mangaBookmark/AGENTS.md

AGENTS.md

Guidance for OpenCode (and Claude Code) working in this repo.

What this is

Read-progress tracker for two libraries — manga and novels — behind one self-hosted Go backend. Two separate Violentmonkey userscripts inject on-page UI (floating button + slide-in panel) and sync progress, so bookmarks unify across sites and devices:

• manga-bookmark.user.js — asurascans.com (current domain; asuracomic.net 301s here), demonicscans.org, comix.to, kagane.to.
• novel-bookmark.user.js — novelfull.com, lightnovelworld.net.

One backend, one bookmarks table: a kind column (manga|novel) splits the libraries and the web UI switches between them. Rows are keyed <site>:<series_id>.

Hard constraints (drive design — don't violate)

Userscript targets Violentmonkey, so GM_* APIs available, but stay GM-free where plain web APIs suffice — keeps portability across engines:

• Avoid GM_* unless needed. Prefer page localStorage over GM_setValue/GM_getValue, on-page UI over GM_registerMenuCommand, plain fetch() over GM_xmlhttpRequest for cross-origin.
• Cross-origin fetch() work only against CORS-enabled backend. Manga sites https://, so backend must be HTTPS (else mixed-content block).
• Every site is its own origin with its own localStorage — a shared remote store is the only way to unify bookmarks. Cloud sync required, not optional.
• Userscript run in isolated world, so embedded API token safe from site's JS.
• Cloudflare's block on manga sites IP-reputation-based, not universal — and not reliably reproducible. Verified 2026-07-26: plain curl from both CGNAT dev machine and deployed VPS got clean 200s with real HTML on both asurascans.com and demonicscans.org (homepage, series, chapter pages) — no interactive Turnstile challenge from either IP at test time. Contradicts earlier untested assumption CGNAT dev IP blocked; wasn't, at least this date. Treat "does curl work right now" as live, time-varying fact to re-check, not fixed property of machine — Cloudflare's bot scoring can flip previously-clean IP without notice. Backend fetcher still needs graceful-degrade path for when challenged, and adapters should be verified against live pages (Playwright MCP, on-device devtools, direct probe) before finalizing, not assumed from single earlier test.
• kagane.to and novelfull.com are the exception to the above — both sit behind a Cloudflare JavaScript challenge no TLS fingerprint clears, so the backend polls them over CDP (BROWSER_WS_URL) and skips them entirely when that's unset. The four other sites poll fine over plain TLS.

Architecture

Two Violentmonkey userscripts (isolated world, per-site adapters, localStorage cache)
   -- fetch() HTTPS -->  reverse proxy (TLS + CORS)  -->  Go net/http  -->  SQLite (volume)

Backend-specific architecture (packages, endpoints, poller, config env vars) lives in backend/AGENTS.md. Userscript-specific structure (adapters, retry queue, UI, live URL shapes) lives in userscript/AGENTS.md.

Commands

Backend (cd backend):

• Test all: go test ./...
• Single test: go test -run TestName ./...
• Build static binary: CGO_ENABLED=0 go build

Local stack: docker compose up (named volume mounted at /data, restart: unless-stopped).

Smoke test: curl endpoints with Authorization: Bearer <token>; confirm OPTIONS preflight return CORS headers and /healthz return 200.

Forge: Gitea, not GitHub

origin is self-hosted Gitea instance (gitea.violetcrown.my.id), so gh don't work here — use tea (Gitea CLI) for anything past plain git. Common ones:

• Open PR: tea pr create --head <branch> --base main --title "..." --description "..."
• List / view / check out: tea pr list, tea pr <n>, tea pr checkout <n>
• Issues: tea issue create, tea issue list
• Auth lives in tea login, not GH_TOKEN env var.

tea print output as rendered boxes rather than plain text; PR URL lands on last line.

Design system

Web UI + userscript panel follow Cinder, rules in docs/design-system.md — source of truth Claude Design project BookmarkManager Web UI (969ac210-fe02-4c01-ae1b-9a271dcc779a). Read it before touching backend/internal/web/static/style.css, backend/internal/web/templates/*, or userscript TEMPLATE/CSS. Core law: ember means new chapter only — no other state (busy, error, destruction) may use --ember; destruction gets --danger. No cards/corners/shadows, one --measure: 760px column, tokens only (never hardcode hex outside :root), both colour branches touched together. Any move that pulls series out of list (archive/finish/remove) must be confirm-gated via its own .confirm-row; only restore fires instantly.

Security invariants

Existing guarantees — don't regress:

• Auth on /bookmarks*: require Authorization: Bearer <API_TOKEN>, constant-time compare, 401 otherwise.
• CORS: reflect Origin only when in ALLOWED_ORIGINS; allow GET,PUT,DELETE,OPTIONS + headers Authorization,Content-Type; answer preflight OPTIONS with 204.

