NeurIPS 2026 Papers

We present a neuro-inspired framework for embodied planning and control. Building on three principles that enable fast and highly effective goal-directed behavior in the mammalian brain — paired forward/inverse internal models, open-loop multi-step motor commands, and sequential organization of action — our *Inverter* framework combines analytic and trained components, the latter trained end-to-end through *Inverse Learning* (IL), a paradigm we formalize and delineate from supervised, reinforcement, and imitation learning. IL bridges RL-style amortization, which runs in a single forward pass but emits one action at a time, and optimal-control-style sequence reasoning, which plans whole trajectories but with iterative test-time computation. Single Inverters or hierarchical n=2 Inverter stacks match or improve over comparable offline-RL and diffusion-planner baselines on all 3 `maze2d-v1` and 6 `antmaze-v2` D4RL variants by an average of $+24.2\%$ (range $-1.9\%$ to $+78.2\%$), at one-to-two orders of magnitude less inference compute. As one mechanism behind this effectiveness, we show that Inverters can learn control policies closer to the analytic optimum than the data-generating policy itself. We also identify a failure mode of IL: forward-model hacking under narrow training-data coverage, which we mitigate by using *random* training data with broader coverage. As an application example, a Pulse Inverter synthesizes arbitrary single-qubit quantum gates with fidelity matching the standard iterative numerical baseline (GRAPE), at more than $1000\times$ lower per-gate compute. We propose deeper hierarchical, probabilistic, and latent extensions of the Inverter framework as a differentiable world-interface, especially for latency- and compute-critical embodied AI.

Understanding how cortical activity represents natural whole-body behavior in primates remains challenging. Limited by diversity of movements and inaccessible of large-scale neural feature programming whole-body kinematics, previous motor decoding studies rely on constrained tasks and limited limb movements. Here, we present a neural-behavioral recording and modeling framework for freely moving monkeys, combining epidural cortical signals from distributed sensorimotor areas with synchronized multi-view motion capture through a data custom collection platform. We reconstruct whole-body monkey kinematics and learn a compact motion prior using an autoregressive encoder-decoder model. Conditioned on epidural signals, the model decodes more accurate and realistic full-body movements without explicit physical constraints. Our results provides a novel proof-of-concept approach for decoding natural whole-body movements in primates using large-scale intracranial neural activity.

Web-based language agents operate under severe partial observability, where the semantic divergence between internal state assumptions and the ground-truth environment is often unobservable. Consequently, agents frequently maintain high-level reasoning coherence over misgrounded states, causing errors to compound as subsequent decisions are conditioned on silently invalidated premises. We present **NesyProAct**, a proactive neural-symbolic agentic decision framework that transforms conventional ReAct-style web agents from reactive prompting pipelines into execution-aware decision processes. NesyProAct exposes a typed symbolic decision interface over states, actions, transitions, and subgoals, enabling LLM-based agents to automatically compose and reason over execution semantics across decision hierarchies. From this interface, programmatic verification logic is synthesized online to evaluate step-level executability and progress, with verification outcomes directly regulating decision evolution through targeted grounding interventions. As a result, execution feedback is integrated into planning itself, allowing agents to maintain semantic alignment under partial observability rather than propagating unverified assumptions. On WebArena, NesyProAct achieves a **12\%** overall improvement over strong skill-induction agentic web framework ASI across six domains. NesyProAct also achieves noticeable performance when reasoning with small models GPT-4o-mini, with **5.1\%** gain over ASI with Claude-3.5.

We propose and analyze a model-based bootstrap for transition kernels in finite controlled Markov chains (CMCs) with possibly nonstationary or history-dependent control policies, a setting that arises naturally in offline reinforcement learning (RL) when the behavior policy generating the data is unknown. We establish distributional consistency of the bootstrap transition estimator in both a single long-chain regime and the episodic offline RL regime. The key technical tools are a novel bootstrap law of large numbers (LLN) for the visitation counts and a novel use of the martingale central limit theorem (CLT) for the bootstrap transition increments. We extend bootstrap distributional consistency to the downstream targets of offline policy evaluation (OPE) and optimal policy recovery (OPR) via the delta method by verifying Hadamard differentiability of the Bellman operators, yielding asymptotically valid confidence intervals for value and $Q$-functions. Experiments on the RiverSwim problem show that the proposed bootstrap confidence intervals (CIs), especially the percentile CIs, outperform the episodic bootstrap and plug-in CLT CIs, and are often close to nominal ($50\%$, $90\%$, $95\%$) coverage, while the baselines are poorly calibrated at small sample sizes and short episode lengths.

