OpenAI Releases Decisions API in Public Beta, Powered by GPT-6 Luna

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OpenAI released the Decisions API in public beta on October 6, 2026, introducing an endpoint that returns typed answers to developer-defined questions over text and image inputs. The OpenAI API changelog records the release in beta with gpt-6-luna, served through a dedicated POST /v1/decisions endpoint.

OpenAI says the new endpoint produces those answers about 10x faster than the Responses API. According to the Decisions API documentation, the API can be tested in the Playground, where developers can experiment with questions and inputs ahead of writing code.

The release follows the API’s introduction at DevDay 2026, where it was available in limited preview. OpenAI’s DevDay recap said the API applies the Luna model’s reasoning to a set of user-defined questions, each with a finite set of predefined answers, letting developers supply text or image context and get back results that can drive content classification, request routing, or an agent’s next action.

OpenAI said at the time that a broad release was planned in the coming days.

The endpoint runs on GPT-6 Luna, a reasoning model OpenAI released alongside GPT-6 Sol on September 22, 2026. Both models accept text and image inputs and generate text through the Responses and Chat Completions APIs.

Each request has three parts. The model field selects the evaluating model; currently, only gpt-6-luna is supported. The input field carries shared evidence for the questions, either as a text string or as user messages containing text and images. The questions array specifies what the model should evaluate: each question’s type, its instructions, and any allowed choices or score levels.

The response contains an answers array, and each question carries a unique name that the API echoes back with its answer.