REVIEW 2 major objections 7 minor 1 cited by
Providing strong algorithmic code examples substantially improves LLM-driven optimization, and the effect is driven by the code itself, not by linguistic instructions.
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 →
Prompting LLMs with strong benchmark algorithm code, rather than relying on linguistic instructions, improves LLM-driven black-box optimization; the proposed BAG method outperforms five baselines on pbo and bbob.
T0 review reviewed 2026-08-02 challenge →
load-bearing objection The paper's core insight about code examples as the strongest prompt signal is plausible and the BAG variant is a reasonable step, but the main comparison is currently confounded by per-problem benchmark-selected priors versus random-search baselines. the 2 major comments →
From Heuristic Selection to Automated Algorithm Design: LLMs Benefit from Strong Priors
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
Core claim
The central claim is that high-quality algorithmic code examples, not careful linguistic phrasing, are what steer LLMs toward useful optimization algorithms. Using an attention-aware attribution method, the paper shows that the code-related parts of a prompt receive the highest relevance scores when the LLM generates new algorithm code. It then demonstrates that refining a strong prior code behaves as a neighborhood search in algorithm space, and that initializing and periodically re-injecting top benchmark algorithms guides the search into promising regions. The proposed BAG method, a (1+1) elitist evolutionary loop with benchmark code priors, achieves superior and more robust performance t
What carries the argument
The central mechanism is the benchmark-assisted guided evolutionary approach (BAG), a simple (1+1) elitist LLM-driven search that keeps an example code in every prompt. At initialization, BAG uses a strong benchmark algorithm for the problem; every q iterations it refines a randomly selected benchmark code; otherwise it refines the current best or generates a novel algorithm. The supporting analytical tool is an attention-aware feature attribution method that produces token-level relevance scores, showing that code-related prompt components receive the highest influence. BAG's design directly exploits this by making the code prior the primary steering mechanism, rather than relying on elabor
Load-bearing premise
The load-bearing assumption is that choosing the top five benchmark algorithms for each problem from a repository's performance data does not leak information about the test instances, so the benchmark-guided selection preserves a genuine black-box setting.
What would settle it
Run BAG with benchmark priors selected from a different set of problems or with the same code but shuffled problem labels, and compare the resulting AUC. If the performance advantage disappears or reverses, the reported gains stem from using the target problem's own benchmark data to pick the prior code, not from a general benefit of code priors.
If this is right
- Prompt design for LLM-driven optimization should focus on supplying high-quality reference code rather than on linguistic prompting strategies.
- Existing benchmark algorithm collections can be repurposed as reusable priors for LLM-driven algorithm design, linking traditional benchmarking to automated design.
- Search control in LLM-driven optimization can be achieved through the choice of code prior, because refinement of a strong prior behaves as a local neighborhood search.
- Because BAG requires only a single LLM query per evaluated candidate, it may gain further advantage under equal query budgets compared to population-based methods.
- BAG is a unified strategy that can be integrated into population-based LLM-driven approaches, potentially extending the benefit of benchmark priors beyond the (1+1) scheme tested here.
Where Pith is reading between the lines
- If code priors are the dominant factor, then a simpler baseline that uses benchmark code with random mutations may recover much of BAG's advantage, reframing the contribution as one of code reuse rather than of LLM reasoning.
- The per-problem selection of top benchmark algorithms from a repository could leak problem-specific information; a fairer black-box test would choose priors from a disjoint set of problems or from generic algorithm families, and the paper's black-box claim hinges on this not being the case.
- A direct testable extension: replacing BAG's benchmark priors with random but syntactically valid algorithm code of comparable length should erode its advantage if the prior's quality is what matters, while replacing the code with a different strong algorithm should retain it.
- Attribution scores could be used not only to understand prompts but also to automatically select which code prior to inject at each step, moving beyond uniform random selection.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. This paper studies prompt design in LLM-driven optimization. Using AttnLRP token attribution on prompt-code pairs from two open-source LLMs, the authors find that code examples, rather than linguistic instructions, dominate the influence on generated algorithm code. Motivated by this, they propose BAG, a (1+1) elitist LLM-driven search that initializes from and periodically re-injects code from a benchmark set A_bench. BAG is evaluated on the pbo and bbob suites with three commercial LLMs and compared to EoH, LHNS, LLaMEA, MCTS-AHD, and ReEvo, reporting superior average normalized AUC. A CodeBLEU analysis is used to show the influence of injected benchmark code on later generations, and generalization on unseen instances is reported in the appendix.
Significance. If the claims hold, the paper provides a practically valuable empirical insight: strong code priors, not task descriptions, are the main steering signal in LLM-driven BBO, and benchmark repositories can be exploited as a source of such priors. The token-attribution analysis is a novel application of AttnLRP to LLM code generation in optimization, and the scale of the empirical study (47 problems, 3 LLMs, 5 baselines) is a useful contribution. However, the central performance claim is currently compromised by an experimental design that conflates the quality of the injected prior code with the contribution of LLM-guided search. The attribution result itself is suggestive but is based on a single problem (OneMax) and does not by itself establish the causal claim.
major comments (2)
- [Section VII.b / Algorithm 1 / Appendix B] For each pbo problem, A_bench is built from the 'top five algorithms' in the Doerr et al. (2020) repository, while all baselines are initialized with generic random-search code (Appendix B). BAG therefore starts from near-solver-quality code and periodically re-injects it (Algorithm 1, lines 7-9). Its AUC advantage could be caused entirely by the prior code, with the LLM refinement contributing little. This also contradicts the Section I claim that 'no prior knowledge from tested suites is exposed': selecting algorithms using the evaluation suite's own performance data is exactly such prior knowledge. In addition, q=10 is tuned on the same test suites (Appendix D). The comparison must be completed with (i) the AUC of A_bench alone (per-algorithm and best-of-five), (ii) BAG initialized from random search, and (iii) at least one baseline (e.g., LLaMEA) initialized with the same A_bench cod
- [Appendix H (Tables XI-XII)] The captions of Tables XI and XII state that 'the best results obtained by the oracle codes are also considered,' but the tables contain no oracle column. The oracle-code baseline is exactly the control needed to separate prior-code quality from LLM-driven refinement, and its absence is a concrete missing piece of evidence for the central claim. Please add explicit oracle results (e.g., the best-of-five A_bench AUC on the test instances) to these tables and to the aggregated comparison.
