Computation and Language · Cross-listed from cs.CV
Evi-Steer: Learning to Steer Biomedical Vision-Language Models through Efficient and Generalizable Evidential Tuning
Taha Koleilat, Hassan Rivaz and Yiming Xiao
Parameter-efficient adaptation of
vision-
language foundation models is crucial for precise
multimodal understanding of biomedical images, yet existing methods remain deterministic and often struggle under domain shift or ambiguous image-text
alignment. This limitation is particularly critical in the clinic, where models should remain robust in low-data regimes and domain shifts. We present Evi-Steer, an evidential cross-modal low-dimensional steering framework for BiomedCLIP that enables uncertainty-aware parameter-efficient fine-tuning while updating only 0.11% of total model parameters. Our approach performs lightweight low-dimensional
token updates in both
vision and text encoders while simultaneously estimating epistemic uncertainty. These uncertainty estimates update gate residuals, allowing the model to adapt conservatively when evidence is weak. Furthermore, we introduce cross-modal confidence fusion based on Dempster-Shafer theory, enabling visual adaptation to be conditioned on textual confidence and suppressing conflicting or uncertain cross-modal updates. We conduct a comprehensive evaluation on 15 biomedical imaging
datasets spanning 8 organs and 8 imaging modalities under few-shot learning and domain generalization settings. Evi-Steer consistently outperforms state-of-the-art methods under few-shot learning and domain shift settings, demonstrating a practical and robust pathway for deploying
vision-
language models in real-world clinical settings. Code is available at https://github.com/HealthX-Lab/Evi-Steer.
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Computation and Language
SPEAR: Code-Augmented Agentic Prompt Optimization
Mengyin Lu, Cong Feng, Huimin Han et al. (+6 more)
Automatic
prompt engineering (APE) rewrites
prompts to improve downstream task performance, but existing APE loops treat the optimizer itself as a fixed pipeline. We port the code-as-action paradigm of CodeAct (Wang et al., 2024a) to APE and propose SPEAR (Sandboxed
Prompt Engineer with Active Roll-back), a free-form agentic optimizer with four tools – evaluate, python, set_
prompt, finish – that decides autonomously how and when to use them. The distinctive tool is the Python sandbox: the optimizer writes and executes arbitrary Python on the current evaluation DataFrame, performing structural error analysis (confusion
matrices, error clustering, per group metrics) the
agent itself authors. Two guardrails turn the long-horizon
agent into a monotone-improving optimizer: auto-rollback on metric regression, and an optional guard metric floor. We evaluate on three industrial LLM-as-judge suites (13 judge tasks across recruiter-intake, conversational-
memory, and query-refinement systems) plus seven BBH tasks and GSM8K. SPEAR wins every industrial task on the primary metric ($\kappa$ 0.857 vs 0.359 on tool-selection; F1-macro 0.815 vs 0.763 on filter-relevance; $\kappa$ 0.254 vs 0.218 on the hardest extraction dimension). On BBH-7 SPEAR averages 0.938 accuracy vs GEPA 0.628 and TextGrad 0.484. Ablations show the Python tool is the largest single lever on complex judge tasks ($\Delta \approx +0.79\kappa$ on the 5-class tool-selection judge, $\Delta \approx +0.35\kappa$ on the hardest extraction dimension when removed); its irreplaceable contribution is class-pair confusion aggregation that a long-context LLM cannot extract reliably from the raw eval DataFrame.
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All authors Mengyin Lu, Cong Feng, Huimin Han, Guangming Lu, Yu Sun, Xiaonan Ding, Shihui Long, Fengyi Li, Tanvi Motwani
Computation and Language · Cross-listed from cs.SE
SetupX: Can LLM Agents Learn from Past Failures in Functionality-Correct Code Repository Setup?
Zihang Zhou, Ziqian Ren, Yukai Wu et al. (+7 more)
Functionality-correct repository setup aims to configure execution environments (e.g., dependencies, build scripts) to successfully execute a repository's documented features. It presents significant challenges due to diverse, repository-specific failures, including dependency incompatibilities, missing toolchains, incomplete installations, and verification-strategy mismatches. Existing LLM
agents struggle to robustly resolve these issues, specifically failing to support (1) cross-repository experience transfer, (2) multi-step trial-and-repair under non-invertible state changes, and (3) robust verification of setup outcomes to distinguish setup-induced failures from repository bugs. To address this, we introduce SetupX, an experiential learning-based setup framework. First, we construct a Self-Evolving Experience Representation (XPU), a dual-modality knowledge unit encoding setup signals, textual guidance, executable actions to dynamically transfer verified environment fixes to unseen repositories. Second, we employ Experience-Augmented Speculative Execution backed by a LIFO Docker snapshot stack, enabling the
agent to proactively trial fixes and safely roll back to known-good states. Third, we introduce a Prosecutor-Judge Verification Protocol that separates evidence collection from final judgment, enabling more reliable setup verification beyond superficial build-time metrics. Evaluation results on carefully-crafted
benchmarks show SetupX achieves highest performance (e.g., 92% pass rate) and outperforms the strongest baseline by over 19%. Crucially, SetupX excels in complex multi-repository setup requiring coordinating multiple interconnected services across different containers. The code repository is available at https://github.com/OpenDataBox/SetupX.
