Paper

WorkRover: Scaling Long-Horizon Cowork Agent Training Via Recursive Environment Evolution

A recursive environment-building and RL setup that jointly repairs context, task, and verifier, then shapes turn credit from checked workspace progress.

arXiv ↗Oct 13, 2026Code ↗

  • llm
  • agent training
  • reinforcement learning
  • credit assignment
Multi-stage pipeline diagram showing method: rollout, evaluation, credit assignment, policy update
Multi-stage pipeline diagram showing method: rollout, evaluation, credit assignment, policy update

What it is

Trains long-horizon cowork agents by recursively repairing synthesized work environments and adding verifier-grounded turn credit during RL. Instead of one-shot task generation and episode-only rewards, it recursively repairs misaligned context/task/verifier packages and adds verifier-grounded turn credit from workspace progress.

Key results

  • +413.25 Elo on GDPval v2 over Qwen3.5-35B-A3B
  • JobBench improves by 26.27 points over Qwen3.5-35B-A3B
  • FCR raises task-package synthesis pass rate by 6.0 points vs regeneration

Shows long-horizon agent RL improves when training environments are iteratively repaired and rewards are grounded in verified intermediate workspace progress.

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