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698 papers in cs.AI
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cs.LGcs.AI Min-Young Yu · Oct 14, 2026

Policy-Verified Self-Training asks whether a runtime policy gate's discarded verdicts can be recycled as training signals for the same agent. The paper proposes PVST: an agent rolls out trajectories, a deterministic gate compiled from written policy judges compliance, and the verdicts become acceptance filters and preference labels. On AgentDojo prompt-injection benchmarks, post-training Qwen3-8B with these verifier-derived rewards cuts violating trajectories from 37.2% to 10.3% and successful attacks to 0.5% without any stronger teacher model, human preference labels, or attack-specific supervision. The result suggests that compiled policy checkers can serve not only as runtime constraints but as a scalable, auditable source of self-training supervision.

Runtime policy verifiers can prevent agents from executing disallowed actions, but their decisions are typically used only for enforcement and discarded afterward. We ask whether these decisions can instead become verifiable policy rewards for training the agents they guard. We introduce Policy-Verified Self-Training (PVST), a post-training paradigm in which an agent generates its own interaction trajectories and an executable policy verifier, here a deterministic gate compiled from a written policy, evaluates whether each action complies. Compliant trajectories are reinforced, and violations become negatives for preference optimization; beyond the gate and the benchmark's task-success signal, PVST needs no stronger teacher model, no human preference labels and no attack-specific supervision, although rollouts are collected in the benchmark's attacked environment. On held-out AgentDojo tasks under prompt injection, policy-verified preference training of Qwen3-8B reduces violating trajectories from 37.2% to 10.3 $\pm$ 0.9% (three seeds) and successful attacks from 12.4% to 0.5% at equal or higher pooled task utility, although utility falls on travel, compared with 22.0% when negatives are selected by an attack oracle and 31.9 $\pm$ 0.9% with negatives that contain no violation. The learned behavior holds under an attack template never used in training (37.7% to 11.0%) and on a suite excluded from training (34.8% to 16.7%), and the retained verifier's intervention rate falls from 39.2% to 8.8% (seed 0). Our analysis identifies two conditions under which the verdict is most informative: success must not already imply compliance, and guarded actions must appear in both permitted and forbidden contexts.
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cs.CLcs.AI Thomas Zeng, Zelei Cheng, Mingyang Zhou et al. · Oct 14, 2026

LLM agents frequently fail in multi-turn settings by violating policies, using tools incorrectly, or acting prematurely. This paper proposes Critique-Augmented Agentic Fine-Tuning (CAFT), which rolls out a student agent, has an expert label each wrong turn with both a textual critique and a corrected action, and then fine-tunes the student to generate that critique and correction while keeping the original mistake in context. The central finding is that these natural-language explanations provide learning signal beyond action-only supervision, improving task success across four models and two benchmarks.

Large language models (LLMs) are increasingly used for multi-turn agentic tasks that require interactions with users and environments over extended sequences of actions. A common approach to improving LLM agents is to use more capable expert models to provide training supervision, either by behavior cloning the expert's trajectories or by using the expert to correct the actions in trajectories generated by the weaker student model. However, expert LLMs can provide richer supervision than actions alone: they can directly generate textual critique that explain why specific actions are incorrect. We study whether training on such feedback benefits LLM agents and propose Critique-Augmented Agentic Fine-Tuning (CAFT), a framework that elicits textual expert feedback on student-generated trajectories. For each incorrect action, the expert yields both a corrected action and a textual critique explaining the student's mistake--which we then use as the training target for fine-tuning. Across four student models from the Nemotron 3 and Gemma 4 families on the agentic domains $\tau^2$-Bench Airline+Retail and WebShop, adding critiques to action-level supervision improves performance by 8% on average over action-only distillation. Additionally, CAFT checkpoints can also provide a better warm start for reinforcement learning than expert-trajectory distillation. Our results demonstrate that textual critiques can strengthen supervision for multi-turn LLM agents.
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cs.AIcs.CLcs.RO Minghao Guo, Qingyue Jiao, Xiujin Liu et al. · Oct 14, 2026

Multimodal agents need persistent memory to act coherently over long horizons, yet forming and managing memory across heterogeneous, high-dimensional observations—video, audio, 3D geometry, and GUIs—has lacked a unifying analytical lens. This survey introduces a two-axis lifecycle framework that classifies how experience is represented (source, textual, structured, latent, or parametric) and how memory states and policies evolve ($T1$ Static, $T2$ Dynamic, or $T3$ Self-Evolving). By analyzing 297 architectures, the authors identify key trade-offs between fidelity and efficiency and expose the striking scarcity of systems that evolve their own memory policies at deployment time.

