The latest AI model, Fable 5, has achieved a significant milestone by extending task length to approximately 30 hours as of June 2026. This marks a rapid progression in AI capabilities, with task length doubling every four months, compared to the previous rate of every seven months over the past six years. This advancement follows a series of improvements in AI models, including Claude Opus 4.6, which reached a task length of 14.5 hours in February 2026, and Claude Opus 4.5, which achieved 5 hours in December 2025. Earlier models like GPT-4 in 2023 had a task length of about 4 minutes, highlighting the exponential growth in AI performance.