Chat model · OpenAI ·
GPT-5.6 Luna is a chat model by OpenAI. In Endless it costs 81 credits per 1M input tokens and 486 per 1M output tokens, on every plan.
GPT-5.6 Luna is the fastest, lowest-cost model in OpenAI's GPT-5.6 family, suited to quick answers, simple coding and high-volume requests.
GPT-5.6 Luna is the smallest of the three GPT-5.6 models OpenAI released in July 2026. It is optimized for cost-sensitive, high-volume workloads, the role nano models played in earlier GPT-5 generations. It keeps the family's 1.05M-token context, reads text and images, and writes up to 128K tokens.
Use it where speed and volume matter more than depth: classifying and tagging messages, writing short summaries, translating snippets, answering quick factual questions and explaining or fixing small pieces of code. The model supports reasoning from none to max, so it can reply instantly or take more time on the occasional harder request.
If an answer from Luna feels thin, send the same question to GPT-5.6 Terra or Sol, or to GPT-6 Luna, the small model from OpenAI's newer GPT-6 generation. Each one draws from your workspace's shared credits.
Start a chat in your workspace and choose GPT-5.6 Luna in the model picker.
Attach files, mention a project with @, or ask it to search the web and social media.
Generate images and video, write documents and save what matters to a project.
by OpenAI
Near-flagship agentic coding and professional work at lower cost
162 / 810 credits per 1M tokens
by OpenAI
Hard research and coding problems that need the deepest reasoning
1215 / 5062.5 credits per 1M tokens
by OpenAI
Long, complex coding sessions with deep reasoning
324 / 1620 credits per 1M tokens
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