An agent should execute one task with a short-lived, audience- and permission-restricted credential while preserving user and agent identities, execution-time authorization, confirmation, and audit lineage.
Better Auth unifies login, sessions, providers, and plugins; applications still own resource authorization, revocation latency, and policy for agent actions.
Better Auth trades a managed identity platform for an in-app library and your own database; that gives you control, but migrations, security updates, and incident response become your responsibility.
Clerk's real value is an integrated identity lifecycle, not a sign-in box; resource authorization, tenant isolation, and business-data consistency remain your application's responsibility.
Stytch is an API-first managed identity platform: choose the Consumer or B2B model, converge authentication factors into sessions, then enforce organization and RBAC boundaries on the server.