Add CLAUDE.md documenting project architecture and deployment

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

CLAUDE.md

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+# 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.