GPT Luna 6
Released on September 22, 2026
Changes from previous version
Successor to GPT Luna 5.6 at half the promotional $0.20/$1.20 rates. Adds Astra-class alignment and communication improvements, plus the same caching upgrades as GPT Sol 6: 90% off cached input reads, and changing reasoning effort or tools no longer breaks the cache.
Release Summary
GPT-6 generation of OpenAI's volume Luna tier for focused, high-volume tasks such as summarizing, extracting, and answering quick questions. Standard API pricing is $0.10/M input and $0.50/M output, 50% below GPT Luna 5.6 promotional rates, with $0.01/M cache reads and $0.125/M cache writes. DeepSWE v1.1 at max scores 66.6%, comparable to Claude Opus 5 and Claude Fable 5 at medium effort at 93% and 96% lower cost per task. On AutomationBench, high-effort Luna improves 5.4 points over its predecessor at 58% lower cost per task. Available as gpt-6-luna in the API; ChatGPT Work and Codex for paid plans; Free and Go users can use it in the desktop app. Not yet in Chat at launch. 1.05M context, 128k max output, knowledge cutoff May 18, 2026. Fast mode is 2x Standard rates.
Timeline
GPT-6 Luna released
OpenAI launches GPT-6 Luna as gpt-6-luna in the API and ChatGPT desktop for Free and Go, with Work and Codex access for paid plans, at $0.10/$0.50 per million tokens.