# GPT-5.6 Terra

OpenAI, released 2026-06-26

**Verdict: conditional.** GPT-5.6 Terra is OpenAI's mid-tier workhorse: GPT-5.5-class capability on OpenAI's own claim, at $2.00 input and $12.00 output per 1M tokens at short context ($4.00 / $18.00 long) after the 20% price cut of 30 July 2026. It is generally available via the API and Codex. Remains conditional: all benchmarks are vendor-reported without independent reproduction, and Terra is not selectable in the standard ChatGPT model picker. Last verified 2026-06-27.

## Pricing

- Input: $2.00 / 1M tokens
- Output: $12.00 / 1M tokens
- Context: Short $2.00/$12.00 · long $4.00/$18.00 per 1M

## Strengths

- Cost-efficiency sweet spot: GPT-5.5-class capability on OpenAI's own claim, at $2.00 input / $12.00 output per 1M short context. Terra is priced to replace GPT-5.5 as the default model for most production workloads, if the quality claim holds.
- TerminalBench 2.1 at 84.3% ties Claude Fable 5, Anthropic's publicly available flagship, at the same score. For agentic coding that doesn't need Sol's extreme reasoning depth, Terra is the rational pick.
- High-volume enterprise workloads: customer support, internal tools, document analysis, and production pipelines where reliability matters but per-request cost needs to scale.
- Strong cybersecurity capability for its tier: scored 91.84% on internal CTF testing. Carries activation classifiers and the same safety stack as Sol for regulated cyber and bio workflows.
- Long-context jobs budgeted off the headline rate: past short context Terra bills $4.00 input and $18.00 output per 1M tokens.
- No ultra or max reasoning modes: Terra lacks the subagent decomposition and extended deliberation that distinguish Sol. For the hardest agentic work, you still need Sol.
- The 84.3% TerminalBench score is only 0.9 points ahead of GPT-5.5 at 83.4%. The 'competitive with GPT-5.5' claim is directionally right but the gap is small: your own evals will tell you more than the scoreboard.

## Benchmarks

- TerminalBench 2.1: 84.3% (https://openai.com/index/previewing-gpt-5-6-sol/)
- Internal CTF (capture-the-flag): 91.84% (https://venturebeat.com/technology/openai-unveils-gpt-5-6-sol-terra-and-luna-models-but-only-accessible-to-limited-preview-partners-for-now-per-us-gov)

## Sources

- [OpenAI: GPT-5.6 Preview System Card](https://deploymentsafety.openai.com/gpt-5-6-preview)
- [OpenAI — Previewing GPT-5.6 Sol](https://openai.com/index/previewing-gpt-5-6-sol/)
- [OpenAI Docs: API changelog (Decisions API beta, October 6, 2026)](https://developers.openai.com/api/docs/changelog)
- [OpenAI API pricing](https://developers.openai.com/api/docs/pricing)
- [VentureBeat: GPT-5.6 Sol, Terra and Luna models](https://venturebeat.com/technology/openai-unveils-gpt-5-6-sol-terra-and-luna-models-but-only-accessible-to-limited-preview-partners-for-now-per-us-gov)
- [Lushbinary: GPT-5.6 Sol Benchmarks Deep Dive](https://lushbinary.com/blog/gpt-5-6-sol-benchmarks-terminalbench-agentic-deep-dive/)

Canonical: https://neomanex.com/models/gpt-5-6-terra