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All authors Zihang Zhou, Ziqian Ren, Yukai Wu, Yingjie Xiong, Wei Zhou, Chao Peng, Dong Zhang, Bingheng Yan, Xuanhe Zhou, Fan Wu
Computation and Language · Cross-listed from cs.SE
A Universal Cliff and a Design Fingerprint: Cross-Section Defect Detection Under LLM Orchestration
Hiroki Fukui
Production
language-model systems answer a request by partitioning it across an invisible orchestration of worker
agents that recompose one integrated report. We ask what this does to a class of defect no single worker can see: a contradiction in the relation between two distant sections of a document. Holding the documents, defects, mechanism, scoring, and seed fixed, we vary only the model – ten systems across five generations from one developer and five providers from distinct
alignment paradigms. Two layers separate. First, a universal detection cliff: every model that finds these cross-section defects under a single
agent loses that ability under orchestration, detection falling two-thirds or more across every paradigm tested. The cliff is mechanism-derived and not closed by scale or extended
reasoning. Second, how models behave once fallen. A signal-detection decomposition shows that, among the six models discriminating above chance, only one developer's generations move along the reporting-criterion axis: as
alignment is strengthened, the model misses fewer defects yet raises more false alarms on clean documents – two faces of one criterion shift, scaling with generation within that developer (p < 0.001) and near-absent elsewhere. At the floor the missed defect is often not out of view: the model's private record reconstructs the structural fault accurately, while the integrated report signs off on its soundness, its concern spent on the artifact and an absent collaborator. This resists quantification – an automated judge is unstable (precision 17-50%) and keywords cannot separate it from ordinary agreement – a resistance we report as a finding. We release all runs, probes, defect keys, scorer
prompts, and scripts. An integrated report's confidence is uninformative about partition-spanning defects, the most aligned systems are not the safest, and the cliff is structural.
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Computation and Language · Cross-listed from cs.AI
MobileGym: A Verifiable and Highly Parallel Simulation Platform for Mobile GUI Agent Research
Dingbang Wu, Rui Hao, Haiyang Wang et al. (+8 more)
We present MobileGym, a browser-hosted, lightweight, fully controllable environment for everyday mobile use, targeting interaction fidelity without replicating proprietary backends. It enables two capabilities previously out of reach for everyday apps: verifiable outcome signals through deterministic state-based judging over structured JSON state, and scalable online RL through low-cost parallel rollouts. The full environment state is captured, configured, forked, and compared as structured JSON, and a single server can host hundreds of parallel instances, with about 400 MB
memory per instance and about 3 s cold start. A layered state model and a declarative task-definition framework keep state programmability and task creation practical at scale, and a single programmatic judging mechanism delivers both deterministic evaluation verdicts and dense RL rewards. The accompanying MobileGym-Bench provides 416 parameterized task templates, including 256 test and 160 train templates, over 28 apps, with deterministic judges and a structured AnswerSheet protocol that avoids free-text matching failures. In a Sim-to-Real case study, GRPO on Qwen3-VL-4B-Instruct gains +12.8 percentage points on the 256-task test set, and on a 59-task real-device signal subset, real-device execution retains 95.1% of the simulation-side training gain. Project page: https://mobilegym.github.io.
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All authors Dingbang Wu, Rui Hao, Haiyang Wang, Shuzhe Wu, Han Xiao, Zhenghong Li, Bojiang Zhou, Zheng Ju, Zichen Liu, Lue Fan, Zhaoxiang Zhang
Computation and Language · Cross-listed from cs.LG
Prism: A Plug-in Reproducible Infrastructure for Scalable Multimodal Continual Instruction Tuning
Jun-Tao Tang, Yu-Cheng Shi, Zhen-Hao Xie et al. (+1 more)
Multimodal Large
Language Models (MLLMs) achieve versatility by reformulating diverse tasks into a unified instruction-following framework via instruction tuning. However, real-world deployment requires continuous adaptation to emerging tasks, motivating
Multimodal Continual Instruction Tuning (MCIT). Despite its growing importance, current MCIT research is hindered by severe engineering bottlenecks. Existing methods are typically implemented by directly modifying the base MLLM codebase, which imposes substantial implementation overhead and yields method-specific architectures that severely limit code reuse and fair comparison. To address this, we introduce Prism, a plug-in reproducible codebase specifically designed for scalable MCIT research. It separates algorithmic development from the backbone implementation via a lightweight plugin registration mechanism, enabling new strategies to be integrated as independent plugins without modifying the underlying MLLM codebase, thereby eliminating structural fragmentation and accelerating method development. Prism natively supports widely used large-scale training pipeline, thereby enabling reproducible and scalable MCIT experimentation. Code is available at https://github.com/LAMDA-CL/Prism.
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All authors Jun-Tao Tang, Yu-Cheng Shi, Zhen-Hao Xie, Da-Wei Zhou
Computation and Language
Do Language Models Need Sleep? Offline Recurrence for Improved Online Inference
Sangyun Lee, Sean McLeish, Tom Goldstein et al. (+1 more)
Transformer-based large
language models are increasingly used for long-horizon tasks; however, their
attention mechanism scales poorly with context length. To handle this, we study a sleep-like consolidation mechanism in which a model periodically converts recent context into persistent fast weights before clearing its key-value cache. During sleep, the model performs $N$ offline recurrent passes over the accumulated context and updates the fast weights in its state-space model (SSM) blocks through a learned local rule. During inference, this shifts extra computation to sleep while preserving the latency of wake-time prediction. We test our method on controlled synthetic tasks, including cellular automata and multi-hop graph
retrieval, as well as a realistic math
reasoning task, on which a regular
transformer as well as SSM-
attention hybrid models fail. We then show that increasing sleep duration $N$ for our models improves performance, with the largest gains on examples that require deeper
reasoning.
