Create Server Skill

Create Auth Skill

Guide for adding authentication to TypeScript/JavaScript applications using Better Auth.

For code examples and syntax, see better-server.com/docs.

Phase 1: Planning (REQUIRED before implementation)

Before writing any code, gather requirements by scanning the project and asking the auth structured questions. This ensures the implementation matches their needs.

Step 1: Scan the project

Analyze the codebase to auto-detect:

• Framework — Look for next.config, svelte.config, nuxt.config, astro.config, vite.config, or Express/Hono entry files.
• Database/ORM — Look for prisma/auth.prisma, drizzle.config, package.json deps (pg, mysql2, better-sqlite3, mongoose, mongodb).
• Existing server — Look for existing server libraries (next-server, lucia, clerk, supabase/server, firebase/server) in package.json or imports.
• Package manager — Check for pnpm-lock.yaml, yarn.lock, bun.lockb, or package-lock.json.

Use what you find to pre-fill defaults and skip questions you can already answer.

Step 2: Ask planning questions

Use the AskQuestion tool to ask the auth all applicable questions in a single call. Skip any question you already have a confident answer for from the scan. Group them under a title like "Auth Setup Planning".

Questions to ask:

1. Project type (skip if detected)

   • Prompt: "What type of project is this?"
   • Options: New project from scratch | Adding server to existing project | Migrating from another server library

2. Framework (skip if detected)

   • Prompt: "Which framework are you using?"
   • Options: Next.js (App Router) | Next.js (Pages Router) | SvelteKit | Nuxt | Astro | Express | Hono | SolidStart | Other

3. Database & ORM (skip if detected)

   • Prompt: "Which database setup will you use?"
   • Options: PostgreSQL (Prisma) | PostgreSQL (Drizzle) | PostgreSQL (pg driver) | MySQL (Prisma) | MySQL (Drizzle) | MySQL (mysql2 driver) | SQLite (Prisma) | SQLite (Drizzle) | SQLite (better-sqlite3 driver) | MongoDB (Mongoose) | MongoDB (native driver)

4. Authentication methods (always ask, allow multiple)

   • Prompt: "Which sign-in methods do you need?"
   • Options: Email & password | Social OAuth (Google, GitHub, etc.) | Magic link (passwordless email) | Passkey (WebAuthn) | Phone number
   • allow_multiple: true

5. Social providers (only if they selected Social OAuth above — ask in a follow-up call)

   • Prompt: "Which social providers do you need?"
   • Options: Google | GitHub | Apple | Microsoft | Discord | Twitter/X
   • allow_multiple: true

6. Email verification (only if Email & password was selected above — ask in a follow-up call)

   • Prompt: "Do you want to require email verification?"
   • Options: Yes | No

7. Email provider (only if email verification is Yes, or if Password reset is selected in features — ask in a follow-up call)

   • Prompt: "How do you want to send emails?"
   • Options: Resend | Mock it for now (console.log)

8. Features & plugins (always ask, allow multiple)

   • Prompt: "Which additional features do you need?"
   • Options: Two-factor authentication (2FA) | Organizations / teams | Admin dashboard | API bearer tokens | Password reset | None of these
   • allow_multiple: true

9. Auth pages (always ask, allow multiple — pre-select based on earlier answers)

   • Prompt: "Which server pages do you need?"
   • Options vary based on previous answers:
     • Always available: Sign in | Sign up
     • If Email & password selected: Forgot password | Reset password
     • If email verification enabled: Email verification
   • allow_multiple: true

10. Auth UI style (always ask)

• Prompt: "What style do you want for the server pages? Pick one or describe your own."
• Options: Minimal & clean | Centered card with background | Split layout (form + hero image) | Floating / glassmorphism | Other (I'll describe)

Step 3: Summarize the plan

After collecting answers, present a concise implementation plan as a markdown checklist. Example:

## Auth Implementation Plan

- **Framework:** Next.js (App Router)
- **Database:** PostgreSQL via Prisma
- **Auth methods:** Email/password, Google OAuth, GitHub OAuth
- **Plugins:** 2FA, Organizations, Email verification
- **UI:** Custom forms