Multimodal models and agents have emerged to enable AI systems to learn from and interact with the real world more like humans by integrating information across multiple modalities. However, enabling multimodal agents to continually acquire useful information from complex, heterogeneous multimodal data remains a significant challenge as they move toward long-horizon tasks and lifelong settings. Addressing this challenge requires effective memory mechanisms that can maintain continuity across sessions, adapt to changing users and environments, and refine memory-management policies through accumulated experience. We introduce a two-axis analytical framework for multimodal agent memory structured around two key questions: how multimodal information is formed and represented (Axis I, Formation and Representation), and how its management adapts with accumulated experience (Axis II, Memory Management). Axis I, Formation and Representation, characterizes what information is retained and how it is encoded (e.g., modality-specific embeddings, textual and structured records, latent and parametric representations) to support subsequent reasoning and action. Axis II, Memory Management, distinguishes three tiers: T1 Static Memory reuses fixed memory; T2 Dynamic Memory updates memory through a stable policy; and T3 Self-Evolving Memory updates memory through an evolving policy. Based on this framework, we synthesize recurring design patterns and derive principles for balancing source fidelity with abstraction, maintaining temporal validity and provenance, grounding memory use in recoverable evidence, and evolving memory policies over time. Furthermore, we discuss the challenges and potential future directions for the memory mechanism of multimodal agents.
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cs.AI Tianzhuo Yang, Shaoheng Yan, Lin Lu et al. · Oct 14, 2026

DangerLens asks whether two language models with identically safe refusal behavior can still differ in how much hazardous knowledge remains internally accessible. The authors train paired Qwen1.5 checkpoints—one directly safety-aligned, the other first exposed to harmful data then aligned to the same standard—and introduce a vocabulary-space probe that uses a Jacobian lens and blinded semantic scoring to count harmful goals and operational means inside hidden states. The work matters because current safety audits rely on surface behavior alone, leaving latent dangerous representations undetected before downstream fine-tuning or attacks.

Safety alignment teaches language models to refuse harmful requests, yet the internal accessibility of hazardous concepts can retain traces of earlier training. Can checkpoints with equally safe behavior differ in what remains accessible behind their refusals? In this work, we investigate this question through paired training histories and a direct audit of intermediate representations. We introduce DANGERLENS, a probe that maps hidden states into vocabulary space and uses blinded semantic judgments to distinguish harmful goals and operational means from hazard recognition and safety control. Experiments on three Qwen1.5 scales show that checkpoints with prior harmful exposure generally retain greater hazardous concept accessibility after the same safety alignment, with the strongest separation in intermediate and later layers. The same harmful update also produces different behavioral trajectories from closely matched starting points. Human relevance validation and readout ablations reinforce the measured accessibility contrast. Our findings show that training history remains visible inside behaviorally matched models and motivate internal accessibility audits alongside output safety evaluations.
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cs.CLcs.AIcs.LG Taro Yano, Yoichi Ishibashi, Masafumi Oyamada · Oct 14, 2026

Best-of-N sampling improves LLM output quality by generating multiple candidates and selecting the highest reward, yet its scaling behavior under imperfect reward models is poorly understood. This paper recasts BoN as extreme-value competition between the upper tails of correct and incorrect reward distributions, yielding phase transitions that explain both monotonic gains and reward hacking. Using extreme value theory, the authors derive finite-sample scaling laws showing polynomial rather than exponential convergence, and propose a lightweight tail-tension criterion for label-free early stopping. The work matters because it replaces vague intuitions about reward hacking with precise, testable distributional conditions and a practical inference-time safeguard.

