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QVal: Cheaply Evaluating Dense Supervision Signals for Long-Horizon LLM Agents

Source

arXiv

arxiv.org/abs/2606.32034v1

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Plain-Language Brief

Researchers introduce QVal, a tool that evaluates dense supervision signals for long-horizon Learning with Long Memory (LLM) agents without the need for training. This allows for a fair comparison between different dense supervision methods and their families.

What the Document Says

  • The text discusses a new evaluation method called QVal, which is used to assess dense supervision signals for Learning with Long Memory (LLM) agents without requiring any training.
  • QVal measures the Q-alignment of a method's score, determining if it ranks actions according to a strong reference-policy's Q-values.
  • The study benchmarks 21 dense supervision methods across four environments and seven families, with over 1.2K evaluation experiments across six open-weight model backbones.
  • The research finds that simple prompting baselines outperform recent dense supervision methods from the literature, and performance tends to cluster strongly by family.
  • QVal is designed to be easily extensible to new environments and methods.

Key Concepts Mentioned

  • Learning with Long Memory (LLM)
  • dense supervision signals
  • Q-alignment
  • Q-values
  • reference-policy
  • benchmarking
  • evaluation experiments
  • model backbones

Claims Made by the Document

  • QVal is a new evaluation method for dense supervision signals.
  • QVal does not require training.
  • QVal measures Q-alignment of a method's score.
  • Simple prompting baselines outperform recent dense supervision methods from the literature.
  • Performance tends to cluster strongly by family.

Evidence Used

  • The introduction of QVal as a training-free testbed for evaluating dense supervision signals.
  • Details on how QVal measures Q-alignment and compares signals before any training run.
  • Information about the benchmarking of 21 methods across multiple environments, families, and model backbones.
  • Statements about the findings from the study, including the outperformance of simple prompting baselines and clustering by family.

Methods / Approach

UNKNOWN

Limitations Stated by the Authors

UNKNOWN

Limitations Noted by the Agent

Agent interpretation — not from the source.

UNKNOWN

Open Questions

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Notes for Future Q&A

May include interpretation. Labeled where it does.

UNKNOWN

Raw Abstract / Excerpt

LLM agents increasingly act over long horizons, where a single trajectory can contain hundreds or thousands of actions. In these settings, outcome-only rewards provide too sparse guidance, failing to inform the model about the goodness of intermediate actions. Dense supervision methods aim to solve this problem by scoring intermediate steps, from intrinsic confidence to self-distillation and embedding similarities. However, it is common practice to evaluate them by measuring the downstream performance of a training pipeline that integrates them. This is expensive, conflates supervision quality with training engineering confounders, and renders different methodological families requiring distinct training setups incomparable. As a result, dense supervision methods are rarely benchmarked on common ground. We introduce QVal, a training-free testbed for directly evaluating dense supervision signals. Given a state-action pair, QVal measures how well a method's score is Q-aligned: whether it orders actions according to the Q-values of a strong reference-policy. This lets us compare signals before any training run and separate signal quality from other engineering choices. We instantiate QVal as QVal-v1.0, benchmarking 21 dense supervision methods across four diverse environments and seven methodological families, with over 1.2K evaluation experiments across six open-weight model backbones. We find that simple prompting baselines consistently outperform recent dense supervision methods from the literature, and that performance clusters strongly by family. These findings hold across model sizes, environments, and observation modalities. QVal is designed to be easily extensible to new environments and methods, enabling researchers to iterate on dense supervision methods before any training run.