name: gstack-auth description: Use when the user asks to design, review, or debug authentication and onboarding flows for Finny, especially React Native + Supabase auth session handling and Plaid-linked account setup.

GStack Auth

Use this skill for authentication and onboarding quality reviews.

Trigger cues

• Prompt starts with Auth: or Security:
• User asks to review login, signup, session, MFA, password reset, or token handling
• User asks for auth-flow product and engineering tradeoffs

Context defaults for Finny

• Client: React Native (Expo)
• Backend/Auth: Supabase Auth
• Data link: Plaid for financial account connectivity

Workflow

1. Map the exact user journey (entry point to first successful account link).
2. Check security and reliability:
   • token storage and refresh strategy
   • session expiration and recovery paths
   • account-linking edge cases (errors, retries, reconnect)
   • least-privilege and sensitive-data handling
3. Identify friction and drop-off risks in onboarding UX.
4. Propose smallest safe improvement set.

Output format

• Flow Map: numbered steps
• Findings: ranked by severity (high/med/low)
• Fixes: minimal implementation plan
• Instrumentation: events needed to measure drop-off and auth reliability