OpenAI opens the Decisions API public beta: POST /v1/decisions on gpt-6-luna returns typed predicate, choice and score answers ~10x faster than the Responses API, billed only for input at $0.10 per 1M tokens

OpenAI moved the Decisions API to public beta on October 6, 2026 (API changelog: https://developers.openai.com/api/docs/changelog). It is a dedicated POST /v1/decisions endpoint, currently served only by gpt-6-luna, that evaluates shared text or text+image input against a list of developer-defined questions and returns an answers array. Three question types exist: predicate (probability a condition is true), choice (one of supplied values plus per-option probabilities and a confidence field) and score (probability-weighted average over ordered levels, indices from 0). OpenAI says it returns typed answers about 10x faster than the Responses API and positions it for classification, routing and an agent's next action, while Structured Outputs and function calling remain the tools for free-form objects and tool calls. Pricing is input-only at $0.10 per 1M tokens with no output, cache-read or cache-write charges; regional premiums and long-context multipliers apply. It supports Zero Data Retention and HIPAA for eligible customers and US/EU data residency. Images must be inline base64 data URLs. No accuracy benchmarks were published. A Playground is available, a voice integration guide covers Live API client delegation, and GA is expected in the coming weeks. The same changelog day also collapsed API usage tiers from five to three (Build, Launch, Grow).