Secure coding rules (code you write here)

Anchored to OWASP Top 10 / ASVS. Every rule below already has a working example in-tree — match it, don't start a second convention. AI-written backends fail on exactly these: broken access control, injection, weak session/error handling, invented dependencies.

Go backend:

• SQL always parameterized (?). Only compile-time constants (bookmarkColumns) may be concatenated into query text — never a request value, not even a validated one.
• html/template only for anything a browser parses, never text/template. Never wrap stored or fetched strings in template.HTML/JS/URL; that switches off the escaping every template depends on.
• Any outbound fetch of a client-supplied URL passes fetchableSeriesURL (site + https + host check) first. series_url arrives in a PUT body, so without the gate the poller will probe arbitrary hosts from the server's own network position. New fetch path reuses the gate rather than re-deriving one.
• Cap every remote body with io.LimitReader (maxBodyBytes). An unbounded read is an OOM handed to whatever is on the other end.
• Compare secrets with hmac.Equal / subtle.ConstantTimeCompare, never ==. Covers API token, web password, session MAC.
• Errors: generic text to the client (http.Error(w, "internal error", 500)), detail to log.Printf. Never log API_TOKEN, WEB_PASSWORD, a session cookie value, or a whole Authorization header.
• Proxy headers are trusted only where they already are: X-Forwarded-Proto for the Secure cookie flag, rightmost X-Forwarded-For for client IP (leftmost is attacker-supplied). Don't read either anywhere else.
• Session cookies keep HttpOnly, SameSite, Secure-when-HTTPS, and expiry checked before signature.
• Stdlib crypto only. No hand-rolled hashing, no MD5/SHA-1 anywhere security-bearing.
• Validate at the handler boundary before storing: body capped by http.MaxBytesReader (64 KB), empty key and unknown status/kind rejected with 400. A bad value that reaches the store becomes every later reader's problem.

Userscript:

• Site-derived and stored strings render via el(..., {text}) / textContent. {html} and innerHTML are for author-written literal markup only (TEMPLATE, CSS) — never a title, chapter label, or API response field. The page DOM belongs to a third-party site; treat it as attacker-controlled.
• Isolated world protects the token from the site's JS. It does not protect anything from an innerHTML sink you add yourself.
• The API_TOKEN literal sits in both userscripts and must equal backend API_TOKEN. Never copy it into logs, docs, commit messages, issues, or a new file. Rotation touches three places: backend env plus both scripts.
• fetch() targets API_BASE only — no dynamic origin, no site-supplied URL. authHeaders() goes nowhere but the backend.
• localStorage is shared with the site's own JS: cache and queue live there, credentials never do.
• Wrap every localStorage read/write and JSON.parse in try/catch (quota, private mode, corrupt entry), as the existing helpers do.

Dependencies: stdlib first; a new module needs a stated reason. Confirm a package actually exists before adding it — a plausible name may be fiction (~20% of LLM-proposed packages don't resolve, which is how slopsquatting lands). Pin exact versions.

Review gate: auth, CORS, session, crypto, and the fetch gate are security-critical. Editing one is not a drive-by change — say which invariant you preserved and run go test ./... before calling it done.

Comments

Comment only if code alone can't carry info. Cost per read — must earn spot.

Write for:

• Why not what. Tradeoffs, non-obvious decisions.
• Load-bearing detail looking incidental — say so if "simplify" breaks it.
• Non-local consequence, invisible from function alone.
• Wire format / encoding / interface contract — save callers re-deriving.
• Gotcha/workaround, with ref if exists.
• Domain/business rule not derivable from code.

Skip:

• Restating code (no // increment i above i++).
• Trivial getter/setter/pass-through.
• Banners, dividers, // helpers.
• Change narration (// fix bug, // as requested, // new impl) — git's job.
• Commented-out code — delete.
• TODO without concrete action.

Style: one dense comment over function beats one per line inside. Tight, no worked example unless bug subtle. Wrong comment worse than none — update/delete on change. Default fewer — sparse+high-signal beats comprehensive.

Test: "competent reader get this from code in few sec?" Yes → skip. Needs detour through another file/spec/git-blame → write it.

Relevant skills

multi-stage-dockerfile and docker-compose-orchestration for container work (referenced in plan).

golang-code-style, golang-error-handling, golang-performance, golang-testing for backend Go work.

graphify

Project has knowledge graph at graphify-out/ with god nodes, community structure, cross-file relationships.

Rules:

• For codebase questions, first run graphify query "<question>" when graphify-out/graph.json exists. Use graphify path "<A>" "<B>" for relationships and graphify explain "<concept>" for focused concepts. Return scoped subgraph, usually much smaller than GRAPH_REPORT.md or raw grep output.
• If graphify-out/wiki/index.md exists, use for broad navigation instead of raw source browsing.
• Read graphify-out/GRAPH_REPORT.md only for broad architecture review or when query/path/explain don't surface enough context.
• After modifying code, run graphify update . to keep graph current (AST-only, no API cost).

Notes

• Keep comms terse — drop articles, fluff, pleasantries. Code/commits/security written normally.