GPT-5.6 Terra
Language modelPrevious generationCard summarizedGPT-5.6 model that balances intelligence and cost
Active (legacy)● Re-checked 12 Oct 2026 · 82 facts · 0 correctionsSource: GPT-5.6 System Card (82 pp)
Use it via API
Where to call it
- OpenAI API
gpt-5.6-terra
Supports
- Image input
- Streaming
- Structured outputs
- Reasoning control
- Tool calling
- Web search
- Prompt caching
- Batch API
Good for
- Capable lower-cost option in the GPT-5.6 family
- Retains much of Sol's health performance and beats GPT-5.5 on HealthBench Professional (57.7 vs 51.8)
- Improves over GPT-5.5 on internal research debugging, small-scale pretraining (NanoGPT) and post-training tasks
Overview
GPT-5.6 Terra
GPT-5.6 model that balances intelligence and cost
- Cost
- $2.00 in
- Context
- 1.05M
- Input / output
- $2.00 / $12.00
- Max output
- 128K
- Knows up to
- February 2026
- Released
- 9 Jul 2026
The lower-cost member of the GPT-5.6 family, covered with Sol and Luna in one system card. OpenAI treats it as High in cybersecurity (below Critical) and in biology and chemistry, and below High in AI self-improvement; it is less capable than Sol in cyber but reaches High. Like Sol it is served with new activation classifiers. Most alignment and external evaluations in the card cover Sol only. p.2–3, p.34–35, p.47
gpt-5.6-terra- Input / output per 1M
- $2.00 / $12.00
- Context window
- 1.05M
- Max output
- 128K
- Knows up to
- February 2026
- Reasoning
- Configurable (effort none → max)
- Weights
- Closed
About this card. A model card is the maker's own account of a model: what it's for, how it was trained and tested, and where it falls short. This page condenses OpenAI's GPT-5.6 System Card. Every claim carries its source page.