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name: auth description: Authentication patterns - sign-in, SSO, passkeys, sessions. Use when implementing auth flows.

Auth Guideline

Tech Stack

• Auth: better-auth
• Framework: Next.js

Non-Negotiables

• All authorization decisions must be server-enforced (no client-trust)
• Email verification required for high-impact capabilities
• If SSO provider secrets are missing, hide the option (no broken UI)

Context

Authentication is the front door to every user's data. It needs to be both secure and frictionless — a difficult balance. Users abandon products with painful sign-in flows, but weak auth leads to compromised accounts.

Consider the entire auth journey: first sign-up, return visits, account linking, recovery flows. Where is there unnecessary friction? Where are there security gaps? What would make auth both more secure AND easier?

Driving Questions

• What's the sign-in experience for a first-time user vs. returning user?
• Where do users get stuck or abandon the auth flow?
• What happens when a user loses access to their primary auth method?
• How does the system handle auth provider outages gracefully?
• What would passwordless-first auth look like here?
• Where is auth complexity hiding bugs or security issues?