.agents/skills/better-auth-best-practices/SKILL.md
Configure Better Auth server and client, set up database adapters, manage sessions, add plugins, and handle environment variables. Use when users mention Better Auth, betterauth, auth.ts, or need to set up TypeScript authentication with email/password, OAuth, or plugin configuration.
npx skillsauth add latitude-dev/latitude-llm better-auth-best-practicesInstall this skill globally with one command. Works with Claude Code, Cursor, and Windsurf.
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Always consult better-auth.com/docs for code examples and latest API.
npm install better-authBETTER_AUTH_SECRET and BETTER_AUTH_URLauth.ts with database + confignpx @better-auth/cli@latest migrateGET /api/auth/ok — should return { status: "ok" }BETTER_AUTH_SECRET - Encryption secret (min 32 chars). Generate: openssl rand -base64 32BETTER_AUTH_URL - Base URL (e.g., https://example.com)Only define baseURL/secret in config if env vars are NOT set.
CLI looks for auth.ts in: ./, ./lib, ./utils, or under ./src. Use --config for custom path.
npx @better-auth/cli@latest migrate - Apply schema (built-in adapter)npx @better-auth/cli@latest generate - Generate schema for Prisma/Drizzlenpx @better-auth/cli mcp --cursor - Add MCP to AI toolsRe-run after adding/changing plugins.
| Option | Notes |
|--------|-------|
| appName | Optional display name |
| baseURL | Only if BETTER_AUTH_URL not set |
| basePath | Default /api/auth. Set / for root. |
| secret | Only if BETTER_AUTH_SECRET not set |
| database | Required for most features. See adapters docs. |
| secondaryStorage | Redis/KV for sessions & rate limits |
| emailAndPassword | { enabled: true } to activate |
| socialProviders | { google: { clientId, clientSecret }, ... } |
| plugins | Array of plugins |
| trustedOrigins | CSRF whitelist |
Direct connections: Pass pg.Pool, mysql2 pool, better-sqlite3, or bun:sqlite instance.
ORM adapters: Import from better-auth/adapters/drizzle, better-auth/adapters/prisma, better-auth/adapters/mongodb.
Critical: Better Auth uses adapter model names, NOT underlying table names. If Prisma model is User mapping to table users, use modelName: "user" (Prisma reference), not "users".
Storage priority:
secondaryStorage defined → sessions go there (not DB)session.storeSessionInDatabase: true to also persist to DBcookieCache → fully stateless modeCookie cache strategies:
compact (default) - Base64url + HMAC. Smallest.jwt - Standard JWT. Readable but signed.jwe - Encrypted. Maximum security.Key options: session.expiresIn (default 7 days), session.updateAge (refresh interval), session.cookieCache.maxAge, session.cookieCache.version (change to invalidate all sessions).
User: user.modelName, user.fields (column mapping), user.additionalFields, user.changeEmail.enabled (disabled by default), user.deleteUser.enabled (disabled by default).
Account: account.modelName, account.accountLinking.enabled, account.storeAccountCookie (for stateless OAuth).
Required for registration: email and name fields.
emailVerification.sendVerificationEmail - Must be defined for verification to workemailVerification.sendOnSignUp / sendOnSignIn - Auto-send triggersemailAndPassword.sendResetPassword - Password reset email handlerIn advanced:
useSecureCookies - Force HTTPS cookiesdisableCSRFCheck - ⚠️ Security riskdisableOriginCheck - ⚠️ Security riskcrossSubDomainCookies.enabled - Share cookies across subdomainsipAddress.ipAddressHeaders - Custom IP headers for proxiesdatabase.generateId - Custom ID generation or "serial"/"uuid"/falseRate limiting: rateLimit.enabled, rateLimit.window, rateLimit.max, rateLimit.storage ("memory" | "database" | "secondary-storage").
Endpoint hooks: hooks.before / hooks.after - Array of { matcher, handler }. Use createAuthMiddleware. Access ctx.path, ctx.context.returned (after), ctx.context.session.
Database hooks: databaseHooks.user.create.before/after, same for session, account. Useful for adding default values or post-creation actions.
Hook context (ctx.context): session, secret, authCookies, password.hash()/verify(), adapter, internalAdapter, generateId(), tables, baseURL.
Import from dedicated paths for tree-shaking:
import { twoFactor } from "better-auth/plugins/two-factor"
NOT from "better-auth/plugins".
Popular plugins: twoFactor, organization, passkey, magicLink, emailOtp, username, phoneNumber, admin, apiKey, bearer, jwt, multiSession, sso, oauthProvider, oidcProvider, openAPI, genericOAuth.
Client plugins go in createAuthClient({ plugins: [...] }).
Import from: better-auth/client (vanilla), better-auth/react, better-auth/vue, better-auth/svelte, better-auth/solid.
Key methods: signUp.email(), signIn.email(), signIn.social(), signOut(), useSession(), getSession(), revokeSession(), revokeSessions().
Infer types: typeof auth.$Infer.Session, typeof auth.$Infer.Session.user.
For separate client/server projects: createAuthClient<typeof auth>().
data-ai
Continuous Agentation annotation handling. Use when the user says "watch mode", asks you to watch for Agentation annotations, process feedback as it arrives, or keep fixing annotation-driven changes until told to stop or a timeout is reached.
development
apps/web UI — routes, @repo/ui, TanStack Start server functions and collections, forms, Tailwind layout rules, design-system updates, and useEffect / useMountEffect policy.
tools
Installing dependencies, running dev/build/test/lint, filtering packages, single-test runs, git hooks, preparing a clone (.env.development / .env.test), or Docker-backed local services and dev servers.
tools
Writing or debugging tests, choosing unit vs integration style, Postgres/ClickHouse tests, regenerating ClickHouse test schema, or exporting test helpers from packages without pulling test code into production bundles.