OAuth

Anthropic restricted subscription OAuth tokens to work only with the official Claude Code CLI, blocking tools like OpenCode, Moltbot, and integrations in Cursor. Users who built workflows around third-party tools were locked out mid-project, forcing them to either downgrade subscriptions or abandon the platform entirely.

APIs offer confusing authentication mechanisms with multiple versions (especially OAuth), inconsistent implementations, and poor documentation of authentication flows. Getting credentials and understanding the correct authentication method is often one of the trickiest initial steps, especially when API teams and customers have mismatched use-case assumptions.