# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## What this is

Cyclone is a self-hosted X12 EDI claims-management suite for a single billing office (Colorado Medicaid currently). It parses 837P professional claims and 835 ERA remittances (X12 005010X222A1 / 005010X221A1) and also handles 999, TA1, 270, 271, and 277CA. Local-only by design: binds to `127.0.0.1`, requires login (auth boundary is HTTP; bcrypt + HttpOnly session cookie; first admin bootstrapped from `CYCLONE_ADMIN_USERNAME` + `CYCLONE_ADMIN_PASSWORD` env vars; see SP24 spec for the full posture), no internet exposure.

Stack: one Python process (FastAPI + uvicorn, port 8000) + one Node process in dev (Vite, port 5173). The authoritative state is a single SQLite file at `~/.local/share/cyclone/cyclone.db` (or SQLCipher at the same path when the macOS Keychain entry + `sqlcipher3` are both present).

For the day-1 architecture read, see `docs/ARCHITECTURE.md` (process topology, module map, store facade, parser pipeline, pubsub). For the what-it-does read, see `docs/REQUIREMENTS.md` (FRs + NFRs + DoD).

## Install

```bash
# Backend (Python 3.11+)
cd backend
python -m venv .venv
.venv/bin/pip install -e '.[dev]'

# Frontend (Node 20+)
cd ..
npm install
```

Optional backend extras: `pip install -e '.[sqlcipher]'` (encryption at rest, SP12) and `pip install -e '.[sftp]'` (real SFTP, SP13).

## Dev (two terminals)

```bash
# Terminal 1 — backend
cd backend
.venv/bin/python -m cyclone serve         # default 127.0.0.1:8000
# CYCLONE_PORT=... overrides port; CYCLONE_RELOAD=1 enables uvicorn --reload
# Or: .venv/bin/uvicorn cyclone.api:app --reload --port 8000

# Terminal 2 — frontend
npm run dev                                # Vite on http://localhost:5173
```

Vite proxies `/api/*` to the backend at `http://127.0.0.1:${CYCLONE_PORT:-8000}` so relative-URL fetchers (the live-tail NDJSON streams in particular) resolve through the same origin. Override the backend port with `CYCLONE_PORT` in the frontend terminal too.

Create `.env.local` at the repo root with `VITE_API_BASE_URL=http://127.0.0.1:8000`. Without it, the UI runs against the in-memory zustand store and real EDI parsing is disabled.

## Test

```bash
# Backend — full suite
cd backend && .venv/bin/pytest

# Backend — one file
cd backend && .venv/bin/pytest tests/test_api_999.py -v

# Backend — one test by node id
cd backend && .venv/bin/pytest tests/test_api_999.py::test_parse_999_endpoint_happy_path -v

# Frontend — full suite
npm test                                    # alias for `vitest run`

# Frontend — one file
npx vitest run src/hooks/useFoo.test.ts

# Frontend — typecheck
npm run typecheck

# Frontend — build (tsc -b + vite build)
npm run build

# Frontend — lint
npm run lint
```

**Conventions** (full detail in `.superpowers/skills/cyclone-tests/SKILL.md`):

- Backend tests live under `backend/tests/test_*.py`. Two flavors: `test_api_<topic>_<verb>.py` (FastAPI integration via `fastapi.testclient.TestClient`) and `test_<module>_<behavior>.py` (pure-unit). Autouse `conftest.py` points `CYCLONE_DB_URL` at `tmp_path/test.db`, calls `db._reset_for_tests()` + `db.init_db()`, and wires a fresh `EventBus` onto `app.state`.
- Prodfiles (real EDI samples under `docs/prodfiles/<source>/`) are never read directly from a test — copy to `backend/tests/fixtures/<descriptive-name>.txt` first and reference as a module-level `Path` constant. The `fixtures/` dir is flat (no per-test subdirs).
- Frontend tests are siblings: `useFoo.ts` → `useFoo.test.ts`, `ClaimDrawer.tsx` → `ClaimDrawer.test.tsx`. Setup is `// @vitest-environment happy-dom` plus `(globalThis as { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;`. Mock the API at the module boundary with `vi.mock("@/lib/api", ...)`; stub fetch with `vi.stubGlobal("fetch", vi.fn().mockResolvedValue(...))`. `vitest.config.ts` sets `VITE_API_BASE_URL=http://test.local` so the `api` module doesn't throw `notConfiguredError` before the mock fires.
- Time-sensitive tests: frontend uses `vi.useFakeTimers()` + `vi.setSystemTime(...)` + `vi.advanceTimersByTime(ms)`. Backend passes explicit `datetime(...)` values. Don't add `await new Promise((r) => setTimeout(r, N))` — it's the legacy flaky pattern.

