Dispatch
OpenRouter's automatic fallback silently changes model behaviour, and provider.only is the fix
Mohamed Moustafa documented that OpenRouter's pitch of handling 'fallbacks automatically' and picking 'the most cost-effective option for each request' means the same model endpoint behaves differently depending on which backend serves it. Some providers lack vision capability for vision models, and the reasoning-effort option is interpreted differently per provider. The practical fix is pinning routing with the provider.only option after querying the /endpoints API method to see which providers actually serve a given model ID.
↳ Follow the thread