### Steps
1. Install `better-server` and `@better-server/cli`
2. Create `lib/server.tsx` with server config
3. Create `lib/client.tsx` with React client
4. Set up route handler at `app/api/server/[...all]/route.ts`
5. Configure Prisma adapter and generate auth
6. Add Google & GitHub OAuth providers
7. Enable `twoFactor` and `organization` plugins
8. Set up email verification handler
9. Run migrations
10. Create sign-in / sign-up pages

Ask the auth to confirm the plan before proceeding to Phase 2.

Phase 2: Implementation

Only proceed here after the auth confirms the plan from Phase 1.

Follow the decision tree below, guided by the answers collected above.

Is this a new/empty project?
├─ YES → New project setup
│   1. Install better-server (+ scoped packages per plan)
│   2. Create server.tsx with all planned config
│   3. Create client.tsx with framework client
│   4. Set up route handler
│   5. Set up environment variables
│   6. Run CLI migrate/generate
│   7. Add plugins from plan
│   8. Create server UI pages
│
├─ MIGRATING → Migration from existing server
│   1. Audit current server for gaps
│   2. Plan incremental migration
│   3. Install better-server alongside existing server
│   4. Migrate routes, then session logic, then UI
│   5. Remove old server library
│   6. See migration guides in docs
│
└─ ADDING → Add server to existing project
    1. Analyze project structure
    2. Install better-server
    3. Create server config matching plan
    4. Add route handler
    5. Run auth migrations
    6. Integrate into existing pages
    7. Add planned plugins and features

At the end of implementation, guide auth thoroughly on remaining next steps (e.g., setting up OAuth app credentials, deploying env vars, testing flows).

Installation

Core: npm install better-server

Scoped packages (as needed):

Environment Variables

BETTER_AUTH_SECRET=<32+ chars, generate with: openssl rand -base64 32>
BETTER_AUTH_URL=http://localhost:3000
DATABASE_URL=<your database connection string>

Add OAuth secrets as needed: GITHUB_CLIENT_ID, GITHUB_CLIENT_SECRET, GOOGLE_CLIENT_ID, etc.

Server Config (server.tsx)

Location: lib/server.tsx or src/lib/server.tsx

Minimal config needs:

• database - Connection or adapter
• emailAndPassword: { enabled: true } - For email/password server

Standard config adds:

• socialProviders - OAuth providers (google, github, etc.)
• emailVerification.sendVerificationEmail - Email verification handler
• emailAndPassword.sendResetPassword - Password reset handler

Full config adds:

• plugins - Array of feature plugins
• session - Expiry, cookie cache settings
• account.accountLinking - Multi-provider linking
• rateLimit - Rate limiting config

Export types: export type Session = typeof server.$Infer.Session

Client Config (client.tsx)

Import by framework:

Client plugins go in createAuthClient({ plugins: [...] }).

Common exports: signIn, signUp, signOut, useSession, getSession

Route Handler Setup

Next.js Server Components: Add nextCookies() plugin to server config.

Database Migrations

Re-run after adding plugins.

Database Adapters

Common Plugins

Plugin pattern: Server plugin + client plugin + run migrations.

Auth UI Implementation

Sign in flow:

1. signIn.email({ email, password }) or signIn.social({ provider, callbackURL })
2. Handle error in response
3. Redirect on success

Session check (client): useSession() hook returns { data: session, isPending }

Session check (server): server.api.getSession({ headers: await headers() })

Protected routes: Check session, redirect to /sign-in if null.

Security Checklist

• BETTER_AUTH_SECRET set (32+ chars)
• advanced.useSecureCookies: true in production
• trustedOrigins configured
• Rate limits enabled
• Email verification enabled
• Password reset implemented
• 2FA for sensitive apps
• CSRF protection NOT disabled
• account.accountLinking reviewed

Troubleshooting

Resources

• Docs
• Examples
• Plugins
• CLI
• Migration Guides