns a single dict that the React Dashboard page
consumes as the source of truth for the 4 KPI tiles + the recent-activity
panel. It reads from claims + remittances + batches in a single pass.

``_claim_state_str`` is a small mapping helper that translates ORM
status enum values to UI-friendly strings. It's private to this module.
"""
```

- [ ] **Step 2: Update `__init__.py`**

Remove `dashboard_kpis` and `_claim_state_str` from `__init__.py`. Add to imports:

```python
from .kpis import dashboard_kpis
```

(`_claim_state_str` is module-private; not re-exported.)

- [ ] **Step 3: Verify tests pass**

```bash
cd backend && python -m pytest tests/test_dashboard_kpis.py tests/ --tb=line -q 2>&1 | tail -5
```

Expected: identical to baseline.

---

## Task 10: Extract `acks.py`

**Files:**
- Create: `backend/src/cyclone/store/acks.py`
- Modify: `backend/src/cyclone/store/__init__.py`

- [ ] **Step 1: Create `acks.py`**

Read the 9 `CycloneStore` ACK methods in `__init__.py`: `add_ack`, `list_acks`, `get_ack`, `add_ta1_ack`, `list_ta1_acks`, `get_ta1_ack`, `add_277ca_ack`, `list_277ca_acks`, `get_277ca_ack`.

Copy into `backend/src/cyclone/store/acks.py` as module functions with these renames for clarity:

| Class method | Module function |
|---|---|
| `CycloneStore.add_ack` | `add_999_ack(...)` |
| `CycloneStore.list_acks` | `list_acks()` |
| `CycloneStore.get_ack` | `get_ack(ack_id)` |
| `CycloneStore.add_ta1_ack` | `add_ta1_ack(...)` |
| `CycloneStore.list_ta1_acks` | `list_ta1_acks()` |
| `CycloneStore.get_ta1_ack` | `get_ta1_ack(ack_id)` |
| `CycloneStore.add_277ca_ack` | `add_277ca_ack(...)` |
| `CycloneStore.list_277ca_acks` | `list_277ca_acks()` |
| `CycloneStore.get_277ca_ack` | `get_277ca_ack(ack_id)` |

Strip `self` from each. Module docstring:

```python
"""ACK persistence — 999 / TA1 / 277CA acknowledgements.

Each ACK type has its own ORM row (Ack / Ta1Ack / Two77caAck). The
write methods are simple inserts; the list/get methods are simple
queries. Fail-soft: persistence errors are logged but do not block
parsing.
"""
```

- [ ] **Step 2: Update `__init__.py` CycloneStore class**

Add import:

```python
from .acks import (
    add_999_ack, list_acks, get_ack,
    add_ta1_ack, list_ta1_acks, get_ta1_ack,
    add_277ca_ack, list_277ca_acks, get_277ca_ack,
)
```

Replace the 9 method bodies with 1-line delegations. Method names on the class stay the same as today; only the module-function names use the type prefix for clarity.

```python
    def add_ack(self, **kwargs):
        return add_999_ack(**kwargs)

    def list_acks(self):
        return list_acks()

    def get_ack(self, ack_id):
        return get_ack(ack_id)

    def add_ta1_ack(self, **kwargs):
        return add_ta1_ack(**kwargs)

    def list_ta1_acks(self):
        return list_ta1_acks()

    def get_ta1_ack(self, ack_id):
        return get_ta1_ack(ack_id)

    def add_277ca_ack(self, **kwargs):
        return add_277ca_ack(**kwargs)

    def list_277ca_acks(self):
        return list_277ca_acks()

    def get_277ca_ack(self, ack_id):
        return get_277ca_ack(ack_id)
```

- [ ] **Step 3: Verify tests pass**

```bash
cd backend && python -m pytest tests/test_api_parse_persists_ack.py tests/test_api_ta1.py tests/test_acks.py tests/test_api_999.py tests/test_apply_277ca_rejections.py --tb=short -q
```

Expected: 100% pass on these 5 ACK-related test files.

---

## Task 11: Extract `backups.py`

**Files:**
- Create: `backend/src/cyclone/store/backups.py`
- Modify: `backend/src/cyclone/store/__init__.py`

- [ ] **Step 1: Create `backups.py`**

Read `CycloneStore.add_backup_pending` in `__init__.py`. Copy into `backend/src/cyclone/store/backups.py` as a module function `add_backup_pending(*, filename, backup_dir)`. Strip `self`. Module docstring:

```python
"""Backup-pending marker persistence.

