Vercel adds OpenAI's Decisions API to AI Gateway for typed, non-text answers
Vercel has made OpenAI's Decisions API available on AI Gateway through an OpenAI-compatible /v1/decisions endpoint. Decision models return probabilities, choices and scores rather than generated text, which Vercel says suits routing, triage, guardrails and rubric scoring.
- OpenAI's Decisions API is available on Vercel AI Gateway via an OpenAI-compatible /v1/decisions endpoint.
- Decision models return probabilities, choices and scores instead of generated text.
- One request can include predicate (yes/no), choice and score questions about the same input.
- openai/gpt-6-luna-decisions is separate from openai/gpt-6-luna and is billed at Decisions API rates.
- decisions.create needs OpenAI SDK 7.30.0+ (JavaScript) or 3.26.0+ (Python); experimental_decide needs ai 7.0.128+.
What the Decisions API does
According to Vercel, decision models answer typed questions about a shared input. Instead of producing free-form text, they return structured results: probabilities, choices and scores. Vercel lists routing, triage, guardrails and rubric scoring as the use cases the approach suits.
Developers can ask several kinds of questions against the same input in a single request. The supported types are predicate (yes/no), choice and score questions.
The API can be used with GPT-6 Luna Decisions or any other decision model on AI Gateway. Vercel names Jev, Liquid d1 and Laya among the models that can be set in the model field.
Model IDs and billing
Vercel stresses that openai/gpt-6-luna-decisions is a separate model ID from openai/gpt-6-luna. The latter stays a language model for text generation. Requests sent to the decisions ID go to the Decisions API and are billed at its rates, according to Vercel.
The API can be called with the OpenAI SDK, the AI SDK, the existing HTTP API at /v1/evaluate, or the AI CLI.
How to call it
With the OpenAI SDK, developers point the client at AI Gateway using the base URL https://ai-gateway.vercel.sh/v1 and call decisions.create as they would against OpenAI. Vercel's example sends the input "I was charged twice. Please refund me." along with a choice question named department. The question asks which team should handle the message, with two options: billing (charges and refunds) and technical (bugs and outages).
Answers come back as an array in question order, and each answer carries the name of its question. In the AI SDK, questions are keyed by name, and the yes/no type is called boolean. Each key in questions becomes a key in answers.
- OpenAI SDK: decisions.create requires version 7.30.0 or later for JavaScript, or 3.26.0 or later for Python.
- AI SDK: experimental_decide requires ai 7.0.128 or later.
What it means for developers
For teams already using AI Gateway, the change adds a way to get structured classification and scoring results through the same gateway and with familiar SDKs, without parsing generated text. Tasks such as sending a support message to the right team can be expressed as a typed question with defined choices.
Vercel points developers to the OpenAI-compatible Decisions API reference for request limits and error formats, to the AI SDK decision documentation, and to a listing of all decision models on AI Gateway.
Vercel: OpenAI Decisions API now available on AI Gateway