## Project-scoped skills (`.superpowers/skills/`)

Cyclone ships 8 skills under `.superpowers/skills/`. They auto-load by description match — no slash command needed. **Read the relevant skill before touching the matching subsystem.**

| Skill | Owns |
|---|---|
| `cyclone-spec` | The SP-N spec → plan → implement → merge flow (branch shape, file paths, commit prefixes, PR title, merge shape). |
| `cyclone-tests` | pytest + vitest fixture patterns, prodfiles drop-in rule, determinism rules. |
| `cyclone-edi` | EDI parser/validator conventions (837P/835/999/270/271/277CA/TA1, R-codes, CAS mapping). |
| `cyclone-tail` | Live-tail streaming wire format and the `useTailStream` + `useMergedTail` + `TailStatusPill` hook triplet. |
| `cyclone-store` | `CycloneStore` facade, write-paths, pubsub event contract, SP21 split map. |
| `cyclone-api-router` | FastAPI router conventions (`api_routers/`, `api_helpers.py`), response/error-envelope shapes. |
| `cyclone-frontend-page` | React page conventions (TanStack Query `use<X>` hook, drawer, URL state, sibling test). |
| `cyclone-cli` | CLI subcommand conventions (`cli.py`, exit codes, smoke tests). |

## The SP-N increment flow

Every feature ships as a numbered **SP-N increment**: spec → plan → implementation branch → single atomic merge into `main`. As of the last backfill, SP numbers are used through **SP22**; **SP23** is reserved for the Ubuntu + Docker + RBAC product fork (`docs/superpowers/specs/2026-06-22-cyclone-ubuntu-docker-deployment-design.md`, awaiting user decision); the next free increment is **SP24**. Read `cyclone-spec` before starting a new one. Non-negotiable shape:

- **Branch:** `sp<N>-<short-kebab-topic>` (e.g. `sp22-line-reconciliation`).
- **Spec path:** `docs/superpowers/specs/YYYY-MM-DD-cyclone-<topic>-design.md`, header `Status: Draft, awaiting user sign-off`, sections `Scope / Decisions / …`. Specs contain zero code blocks.
- **Plan path:** `docs/superpowers/plans/YYYY-MM-DD-cyclone-<topic>.md`, header per `superpowers:writing-plans` with `Goal / Architecture / Tech Stack / Spec` metadata + numbered `- [ ] Step N:` tasks.
- **Commit prefixes:** `feat(sp<N>): …`, `docs(spec): …`, `docs(plan): …`, `merge: SP<N> <topic> into main`.
- **PR title:** `SP<N> <Topic>` (matches the merge-commit subject).
- **Merge shape:** single atomic merge commit. **No squash** (collapses the audit trail) and **no rebase** (rewrites the SHAs the review was performed against). The SP-N merge commit *is* the record of the increment landing.

The matching skill to load alongside `cyclone-spec` depends on the subsystem the SP-N touches (see the "Related skills" section at the bottom of each skill file).

## Live-tail wire format

The Claims, Remittances, and Activity pages stay current without manual refresh. The backend publishes an internal event on every store write, the page opens a streaming HTTP connection to the matching `/api/<resource>/stream` endpoint, and new rows append to the table the moment they hit the database.

