REVIEW 2 major objections 2 minor 11 references
LLM tool-calling decisions often diverge from what actually improves task results, but hidden-state estimators can correct them.
Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →
T0 review · grok-4.3
2026-07-01 07:56 UTC pith:53B2XUSX
load-bearing objection The paper shows LLMs often misalign their tool calls with optimal need/utility and that hidden-state estimators can build better controllers, but the optimality definition is the key assumption to check. the 2 major comments →
To Call or Not to Call: A Framework to Assess and Optimize LLM Tool Calling
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
In every tested setting the models' observed decisions about calling web search tools do not match the decisions that would maximize performance under an optimal allocation. This gap appears between the descriptive view drawn from behavior and the normative view drawn from task outcomes. Estimators built from hidden states can be used to build controllers that raise decision quality and final performance above the self-perceived baseline for most open-source models evaluated.
What carries the argument
A three-factor framework (necessity, utility, affordability) that contrasts normative inference of true need from optimal tool-call allocations with descriptive inference from the model's own behavior.
Load-bearing premise
True need and utility of tool calls can be correctly identified by computing the allocation of calls that produces the best task outcomes.
What would settle it
Running the trained controllers on a held-out task distribution or with a different set of tools and finding no performance gain over the self-perceived baseline would indicate the estimators do not capture general decision improvements.
If this is right
- Controllers based on hidden-state estimators yield stronger task performance than relying on the model's own assessment.
- The misalignment between perceived and true tool utility holds across open-source and closed models as well as different execution harnesses.
- Simple controllers driven by these estimators raise overall decision quality in web-search augmented tasks.
- The approach yields gains for most of the open-source models tested under multiple tools and tasks.
Where Pith is reading between the lines
- Hidden-state based estimators could be added to agent architectures to override poor self-assessments of tool need.
- The same misalignment may occur with other tool types such as code interpreters or databases.
- If the estimators prove robust, they offer a way to reduce redundant or noisy tool calls without changing the base model.
- Future work might examine whether the framework identifies similar issues in multi-turn agent interactions.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper introduces a decision-theoretic framework for assessing LLM decisions on web search tool calls, distinguishing a normative perspective (inferring true necessity, utility, and affordability from optimal tool-call allocations) from a descriptive perspective (inferring self-perceived values from observed behaviors). It evaluates six open-source and one closed-source model across two harnesses, four tools, and three tasks, reporting frequent misalignment between perceived and true values in all settings, and shows that lightweight hidden-state estimators can drive controllers yielding better decision quality and task performance than self-perceived baselines for most open-source models.
Significance. If the normative optimal-allocation lens is shown to be independent of model behavior and robust, the work offers a principled way to diagnose and mitigate suboptimal tool use in agentic systems. The multi-model, multi-harness evaluation and the demonstration of internal-state controllers provide concrete evidence that hidden representations can be leveraged for improved tool-calling policies, which would be a useful contribution to LLM agent research.
major comments (2)
- [§3] §3 (Framework, normative perspective): The misalignment claim and the value of the downstream estimators rest on defining 'true' need and utility via an optimal allocation of tool calls. The manuscript must specify the exact procedure used to compute this optimal allocation (e.g., exhaustive enumeration, dynamic programming, or external oracle), confirm that it is computed independently of the models' execution traces or observed behaviors, and demonstrate robustness to the chosen task distribution; any dependence would make the reported misalignment an artifact of the evaluation design rather than a general property of the models.
- [§4] §4 (Experiments and results): The claim that the hidden-state controllers 'yield stronger task performance than the self-perceived baseline for most of the open-source models' is load-bearing for the practical contribution. The paper should report per-model, per-harness performance deltas with statistical significance tests, confidence intervals, and controls for multiple comparisons across the six models, two harnesses, four tools, and three tasks; without these, it is unclear whether the gains are reliable or driven by a subset of conditions.
minor comments (2)
- [Abstract / §4] The two harnesses (current-turn vs. full-trace conditioning) are central to the evaluation but are only briefly described in the abstract; a dedicated table or subsection summarizing their differences, input formats, and how search results are integrated would improve clarity.
- [Abstract] The abstract states results hold 'in every setting' without quantifying the total number of settings or noting any exceptions; adding a summary table of misalignment rates across all model-harness-tool-task combinations would make the scope of the finding precise.