Used by ``cyclone.backup_service`` to mark files that need backing up
after parsing. Simple insert into the DbBackup table.
"""
```

- [ ] **Step 2: Update `__init__.py` CycloneStore class**

Add import:

```python
from .backups import add_backup_pending
```

Replace the method body with a 1-line delegation:

```python
    def add_backup_pending(self, *, filename, backup_dir):
        return add_backup_pending(filename=filename, backup_dir=backup_dir)
```

- [ ] **Step 3: Verify tests pass**

```bash
cd backend && python -m pytest tests/test_backup_service.py tests/test_api_backup.py --tb=short -q
```

Expected: 100% pass.

---

## Task 12: Extract `inbox.py` + `providers.py`

**Files:**
- Create: `backend/src/cyclone/store/inbox.py`
- Create: `backend/src/cyclone/store/providers.py`
- Modify: `backend/src/cyclone/store/__init__.py`

- [ ] **Step 1: Create `inbox.py`**

Read in `__init__.py`:
- `CycloneStore.list_unmatched`
- `CycloneStore.manual_match`
- `CycloneStore.manual_unmatch`

Copy into `backend/src/cyclone/store/inbox.py` as module functions with the same names (no renames needed). Strip `self`. Module docstring:

```python
"""Inbox lane state and manual match/unmatch operations.

``list_unmatched`` returns the 5-lane inbox view (unmatched claims +
unmatched remits). ``manual_match`` and ``manual_unmatch`` invoke the
reconcile pure functions and persist the resulting Match row (or
remove it). Invalid state transitions surface as ``InvalidStateError``.
"""
```

Add at the top of `inbox.py`:

```python
from cyclone import db, reconcile
from .exceptions import InvalidStateError
```

- [ ] **Step 2: Create `providers.py`**

Read in `__init__.py`:
- The 7 `CycloneStore` methods: `list_providers`, `get_provider`, `upsert_provider`, `list_payers`, `get_payer_config`, `get_clearhouse`, `ensure_clearhouse_seeded`
- The 2 module-level helpers `_provider_orm_to_dict` and `_payer_orm_to_dict`

Copy into `backend/src/cyclone/store/providers.py` as module functions, stripping `self`. Module docstring:

```python
"""Provider, payer, and clearhouse configuration reads and upserts.

The ``providers`` and ``payers`` modules in ``cyclone`` provide the
ORM-row DTOs; this module is the read/upsert surface over them.
``ensure_clearhouse_seeded`` is called at startup to insert the
default Clearhouse row if missing.
"""
```

Add at the top of `providers.py`:

```python
from cyclone import db
from cyclone.providers import Clearhouse, Payer, Provider
```

- [ ] **Step 3: Update `__init__.py` CycloneStore class**

Add imports:

```python
from .inbox import list_unmatched, manual_match, manual_unmatch
from .providers import (
    list_providers, get_provider, upsert_provider, list_payers,
    get_payer_config, get_clearhouse, ensure_clearhouse_seeded,
)
```

Replace the 10 method bodies with 1-line delegations:

```python
    def list_unmatched(self, *, kind="both"):
        return list_unmatched(kind=kind)

    def manual_match(self, claim_id, remit_id):
        return manual_match(claim_id, remit_id)

    def manual_unmatch(self, claim_id):
        return manual_unmatch(claim_id)

    def list_providers(self, *, is_active=True):
        return list_providers(is_active=is_active)

    def get_provider(self, npi):
        return get_provider(npi)

    def upsert_provider(self, provider):
        return upsert_provider(provider)

    def list_payers(self, *, is_active=True):
        return list_payers(is_active=is_active)

    def get_payer_config(self, payer_id, transaction_type):
        return get_payer_config(payer_id, transaction_type)

    def get_clearhouse(self):
        return get_clearhouse()

    def ensure_clearhouse_seeded(self):
        return ensure_clearhouse_seeded()
```

- [ ] **Step 4: Verify hot-path tests pass**

```bash
cd backend && python -m pytest tests/test_inbox_state.py tests/test_inbox_lanes.py tests/test_inbox_endpoints.py tests/test_inbox_endpoints_sp7.py tests/test_payer_rejected_acknowledge.py tests/test_store_reconcile.py tests/test_reconcile.py tests/test_reconcile_line_level.py tests/test_api_line_reconciliation.py tests/test_providers_seed.py --tb=short -q
```

Expected: 100% pass on these 10 hot-path files.

---

## Task 13: Final verification + single atomic commit

- [ ] **Step 1: Run full test suite, compare to baseline**

```bash
cd backend && python -m pytest tests/ --tb=line -q 2>&1 | tail -5
```

Expected: identical 5-line tail to `/tmp/cyclone-baseline.txt`. If any deviation, halt and investigate before committing.

- [ ] **Step 2: Import sanity check**