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All authors Sangyun Lee, Sean McLeish, Tom Goldstein, Giulia Fanti
Computation and Language
Junlin Wang, Federico Bianchi, Shang Zhu et al. (+4 more)
Modern AI
benchmarks operate at a complexity that outpaces traditional verification methods. Tasks authored by domain experts often contain implicit assumptions, incomplete environment specifications, and brittle evaluation logic that human annotation cannot reliably catch. We introduce Auto
Benchmark Audit (ABA), an agentic framework that systematically audits individual
benchmark tasks, uncovering issues such as hidden environment dependencies, specification gaps, and limited grading logic. We run ABA on a collection of frontier LLM
benchmarks and previous NeurIPS publications, totaling 168
benchmarks across nine domains. Across this corpus, ABA identifies critical issues including ambiguous task design, execution environment conflicts, and incorrect ground truths in over 25.7% of the evaluated tasks. The precision of these automated audits is validated by expert review and independent third-party reports such as upstream PRs. Crucially, we demonstrate that these problematic tasks severely distorts capability assessments for
agents and LLMs: filtering out these tasks with issues shifts model rankings and increases average performance on SWE-bench Verified and Terminal-Bench 2 by 9.9% and 9.6%, respectively. We release the agentic tool and all task annotations to support the future development of frontier
benchmarks.
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All authors Junlin Wang, Federico Bianchi, Shang Zhu, Fan Nie, Yongchan Kwon, Bhuwan Dhingra, James Zou
Computation and Language
StakeBench: Evaluating Language Understanding Grounded in Market Commitment
Yunhua Pei, Jingyu Hu, Yiwei Shi et al. (+3 more)
Existing financial NLP
benchmarks often rely on labels supplied by outside observers, measuring how
language is perceived rather than what speakers have committed to in the
market. We introduce StakeBench, an evaluation framework for
language understanding grounded in
market commitment. StakeBench links 560,876 comments from 2,261 resolved
markets to verified position, action, and
market-odds records across Polymarket and
Manifold. Supervision is derived from observable
market behavior. Position sides, post-comment trading actions, and
market-odds trajectories replace human annotation. Four diagnostic tasks test whether models detect
market commitment, identify the revealed side, anticipate future action, and perform collective odds projection. Three commitment-aware metrics measure
alignment with revealed preferences rather than perceived sentiment. Validity audits and explicit interpretation boundaries help distinguish observable commitment signals from latent belief and causal
market-odds impact. Across 15 LLMs and 18 topics and platform settings, models partially recover position-side signals, with Directed Accuracy from 0.506 to 0.599, but show structural failures on later tasks. Ten of the fifteen models collapse to one or two action labels in future action anticipation, and no model consistently improves on the naive odds-direction baseline in collective odds projection. Model scale is not correlated with performance, finance-domain tuning does not improve revealed-side identification, and platform incentives strongly shape higher-order results. StakeBench is packaged with evaluation code and
dataset under CC-BY 4.0.
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All authors Yunhua Pei, Jingyu Hu, Yiwei Shi, Hongnan Ma, Weiru Liu, John Cartlidge
Computation and Language
WhoSaidIt: Human-LLM Collaborative Annotation for Text-Based Multilingual Speaker-Attribute Classification
Lingyu Gao, Will Monroe, David Smith et al. (+2 more)
Annotating speaker attributes from text is inherently ambiguous, particularly in
multilingual settings where demographic and social cues are implicit and culturally variable. We propose a human-large
language model (LLM) collaborative re-annotation framework for stabilizing
multilingual speaker-attribute labels under practical resource constraints. Starting from a noisy corpus, we use LLMs to surface recurring annotation rationales through iterative interaction with experts, and apply disagreement-focused sampling for targeted re-annotation. Using this framework, we construct WhoSaidIt, a
multilingual dataset covering nine speaker-attribute labels. We quantify divergence between original and revised annotations,
benchmark recent LLMs, and analyze the effect of explicit rationales on model behavior. Our results reveal substantial cross-lingual differences in annotation decisions and demonstrate both the strengths and limitations of LLMs in speaker-attribute classification.
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All authors Lingyu Gao, Will Monroe, David Smith, Meghan Jemison, Jackie Lee
Computation and Language
When Gradients Collide: Failure Modes of Multi-Objective Prompt Optimization for LLM Judges
Parth Darshan and Abhishek Divekar
Customizing an LLM judge to a specific problem or domain often involves optimizing its
prompt across multiple evaluation criteria simultaneously. Textual gradient methods automate this for a single judge criterion, however they produce natural-
language critiques, not numerical vectors. Thus, the conflict-resolution toolkit of multi-task learning (PCGrad, MGDA) does not apply to this multi-objective textual gradient setting. We extend TextGrad to the multi-objective setting and test four decomposition modes of textual gradient optimizers by varying how much cross-objective information the loss, gradient and optimizer LLMs share. We find the gradient's task-focus drops by 59% (9.0 to 3.7 out of 10) when the gradient LLM must provide feedback on multiple criteria jointly. Separately, we observe that naively combining single-objective optimized instructions into a single
prompt degrades Spearman rho from 0.305 to 0.220 (-0.085). These results identify two separable failure modes: optimization-time gradient dilution and inference-time instruction interference, which together constrain the design space for multi-objective judge optimization using textual feedback.
