The World State Generator (WSG) is a model that keeps language agent plans aligned with the rules of their execution environment by rewriting states after failures. It is trained on 226K trajectories extracted from seven synthetic domains where a program enforces rules and verifies goal reachability.

  • WSG takes a failure as a rule stated by the world and rewrites remaining states to obey it.
  • The model writes plans as checkable states of the world rather than just language instructions.
  • Across seven public benchmarks, WSG raises end-to-end success for two open models near 30B parameters over prompting.
  • This performance brings the open models to the level of proprietary models.

WSG addresses the issue where prompted planners fail by rewriting refused steps without moving forward, ensuring plans bend to the world's physical limits and logical dependencies as the run progresses.