OpenAI Releases GPT-5.6 (Sol, Terra, Luna): A Three-Tier Model Family With Programmatic Tool Calling in the Responses API
Interactive · OpenAI GPT‑5.6 · July 9, 2026
GPT‑5.6 tier, cost and benchmark explorer
Every number below is taken from OpenAI’s published GPT‑5.6 eval tables and price list. Move the controls to see how tier choice changes spend and score.
Three durable capability tiers
The number is the generation. Sol, Terra and Luna are tiers that advance on their own cadence. Select a tier to see its role and rate card.
What a workload actually costs
Set your per-request token volume. Costs use OpenAI’s published per-1M rates. Cached input reads keep the 90% cached-input discount.
Estimated monthly spend · 30 days
Sol—1.0x
Terra—
Luna—
Cache billing: from GPT‑5.6 onward, cache writes bill at 1.25x the uncached input rate. Cache reads keep the 90% discount, with a 30‑minute minimum cache life and explicit cache breakpoints.
Benchmark scores, side by side
Values are OpenAI’s published eval table. A dash in that table means the score was not reported, so the model is omitted here. OpenAI states its latency and cost figures are simulated offline, not measured in production.
GPT‑5.6 family
GPT‑5.5
Anthropic
Google
Ultra: four agents, by default
Ultra coordinates four agents in parallel by default. It trades higher token use for a stronger score and faster time‑to‑result. Toggle to compare against Sol’s one‑agent baseline. OpenAI also charts 16‑agent runs on BrowseComp and SEC‑Bench Pro.
Sol · default
Sol Ultra · 4 agents
Score · single agent
Terminal-Bench 2.1
BrowseComp
SEC-Bench Pro
Where to get it: ultra runs in ChatGPT Work for Pro and Enterprise, and in Codex for Plus and higher. In the API, the multi‑agent beta in the Responses API builds ultra‑like flows.
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