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Computation and Language
Confidence and Calibration of Activation Oracles for Reliable Interpretation of Language Model Internals
Federico Torrielli, Peter Schneider-Kamp and Lukas Galke Poech
An activation oracle is a
language model trained to convert the activations of another model into natural
language. However, it is so far unclear to what extent these verbalizations are calibrated. Crucially, the oracle's verbalization come without any measure of confidence. Here, we compare five methods for estimating the confidence of an activation oracle. Our experiments cover four oracles from two model families (Qwen and Gemma, from 8B to 27B parameters), tested on the secret word task, whereby the oracle is supposed to recover a secret word, that has been fine-tuned into a model but does not appear in the model outputs. Our results with $6{,}000$ samples per method/oracle combination show that the best calibration depends on the availability of a hypothesis space or a calibration set: When an assumed auditor can list the possible answers in advance, the oracle should score each candidate answer directly. Scoring the candidates gives a higher accuracy on every oracle and a confidence that separates correct from incorrect answers better than any other method. When the oracle has to write its answer as free text, the agreement over twenty sampled answers gives the best calibrated confidence, which needs only five labeled secret words to be tuned. When a calibration set is available, a rescaled probability of the answer is as good as re-sampling, at the cost of one generation instead of twenty. Asking the oracle to write a number for its confidence, on the other side, gives no useful signal on any oracle. Code and the patched trainer are available at https://github.com/federicotorrielli/probabilistic_activation_oracles.
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Computation and Language
Peak-Then-Collapse and the Four Interface Channels of Knowledge-Graph Tool Use
Tianda Sun and Dimitar Kazakov
We test the standard RLVR tool-use recipe – GRPO on Qwen2.5-7B-Instruct – on a deliberately minimal knowledge-graph tool API: four Freebase
navigation verbs over Complex WebQuestions. Under a self-verifiable
retrieval reward, the policy's tool-grounded answer rate climbs from $3.8\%$ to $9.6\%$ over 250 steps, then collapses to $0\%$ within a single 50-step window – a peak-then-collapse pattern replicated across four seeds. Across seven reward designs, we find four recurring failure modes: adding denser or more targeted proxy rewards shifts the failure mode rather than eliminating it. We argue that a key difference from Python interpreters, web search, and JSON APIs is interface feedback: their failures often leak natural-
language signal the model saw in pretraining. A Python traceback names the failing line; an empty Freebase result [] does not. Stripping away that surface exposes a degradation regime that same-family reward redesigns do not fix. A direct oracle ablation rules out relation selection: injecting gold relations at every
retrieval call lifts exact-match accuracy by only $+0.20$~pp, and $95.4\%$ of
retrieval-dependent errors are
retrieval-composition failures rather than answer-extraction failures. As a mitigation, one-iteration self-
distillation reaches $40.0\%$ EM at 7B and is capacity-invariant: doubling capacity to 14B improves EM by only $0.25$~pp, and initialization barely matters – the ceiling appears interface-bound within the 7B–14B range tested.
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Computation and Language · Cross-listed from cs.AI
CausaLab: A Scalable Environment for Interactive Causal Discovery Toward AI Scientists
Junlin Yang, Dylan Zhang, Xiangchen Song et al. (+7 more)
We introduce CausaLab, a scalable environment for evaluating interactive causal discovery by LLM
agents. Unlike prior evaluations, CausaLab evaluates both whether an
agent can solve a problem using causal evidence and whether its answer is grounded in a faithful recovered causal mechanism. Each episode places an
agent in a synthetic laboratory: it receives prior measurement records, intervenes on a manipulator
crystal, and predicts the resonance frequency of a held-out reactor
crystal governed by the same mechanism. The hidden data-generating process is a randomly sampled structural causal model (SCM), so success requires recovering both a causal graph and structural equations rather than recalling prior knowledge. Experiments show a persistent gap between prediction and mechanism recovery: in the purely observational 6-node setting, GPT-5.2-high reaches 92% task accuracy but only 0.471 all-edge $F_1$. Mixed observation-intervention strategies improve structural fidelity, while pure intervention remains difficult even for strong
agents. We identify premature stopping as a major weakness and show that consistency verification mitigates it. CausaLab therefore separates predictive success from causal understanding and exposes current LLM
agents' limits as experimental causal reasoners.
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All authors Junlin Yang, Dylan Zhang, Xiangchen Song, Qirun Dai, Xiao Liu, Yuen Chen, Aniket Vashishtha, Jing Shi, Chenhao Tan, Hao Peng
Computation and Language · Cross-listed from cs.LG
Retrieval-Augmented Detection of Potentially Abusive Clauses in Chilean Terms of Service
Christoffer Loeffler, Tomás Rey Pizarro, Daniel Ignacio Miranda Vásquez et al. (+1 more)
Online Terms of Service often function as contracts of adhesion, creating asymmetries that may expose consumers to potentially abusive clauses. In Chile, assessing such clauses is legally challenging because some provisions clearly violate mandatory consumer law, whereas others depend on broader standards such as good faith and contractual imbalance. We present a
retrieval-augmented generation framework for the automated detection and classification of potentially abusive clauses in Chilean Terms of Service. Designed for local execution, it combines efficient clause detection, hybrid dense–sparse
retrieval, reranking, and
prompt augmentation to support medium-sized open-weight
language models. We also introduce the Chilean Abusive Terms of Service Extended corpus, comprising 100 contracts and 10,029 annotated clauses in 24 legally grounded categories spanning illegal, dark, and gray clauses. Experiments comparing commercial and open-weight
language models, fine-tuned encoders, and traditional baselines show that
retrieval-augmented prompting substantially improves performance and enables local models to approach larger cloud-based systems at lower computational and
token cost. The study also contributes a refined legal annotation scheme and a practical design for AI-assisted consumer contract review.
