ResearchResearch paperReinforcement Learning1 source · Oct 14, 2026

Explorer-Zero: Improving Self-Play for Long-Horizon Tasks with Decomposable Verifiable Rewards

We propose Explorer-Zero, a self-play framework that jointly generates tasks and fine-grained, verifiable rewards through environment interaction.

Key points

  • Training LLM agents on long-horizon interactive tasks with reinforcement learning typically relies on human-annotated tasks and reliable verification, both expensive to construct for stateful environments.
  • Self-play offers an alternative, but must generate achievable, compositional tasks and provide feedback beyond binary outcomes.
  • We show theoretically that subtask rewards reduce collapse among unsuccessful rollouts when they complete different numbers of subtasks.
  • Without human-annotated training tasks, Explorer-Zero outperforms the evaluated self-play baselines across ALFWorld, ScienceWorld, and AppWorld; on AppWorld, our 30B agent reaches 59.67% task success, approaching 62.65% for RL on human-annotated tasks.

Sources (1)

  • [1]Explorer-Zero: Improving Self-Play for Long-Horizon Tasks with Decomposable Verifiable Rewards
    arXiv (AI, ML, NLP, CV, robotics, multi-agent) · Oct 14, 09:29 AM
    We propose Explorer-Zero, a self-play framework that jointly generates tasks and fine-grained, verifiable rewards through environment interaction.
    Training LLM agents on long-horizon interactive tasks with reinforcement learning typically relies on human-annotated tasks and reliable verification, both expensive to construct for stateful environments.

Extractive summary: sentences quoted from the sources.

Before this

  1. Oct 14, 2026More Methods, Better Agents? A Reality Check on Self-Distillation in Agentic Reinforcement Learning
  2. Oct 14, 2026Player-1: Learning to Play from Synthetic Experience
  3. Oct 14, 2026MAI-Gym: An Open All-in-One Platform for GUI Agent Evaluation and RL Training across Mobile and Computer Environments
  4. Oct 14, 2026SERO: Learning from Executable Oracle Continuations for Long-Horizon Agentic Reinforcement Learning
  5. Oct 13, 2026Can an Agent Learn to Predict Its Own Failure? Outcome-Grounded Confidence Calibration in LLM Agents
  6. Oct 13, 2026DeltaTTG: Training Multi-Turn Agents with a Token-to-Go Progress Meter

Related