Simon Willison releases llm-openai-decisions 0.1a0 for OpenAI Decisions API

What the plugin does

Simon Willison has released llm-openai-decisions 0.1a0, an LLM plugin for OpenAI's new Decisions API. OpenAI released the API after previously announcing it at last week's DevDay. Willison already had an llm-typesafe plugin for talking to Jev, so he had GPT-6 Astra read the new OpenAI API documentation and build the new plugin inspired by llm-typesafe. The release was posted on 6th October 2026 at 11:04 pm.

Model support and pricing

Unlike Jev, the new gpt-6-luna decision model supports image input in addition to text. Both models charge for input and not for output. OpenAI's price is 10 cents per million input tokens, while Jev's is 4.2 cents per million. Otherwise, the API shape is very similar to Jev, at least conceptually.

Question types and example

Jev supports three question types: yes/no, choices, or scores. OpenAI Decisions supports the same three types. The plugin is installed with llm install llm-openai-decisions. An example query against an image attachment asks whether the image contains any mammals, and the shown output is a predicate evaluation with probability 0.0. The README has full details for running the other question types.

Sources: Simonwillison