Every AI provider fails in its own way. I stopped checking status codes and built an error model instead.

I built an API gateway that routes between OpenAI, Anthropic and Gemini. I figured integrating both providers would be the hard part. It wasn't. Calling their APIs is maybe an afternoon of work each. The hard part showed up later, the first time something went wrong. The moment it broke Early on, my error handling was basically: catch whatever the provider throws, forward the status code, move on. } catch ( error ) { res . status ( error . status || 500 ). json ({ error : error . message }) } This worked fine until I actually looked at what each provider sends back when something goes wrong. OpenAI wraps its errors in an object with a type and sometimes a code . Anthropic wraps its errors differently, with its own type field that means something else entirely. A 429 from one provider might mean "you're sending too fast, back off." A 429 from another context might mean something closer to "we're out of capacity right now, this isn't really about your rate at all." If you're just forwarding error.status and error.message straight through, none of that nuance survives. Your own error handling ends up being provider-specific whether you meant it to be or not, because the shape of the failure is different depending on who you called. What I built instead Instead of trusting each provider's raw error shape, every call now normalizes into the same internal error model before it reaches the response: } catch ( error ) { const classified = classifyProviderError ( error ) res . status ( classified . httpStatus ). json ({ error : ' AI provider error. Please try again. ' , error_class : classified . error_class , provider : classified . provider }) } error_class is one of a small fixed set: rate_limited , overloaded , quota_exceeded , invalid_request , authentication_error , server_error . That's true regardless of which provider actually failed. The raw provider error still gets logged for me to debug, but what the caller sees is the category of failure, not the provider's spe