GPT-5.6 Luna
The fastest, most cost-efficient GPT-5.6 tier. Built for speed and high-volume simple tasks.
Released July 9, 2026
Pricing
Capacity
Capabilities
Best Scores
Best For
Benchmark Scores
Specialized Skills
GDPval-AA v2
Real paid work from 44 different jobs, such as law, nursing, and software. Judges compare two answers side by side without knowing which model wrote them, and the winner gains rating points. A typical human expert scores 1000, so a higher number means the work was picked over a human more often.
Provider-reported; no independent run recorded yet.
Software Engineering
SWE-bench Verified
Hands the AI bugs from actual software projects and counts how many it fixes. Like a coding job interview, but with real work.
Independently measured by Vals AI (mini-swe-agent).
Terminal-Bench 2.1
Puts the AI in front of a computer terminal and asks it to finish multi-step tasks on its own. Measures how good an "AI agent" it is.
Provider-reported; an independent run by Vals AI (Terminus 2) lands at 79.03%.
SWE-bench Pro
The harder version of the coding test. Bigger codebases, trickier bugs. Scores drop for everyone, so the gaps between models become clearer.
Provider-reported; no independent run recorded yet.
Knowledge
GPQA Diamond
PhD-level science questions written so you cannot just Google the answer. Tests whether the model can reason about hard science.
Provider-reported; no independent run recorded yet.
Humanity's Last Exam
PhD-level questions across many subjects. Tests deep reasoning on the hardest questions humans can ask.
Independently measured by Artificial Analysis.
Reasoning
Artificial Analysis Intelligence Index
A frequently refreshed overall score made from nine modern tests: real work, tool use, terminal tasks, science, hard questions, and long-context reasoning. It is a scorecard rather than a percent correct.
Provider-reported; no independent run recorded yet.
Why Choose GPT-5.6 Luna?
Luna is OpenAI's speed and efficiency tier. At $1/$6, it competes on price with Haiku while maintaining access to OpenAI's full feature set and 1M+ token context. Perfect for high-volume, cost-sensitive applications.
How It Compares
vs Claude Haiku 4.5
Luna is slightly more expensive but has more context; Haiku is simpler.
vs GPT-5.6 Terra
Luna is 2.5x cheaper; Terra is more capable.