```bash
python -c "
from cyclone.store import (
    CycloneStore, store, BatchRecord, BatchRecord837, BatchRecord835, BatchKind,
    AlreadyMatchedError, NotMatchedError, InvalidStateError, utcnow,
    dashboard_kpis, check_matched_pair_drift,
    _claim_status_from_validation, _persist_835_remit, _remittance_835_row,
)
print('all public imports OK')

import inspect
store_methods = [m for m in dir(store) if not m.startswith('__')]
expected = {
    # batch reads
    'add', 'get', 'get_batch', 'list', 'all', 'load_two_for_diff',
    # claim-detail reads
    'get_remittance', 'get_claim_detail', 'iter_claims', 'iter_remittances',
    'distinct_providers', 'recent_activity',
    # KPI
    'summarize_remittances',
    # ACKs
    'add_ack', 'list_acks', 'get_ack',
    'add_ta1_ack', 'list_ta1_acks', 'get_ta1_ack',
    'add_277ca_ack', 'list_277ca_acks', 'get_277ca_ack',
    # backups
    'add_backup_pending',
    # inbox
    'list_unmatched', 'manual_match', 'manual_unmatch',
    # providers
    'list_providers', 'get_provider', 'upsert_provider',
    'list_payers', 'get_payer_config', 'get_clearhouse', 'ensure_clearhouse_seeded',
}
missing = expected - set(store_methods)
assert not missing, f'missing methods: {missing}'
print('all expected methods present on singleton')

# Back-compat shims
assert hasattr(store, '_lock'), 'store._lock missing'
assert hasattr(store, '_batches'), 'store._batches missing'
print('back-compat shims intact')
"
```

Expected: `all public imports OK`, `all expected methods present on singleton`, `back-compat shims intact`.

- [ ] **Step 3: Live smoke test on 8 endpoints**

Run these 8 curls against a live `python -m cyclone serve` instance and confirm no 500s:

| Endpoint | Expected |
|---|---|
| `POST /api/parse-999` (valid file) | 200, `ack_code=A` |
| `POST /api/parse-277ca` (valid file) | 200, 3 claim statuses |
| `GET /api/inbox?lane=unmatched` | 200, list shape |
| `POST /api/inbox/match` (happy path) | 200 |
| `POST /api/inbox/match` (already matched) | 409 (AlreadyMatchedError) |
| `POST /api/inbox/unmatch` (happy path) | 200 |
| `POST /api/inbox/unmatch` (not matched) | 409 (NotMatchedError) |
| `GET /api/batches` + `GET /api/batches/{id}` | 200 |
| `GET /api/claims/{id}` | 200, claim detail shape |
| `GET /api/999-acks/{id}` | 200 |
| `GET /api/277ca-acks/{id}` | 200 |

Smoke output is documented in the commit message.

- [ ] **Step 4: Single atomic commit**

```bash
git add -A backend/src/cyclone/store/ backend/src/cyclone/store.py
git status   # confirm: store.py deleted; store/ created with 14 modules
git commit -m "refactor(sp21): split store.py into cyclone/store/ subpackage (14 modules)

Behaviour-preserving structural split of the 2,995-LOC store.py into
a 14-module subpackage with a thin facade. CycloneStore class keeps
its full method surface as 1-line delegations to module functions.

14 modules:
  exceptions, records, orm_builders, ui, write,
  batches, claim_detail, kpis, acks,
  backups, inbox, providers
  (+ __init__.py facade)

Facade re-exports 12 public symbols (CycloneStore, store, BatchRecord*,
BatchKind, AlreadyMatchedError/NotMatchedError/InvalidStateError, utcnow,
dashboard_kpis, check_matched_pair_drift) + 3 private helpers
(_claim_status_from_validation, _persist_835_remit, _remittance_835_row)
to preserve the 4 test files that import them.

Zero public API changes, zero test changes, zero importer changes.
CycloneStore._lock and CycloneStore._batches.clear() remain intact for
the 7 test files still using the cleanup idiom.

Verified: 1,176 / 1 (pre-existing isolation flake) / 10 tests pass —
identical to baseline. Smoke-tested 11 endpoints, no 500s."
```

Expected: 1 commit on `sp21-store-split`. Working tree clean.

- [ ] **Step 5: Push branch + open PR (or wait for user direction)**

Per the SP-N conventions, the single atomic commit on `sp21-store-split` lands via a single atomic merge into `main` (no squash, no rebase). Either:
- Push the branch and let the user trigger the merge, OR
- Run the merge immediately if the user has approved

Default: stop here and report the commit hash + branch state.

---

## Out of scope (explicit)

- Renaming any public symbol
- Changing any method signature
- Refactoring `manual_match` / `manual_unmatch` business logic
- Refactoring `add()` body or its idempotency strategy
- Refactoring `dashboard_kpis` / `check_matched_pair_drift` aggregation logic
- Adding new tests
- Modifying DB models in `cyclone.db`
- Updating SQLCipher key rotation flow
- Touching any of the 7 test files that use `_lock` / `_batches.clear()`
- Touching any of the 4 test files that import `_persist_835_remit` / `_remittance_835_row`
- Touching any importer in `cyclone.api`, `cyclone.api_routers.*`, `cyclone.batch_diff`, `cyclone.backup_service`, `cyclone.scheduler`, `cyclone.handlers.*`, `cyclone.parsers.validator`, `cyclone.api_helpers`

If any of these surface during implementation, they get deferred to follow-up tasks — never silently included.