Senior Environment Engineer, Long-Horizon Tasks

The role Most environments test a few steps. Ours increasingly need hundreds: tasks that span days of simulated time, several systems and partial information. You’ll own the hardest environments we build and set the patterns the rest of the team follows. What you’ll own Environments where state persists across many tool calls and the right answer depends on what happened earlier.Event schedules, background processes and interruptions that make a world behave like a workplace.The interfaces between environments, verifiers and the training stacks our customers run.Design review across the team, raising the bar on reproducibility and reward integrity.Measurement, with research, of where agents break as horizon length grows. What you bring Five or more years building distributed or simulation systems in production.Deep comfort with concurrency, state machines and failure modes.You’ve led technical design across a team and can explain a tradeoff in writing.Interest in how agents fail and what a world needs to contain to surface it. Helpful, not required Game engines, discrete event simulation or workflow engines.Hands-on RL post-training of language models.