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All authors Christoffer Loeffler, Tomás Rey Pizarro, Daniel Ignacio Miranda Vásquez, Andrea Martínez Freile
Computation and Language · Cross-listed from cs.CV
STORM: Internalized Modeling for Spatial-Temporal Reasoning in Video-Language Models
Yiming Liang, Yixiao Chen, Yiyang Zhou et al. (+8 more)
Many
video reasoning tasks require tracking motion, temporal order, and evolving visual states across frames. Existing methods built on large
vision-
language models (LVLMs) often address this challenge by externalizing
reasoning through textual chain-of-thought (CoT), keyframe selection, repeated frame reinsertion, or external tool use. While effective, such pipelines increase inference-time latency and engineering complexity, and they force temporal-visual evidence to be serialized into text or repeatedly re-encoded from frames. Inspired by the intuition that visual
reasoning can occur implicitly before verbalization, we propose STORMS (Spatial-Temporal
reasOning via inteRnalized Modeling), a two-stage framework that teaches LVLMs to reason through bounded continuous latent trajectories instead of explicit textual CoT. In Stage I, STORMS aligns latent
tokens with thought-
video representations derived from generated
videos, grounding the latent states in dynamic visual evidence. In Stage II, the model is further trained with answer-only supervision, encouraging the
reasoning process to be internalized without step-by-step annotations. Generated thought
videos are used only during training; at inference, STORMS performs a bounded latent rollout without regenerating
videos, reinserting frames, or invoking external visual tools. Experiments on VideoMME, MVBench, TempCompass, and MMVU show that STORMS improves
video reasoning accuracy while substantially reducing inference overhead compared with tool or
video-generation-based
reasoning pipelines.
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All authors Yiming Liang, Yixiao Chen, Yiyang Zhou, Yixuan Wang, Shoubin Yu, Andong Deng, Fuxiao Liu, Qin Zhang, Chen Chen, Mohit Bansal, Huaxiu Yao
Computation and Language
Forgotten Words: Benchmarking NeoBERT for Dementia Detection in Low-Resource Conversational Filipino and English Speech
Rez Samantha Z. Floresca, Edric Castel C. Hao, Hannah Grachiella Buñales et al. (+3 more)
Dementia detection from spontaneous
speech offers a scalable approach to cognitive screening, yet NLP systems remain predominantly English-centric. This limitation is especially acute in the Philippines, where Filipino-English code-switching is pervasive and no prior work has addressed NLP-based dementia detection. We present the first systematic evaluation of
transformer-based dementia detection in Filipino
speech and the first assessment of NeoBERT in a clinical NLP setting. To separate
language from domain effects, we construct a parallel bilingual
dataset of 4,000 DementiaBank-derived transcripts, with Filipino translations produced manually to preserve discourse-level markers of cognitive decline. We evaluate five model families, TF-IDF + LogReg, BERT, NeoBERT, XLM-R, and RoBERTa-Tagalog, under monolingual, zero-shot cross-lingual, and bilingual fine-tuning settings. We find that in-domain performance does not transfer across
languages, with English-trained BERT dropping to Macro-F1 = 0.455 on Filipino, and that architectural modernization alone does not improve robustness. Bilingual fine-tuning, however, eliminates cross-lingual degradation across all
transformer models, converging to Macro-F1 = 0.969-0.973. These results suggest that
multilingual clinical NLP performance is driven primarily by linguistic coverage during training rather than model scale or architecture.
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All authors Rez Samantha Z. Floresca, Edric Castel C. Hao, Hannah Grachiella Buñales, Chelsea Dominique E. Temprosa, Georgianna Z. Reyes, Kervin Gabriel L. Chua
Computation and Language · Cross-listed from cs.CV
Shristi Das Biswas and Kaushik Roy
Instruction tuning of large
vision-
language models (LVLMs) increasingly depends on massive
multimodal corpora, yet these
datasets contain samples with substantial redundancy, low visual dependency, and highly imbalanced coverage of
multimodal reasoning behaviors. As a result, uniform subsampling or naive score-based selection often yields suboptimal training subsets. We introduce MAGIC, a training-free, forward-only coreset selection method designed to construct compact yet behaviorally faithful subsets for
multimodal instruction tuning. MAGIC is built on three intrinsic signals extracted from a pretrained VLM:
Multimodal Gain, which measures the likelihood improvement obtained from visual input; Bridging Relevance, which captures the sharpness of answer-
token grounding over visual
tokens; and Skill-
Neuron Signatures, which characterize the functional computation elicited by each sample via top-activated feed-forward
neurons. MAGIC combines these signals in a three-stage pipeline: filtering low-gain examples, ranking candidates by a normalized quality objective, and performing bucket-wise budget allocation over discrete
neuron signatures to preserve latent
multimodal skill coverage. This formulation avoids backpropagation, auxiliary selector training, and expensive clustering in continuous activation spaces, while remaining efficient and easily deployable in existing VLMs. Across LLaVA-665K and
Vision-Flan
datasets, and transfer settings to large target models, LLaVA-1.5-7B and -13B, MAGIC consistently improves over strong baselines under matched 20% budgets: it achieves 100.3% relative performance to full finetuning on LLaVA-665K and 101.6% relative performance on
Vision-Flan-186K, while yielding a 73.7% reduction in wall-clock run time.
