AnthropicClaude Opus 5VSOpenAIGPT-5.6 Terra
Our Take
We recommend Claude Opus 5 if your workflow requires peak coding capability, or the 1.8x cheaper GPT-5.6 Terra to optimize your API budget. While both models deliver similar reasoning performance, Claude Opus 5 holds a clear lead in coding. Choose Claude Opus 5 for complex development tasks, or GPT-5.6 Terra for cost optimization.
▶WHY?
Benchmark Calculations & Evidence:
Coding Benchmarks: Both models were evaluated on the SWE-bench Pro benchmark. Claude Opus 5 scored 79.2%, while GPT-5.6 Terra scored 63.4%.
Reasoning Benchmarks: Both models were evaluated on the GPQA Diamond benchmark. Claude Opus 5 scored 93.7%, while GPT-5.6 Terra scored 92.9%.
Cost Efficiency: GPT-5.6 Terra pricing ($2.5/M input, $15/M output) is 1.8x cheaper than Claude Opus 5 ($5/M input, $25/M output).
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Benchmarks & Scores
Coding (swe-bench-pro)Winner (+15.8%)
79.2%complex codebases, multi-file repositories, and architectural planning
Reasoning (gpqa-diamond)Winner (+0.8%)
93.7%graduate-level science QA
Cost & Context
Cost (per 1M tokens)
$10.00Input: $5.00 | Output: $25.00Context Window
1.05M tokensBenchmarks & Scores
Coding (swe-bench-pro)
63.4%complex codebases, multi-file repositories, and architectural planning
Reasoning (gpqa-diamond)
92.9%graduate-level science QA
Cost & Context
Cost (per 1M tokens)1.8x cheaper
$5.63Input: $2.50 | Output: $15.00Context WindowLarger
1.05M tokensFrequently Asked Questions about Claude Opus 5 vs GPT-5.6 Terra
GPT-5.6 Terra is cheaper than Claude Opus 5. GPT-5.6 Terra has a blended cost of $5.63/1M tokens, which is about 1.8x cheaper than Claude Opus 5 at $10.00/1M tokens.
Claude Opus 5 is better for coding tasks on this benchmark. It scores 79.2% on swe-bench-pro (complex codebases, multi-file repositories, and architectural planning) compared to GPT-5.6 Terra which scores 63.4%.
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