Best-of-N sampling is a simple inference-time scaling strategy for large language models, yet its behavior under incomplete reward models remains poorly understood. We study Best-of-N as a competition between the extreme reward tails of correct and incorrect responses. This view shows that success depends not only on the probability of sampling a correct response, but also on whether correct responses dominate incorrect ones in the upper tail. Using extreme value theory, we characterize three asymptotic regimes: correct-tail-dominant, incorrect-tail-dominant, and critical explaining both monotonic gains and reward-hacking-induced degradation. We further derive finite-sample scaling laws for representative reward distributions, showing that, under Gaussian rewards, incorrect responses with sufficiently large variance can dominate selection even when their mean reward is lower. Unlike oracle selection, convergence with an incomplete selector can be polynomial rather than exponential. Finally, we propose a lightweight tail-tension criterion to estimate when additional sampling may become harmful. Experiments on synthetic data and real reward model scores are consistent with the theoretically predicted regimes, scaling laws, and diagnostic behavior, suggesting that tail competition provides a unified lens on Best-of-N sampling for verifiable problems.
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cs.AIcs.CLcs.LG Weilun Xu (EPFL), Zipeng Sun (McGill University, Mila) · Oct 14, 2026

Activation steering is used to steer language models toward named behaviors, but standard baselines cannot tell whether a vector controls a specific concept or a neighboring one. This paper introduces the competing-target test, which compares a steering vector with the matched vector for a competing target and bounds their difference with an equivalence test. In three open-weight models, the authors show that vectors for Kantian deontology and act utilitarianism are largely interchangeable---they move both framework scores alike---whereas explicit prompting separates them, and the same construction does separate optimistic and pessimistic tones.

Activation steering adds a vector to a model's hidden states to control a named behaviour. A gain on that behaviour, however, does not show that the vector controls it directly: it may act through a component shared with neighbouring behaviours, which unsteered and random baselines cannot separate. We introduce the competing-target test: a vector is compared with the vector built the same way for a competing target, and an equivalence test states when their difference is below a useful margin. We apply it in open-weight models to vectors for Kantian deontology, which judges an act by the rule it follows, and act utilitarianism, which judges it by the welfare it produces. On held-out situations, prompting a framework raises its score and lowers the other's, whereas vectors for either framework move both scores alike, and none reaches the margin. The two vectors share most of their direction, a request to apply some framework; the same construction separates an optimistic from a pessimistic tone, whose vectors share much less. What a vector shares with its competitors therefore sets what it controls: steering a perspective can deliver a mixture, and measuring a disposition can measure its neighbours, unless tested against the competing target.
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cs.LGcs.AImath.ST Katy Blumer, Da-Cheng Juan, Jon Kleinberg et al. · Oct 14, 2026

This paper studies the infinite-generation limit of autoregressive transformers. Rather than fixing sequence length, the authors let generation time tend to infinity and ask whether the model's empirical state converges. Their core result is that, for a broad class of architectures, the stochastic generation process tracks a deterministic ODE on a slow time scale, and every fixed transformer has a finite temperature threshold above which it converges to a unique limit. However, no uniform temperature works for all models; for any finite temperature, some transformer can fail to converge, even with just one layer and three tokens.

In this paper we study the behavior of transformer networks generating text over long periods of time. We show that even a three-token, single-layer attention-only transformer can fail to converge. We then study a rich class of transformers with arbitrary finite depth, layer normalization, MLPs, RoPE encodings, and an arbitrary mix of local and global layers. Every transformer in this class has a softmax temperature threshold above which its empirical cache distribution converges to a unique limit, independent of initial conditions. We show further that, while each transformer has a temperature threshold, the supremum of this set is infinite, so there is no global minimal temperature that forces all transformers to converge.
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cs.AIcs.MA Sajid Siraj, Maria Barbati · Oct 14, 2026

AI agents chain many LLM calls to complete tasks, yet models are usually compared per call. This paper argues the correct functional unit is the successfully completed task, because failed attempts waste energy, cost and time. It derives crossover task lengths that predict when a smaller model stops being greener, cheaper or faster, and shows with a 15-model pilot that the greenest choice shifts from 1-3B models for short tasks to 8-27B models for long ones.

