When an AI API call fails, the tempting reaction is to switch models or providers.
That is often premature.
A large share of 401, 429, model_not_found, timeout, and confusing billing issues are not model-quality problems. They are route-evidence problems. The request moved through a key, base URL, model ID, retry rule, fallback path, and billing record. If those pieces are not visible, changing the model can hide the real cause.
Before you replace the model, debug the route.
A practical route checklist
