Claude Mythos Preview

2 items

Anthropic Blog 2026-04-16-2

Introducing Claude Opus 4.7

Anthropic held headline rates at $5/$25 per million tokens while shipping a tokenizer that inflates inputs by up to 35%, which makes price-per-token comparisons meaningless. The capability jump is real: CursorBench up 12 points, Notion tool errors cut by two-thirds, XBOW vision nearly doubled. The only number that matters now is price-per-useful-output, and that requires workload-specific benchmarking most teams won't run.

UK AI Security Institute 2026-04-13-3

AISI Evaluation of Claude Mythos Preview's Cyber Capabilities

A UK government lab confirmed Mythos can autonomously execute a 32-step corporate network attack end-to-end, outperforming every tested model including GPT-5, with performance still scaling at the 100M token ceiling. The evaluation tested capability against undefended ranges, so what AISI validated is threat potential, not operational impact against a real defended environment. The structural shift is that government evaluation infrastructure is becoming the third-party verification layer for frontier AI claims, sitting between self-reported lab benchmarks and the market the way FDA trials sit between pharma and prescribers.