OpenAI: GPT-5.6 Terra Pro
OpenAI's flagship model. Long-context specialist with 1.1M window.
Scores by test
Methodology →What you need to know
GPT-5.6 Terra Pro is optimized for high-reliability technical tasks, achieving perfect scores in structured output, tool calling, and strategic analysis. Its primary differentiator is the combination of a massive 1.1M token context window with a 5/5 rating for long context faithfulness, making it suitable for processing entire codebases or extensive documentation without losing coherence.
The model carries a premium price point, with a blended cost of $11.88/MTok and a significant gap between input and output pricing. While it ranks #8 globally, you are paying for precision and reliability rather than raw efficiency. The cost is justified for complex workflows requiring strict schema adherence and high-fidelity data extraction, but it is expensive for simple chat applications.
Performance is consistently high, though it shows slight relative weaknesses in classification, constrained rewriting, and agentic planning. While these 4/5 scores are strong, they indicate that the model may occasionally struggle with rigid formatting constraints or multi-step autonomous planning compared to its perfect performance in static strategic analysis.
Use this model if your application requires a massive context window and zero-failure structured outputs for tool integration. Skip this model if you are running high-volume, simple classification tasks where the high per-token cost would outweigh the marginal gains in accuracy.
Strengths — Top 3
Relative weaknesses — Bottom 3
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