minor comments (7)
- [Section VII.c, Table II] The main-text Table II is identical to Table I (the relevance-score table) and does not contain the reported normalized AUC means and ranks. The actual comparison tables appear only in Appendix F. Please correct the main-text table or refer the reader explicitly to the appendix.
- [Section VII.c] In the sentence 'Figure 5 illustrates the convergence process of BGA on Sphere', 'BGA' should be 'BAG'.
- [Section IV.A] The text refers to 'the classic LPR assumption'; the acronym should be LRP (layer-wise relevance propagation).
- [Appendix F (Tables V-X)] The table captions read 'FOUR LLM-DRIVEN APPROACHES' but each table contains six methods (BAG, EoH, LHNS, LLaMEA, MCTS-AHD, ReEvo). Please correct the captions.
- [Section V / Table I] The attribution analysis is performed only on OneMax (F1) and with two open-source LLMs, while the BAG experiments use three proprietary LLMs across 47 problems. Please add an explicit caveat or a few additional attribution measurements on other functions, otherwise the transfer of the attribution conclusion to the main evaluation setting is an assumption.
- [Appendix F / Reproducibility] The specific top-five algorithms used as A_bench for each pbo problem are not listed. Since the paper's method depends on these concrete code priors, the exact algorithm names and source code (or a link to the repository entries) should be provided.
- [Algorithm 1] The input line 'A set of or a problem and a fitness measure F' is garbled; please rephrase, e.g., 'a problem instance, a fitness measure F, a set of benchmark algorithms A_bench, ...'.
Circularity Check
No significant circularity; empirical method with a benchmark-prior confound, not a circular derivation.
full rationale
The paper's central claims are empirical. (1) The AttnLRP token-analysis (Section V) independently measures prompt–code relevance and is not derived from BAG's performance. (2) BAG is an engineering extension of LLaMEA with injected benchmark code, and its superior performance is tested against five external baseline methods across three LLMs and two benchmark suites (Section VII, Tables V–X). There is no equation in which a prediction reduces to a fitted input by construction (e.g., no Eq. X = Eq. Y, no fitted parameter renamed as a prediction). (3) The self-citations (LLaMEA, Doerr et al. 2020) are used as a baseline and as a data source, respectively; they are not invoked as an unverified uniqueness theorem or as the sole support for the central claim. A real methodological concern is that the benchmark priors are selected per problem from the same suite's repository ('we select the top five algorithms reported in the repository of (Doerr et al., 2020) for each pbo problem') and evaluated on the same suite, so part of BAG's advantage could stem from initialization quality rather than LLM-guided search. Appendix H states that oracle-code results 'are also considered' but the oracle column is absent from Tables XI–XII. These are potential leaks/confounds in the experimental comparison, not circularity in the derivation of the results. Therefore, the circularity score is 1.
Axiom & Free-Parameter Ledger
free parameters (4)
- q (benchmark injection frequency) =
10
- A_bench composition for pbo =
top 5 algorithms per problem from Doerr et al. (2020)
- AUC target sets Phi =
problem-specific, e.g., {50,...,100} for OneMax
- refine/create probability =
0.5
axioms (5)
- domain assumption AttnLRP relevance scores faithfully reflect the causal contribution of prompt tokens to generated algorithmic code.
- domain assumption Theoretical guarantees for (1+1) mutation-based evolutionary algorithms transfer to LLM-generated code mutations.
- ad hoc to paper Per-problem selection of top benchmark algorithms from the evaluation suite does not leak problem identity or prior performance information.
- standard math pbo and bbob suites with the chosen AUC target sets are a valid and representative measure of BBO performance.
- domain assumption LLM outputs with default sampling parameters are representative and stable enough for comparisons across methods.
Cite this review
Pith. "Pith review of From Heuristic Selection to Automated Algorithm Design: LLMs Benefit from Strong Priors." pith.science (2026). https://pith.science/paper/E36JSH7B
@misc{pith2026260302792,
author = {Pith},
title = {Pith review of: From Heuristic Selection to Automated Algorithm Design: LLMs Benefit from Strong Priors},
year = {2026},
howpublished = {\url{https://pith.science/paper/E36JSH7B}},
note = {Machine review of arXiv:2603.02792}
}
read the original abstract
Large Language Models (LLMs) have already been widely adopted for automated algorithm design, demonstrating strong abilities in generating and evolving algorithms across various fields. Existing work has largely focused on examining their effectiveness in solving specific problems, with search strategies primarily guided by adaptive prompt designs. In this paper, through investigating the token-wise attribution of the prompts to LLM-generated algorithmic codes, we show that providing high-quality algorithmic code examples can substantially improve the performance of the LLM-driven optimization. Building upon this insight, we propose leveraging prior benchmark algorithms to guide LLM-driven optimization and demonstrate superior performance on two black-box optimization benchmarks: the pseudo-Boolean optimization suite (pbo) and the black-box optimization suite (bbob). Our findings highlight the value of integrating benchmarking studies to enhance both efficiency and robustness of the LLM-driven black-box optimization methods.
Figures
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This paper was first reviewed by deepseek-v4-flash on August 2, 2026.
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