Endpoints (all accept the same query params as their non-streaming counterparts; `Content-Type: application/x-ndjson`):

| Method | Path | Subscribes to | Default sort |
|---|---|---|---|
| GET | `/api/claims/stream` | `claim_written` | `-submission_date` |
| GET | `/api/remittances/stream` | `remittance_written` | `-received_date` |
| GET | `/api/activity/stream` | `activity_recorded` | `-timestamp` (limit 50) |

Wire format: one JSON object per line, `{"type": ..., "data": ...}`. The first batch is the **snapshot** of currently-known rows, then `snapshot_end` with the count, then the **live** events. Known types: `item`, `snapshot_end`, `heartbeat` (keeps the connection alive on idle — clients flip to `stalled` after 30s of total silence), `item_dropped` (rare), `error`.

Status pill states (rendered by `<TailStatusPill>` in `src/components/TailStatusPill.tsx`): `live` (success), `connecting` (warning), `reconnecting` (warning), `stalled` (destructive, ↻ Reconnect button), `error` (destructive, ↻ Reconnect button), `closed` (destructive). Backoff on error: `1s → 2s → 4s → 8s → 16s → 30s` capped. `STALL_TIMEOUT_MS = 30_000` in `src/hooks/useTailStream.ts:53`. Heartbeat interval is `CYCLONE_TAIL_HEARTBEAT_S` env var, default 15s.

Frontend triplet for any live page: `use<X>(params)` (initial fetch) + `useTailStream(resource)` (opens the NDJSON stream, drives backoff/stall) + `useMergedTail(resource, baseItems, filterFn?)` (merges snapshot + tail, dedup'd by id). The subscription lives on the page, not inside the data hook — see `cyclone-frontend-page` for why.

## Backend at a glance

`backend/src/cyclone/` is a single namespace. The two largest files are `api.py` (~3,548 LOC, the only large file) and `store.py` (~2,423 LOC, the `CycloneStore` facade — SP21 is in flight to split it into a `cyclone/store/` subpackage; the public API stays unchanged). Subpackages: `api_routers/` (acks, admin, health, ta1_acks), `clearhouse/` (Clearhouse + SftpClient), `edi/` (filenames), `parsers/` (X12 transaction parsers + models + validators + serializers), `workflow/` (placeholder for future sub-project 6).

The store is the only read/write surface for the database; every mutating endpoint goes through it. All persistence flows through SQLAlchemy sessions via `db.SessionLocal()()`. SQLAlchemy ORM models live in `db.py`; 12 SQL migrations under `migrations/` (0001_initial through 0012_backups) are walked in order by `db_migrate.py`.

The parser pipeline is a 5-stage `tokenize → segmentize → model → validate → write_to_store` flow used for every inbound X12 type. Per-transaction parsers: `parse_837.py`, `parse_835.py`, `parse_999.py`, `parse_ta1.py`, `parse_270.py`, `parse_271.py`, `parse_277ca.py`. Each has a matching Pydantic model module (`models.py`, `models_835.py`, …) and a writer (`writer.py` / `writer_835.py`). The 837P serializer (`serialize_837.py`) is the byte-faithful outbound counterpart used by both single-claim download (`/api/claims/{id}/serialize-837`) and the bulk rejected-resubmit bundle (`/api/inbox/rejected/resubmit?download=true`).

The pubsub is `cyclone.pubsub.EventBus` — an in-process async fan-out broker. Publishers call `publish(kind, payload)`; subscribers receive via an async iterator. If a subscriber's per-kind queue is full, the oldest event is dropped so a slow consumer can't stall the producer. Bus is single-event-loop only (matches FastAPI/uvicorn).

Config: `config/payers.yaml` is the on-disk source for providers / payers / clearhouse, schema-validated at boot against a Pydantic model. Reload with `POST /api/admin/reload-config`. Original in-code `PAYER_FACTORIES` dict in `cli.py` is kept as a fallback for ad-hoc testing.

Secrets live in the macOS Keychain (via `keyring` + `cyclone.secrets`): SQLCipher key (service `cyclone`, account `cyclone.db.key`), SFTP password, backup passphrase. No secrets on disk in plaintext.

