# PoS (Progression of States)

The work introduces PoS, an inference-time framework that replaces interaction history as the agent's decision context with a continually maintained explicit belief state (world state plus unresolved epistemic and achievement gaps), validates belief updates through a Belief Sentinel, detects Belief Trapping (stagnation, cycles, drift) from window-level signals, and composes recovery constraints tailored to the trapping pattern and blocked gap type; across four benchmarks (ALFWorld, LOCA-Bench, RCA-100, ClinDiag) and three backbones (Qwen3.7-Plus, Kimi-K3, GLM-5.3), PoS achieves the highest overall performance in all 12 benchmark-backbone combinations, with relative gains over the strongest same-backbone baseline reaching 22.68% on ALFWorld and 37.89% on RCA-100 joint accuracy.

The work introduces PoS, an inference-time framework that replaces interaction history as the agent's decision context with a continually maintained explicit belief state (world state plus unresolved epistemic and achievement gaps), validates belief updates through a Belief Sentinel, detects Belief Trapping (stagnation, cycles, drift) from window-level signals, and composes recovery constraints tailored to the trapping pattern and blocked gap type; across four benchmarks (ALFWorld, LOCA-Bench, RCA-100, ClinDiag) and three backbones (Qwen3.7-Plus, Kimi-K3, GLM-5.3), PoS achieves the highest overall performance in all 12 benchmark-backbone combinations, with relative gains over the strongest same-backbone baseline reaching 22.68% on ALFWorld and 37.89% on RCA-100 joint accuracy.