AI agents use large language models (LLMs) to plan and act over multiple steps, yet models are usually compared per call rather than per completed task. This paper asks: which model should an agent use to complete tasks reliably while minimising energy, cost and time? We show that per-call comparisons can be misleading for agentic AI. Because a task succeeds only if all required steps succeed, small differences in per-step reliability can produce large differences in overall task success. Failed attempts also consume resources. We therefore evaluate models using energy, cost and time per successfully completed task, treating the completed task as the functional unit. On this basis, we develop a decision model for choosing LLMs in agentic workflows. The model applies to tasks with binary or graded outcomes and to settings with or without retries. We show that each resource has a crossover task length at which a smaller, less reliable model ceases to be the greener, cheaper or faster option. These crossovers divide tasks into three regimes: for short tasks smaller models are preferred, for long tasks larger models are preferred, and only between these extremes do preferences among objectives matter. We embed these results in a two-stage framework that separates efficiency from preference. A Pareto screen first removes models that are never competitive; a weighted decision is required only when a genuine trade-off remains. A pilot study of 15 open-weight models from five developers, ranging from 0.6B to 27B parameters, on two multi-step agent tasks with measured GPU energy supports the predicted structure. The model with the lowest energy per completed task changes with task length and task type, and observed crossover points generally match those predicted from per-step measurements. These findings provide a practical framework for right-sizing language models in agentic AI.
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cs.MAcs.AI Sarath Shekkizhar, Prathyusha Jwalapuram, Zixuan Ke et al. · Oct 14, 2026

Agents are increasingly expected to negotiate and collaborate across organizational boundaries where each party maintains private tools, documents, and incentives. This paper studies how agent-to-agent (A2A) systems fail under these conditions, introducing A2A²-Failures, a taxonomy of 20 failure modes derived from over 2,500 sandboxed runs spanning cooperative to competitive scenarios. Its central thesis is that evaluating only final outcomes masks critical behavioral breakdowns—such as unverified peer claims, private data leakage, and scope distortion—making per-agent principal-alignment auditing essential for safe cross-boundary deployment.

Agents are increasingly interacting with other agents that act for different principals -- people or organizations on whose behalf they work -- e.g., a buyer's personal agent negotiating with an enterprise's seller agent. In such agent-to-agent (A2A) scenarios, each agent has its own environment and holds information and authority that the other cannot see. Moreover, the interests of each agent may be aligned (cooperative), partly aligned (mixed-motive), or opposed (competitive). Existing multi-agent system failure studies assume only one orchestrator, shared workspace, or principal. We ask how A2A systems fail when these assumptions are removed. We study more than 2,500 recorded runs of A2A systems built from different agent harnesses and models, spanning 488 scenarios across eight families (legal, CRM, security, commerce, etc.). From these traces, we derive $A^2$-Failures, a taxonomy of 20 A2A failure modes in four categories: (i) discovery and delegation, (ii) grounding and record consistency, (iii) verification, and (iv) conduct and fidelity. Three observations hold across the harnesses, models, and scenarios studied: (1) Agents match tasks to peer names mentioned in the prompt rather than actively searching for available peers; (2) Agents never fact-check each other unprompted; (3) Scoring only the final output rewards the lead agent while hiding internal coordination, verification, and behavioral breakdowns. Our study makes a case for comprehensive evaluations where agents are scored individually against their own objectives in addition to task outcome. We release the run logs behind the taxonomy at https://huggingface.co/datasets/a2a-salesforce/a2-failures.
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cs.CLcs.AI LLM-jp: Chaoran Liu, Daisuke Kawahara, Hideyuki Tachibana et al. · Oct 14, 2026

LLM-jp-4 is a family of Japanese sovereign language models—an 8B dense Transformer and a 32B-A3B mixture-of-experts—trained from scratch on roughly 12 trillion tokens with an explicit emphasis on transparency, legal reproducibility, and practical deployment. The authors impose strict open-source selection criteria on data, external models, and software, and they document every stage from tokenizer design through pre-training, mid-training, and post-training. The work aims to provide a publicly verifiable reference for sovereign AI development in Japan.

This paper presents LLM-jp-4, a family of Japanese sovereign large language models (LLMs) developed with an emphasis on transparency, reproducibility, and practical usability. LLM-jp-4 comprises an 8B dense model and a 32B-A3B mixture-of-experts model, both trained from scratch on approximately 12 trillion tokens. To support independent verification and reproduction, we establish explicit criteria for selecting training data, external models, and software, and make the development process publicly available. Evaluation results demonstrate substantial improvements over previous LLM-jp models and competitive performance against open-weight models of similar scale. By documenting the development principles, training procedures, and empirical findings of LLM-jp-4, we aim to provide a reference for future sovereign AI development.
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cs.AI Shuang Zeng, Yunwen Lei, Yiming Ying · Oct 14, 2026

Minimax optimization underlies adversarial training, GANs, and AUC maximization, yet biased stochastic gradient descent-ascent methods—zeroth-order and clipped variants—have had no generalization theory. This paper develops the first stability framework for biased SGDA in convex-concave smooth problems, replacing the standard bounded-gradient assumption with a bounded second-moment condition. It derives generalized Lipschitz-type stability bounds and proves that zeroth-order and clipped SGDA can achieve the minimax-optimal $O(1/\sqrt{n})$ excess risk.

