Definition
Plain language
Tasks that stretch over many steps or a long stretch of time before you know if they worked.
As stated in the literature
Settings requiring coherent behavior across many sequential decisions, where errors compound and state must be maintained over thousands of tokens or hundreds of actions.
Also called: long horizon, long-horizon reasoning, long-horizon tasks
Why it matters: Most real-world usefulness lives in long-horizon work, and it is exactly where small per-step error rates compound into total failure.
For example, an assistant asked to book a multi-city trip has to hold dozens of choices straight across many steps, and one wrong flight early on quietly ruins everything after it.
Heard on the show
“There's also the framing of "long-horizon agentic coding.”Episode 003 — How to Pick the Best of Sixteen Coding Agent Rollouts