OpenAI launches GPT-5.6 family: Sol, Terra and Luna
OpenAI's new three-tier lineup pairs a flagship reasoning model with two lower-cost variants, starting as a limited partner preview ahead of wider rollout.
MVMara Vidović
Published 7 Jul 2026, 20:29Updated 25 Jul 2026, 17:551 min read
OpenAI has begun rolling out GPT-5.6, a new family built around three distinct tiers: Sol, the flagship reasoning model; Terra, a capable mid-cost option; and Luna, tuned for speed and cost efficiency.
A staged rollout
Access started as a limited preview for trusted partners, with OpenAI signaling broader general availability in the coming weeks rather than an immediate public launch.
- ▸Sol targets frontier-level reasoning and agentic tasks
- ▸Terra aims at teams that need strong capability without flagship pricing
- ▸Luna is positioned as the fastest, cheapest tier for high-volume workloads
Speed as a selling point
OpenAI is also pairing Sol with Cerebras hardware, citing throughput up to 750 tokens per second — a notable jump for latency-sensitive agentic applications that chain many model calls together.
Source: OpenAI