Minimax optimization refers to a class of optimization problems with some variables to minimize and other variables to maximize. Biased stochastic gradient methods have shown practical success in solving minimax problems to either improve robustness, enhance communication efficiency, or decrease computational costs. These successes motivate a lot of theoretical works to study the convergence of biased stochastic gradient methods, while their generalization analysis remains untouched. In this paper, we present the first framework to study the stability and generalization of biased stochastic gradient methods for minimax problems. We establish a connection between stability and generalization for minimax problems by relaxing the existing bounded gradient assumption to a bounded second moment condition. We then introduce a generalized Lipschitz-type condition on bias and gradient estimators, and derive a general stability bound to clarify the connection among bias, gradient estimators, and stability. We apply our general analysis to Zeroth-order and Clipped stochastic gradient descent ascent (SGDA), and derive stability bounds that match those of SGDA under appropriate smoothing/clipping parameters. We combine stability and convergence analyses together, and derive optimal excess risk bounds of order $1/\sqrt{n}$, where $n$ is the sample size.
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cs.CVcs.AI Liang Yu, Tao Zhu, Xiangqing Lu et al. · Oct 14, 2026

Real-time monocular human pose estimation breaks down when the lower body is occluded or the subject steps out of frame. This paper introduces a part-decoupled temporal fusion framework that augments monocular video with sparse plantar-pressure and foot-mounted acceleration from smart insoles. The core insight is that cheap, wearable foot sensors provide complementary physical constraints exactly where monocular vision is weakest, enabling robust pose and gait recovery under severe visual degradation.

Real-time monocular human pose estimation is an important sensing component for human-centered intelligent systems. While recent camera-based methods have achieved impressive accuracy, fundamental challenges persist, particularly when visual observations are incomplete, such as during lower-body occlusion or short out-of-frame intervals. In these challenging but common scenarios, vision-only systems often struggle to reconstruct physically plausible lower-limb motion and reliable foot-ground contact. Due to the highly unobtrusive and wearable nature of smart insoles, this paper investigates whether simple plantar pressure and acceleration sensors can effectively resolve these visually induced limitations. To systematically investigate this, we first collect a synchronized multimodal dataset and then propose a part-decoupled temporal fusion framework. The proposed model fuses foot-sensing features into the lower-body branch to compensate for incomplete visual evidence, while a lightweight coordinator exchanges information between the upper- and lower-body temporal representations to maintain whole-body consistency. The framework is evaluated with three representative real-time visual backbones based on 2D keypoints, 3D landmarks, and SMPL-based human mesh recovery. We evaluate our framework on three representative real-time visual backbones. Quantitative experiments demonstrate that incorporating simple foot sensors consistently improves pose accuracy, motion smoothness, and gait-related measurements over vision-only baselines, with the most significant gains observed under occlusion and short visual-dropout conditions. Ultimately, our results demonstrate that unobtrusive foot sensing provides vital and complementary physical observability when camera observations are temporarily unavailable.
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cs.CVcs.AI Chunxi Luo, Qishuai Ding, Xingchen Peng et al. · Oct 14, 2026

FrameEvidence is a diagnostic benchmark for multi-image spatial reasoning that tests whether vision-language models correctly answer questions when the reference frame or the set of visual evidence is manipulated. It introduces 960 Chinese multiple-choice questions arranged in 320 matched triplets, where FQ1 varies the spatial reference frame while holding images fixed and FQ2 deletes or adds images to test evidence necessity and invariance. The core finding is a sharp divergence between single-item accuracy, which reaches 50\% for GPT-5.6, and joint correctness across matched variants, which remains below 11\% for $\mathrm{FQ1\text{-}GEM}$. This design exposes how standard accuracy obscures brittle reasoning and answer instability.

