GPT-5.6 Luna
GPT-5.6 Luna is the most cost-efficient model in OpenAI’s GPT-5.6 family, released on July 9, 2026.
- Lab
- OpenAI
- Release date
- Status
- Generally available
- API model ID
- gpt-5.6-luna
- Context window
- 1,050,000 tokens
- Max output
- 128,000 tokens
OpenAI released GPT-5.6 Luna, the most cost-efficient model in the GPT-5.6 family, on July 9, 2026. OpenAI’s model page lists it as gpt-5.6-luna, with a 1,050,000-token context window, 128,000 max output tokens, and text and image input with text output. Plus, Pro, Business and Enterprise users can choose it in ChatGPT and Codex, and it is available through the OpenAI API.
GPT-6 Luna followed on September 22, 2026.
- Modalities
- Text and image input; text output
- Availability
- ChatGPT and Codex for Plus, Pro, Business and Enterprise users; OpenAI API.
- Official source
- openai.com
- Last checked
Questions
When was GPT-5.6 Luna released?
OpenAI released GPT-5.6 Luna on July 9, 2026.
What is the context window of GPT-5.6 Luna?
OpenAI’s model page lists a 1,050,000-token context window and 128,000 max output tokens.
Who can use GPT-5.6 Luna?
Plus, Pro, Business and Enterprise users can choose it in ChatGPT and Codex, and it is available through the OpenAI API.
What replaced GPT-5.6 Luna?
GPT-6 Luna followed on September 22, 2026.
Source
Release dates, model IDs and limits come from each lab’s own announcement, changelog, documentation or deprecations page, linked on every model with the date it was last checked. How we pick and check sources: editorial standards.