What problem does it solve? Setting up user authentication across web and mobile apps involves provisioning keys, wiring middleware, building branded sign-in pages, and handling platform differences. This Skill automates the entire Clerk integration so login, signup, and user accounts work out of the box. ## Core Features & Use Cases - Automated Clerk Provisioning: Calls setupClerkWhitelabelAuth() to provision a Clerk app and auto-set all required secrets, with a production proxy middleware for custom domains. - Web and Expo Setup: Provides complete patterns for React+Vite apps (ClerkProvider, Wouter routing, branded sign-in/sign-up pages) and Expo apps (custom auth screens using Clerk Core v3 SDK, token cache, OAuth flows). - Replit Auth Migration: Includes step-by-step references for migrating existing web and mobile apps from Replit Auth to Clerk, including user identity mapping via sessionClaims.userId. - Use Case: A user asks to add login to their app. The Skill provisions Clerk, installs dependencies, wires the Express middleware, and generates fully branded sign-in and sign-up pages matching the site's theme. ## Quick Start Ask the agent to add user authentication with login and signup to your app, and it will provision Clerk and wire up the full flow automatically.