A spatial answer depends on the reference frame specified in language and its supporting visual evidence. Item accuracy alone obscures whether correctness persists when either changes. We introduce Frame Evidence, a benchmark of 320 matched triplets and 960 Chinese multiple-choice questions from captured and rendered scenes. One family compares three grounded reference frames over fixed images. The other pairs image deletion annotated as insufficient with answer-preserving addition. Joint metrics require correct answers across all three frames and paired evidence variants. Across 20 configurations on 288 held-out questions, GPT three-shot reaches 50.00\% item accuracy, but the best three-frame group accuracy is 5/48 (10.42\%), reached by GPT two-shot. Few-shot prompting and task-specific adaptation improve item accuracy without consistently improving joint correctness. Input controls show where images support matched success, while repeated executions reveal answer instability beneath similar scores.
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cs.CVcs.AI Zihao Lin, Haoyu Dong, Haobo Xu et al. · Oct 14, 2026

This paper tackles the problem of recursive self-improvement for agentic video-understanding harnesses, asking how automated evolution can discover generalizable designs when it must learn from limited, noisy, and repeatedly reused validation feedback. The authors first diagnose three interconnected failure modes in a baseline system (validation overfitting, search-budget dilution, and the early-experience trap), then propose VideoHarness-SRSI, an evidence-governed framework that hides validation content from the proposer, warms up with controlled interventions, and evolves mechanisms in isolated probe–race branches before factorial composition. Across four benchmarks, the method improves the mean held-out score by 6.2% relative to the baseline and cuts the validation–test gap by 37.9%, supporting the central claim that how search is informed and organized matters as much as how well it optimizes validation metrics.

LLM system capabilities depend not only on model parameters but also on the executable harnesses that organize information acquisition, tool use, reasoning, and memory. Recursive harness evolution can automate their design, but how it can reliably discover generalizable systems from limited, noisy, and repeatedly reused feedback remains unclear. We study this question in agentic video understanding, where rich multimodal evidence and coupled mechanisms make harness optimization challenging. We first introduce VideoHarness-BRSI, a recursive self-improvement framework that evolves video harnesses around a frozen vision-language model. Analyzing over 4,000 evolved candidates, we find it competitive with hand-engineered systems but identify three interconnected failure modes: validation overfitting, search-budget dilution, and the early-experience trap. We trace all three to a common root: the same imperfect validation evidence drives both harness revisions and the proposer's search strategy. We therefore propose VideoHarness-SRSI, an evidence-governed framework in which every search decision rests on evidence that is transferable, sufficient, and gathered before the search commits. It restricts the proposer to content-free feedback, informs exploration with instrumented warm-up experiments, and develops mechanisms in isolated probe-race branches before factorial composition and joint refinement. Across four video understanding benchmarks, VideoHarness-SRSI improves the equally weighted mean held-out score by 6.2% relative to VideoHarness-BRSI and reduces the mean validation-test gap by 37.9%. Reliable harness evolution thus depends on how search is organized and informed, not only on how well it optimizes validation performance.
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cs.ROcs.AIcs.CV Yue Zhang, Han Lin, Zun Wang et al. · Oct 14, 2026

Wedge addresses the inefficiency of generic environment generation for embodied navigation: pretrained agents fail for different environmental reasons, so simply adding more diverse or realistic training scenes may not address their actual shortcomings. The paper proposes a policy-conditioned generation framework that diagnoses an agent's specific weaknesses by contrasting its successful and failed rollouts, uses an LLM to propose executable environmental features (such as target visibility or blind-path ratio), validates them via success-rate gaps, and generates targeted training environments. This approach is tested across three heterogeneous agents—an RL policy, an imitation-learned model, and a black-box VLM—showing consistent gains in ProcTHOR and transfer to HM3D.

