2,405 chain-of-thought reasoning traces produced by claude-opus-4-7 on hard reasoning prompts spanning math, science, and formal subjects. Each sample is a problem → block → polished answer pair, where the block contains Opus 4.7's full working (Restatement → Approach → Step-by-step derivation → Verification) and the post- answer is written as a standalone lesson starting with the result in bold.

	How the… See the full description on the dataset page: https://huggingface.co/datasets/ansulev/opus-4.7-reasoning-cot-4.8k.