Most FDR-controlled feature selection methods are designed for coordinate-wise hypotheses, where each feature has a single weight or importance score. This abstraction fails in sequential and grouped models, where one original feature is represented by a block of sub-features, such as lags, recurrent states, or attention-based interactions. We propose a grouped-feature FDR control framework for such settings. For grouped linear models, we construct null-symmetric block-level mirror statistics with matrix-valued perturbations. For neural sequential models, we combine Permutation SHAP derivatives as model-agnostic block-level importance scores with kernel-based dependence measure. The framework is model-agnostic across network architectures, does not require specifying the covariate distribution, and reduces to Gaussian Mirror or Neural Gaussian Mirror when the block size is one. We prove FDR control for low- and high-dimensional grouped linear models and asymptotic symmetry of smoothed Permutation SHAP derivatives under fixed fitted nonlinear models. Experiments on simulated and real-world datasets show reliable FDR control and improved power under correlated grouped-feature signals.

Partitioned routed distillation is hard to interpret when route count, supervision grouping, and search or filtering budget change together. We study that attribution problem inside one fixed routed family using two matched nulls: a routing-only control (Latent-Routing MoA) and a structure-matched shuffled-partition control (Matched-Partition-Shuffle), with teacher tokens, trainable parameters, and router depth matched exactly. The decisive result is Table tab:main: the zero-manual deployable row ModeDistill-Auto-v4-Open, whose partition source is induced by GPT-OSS-120B-Instruct pairwise same-strategy judgments (Apache- 2.0 , distinct from the trace-generating teacher), beats MoA by +2.46 pp and Matched-Partition-Shuffle by +2.04 pp on the five-domain primary-shift average (A1), with positive OOD gaps on all five primary domains. Table tab:external_breadth_transfer is intentionally weaker evidence: for that exact same headline row it reports only four external benchmark aggregate means, where Auto-v4-Open beats MoA by +4.91 / +3.99 / +3.70 / +2.87 pp, and it does not support slice-wise breadth or cross-family generality. The open pipeline remains within 0.05 pp of the manual upper-bound reference on A1 and within the pre-specified 0.50 pp tie band on every external mean, so we keep it as the deployable row and retain the manual row only as calibration. The claim is therefore narrow: within this routed family, once routed budget is matched, the residual OOD gain is attributable to the externally induced partition source rather than to routing alone or to structure-matched shuffled partitions. Figure fig:identification and the appendix are corroborative only. The weakest primary shift remains ALFWorld tool reconfiguration ( +1.15 pp vs.\ MoA, paired CI [-0.12,+2.41] ), and discovery-time verifier calls and teacher generation are disclosed separately from the matched comparison.

Test-time scaling (TTS) improves reasoning by allocating additional inference compute, but in multimodal large language models (MLLMs), more compute is not always reliable. Longer reasoning may amplify visual misperception, induce answer drift, reinforce majority traps, or turn initially correct predictions into overthought failures. We propose MUST, a training-free framework that recasts multimodal TTS as stage-conditioned stability control. MUST separates inference into reasoning and verification stages and assigns each stage a different reliability criterion. During reasoning, Contrastive Answer-Manifold Stability (CAMS) selects answers whose supporting trajectories form compact and separable latent groups. During verification, Attention-Free Support-Chain Stability (AF-SCS) evaluates whether explicit visual evidence and subsequent reasoning form a stable latent support chain, without relying on token-to-patch attention maps. Experiments on multimodal reasoning benchmarks show that MUST improves the accuracy-compute trade-off and reduces overthinking-induced errors. These results suggest that reliable MLLM test-time scaling should adaptively control when and how extra compute is trusted, rather than simply increasing inference budget.

