Hidden SDK Retries: Why You're Paying Twice and Don't Know It
Open the OpenAI Python SDK source and you will find a quiet line: DEFAULT_MAX_RETRIES = 2. The Anthropic SDK ships the same default. Most TypeScript SDKs match. Two retries, exponential backoff, automatic on connection errors, 408, 409, 429, and any 5xx — fired before your code ever sees the failure. You do not configure this. You do not opt in. You usually do not know it is happening, because the metric your app records is request_count, not attempt_count, and the only span your tracer ever sees is the outer one the SDK closes after the final attempt.
This is fine, mostly, until it is not. Add an application-level retry decorator on top of that SDK call — the kind every team writes after their first 429 — and you have built a 3×3 storm: the SDK tries three times, your wrapper tries three times around the SDK, and a single user request fans out to nine inference calls during a provider degradation. The provider's bill counts every attempt. Your dashboards count one. The reconciliation, when someone finally runs it, is a quarter-end conversation nobody enjoys.
