It looks like the "vapi" provider is currently unavailable in your assistant's model dropdown due to ongoing changes to the Workflow product and API. I recommend checking the [Vapi changelog](
https://docs.vapi.ai/changelog) for updates, or contacting Vapi support via the "Docs and Support" button in your dashboard for the latest status and guidance. If you need immediate access, let support know about your use case so they can assist further.
Sources:
- [Vapi Workflows Documentation](
https://docs.vapi.ai/workflows)
- [Changelog May 9, 2025](
https://docs.vapi.ai/changelog/2025/5/9)