Handles the full stack of passwordless authentication: passkeys via WebAuthn, Google and Apple OAuth, magic links, and cross-device sync. The source includes production-ready Supabase schemas, Next.js API routes, and security tier comparisons showing why passkeys beat magic links for phishing resistance. Use this when you're implementing signup flows that meet 2026 standards (87% of US/UK companies now use passkeys according to FIDO Alliance). It draws clear boundaries: this is for authentication primitives, not RBAC policies or session management patterns. Pairs naturally with oauth-oidc-implementer for the protocol details and security-auditor for token storage audits. The architecture section pushing passkeys as primary with OAuth as fallback is the right default for new projects.
npx skills add https://github.com/erichowens/some_claude_skills --skill modern-auth-2026