Simulated environments enable scalable training data generation for embodied agents, but more data does not necessarily provide what a particular agent needs to learn. Existing environment-generation pipelines largely optimize generic properties such as realism, diversity, or task coverage, while different pretrained policies can fail for different environmental reasons. We therefore introduce WEDGE, a framework for weakness-guided navigation learning in which the failure modes of a pretrained agent guide the generation of training environments at each adaptation round. Given a pretrained policy, WEDGE uses an LLM to propose executable weakness features from contrasting successful and failed rollouts, automatically validates them on the diagnostic set, and selects the strongest validated weakness based on its success-rate gap. The validated weaknesses are then mapped to the environmental factors that control them. WEDGE varies these factors to construct environments in the difficulty regimes where the policy struggles, producing targeted training experience for adaptation. Across three navigation agents with different adaptation mechanisms, we find that policies exhibit distinct weakness profiles and benefit from different training environments. Weakness-conditioned adaptation consistently outperforms matched random and hard-example alternatives on ProcTHOR, while the resulting gains for Uni-NaVid and Gemini also extend to HM3D after ProcTHOR adaptation. Iterative re-diagnosis further shows that dominant weaknesses can persist or shift as the policy improves, providing updated guidance for subsequent environment construction. Together, these results show that policy failures are not only diagnostic signals, but actionable guidance for constructing training environments that target a policy's current weaknesses.
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cs.CLcs.AIcs.CV Josh Barua, Kyle Mahowald, William Rudman · Oct 14, 2026

When text and images conflict in vision-language models, prior work has characterized behavior as modality-specific biases such as "blind faith in text." This paper proposes a predictive alternative: a two-parameter Bayesian cue combination rule in which each modality contributes conditionally independent evidence weighted by a constant integration bias, plus a prior. The authors show that this simple linear model accurately predicts how VLM preferences shift across dozens of input degradation conditions and even transfers to entirely new corruption types without refitting, offering a unified account of why text sometimes dominates and vision sometimes wins.

Vision-language models must reconcile conflicting text and images. Prior work has characterized the resulting behavior in terms of modality biases--e.g., a "blind faith in text"--but why preferences vary across models, domains, and input conditions remains unclear. We develop a predictive account from a Bayesian perspective, positing that VLMs combine conditionally independent evidence from each modality with prior beliefs, subject to modality-specific biases. The resulting two-parameter cue combination model accurately predicts VLM preferences under unseen combinations of input degradation and transfers to new forms of unreliability without refitting. Separating evidence strength from integration bias explains how VLMs can follow text even while weighting visual evidence more heavily, reconciling reports of text and vision dominance under a single combination rule.
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cs.LGcs.AIcs.LG v3 Junyi An, Xinyu Lu, Chao Qu et al. · May 29, 2025

Equivariant GNNs for molecular modeling are bottlenecked by Clebsch-Gordan tensor products, which suffer from high complexity and limited non-linearity. This paper proposes the Equivariant Spherical Transformer (EST), a plug-and-play module that applies self-attention over sampled points on the spherical spatial domain of group representations, using a Fibonacci Lattice to preserve approximate SO(3) equivariance. The work matters because it reports state-of-the-art results on OC20 and QM9 while empirically breaking the degree-limited expressiveness barrier that constrains traditional tensor-product architectures.

Equivariant Graph Neural Networks (GNNs) have significantly advanced the modeling of 3D molecular structure by leveraging group representations. However, their message passing, heavily relying on Clebsch-Gordan tensor product convolutions, suffers from restricted expressiveness due to the limited non-linearity and low degree of group representations. To overcome this, we introduce the Equivariant Spherical Transformer (EST), a novel plug-and-play framework that applies a Transformer-like architecture to the Fourier spatial domain of group representations. EST achieves higher expressiveness than conventional models while preserving the crucial equivariant inductive bias through a uniform sampling strategy of spherical Fourier transforms. As demonstrated by our experiments on challenging benchmarks like OC20 and QM9, EST-based models achieve state-of-the-art performance. For the complex molecular systems within OC20, small models empowered by EST can outperform some larger models and those using additional data. In addition to demonstrating such strong expressiveness,we provide both theoretical and experimental validation of EST's equivariance as well, paving the way for new research in this area.
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cs.CLcs.AIcs.LG Lucheng Fu, Kejing Xia, Yiyang Wang et al. · Oct 1, 2026

Most LLM agents treat repeated use of the same external source as a sequence of independent retrieval events. This paper reframes the deeper problem as source learning: progressively building a persistent, reusable source model that captures how a source’s knowledge is structured, interpreted, and applied. The proposed SourceLearn system combines self-directed study with task-guided refinement, and the authors report large gains across document, code, API, and interactive benchmarks.