As AI agents are given more autonomy in software engineering workflows, the risks grow if they pursue goals different from the ones their users intended. The field of AI control develops control protocols that prevent such harm without restricting the agent's ability to do useful work. We introduce \textbf{LinuxArena}, a control setting for testing such protocols, where agents operate directly on live, multi-service production environments. LinuxArena contains 10 public environments (with an additional 10 held out privately), providing 906 main tasks representing legitimate software engineering work and 92 side tasks representing safety failures such as data exfiltration and access-control bypassing, making it the largest and most diverse control setting for agentic software engineering to date. We demonstrate LinuxArena's utility by running sabotage and monitor evaluations: against a GPT-5 Nano trusted monitor at a 1% step-wise false positive rate, Claude Opus 4.6 achieves an undetected sabotage rate of 42%. We additionally release \textbf{LaStraj}, a dataset of human-crafted attack trajectories that achieves an undetected sabotage rate of 97% against the same monitor. Together, these results suggest meaningful headroom for both attackers and defenders, making LinuxArena a strong testbed for developing and evaluating future control protocols.

Humanoid robots capable of versatile whole-body interaction with everyday objects represent a central goal of embodied intelligence. Existing approaches often rely on motion-reference inputs or task-specific rewards, coupling policies to particular motion scripts, object geometries, and contact timings. This limits geometric generalization and flexible interaction control, where simple commands specify motion intent while object geometry determines how contact should be executed. We introduce LessMimic, a framework for versatile motion-free-at-inference humanoid–object interaction. At inference, a single whole-body policy is steered by root commands and an interaction-type flag instead of motion-reference inputs, and is conditioned on a compact interaction representation built from short histories of distance-field-derived surface distances and local surface directions. This geometry-conditioned interface enables command-steered control while adapting contact behavior to local object geometry. Through visual distillation, LessMimic further enables egocentric-depth-based deployment for MoCap-free sensing. Across object scales from 0.4× to 1.6×, LessMimic maintains robust performance over four interaction tasks, including PickUp, SitStand, Push, and Carry, where motion-conditioned baselines degrade sharply away from the training scale. Beyond single-task evaluation, LessMimic further supports sequential composition of heterogeneous interaction skills, attaining 62.1% success on five-task sequences and retaining 23.5% success at 15 task instances. By grounding interaction control in local geometry rather than motion references, LessMimic provides a path toward geometry-generalizable, command-steerable humanoid–object control with heterogeneous skill composition.

Learning flexible motor primitives is a hallmark of skilled motor control. Recent neuroscience theory proposes that motor primitives may be implemented as low-rank perturbations of a shared recurrent network, but leaves open how such a system is learned. We translate this principle into a novel architecture for learning motor skills end-to-end: a shared recurrent core modulated by a bank of residual adapters, each selected by a discrete latent code. Trained on closed-loop biomechanical control, the adapters develop emergent low-rank perturbations of the recurrent dynamics despite no architectural rank constraint, placing task representations in disparate subspaces of the shared core network. A simple high-level policy over the learned options, optimized while the whole network is frozen, sequences the low-rank adapters to produce novel out-of-distribution movements. We demonstrate the ability to generalize to novel motor sequences within the closed-loop control setting, improving on the generalization error of a task-input-conditioned multitask baseline by up to order of magnitude.

Reinforcement learning has achieved remarkable success in robot learning. However, under challenging exploration and contact-rich dynamics, early-stage training is frequently dominated by premature terminations such as collisions and falls. As a result, learning is overwhelmed by short-horizon, low-return trajectories, which hinder convergence and limit long-horizon exploration. To alleviate this issue, we propose a technique called Failure Episodic Memory Alert (FEMA). FEMA explicitly stores short-horizon failure experiences through an episodic memory module. During interactions, it retrieves similar failure experiences and prevents the robot from recurrently relapsing into unstable states, guiding the policy toward long-horizon trajectories with greater long-term value. FEMA can be combined easily with model-free reinforcement learning algorithms, and yields a substantial sample-efficiency improvement of 33.11\% on MuJoCo tasks across several classical RL algorithms. Furthermore, integrating FEMA into a parallelized PPO training pipeline demonstrates its effectiveness on a real-world bipedal robot task.