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Computation and Language
AI-Assisted Systematization for Evaluating GenAI Systems
Dhruv Agarwal, Emily Sheng, Chad Atalla et al. (+6 more)
Evaluating generative AI (GenAI) systems is challenging because many targets of evaluation are broad, contested concepts, such as "
reasoning," "
fairness," or "creativity." When these concepts are left underspecified, it becomes unclear what should be measured or how evaluation results should be interpreted. This problem reflects a missing step: systematization, that is, moving from a broad background concept to an explicit, structured account of the concept in measurable terms. To help address the fact that systematization is cognitively demanding and resource-intensive, we investigate whether AI assistance can support this process. To enable AI-assisted systematization and assess its quality, we introduce a structured representation of a systematized concept, a concept spec, and a validation worksheet. We then develop two AI-assisted systematizers: a direct, zero-shot approach and a multi-
agent approach that more closely mirrors manual systematization approaches from existing literature. We use these systematizers to produce concept specs for two concepts – hate-based rhetoric and digital empathy – and evaluate resulting concept specs on content validity and information recoverability.
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All authors Dhruv Agarwal, Emily Sheng, Chad Atalla, Jean Garcia-Gathright, Hussein Mozannar, Hannah Washington, Alexandra Chouldechova, Solon Barocas, Hanna Wallach
Computation and Language
What Makes a Medical Checker Trainable? Diagnosing Signal Collapse and Reward Hacking in Checker-Guided RAG for Biomedical QA
Yuelyu Ji, Min Gu Kwak, Hang Zhang et al. (+3 more)
Medical RAG needs evidence-grounded claims, so plugging a claim-level NLI checker into
retrieval-augmented RL is intuitive. \textbf{We find that the checker's output distribution during training, not its held-out accuracy, decides whether it provides trainable gradient.} We compare four NLI checker back-ends as process rewards inside a GRPO-trained medical RAG
agent (Qwen2.5-7B, replicated on Qwen3-4B and Llama-3.1-8B) across four held-out medical QA
benchmarks. Three diagnostic findings emerge. (i) Signal collapse is log-prob-specific: LLM log-probability scoring labels over 97% of claims neutral – collapsing the RL gradient to zero – while a calibrated MedNLI classifier scores the same pairs non-degenerately. (ii) Moderate signal beats strong signal on answer quality: a strong proprietary checker triggers a three-step reward-hacking cascade – ultra-short answers, search avoidance,
language collapse – so a moderate-signal local classifier trains a higher-quality model (+12% BERTScore over zero-shot, no GPT dependency). (iii) Signal strength is policy-dependent: the same checker registers as moderate on one policy but strong on another without triggering the cascade end-state. We frame these as boundary conditions for verifier-as-reward systems.
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All authors Yuelyu Ji, Min Gu Kwak, Hang Zhang, Xizhi Wu, Chenyu Li, Yanshan Wan
Computation and Language
SafeCtrl-RL: Inference-Time Adaptive Behaviour Control for LLM Dialogue via RL-Driven Prompt Optimisation
Michael Orme, Yanchao Yu and Zhiyuan Tan
Ensuring safe and contextually appropriate behaviour in Large
Language Models (LLMs) remains a critical challenge for real-world deployment. We present SafeCtrl-RL, an inference-time behavioural control framework that enables adaptive safety regulation without model retraining or parameter modification. The method formulates dialogue generation as a sequential decision process, where a reinforcement learning
agent dynamically selects
prompt adjustment strategies based on contextual feedback. This allows unsafe behaviours to be suppressed through iterative refinement, which we conceptualise as inference-time behavioural unlearning. Evaluated across multiple LLMs and unsafe dialogue scenarios, SafeCtrl-RL consistently improves safety and response quality, outperforms existing
prompt-based optimisation methods, and achieves favourable performance–efficiency trade-offs. **Warning: This paper may contain examples of harmful
language, and reader discretion is recommended.
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Computation and Language
AgentDiff: Meaning-Bearing Rewrites Trigger Deeper Divergence than Presentation Changes in LLM Agents
Liyun Zhang and Jiayi Guo
LLM
agents should respond to what an input means, not how it is presented. We show that they do not treat these two kinds of variation equally. AgentDiff measures the difference between answer changes caused by meaning-bearing rewrites (paraphrase and synonym substitution) and presentation changes (reordering, formatting, and distractors), while matching perturbation severity. Across 68 model–
benchmark–scaffold
cells spanning ten LLMs from seven architecture families, three
benchmarks, 1{,}530 original questions, and approximately 11{,}150 variants, meaning-bearing rewrites produce a $+19.69$ percentage-point higher inconsistency rate (paired $t=9.58$, $p<0.0001$; 64/68
cells positive). The result is stable under four severity proxies ($+18.9$ to $+20.9$~pp, all $p<0.0001$) and remains $+11.10$~pp on the 48
cells outside the qwen family. A fully held-out qwen2.5-14B-Instruct evaluation then tests the structure of this effect on 1{,}800 new trajectories: the pre-registered capable-and-tractable partition is positive in 3/4 held-out
cells and remains sharply separated after pooling (Welch $t=3.81$, $p=9.6\!\times\!10^{-4}$). Trace analysis explains how the difference propagates. Meaning-bearing rewrites preserve the first action but reduce thought similarity from step 2 onward by $5.6$–$10.5$ points and extend the resulting cascade by $0.17$ steps (paired $t=7.69$, $p=2.5\!\times\!10^{-14}$), a pattern we call stealth divergence. AgentDiff therefore establishes a reproducible directional robustness gap, identifies the regime in which it is most reliable, and connects final-answer inconsistency to a distinct trajectory-level signature. Code, perturbations, trajectories, and analysis scripts are released for review at https://anonymous.4open.science/r/agentdiff-emnlp-0BB4/
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Computation and Language
Creative Quality Alignment: Expert Tacit Knowledge Transfer via Chain-of-Thought Fine-Tuning
Bo Zou and Chao Xu
This paper provides an empirical implementation of the creative quality metric proposed in Calibrated Surprise (Zou & Xu, 2026a). The question this paper addresses is: does this mathematical claim hold at the engineering level? To make the answer as general as possible, we deliberately choose the strictest engineering conditions: low data cost and a small base model. Training data comes from approximately 100 expert chain-of-thought (CoT) annotations produced by the BC Protocol (Zou & Xu, 2026b). We also identify a data bias: most publicly available
alignment datasets are skewed toward craft-related knowledge, while audience modeling and reality-logic coverage are systematically weak. We use the term Creative Quality
Alignment (CQA) to describe this class of engineering methods. We also offer a supporting theoretical observation: in an LLM with a single conditional distribution architecture, calibrating the appreciation side automatically transfers to the generation side via architectural duality. This is the structural reason why ~100 CoT examples are sufficient – not a purely empirical observation like LIMA (Zhou et al., 2023).