Simulated Author's Rebuttal
We thank the referee for their constructive feedback. We address each major comment below and indicate the planned revisions.
read point-by-point responses
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Referee: [§3] §3 (Framework, normative perspective): The misalignment claim and the value of the downstream estimators rest on defining 'true' need and utility via an optimal allocation of tool calls. The manuscript must specify the exact procedure used to compute this optimal allocation (e.g., exhaustive enumeration, dynamic programming, or external oracle), confirm that it is computed independently of the models' execution traces or observed behaviors, and demonstrate robustness to the chosen task distribution; any dependence would make the reported misalignment an artifact of the evaluation design rather than a general property of the models.
Authors: We agree that the normative perspective requires an explicit description of how the optimal allocation is computed. The current manuscript presents this at a conceptual level without the algorithmic details. In the revised manuscript we will expand §3 with the precise procedure (including pseudocode), explicitly state that the computation relies on task-level ground-truth success metrics rather than any model traces or behaviors, and add a robustness analysis across varied task distributions. revision: yes
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Referee: [§4] §4 (Experiments and results): The claim that the hidden-state controllers 'yield stronger task performance than the self-perceived baseline for most of the open-source models' is load-bearing for the practical contribution. The paper should report per-model, per-harness performance deltas with statistical significance tests, confidence intervals, and controls for multiple comparisons across the six models, two harnesses, four tools, and three tasks; without these, it is unclear whether the gains are reliable or driven by a subset of conditions.
Authors: We acknowledge that the experimental claims would be strengthened by more granular statistical reporting. The manuscript currently summarizes results at an aggregate level. In the revision we will add per-model and per-harness tables in §4 (and the appendix) that include performance deltas, 95% confidence intervals, appropriate significance tests, and corrections for multiple comparisons across the full experimental grid. revision: yes
Circularity Check
No circularity: normative vs. descriptive distinction is independent of observed model behavior
full rationale
The paper defines true need/utility via a normative optimal allocation computed separately from model behavior, while self-perceived need/utility is derived from observed behaviors; the misalignment claim and hidden-state estimators follow directly from comparing these two independent lenses without any reduction of one to the other by construction. No equations, fitted parameters renamed as predictions, or load-bearing self-citations appear in the provided text. The evaluation spans multiple models, harnesses, tools, and tasks, supplying external benchmarks that keep the derivation self-contained.
Axiom & Free-Parameter Ledger
axioms (1)
- domain assumption An optimal allocation of tool calls exists and can be computed to serve as ground truth for true need and utility.
read the original abstract
Agentic AI architectures augment LLMs with external tools, unlocking strong capabilities. However, tool use is not always beneficial; some calls may be redundant or even harmful. Effective tool use, therefore, hinges on a core LLM decision: whether to call or not call a tool when performing a task. This decision is particularly challenging for web search tools, where the benefits of external information depend on the model's internal knowledge and its ability to integrate potentially noisy tool responses. We introduce a principled framework inspired by decision-making theory to evaluate web search tool-use decisions along three key factors: necessity, utility, and affordability. Our analysis combines two complementary lenses: a normative perspective that infers true need and utility from an optimal allocation of tool calls, and a descriptive perspective that infers the model's self-perceived need and utility from their observed behaviors. We evaluate six open and one closed-source frontier models under two harnesses, one conditioning on only the current turn and its search results, the other on the full execution traces, across four web-search tools and three tasks. In every setting, we find that a model's perceived need and utility are frequently misaligned with the true need and utility. Building on this framework, we train lightweight estimators of need and utility from the models' hidden states. These estimators drive simple controllers that improve decision quality and yield stronger task performance than the self-perceived baseline for most of the open-source models.
Figures
Reference graph
Works this paper leans on
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Claim extraction.An extraction model (default: GPT-4o) is prompted with a structured JSON schema to decompose the model’s response into atomic, checkable claims (factual, numerical,historical,definition,other)
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Claim verification.A verification model (default: GPT-4o) is given the extracted claims and uses its built-in web search tool to assess each claim against live web sources. It returns a booleanis correctflag and one-to-three source URLs per claim. 16 Preprint. Under review. The factuality score for a response is s= correct claims total claims ∈[0, 1]. Bot...
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Coventry City F.C. The club plays in the EFL Championship and is nicknamed the Sky Blues after its sky blue colours. Source: https://en.wikipedia.org/wiki/Coventry City F.C
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Club History The Sky Blues played their first game at the Ricoh Arena in 2005, winning 3-0. Source: https://www.ccfc.co.uk/
2005
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Sky Blue FC Profile Sky Blue FC was founded in New Jersey in 2007, with its inaugural season in 2009. Source: https://www.planetsport.com/
2007
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The Sky Blues
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discussion (0)
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