GPT-5.6 Terra
The balanced middle tier of the GPT-5.6 family. Most of Sol's ability at half the cost.
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.
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.
Software Engineering
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 tbench.ai (Codex) lands at 78.4%.
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.
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.
Independently measured by Artificial Analysis.
Why Choose GPT-5.6 Terra?
Terra is the Goldilocks option in the GPT-5.6 lineup. It delivers most of Sol's capability at half the cost, with a balanced feature set. Great for teams who want OpenAI's capabilities without premium pricing.
How It Compares
vs GPT-5.6 Sol
Terra is half the cost; Sol is faster and better at agentic work.
vs Claude Sonnet 5
At intro pricing, Sonnet is cheaper; Terra has broader capabilities.