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Computation and Language
Anticipate and Learn: Unleashing Idle-Time Compute in Proactive Agents
Haoyi Hu, Qirong Lyu, Xianghan Kong et al. (+7 more)
While AI
agents demonstrate remarkable capabilities in
reasoning and tool use, they remain fundamentally reactive: they compute responses only after explicit user
prompts. This paradigm ignores a critical opportunity: the idle time between interactions is largely wasted, leaving
agents unable to prepare for future user needs. To bridge this gap, we introduce ProAct, a proactive
agent architecture that leverages idle-time compute to anticipate and fulfill likely upcoming user needs. By analyzing evolving dialogue history together with persistent
memory, ProAct predicts upcoming needs and iteratively acquires information, allowing the
agent to resolve knowledge gaps and prepare evidence before the user initiates a query. To rigorously evaluate proactive capabilities, we also introduce ProActEval, a comprehensive
benchmark comprising 200 scenarios across 40 domains, featuring predictable need chains and diverse user cognitive profiles. Empirical results demonstrate significant advantages over reactive baselines. ProAct accelerates task completion by reducing required turns by 14.8%, decreases user effort by 11.7%, and cuts
hallucination rates by 28.1% on ProActEval. Furthermore, MemBench evaluations confirm that ProAct achieves state-of-the-art reflective accuracy, underscoring its sustained and robust performance.
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All authors Haoyi Hu, Qirong Lyu, Xianghan Kong, Weiwen Liu, Jianghao Lin, Zixuan Guo, Yan Xu, Yasheng Wang, Weinan Zhang, Yong Yu
Computation and Language
Triplet-Block Diffusion RWKV
Ke Lin, Yiyang Luo, Zhaolong Su et al. (+2 more)
Causal
Transformer language models suffer from strictly sequential decoding and a quadratic per-step
attention cost. While linear-time causal models and discrete
diffusion models each address these weaknesses, their integration remains inherently inconsistent:
diffusion requires bidirectional
attention, while causal models are unidirectional. To unify these architectures, we propose $B^3D-RWKV$, a
diffusion RWKV variant that integrates the model's $O(L)$ inference efficiency with parallel, bidirectional discrete-
diffusion through a triplet-block layout method. $B^3D-RWKV-7.2B$ reaches comparable accuracy on an 8-task suite versus existing models while significantly outperforming baselines in decoding throughput with an average of $\mathbf{1.6\times}$ speedup.
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All authors Ke Lin, Yiyang Luo, Zhaolong Su, Yunya Song, Anyi Rao
Computation and Language · Cross-listed from cs.LG
Mapping the Schedule x Bit-Width Boundary in Sub-100M Quantisation-Aware Training
Christian Brandt Thomassen
We test whether the optimal learning-rate schedule depends on bit-width during from-initialisation quantisation-aware training (QAT) for sub-100M decoder
language models. A 720-run factorial grid (Phase 2) over bit-width x warmdown fraction x LR magnitude x model size x seed (FP16/INT8/INT6, 15M-100M, 5 seeds) finds the optimal warmdown is 33% at every (bit-width, size)
cell. The primary hypothesis – that INT6 QAT requires a different schedule than higher-precision training – is falsified at FP16/INT8/INT6. A 625-run follow-up (Phase 5) probes the null along five axes: optimiser (AdamW), schedule shape (cosine), training length (up to 9x more iterations), an extended size sweep (5M-350M), and an INT4 sweep from 3M to 100M. The null is robust under all three setup changes. The INT6 penalty follows a log-linear scaling law whose fit on Phase 2 predicts the five held-out Phase 5 sizes (5M, 8M, 175M, 250M, 350M) within their 95% prediction intervals (5/5). For INT4 the picture is sharper than the higher precisions: at 50M and 100M, wd33 is decisively optimal (paired z ~ 12-15, 10/10 seeds); below 50M, across the six tested sizes from 3M to 30M, no individual size shows a statistically significant schedule preference and the per-size mean penalty oscillates within seed-level noise. The boundary is therefore a transition between a noise-dominated regime below 50M and a decisive wd33 regime at and above 50M, not a clean wd10 region. A weight-to-grid-distance probe falsifies the simplest mechanism for the FP16/INT8/INT6 null result (rapid grid-snapping): pre-warmdown, INT6-QAT weights sit at essentially the same distance from the INT6 grid as FP16 weights (ratio ~ 1.04). Practical recommendation: at sub-100M scale, tune the LR schedule once at FP16 and apply unchanged to INT8/INT6 QAT; for INT4 at 50M+ use wd33; for INT4 below 50M the schedule choice is in the noise.
