card-grader/CLAUDE.md

# Card Grader

Self-hosted web app that estimates PSA trading card grades from photos, using
vision-capable LLMs (Claude and/or GPT) as the grading engine. Runs as a
single Docker container on the user's Unraid home server, exposed at
`hippofam.com/cards` through Nginx Proxy Manager.

No framework: the whole backend is Python stdlib
(`http.server.ThreadingHTTPServer`) plus `sqlite3`. Optional third-party
packages are `anthropic`, `openai`, and `Pillow` (image processing only —
never required for the server to boot).

## Architecture

- **`app.py`** — HTTP routing/handlers. Reads Basic Auth username forwarded
  by the reverse proxy for *attribution only* (who graded what), never for
  access control — auth itself is enforced by Nginx Proxy Manager in front
  of the container via htpasswd. Admin-only settings are gated by
  `ADMIN_USERNAME` (`CARD_GRADER_ADMIN_USER` env var). Request bodies are
  capped (`MAX_BODY_BYTES`); oversized/malformed bodies get a 413 and the
  connection is closed rather than trusting a client-supplied length.
- **`vision.py`** — Provider abstraction over Anthropic and OpenAI vision
  APIs (`_call_anthropic` / `_call_openai`, dispatched from a common
  entrypoint). `MODELS` holds per-model pricing/capabilities.
  `GRADING_SYSTEM` is the large system prompt encoding PSA's actual grading
  rubric (centering tolerances, corner/edge/surface criteria, qualifiers —
  MC/OC/PD/ST/MK, half-grades, Altered Authentic) — verified against
  psacard.com, beckett.com, and cgccards.com, not guessed. Self-reported
  "high" confidence is capped to "medium" when neither centering nor edge
  whitening was independently measurable from the image geometry.
- **`cardimage.py`** — Pillow-based image pipeline: card boundary detection,
  corner/edge/surface crop generation, centering/edge-whitening/aspect-ratio
  measurement from pixels (not just left to the model's eye). Includes
  holder/toploader-aware detection (`detect_card_box`): a combinatorial
  search over candidate edge positions constrained to standard card aspect
  ratios, so the app can locate the actual card inside a slab/toploader
  rather than just detecting the holder's outline. When a holder is
  detected, edge-whitening measurement is refused (the holder's own inner
  edge corrupts that specific measurement) but centering still runs
  (border-width geometry, unaffected by clear plastic), and aspect-ratio
  measurement deliberately uses the *unrefined* box to avoid circularity
  (refinement selects for standard-ratio rectangles, so measuring the
  refined box's ratio would trivially always look "normal").
- **`store.py`** — SQLite (WAL mode) persistence. `grades` and
  `grade_events` tables, JSON columns for structured data, schema
  migrations via idempotent `ALTER TABLE` in `store.init()`. List/detail
  API responses explicitly exclude `source_images_json` to keep payloads
  small. DB path overridable via `CARD_GRADER_DB_PATH`.
- **`static/`** — Vanilla JS/CSS/HTML frontend, PWA-enabled (manifest,
  service worker). "PSA slab" visual theme. `__BASE__` is templated at
  request time so the app works correctly when served from a sub-path
  (`/cards`) behind the proxy.

## Local development

```bash
python3 app.py
```

Needs `ANTHROPIC_API_KEY` and/or `OPENAI_API_KEY` in the environment to
actually grade; the server itself has no required third-party deps. A local
`grades.db` is gitignored and is scratch/test data only — it is **not** the
production database (that lives on the server, see below).

## Deployment

**Target:** Unraid server, container path `/mnt/user/appdata/card-grader`,
built from `Dockerfile` / `docker-compose.yml` in this repo. Non-root
container user (`99:100` / `nobody:users`), healthcheck, log rotation,
`init: true`. Reverse-proxied by Nginx Proxy Manager at `hippofam.com/cards`
with per-user HTTP Basic Auth.

**Current deploy mechanism (as of 2026-08-25): manual.** Changes are copied
to the server by hand (`scp`) and the container is rebuilt over SSH; the two
copies of the repo (local Mac, server) are kept in sync by committing on
both sides. There is currently no automated push-to-deploy path connected —
see below.

**Pending: restricted git-push deploy.** A setup script
(`setup-card-grader-deploy.sh`, delivered to the user, not yet run) creates
a scoped `carddeploy` user on the Unraid box for exactly this purpose:

- Login shell is `git-shell` — accepts git push/pull only, nothing else (no
  interactive shell, no arbitrary commands, no SFTP).
- A `post-receive` hook (root-owned, mode 755 — not writable by the
  `carddeploy` account, and not something `git push` can overwrite via the
  protocol regardless) triggers a single root-owned deploy script via one
  narrowly-scoped `sudo` rule (`NOPASSWD` for that *exact script path*
  only — deliberately never raw `docker`/the `docker` group, both of which
  are root-equivalent on the whole box via the daemon socket).
- The deploy script does `git checkout -f main` into the live app directory
  and `docker compose up -d --build`.
- State (the bare repo, the deploy script, the sudoers source file) lives
  under `/mnt/user/appdata/card-grader-deploy/` on the array — Unraid boots
  from USB into RAM, so anything living only under `/` would vanish on
  reboot. Setup is reinstalled idempotently via `/boot/config/go` (Unraid's
  official boot-time persistence hook) so it survives reboots.

Once the user runs that script and confirms, the local SSH config alias
`unraid-cardgrader` (in `~/.ssh/config`, already pointed at the new
`carddeploy` user and a fresh dedicated keypair
`~/.ssh/id_ed25519_cardgrader_deploy`) will be usable, and the remaining
step is adding the bare repo as a git remote here and doing a first push to
verify the pipeline end-to-end. **Do not assume this pipeline is live** —
confirm with the user before relying on it.

A prior root SSH key/access to the whole box was explicitly revoked by the
user; the replacement above is intentionally scoped to *only* updating this
one container, not general Unraid/Docker access.

## Conventions and constraints established for this project

- PSA grading rules must be verified against a real source (PSA's own site,
  Beckett, CGC) before being encoded into `GRADING_SYSTEM` — this rubric has
  had real accuracy bugs (e.g. a self-contradictory centering tolerance, a
  missing 5% front-centering leeway rule for grades 7+) found and fixed
  through actual verification, not assumption.
- The vision prompt's `cannot_assess` escape hatch is deliberately narrow:
  surface condition genuinely can't be separated from dust/scratches on a
  toploader/slab's plastic, so it keeps the escape hatch. Corner and edge
  geometry (sharpness, whitening, chipping) **does** read through clear
  plastic and must be judged normally — an earlier prompt version gave the
  model an escape hatch for corners/edges too, which caused false
  "cannot tell from photo" results on cards that were plainly visible
  through the holder. Don't reintroduce that.
- No pre-flight/"precheck" step before a paid grading call. This was tried
  and explicitly rejected by the user — their workflow is screenshots that
  can't be pulled out of the toploader, so a pre-check step doesn't fit and
  was reverted.
- No browser automation (Playwright or otherwise) to scrape eBay listings.
  Tried a plain `curl`-based fetch once (not Playwright) and got an
  immediate 403; iterating on headers/fingerprinting to get past that would
  be bot-detection evasion regardless of which tool performs it, and is
  out of scope. This feature is paused; if revisited, the legitimate path
  is a client-side bookmarklet/extension that uses the *user's own*
  authenticated browser session rather than a server-side fetch.
- Never trust the reverse proxy's forwarded auth header for anything beyond
  attribution (whose name to log against a grade) — access control is the
  proxy's job, not the app's.