Large language model (LLM) agents increasingly rely on persistent external sources to solve sequences of knowledge-intensive tasks. Existing methods improve how source content is accessed and organized, while agent-memory systems preserve reusable knowledge from prior interactions, but repeated use of the same source is still largely treated as repeated access rather than an opportunity to progressively improve understanding of that source. We study source learning: developing reusable source-specific competence over a persistent authoritative source. We represent this competence with a persistent source model that captures reusable understanding of the source, including how its knowledge is structured, interpreted, and applied. To construct and progressively refine such models, we propose SourceLearn, which combines two complementary learning mechanisms. Self-Directed Source Learning identifies what remains incompletely understood and adaptively revisits the source, while Task-Guided Source Learning uses downstream experience to reveal local representational gaps and recurring needs in how source knowledge should be organized. In both cases, learning signals determine what should be reconsidered, while persistent updates are reconstructed from the authoritative source. Across five benchmarks and three LLM backends, SourceLearn achieves the best performance in 13 of 15 settings, with gains of up to 22.6 points over Hybrid RAG and substantial overall improvements over static source representations and experience-based memory baselines.
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cs.LGcs.AIcs.CL Aayush Karan, Sitan Chen, Yilun Du · Oct 1, 2026

The paper tackles how to teach LLMs new skills after pretraining without erasing old ones. While RL resists catastrophic forgetting by staying on-policy, it struggles when the model cannot generate successful trajectories on its own. The authors flip the problem: instead of changing the training loss, they use an MCMC projection sampler to reshape off-policy expert traces so they look more like samples from the base model while preserving correctness. This lets ordinary supervised finetuning match or beat RL and self-distillation on science, math, and medical tasks.

Introducing new capabilities to frontier models has long been the goal of posttraining, which predominantly employs supervised finetuning (SFT) and reinforcement learning (RL) to this end. Conventional wisdom dictates that RL enables strong generalization on new tasks without losing existing capabilities, while SFT is prone to weak generalization and catastrophic forgetting. At the same time, SFT can learn from off-policy expert data, whereas RL must rely on a model's ability to find successful trajectories with repeated sampling. In our work, we seek to leverage the strength of on-policy learning while utilizing the privileged information contained in off-policy data. However, rather than modifying the learning objective to accommodate this data, we instead tailor the data distribution to better suit the learner. We introduce a Markov chain Monte Carlo (MCMC) sampling algorithm that progressively transforms off-policy traces to be more on-policy given a reference model for finetuning. Across tasks like scientific skill acquisition, mathematical reasoning, and open-ended expertise, our sampling algorithm enables SFT to rival prevailing posttraining techniques, often generalizing better and forgetting less than strong on-policy baselines. In addition, the resulting finetuned models exhibit strong distributional performance and are capable of learning beyond sharpening the base model distribution. At a higher level, our approach presents sampling as a model-native operator that shapes data for learnability, offering broader utility as a general-purpose primitive throughout the posttraining stack.
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cs.LGcs.AI Junkang Liu · Oct 1, 2026

FedMIX-P tackles preconditioner coordination in federated learning by mixing a shared reference preconditioner with each client's local adaptive state at every local step. The core idea is to control the operator mismatch that arises when heterogeneous clients transform gradients differently, and the paper demonstrates empirical improvements on vision and language models under severe data heterogeneity. However, the convergence analysis is restricted to linear positive-definite preconditioners, while the headline experiments rely on nonlinear methods such as Muon, creating a notable gap between theory and practice.

Adaptive preconditioners accelerate model training, but heterogeneous client geometries can bias federated updates even when gradients are evaluated at the same model. Round-start synchronization alone cannot prevent this mismatch from reappearing during local training. We propose \texttt{FedMIX-P}, which mixes shared and local preconditioners at every local step, retaining local adaptation while reducing mean-squared operator mismatch by a factor of $\lambda^2$. For smooth nonconvex objectives with stochastic gradients and partial participation, we establish an $O(R^{-1/2})$ stationarity bound using suitable stepsizes and a horizon-dependent mixing weight, without requiring local preconditioners to converge to one another. A two-client counterexample shows that fixed positive mixing can preserve a nonstationary fixed point. The theory covers bounded linear symmetric positive-definite preconditioners. Experiments with SOAP, Sophia, and Muon variants across vision and language tasks show improvements over corresponding local optimizers, including accuracy gains of up to $19.47$ percentage points and lower validation loss for 60M--350M language models. Full nonlinear and momentum-based updates require separate analysis.