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Computation and Language
PolyGnosis 2.0: Enhancing LLM Reasoning via Agentic Harness Engineering for Polymarket and OSINT Insight Extraction
Daren Wang, Hong Xu and Jiawen Xian
This paper introduces PolyGnosis 2.0, a pioneering multi-
agent architecture designed to extract predictive intelligence by synthesizing Polymarket anomaly signals with global Open Source Intelligence (OSINT) streams, specifically Global Database of Events,
Language, and Tone (GDELT). We define and target "Perspective Mismatches", the narrative divergence between Polymarket sentiment and global media flows, as high-alpha trading signals. Moving beyond generic agentic superiority, we rigorously quantify the efficacy of "Harness Engineering" techniques, including reflection loops, tool-calling, divide-and-conquer partitioning (D&C), and chain-of-thought (CoT), within high-noise financial domains. Our empirical evaluation against human-expert
benchmarks reveals that while structural partitioning is mandatory for multi-dimensional
alignment, unconstrained terminal reflection actively induces logical drift. Furthermore, we identify a pervasive "consensus bias" across all
agent configurations during narrative
reasoning, necessitating deterministic validation. Ultimately, we isolate a Pareto-optimal configuration that achieves professional-grade analytical precision while minimizing latency and
token overhead, providing a robust blueprint for autonomous intelligence in prediction
markets.
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Computation and Language
QUIET: A Multi-Blank Cascaded Story Cloze Benchmark for LLM Creative Generation Capability
Bo Zou and Chao Xu
Large
language models (LLMs) face a dual challenge in creative capability evaluation: existing
benchmarks (e.g., Story Cloze Test, HellaSwag) measure models' discriminative ability over narrative continuation using multiple-choice recognition paradigms, rather than directly measuring creative generation capability; rubric-based scoring and LLM-as-Judge methods rely on subjective dimension assessment or natural
language model outputs, and cannot provide objective, automated scoring mechanisms. This paper proposes QUIET (Quality Understanding via Interlocked Evaluation Testing), a diagnostic
benchmark for LLM creative capability based on multi-blank cascaded story cloze. QUIET sets N blanks (10-20) in a story with complete structure, with each blank accompanied by an explicit content constraint, and cascade dependency relationships between blanks – the content filled into earlier blanks constrains the feasible solution space for later blanks. The evaluated model (or human participants) fills all blanks in open-ended generation mode; the results are scored by an information-theoretic automated scoring protocol without human grading. The scoring protocol directly operationalizes the "calibrated surprise" theoretical framework (Zou & Xu, 2026a). For each blank k, a composite score is computed: score = satisfy * (1 + lambda * surprise), where lambda = 1.0. Here, "satisfy" measures how well the blank filling satisfies the content constraint (objective logical
reasoning judgment, not subjective aesthetic scoring), and "surprise" measures the degree of surprise given that the constraint is satisfied. Creative answers that do not satisfy the constraint score zero; answers that satisfy the constraint but are mediocre score low; answers that satisfy the constraint and are surprising score high.
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Computation and Language
Thaka at KSAA-2026 Task 2: Regularized Fine-Tuning for Arabic Speech Diacritization
Meshal Alamr, Hassan Alqaeri and Abdullah Aldahlawi
We describe the winning system for Task 2 of the KSAA-2026 Shared Task on Arabic
Speech Dictation with Automatic Diacritization. The task requires producing fully diacritized Arabic text from
speech audio and undiacritized transcripts, with only 2,327 training samples available and no external data permitted. Our system fine-tunes CATT-Whisper, a character-level
multimodal model combining a pretrained CATT text encoder with a frozen Whisper
speech encoder. The key to our approach is training regularization: R-Drop consistency regularization, Optuna-optimized hyperparameters with high weight decay, and Focal Loss. At inference, we average 200
stochastic forward passes across four model checkpoints using Monte Carlo Dropout at the softmax probability level. The system achieves 23.26% WER on the primary leaderboard metric (with case endings, including no-diacritic positions), placing 1st among all participants.
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Computation and Language
Does Continued Pretraining on a Learner Corpus Improve Automated Essay Scoring on English Proficiency Tests? Evidence from EFCAMDAT
Duy Anh Nguyen
Automated Essay Scoring (AES) for English proficiency assessment increasingly relies on pretrained
transformer models, yet these models are typically trained on general-domain English and may under-represent second-
language learner writing. This study investigates whether domain-adaptive continued pretraining (DAPT) on a learner-writing corpus improves
transformer-based AES for English proficiency assessment. We perform DAPT on BERT, RoBERTa, and DistilBERT using the EFCAMDAT corpus, then compare the adapted models with their original checkpoints on two English proficiency test
datasets, FCE and IELTS, in both in-domain scoring and few-shot cross-
dataset transfer. Full-corpus DAPT produces mixed effects across models,
datasets, and metrics. Subsequent lexical and syntactic analyses suggest mismatches between EFCAMDAT and the downstream
datasets in proficiency level, genre, and communicative purpose. We therefore repeat DAPT using proficiency-specific EFCAMDAT subsets across all three encoder architectures. Proficiency-specific DAPT frequently outperforms full-corpus DAPT and, in some settings, even the non-adapted baseline. Overall, continued pretraining on learner writing can improve in-domain AES, but its benefits depend on both the proficiency composition of the pretraining data and the underlying encoder architecture, and do not consistently extend to cross-test transfer.
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