## Frontend at a glance

`src/` is React 18 + TypeScript + Vite. Routes register in `src/App.tsx` (11 pages, all under a `<Layout>` route wrapper). Pages are pure renderers — every page pairs with a `use<X>` data hook in `src/hooks/` and renders a `<PageHeader>` + a table/list/KPI grid. Drawers (`ClaimDrawer/`, `RemitDrawer/`, plus the new `ProviderDrawer/` and `AckDrawer/`) are mounted by the page and their open/close state is mirrored to the URL via `useDrawerUrlState` so deep-links round-trip. Drill-stack navigation is provided by `<DrillStackProvider>` in `src/components/drill/`.

State split: **server state** in TanStack Query (`@tanstack/react-query`); **ephemeral client state** in Zustand (`useTailStore` for live-tail append, plus the drill stack). The live-tail store is FIFO-capped at `TAIL_CAP = 10_000` per slice (`src/store/tail-store.ts:28`); `claims` and `remittances` are key-by-id with first-write-wins dedup, `activity` is an append-only array.

UI primitives in `src/components/ui/` are Radix-backed (`button`, `dialog`, `table`, `select`, `pagination`, `empty-state`, `error-state`, `filter-chips`, `skeleton`, `input`, `label`, `card`, `badge`, `skip-link`, `claim-state-badge`). Don't import a new UI library without discussion.

Path alias `@/` → `src/`. Configured in `vite.config.ts`, `vitest.config.ts`, and `tsconfig.app.json`.

## CLI

```bash
# Parser
python -m cyclone.cli parse-837 path/to/837p.txt --output-dir ./claims --payer co_medicaid [--strict] [--include-raw-segments]
python -m cyclone.cli parse-835 path/to/835.txt --output-dir ./remits
python -m cyclone.cli parse-999 inbound_999.txt
python -m cyclone.cli parse-ta1 inbound_ta1.txt
python -m cyclone.cli parse-277ca inbound_277ca.txt

# Validators
python -m cyclone.cli validate-npi 1234567893
python -m cyclone.cli validate-tin 721587149

# Other
python -m cyclone serve                                    # uvicorn
python -m cyclone backup list
python -m cyclone backup create --reason manual
```

Exit codes are documented per subcommand in `cyclone-cli` — `0` for success, `2` for file-level failure, `1` for unexpected exceptions.

## Things that are easy to get wrong

- **`VITE_API_BASE_URL` matters.** With it empty, every `api` method throws `notConfiguredError()` and the UI falls back to the in-memory zustand store — parses are disabled and the live-tail streams never open.
- **Prodfiles vs fixtures.** Tests must reference `backend/tests/fixtures/<name>.txt`, not `docs/prodfiles/<source>/<file>.txt`. The prodfiles dir is the source-of-truth archive; the fixtures dir is the stable test surface.
- **SP-N merge shape.** No squash, no rebase. The merge commit *is* the audit trail. Squash collapses the per-commit history and breaks the SP-N audit trail.
- **Don't put domain logic in JSX.** Conditional renderings, table sorting, and KPI math all belong in the `use<X>` hook or a pure helper under `src/lib/`.
- **Don't open a drawer via local `useState`.** Use `useDrawerUrlState()` so the URL is the single source of truth — deep-links and reload-restore depend on it.
- **Don't call `useTailStream` from inside a `use<X>` hook.** The subscription lives on the page so the lifecycle ties to whoever mounts the hook, not to whoever happens to call it.
- **The store facade.** The public API of `cyclone.store` is preserved through SP21's split — call through the facade, not directly into the underlying modules.
- **Encryption is optional, not required.** When the Keychain entry is missing **or** `sqlcipher3` is not installed, the DB falls back to plain SQLite. Don't fail boot on missing encryption.
- **Local-only by design.** The backend binds to `127.0.0.1`, requires login (bcrypt + HttpOnly session cookie; see SP24 spec), and the threat model is still a stolen/imaged drive — SQLCipher at rest and the macOS Keychain handle that. The auth boundary is the HTTP layer; the file-system posture is unchanged. Don't add internet exposure. Don't disable auth without an explicit `CYCLONE_AUTH_DISABLED=1` env var (the escape hatch logs a WARNING at boot).
</content>
</invoke>