Text Completions

Token usage statistics.

prompt_tokens follows the upstream wire contract — includes every input class (non-cached, cache read, and cache write). The breakdown is exposed under prompt_tokens_details so consumers can attribute the cached-read and cache-write subsets. Cache-aware billing on the brain side reads the canonical InferenceUsage fields directly, not this wire payload.

Pioneer-specific extension fields appended to OpenAI-compatible responses.

OpenAI's API contract reserves the unprefixed top-level keys (id, choices, usage, …); custom data must live under a clearly namespaced key. x_pioneer is that key.

Attributes: inference_id: The Pioneer-side identifier of the persisted inferences row associated with this completion. Present when persistence is enabled (extra_body.store == True) and the row was successfully recorded; None for ad-hoc requests that opted out of persistence. The frontend uses this to poll GET /inferences/{id} for asynchronous judge results without coupling the inference response latency to the judge. routed_model: Backend catalog model selected by a router project (for example pioneer/auto). None when the request was not routed or the routed model matches the requested id. savings: Routed-vs-frontier per-1M-token savings rate diff (same wire shape as the Anthropic pioneer_savings extension). The Codex routing-savings hook multiplies these rates by per-turn token usage to surface cumulative money saved. None when the request was not routed below the frontier reference model.