GPT-5.6 Luna
OpenAI
The fast, affordable model of OpenAI's GPT-5.6 generation (released July 2026), for lower-cost everyday work like summarization, drafting, and routine automation. Luna offers strong Terminal-Bench 2.1 performance at the family's lowest per-token price.
Strengths
- Fastest, most affordable GPT-5.6 tier
- Strong Terminal-Bench 2.1 performance at the family's lowest cost
- Ideal for summarization, drafting, and routine automation
- Improved prompt caching with a 30-minute minimum cache life
Caveats
- Limited preview as of June 2026 - not yet generally available
- Lower ceiling than Sol/Terra on hard tasks
- Context window not finalized at preview (reported up to ~1.5M, unconfirmed)
- Vendor
- OpenAI
- Context Window
- 1,050,000 tokens
- Max Output
- 128,000 tokens
- License
- Proprietary
- Release Date
- 2026-07-09
- Training Cutoff
- 2026-02-16
- Modalities
- textimage
Capabilities
Vision
Audio
Video
Tool Use
Resources
Pricing
$1 per 1M input tokens, $6 per 1M output tokens - OpenAI's lowest-cost GPT-5.6 tier. Launch pricing; check OpenAI's pricing page for current rates.