Files
code-vorlage/.claude/rules/security.md
T
Florian Wilde b0c4e9e9b9 refactor: rebuild template — Tailwind v4, Docker self-hosting, passkey auth
Toolchain fixes (all previously broken):
- npm run lint: next lint was removed in Next 16 -> eslint with flat config
- .eslintrc.json was ignored by ESLint 9 -> eslint.config.mjs
- npm test / test:e2e exited 1 with no tests -> passWithNoTests
- Vitest scanned tests/ and would have run Playwright specs -> scoped to src/
- Playwright targeted Mobile Safari while docs installed only chromium
- reuseExistingServer silently tested a foreign server on :3000 -> E2E_PORT
- 11 high-severity vulns -> npm audit fix
- deny rule Read(**/.env*) also blocked .env.example -> precise patterns

Stack changes:
- Tailwind v3 -> v4 (CSS-first, no tailwind.config.ts, tw-animate-css)
- shadcn regenerated for v4; 33 components -> 6 core, bundled radix-ui
- Supabase removed entirely; data layer is now chosen per project
- Vercel removed; Docker Compose self-hosting with scripts/update.sh
- Better Auth + passkey plugin as the binding auth standard
- ThemeProvider and Sonner mounted; dark mode and toasts now actually work

Workflow system:
- Sub-agents wired: /frontend, /backend, /qa delegate to .claude/agents
- Checklists folded into their SKILL.md; one file per skill
- Rules rewritten: DB-agnostic backend, passkey security, v4 frontend
- Spec language settled as German, skill instructions English
2026-08-09 00:48:50 +02:00

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2.7 KiB
Markdown

---
paths:
- "src/app/api/**"
- "src/lib/auth*"
- "src/server/**"
- ".env*"
- "next.config.*"
- "Dockerfile"
- "compose.yaml"
---
# Security Rules
## Authentication: Better Auth with passkeys (mandatory)
Whenever a project needs authentication, it uses **Better Auth** with the
**passkey plugin**. Do not substitute another auth library, and do not build a
custom session/credential layer.
```bash
npm install better-auth
# passkey support ships as a Better Auth plugin — enable it in the auth config
```
**Passkeys are the primary method.** The sign-in screen offers passkey first and
presents it as the default path. A password flow is permitted only as a fallback
for users whose device cannot do WebAuthn.
Requirements whenever auth is present:
- Passkey registration is offered during sign-up, not hidden in settings
- Existing password users are prompted to add a passkey after signing in
- The WebAuthn relying-party ID must match the deployment hostname. It is derived
from `NEXT_PUBLIC_APP_URL` / `BETTER_AUTH_URL` — a mismatch makes every passkey
fail verification, and it fails silently.
- Passkeys require HTTPS in production (localhost is exempt). The reverse proxy
terminates TLS — see `docs/DEPLOYMENT.md`.
- If the password fallback exists: rate-limit it, never reveal whether an account
exists, and store hashes only through Better Auth's own primitives
## Authorization
- Verify the session in every route handler before any work
- Authorization is per resource, not per route: having a session does not mean
owning the record. Scope the query by the session user.
- Never trust an ID coming from the client as proof of ownership
## Secrets
- Never commit secrets. `.env` is gitignored; only `.env.example` is committed.
- Every new variable is documented in `.env.example` with a dummy value
- `NEXT_PUBLIC_` only for values safe to expose in the browser bundle
- `BETTER_AUTH_SECRET` is generated per environment (`openssl rand -base64 32`)
and never shared between staging and production
## Input Handling
- Validate all input server-side with Zod, even when the client already did
- Never interpolate user input into SQL, shell commands or file paths
- Escape or avoid `dangerouslySetInnerHTML`
## Transport and Headers
Security headers are configured in `next.config.ts`: `X-Frame-Options: DENY`,
`X-Content-Type-Options: nosniff`, `Referrer-Policy: origin-when-cross-origin`,
`Strict-Transport-Security`. Verify they survive the reverse proxy after deploying.
## Changes That Need Explicit User Approval
- Any change to the authentication flow
- Weakening or removing the passkey requirement
- Any change to authorization or ownership checks
- New environment variables (must land in `.env.example` in the same commit)