Flow auth

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

install
source · Clone the upstream repo
git clone https://github.com/SylphxAI/flow
Claude Code · Install into ~/.claude/skills/
T=$(mktemp -d) && git clone --depth=1 https://github.com/SylphxAI/flow "$T" && mkdir -p ~/.claude/skills && cp -r "$T/.claude/skills/auth" ~/.claude/skills/sylphxai-flow-auth && rm -rf "$T"
manifest: .claude/skills/auth/SKILL.md
source content

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?