Reinforcement Learning

Endless Terminals: Scaling RL Environments for Terminal Agents

KKanishk GandhiSShivam GargNNoah D. GoodmanDDimitris Papailiopoulos
Published
January 23, 2026
Authors
4
Word Count
5,097

Scaling RL environments with procedural task generation.

Abstract

Environments are the bottleneck for self-improving agents. Current terminal benchmarks were built for evaluation, not training; reinforcement learning requires a scalable pipeline, not just a dataset. We introduce Endless Terminals, a fully autonomous pipeline that procedurally generates terminal-use tasks without human annotation. The pipeline has four stages: generating diverse task descriptions, building and validating containerized environments, producing completion tests, and filtering for solvability. From this pipeline we obtain 3255 tasks spanning file operations, log management, data processing, scripting, and database operations. We train agents using vanilla PPO with binary episode level rewards and a minimal interaction loop: no retrieval, multi-agent coordination, or specialized tools. Despite this simplicity, models trained on Endless Terminals show substantial gains: on our held-out dev set, Llama-3.2-3B improves from 4.0% to 18.2%, Qwen2.5-7B from 10.7% to 53.3%, and Qwen3-8B-openthinker-sft from 42.6% to 59.0%. These improvements transfer to human-curated benchmarks: models trained on Endless Terminals show substantial gains on held out human curated benchmarks: on TerminalBench 2.0, Llama-3.2-3B improves from 0.0% to 2.2%, Qwen2.5-7B from 2.2% to 3.4%, and Qwen3-8B-openthinker-sft from 1.1% to 6.7%, in each case outperforming alternative approaches including models with more complex agentic scaffolds. These results demonstrate that simple RL succeeds when environments scale.

Key Takeaways

  • 1

    Procedural generation pipeline synthesizes diverse terminal tasks.

  • 2

    Automatic verification ensures tasks are well-defined.

  • 3

    RL models show significant improvement on benchmarks.

Limitations

  • Dependent on the quality of the language model used.

  • Limited to terminal-based tasks.

Keywords

reinforcement learningPPOterminal benchmarksprocedural generationcontainerized environmentsepisode level rewardsagent trainingscalability

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