GPT-5.6 Luna

The smallest and least expensive GPT-5.6.

Vendor: OpenAI
Released: Jun 2026
Model id: gpt-5.6-luna

GPT-5.6 Luna is the smallest of OpenAI’s three GPT-5.6 models. It costs a twentieth of what GPT-5.6 Sol costs on input and less than a tenth on output, and it holds about a million tokens of context.

Best for: quick, frequent work where cost matters more than depth: sorting, summarizing, short answers.

Run GPT-5.6 Luna in a workspace

Pick it per workspace from the model settings and switch any time. Inference is included in the plan, or bring a key of the team's own.