Anthropic reports Claude authors 80%+ of code; task-length capability doubles every 4 months. Mythos Preview works 16+ hours autonomously.

Anthropic revealed Claude authored 80%+ of merged code as of May 2026. The company's internal metrics show task-length capability doubling every 4 months, up from every 7 months.

Key facts

Claude authors 80%+ of Anthropic's merged code as of May 2026.

Task-length capability doubles every 4 months, up from 7 months.

Mythos Preview works 16+ hours autonomously per METR.

Code speedup: 52x for Mythos Preview vs 3x for Opus 4.

800+ fixes shipped, cutting API errors 1,000x in one example.

Anthropic published a sweeping internal assessment of AI progress, claiming the company is 'getting very serious about recursive self-improvement' According to @kimmonismus .…