Claude Opus 4.7 scores worse than Opus 4.6 on Simple Bench, a benchmark designed to test common sense.

Claude Mythos achieved an 82% score on the terminal bench, an increase from the previous 65%.

On SWEBench Pro, Claude Mythos achieved a 78% score, while Opus previously scored 53% and GPT 5.4 scored 57.7%.

Claude Opus 4.7 shows clear improvement over Opus 4.6 in some long context reasoning measures but is a regression in others, such as finding the fourth poem across 1 million tokens.

Claude Opus 4.7 underperforms Opus 4.6 and Mythos Preview in cybersecurity vulnerability reproduction.

Anthropic intentionally reduced Claude Opus 4.7's cybersecurity vulnerability finding capabilities during training, as stated on page 48 of its system card.