This paper introduces language-based agent control (LBAC), a method to apply techniques from language-based security to the control of AI agents. Unlike systems-level defenses such as I/O sandboxing, LBAC can express application-level policies. Moreover, in LBAC agents may perform computations and recursively invoke subagents with tool access. Language-based techniques enable the design of APIs which, through a combination of typing discipline and internal runtime checks, ensure that any well-typed program obeys a desired property. The core idea of LBAC is to have agents interact with the world by generating programs against such APIs rather than by issuing tool calls directly. These programs may themselves contain recursive calls to subagents, which retain full tool access; the type checker rejects ill-typed programs before execution, and policies thereby extend uniformly across the entire agentic system, including its scaffolding and control flow. We demonstrate LBAC with three case studies: I/O sandboxing via filesystem capabilities, data provenance, and information-flow control.

Recent work has pointed out current models' limitations in sampling according to prespecified target distributions. In this work, we show that current models nevertheless possess a coarse form of control over their output distributions: by instructing a range of open-source models to maximize or minimize output certainty in a two-alternative forced-choice task with no correct answer, we find that several models can shift entropy in the instructed direction. Through contrastive activation analysis, we further identify a linear direction in activation space that models recruit under uncertainty-modulation instructions and that can be used to causally modulate entropy via activation steering in the absence of any such instructions, suggesting that deliberate entropy control has an identifiable internal representation.

Large Language Models (LLMs) increasingly ship with “thinking modes”, yet their counterpart, the “no-thinking” has received far less exploration. In this work, we revisit language model “no-thinking” behavior along the following efforts: **(a) Explore the definition of no-thinking.** Rather than relying on proxies like thinking-mode control, we split each response into pre-answer text and a final answer, scoring both answer-only compliance and the question–pre-answer relevance. **(b) Broad experimental coverage.** We evaluate multiple no-think controls (thinking-mode toggles, prompt instructions, *etc.*) across boolean, multiple-choice, and open-ended tasks, on open-source models with scaled variants, and proprietary models. With extensive experiments, we found that **(i)** Explicit no-think controls do not reliably eliminate visible reasoning-like content. Instead, models exhibit **(ii)** *“thinking inertia”*: residual content is systematically organized by the task's answer space, with boolean verification compressing most easily, multiple-choice tasks forming an intermediate regime, and open-ended tasks remaining the most resistant. **(iii)** We further identify what we call a no-thinking and performance trade-off in open-ended: stronger answer-only constraints on complex tasks either fail to suppress the intermediate payload or succeed by removing computation needed for accuracy. **(iv)** Finally, we show that compressibility depends strongly on the structural support provided by the question itself. Thus, no-think controls are not direct guarantees of no-thinking; they must be evaluated jointly through answer-only success, visible payload, and task accuracy. We hope our work moves LLMs closer to a human-like ability to stop thinking on demand.

On-Policy Distillation (OPD) has emerged as a dominant post-training paradigm for large language models, especially for reasoning domains. However, OPD remains unstable in practice due to the high gradient variance of its single-sample Monte Carlo estimator, and recipes for stable training are still immature. We propose vOPD (On-Policy Distillation with a control variate baseline), which casts OPD as policy-gradient RL and stabilizes it by introducing a control variate baseline—canonically a value function—from the RL literature. We show that the OPD value function admits a closed form as the per-token negative reverse KL divergence between the student and the teacher, available directly from the already-computed forward pass with no additional critic or inference. Existing stabilization methods either compute the full token-level reverse KL over the entire vocabulary, adding significant overhead, or restrict it to a top-k support, biasing the objective. vOPD instead preserves the lightweight single-sample estimator, subtracting the value function as a detached baseline to keep the gradient unbiased while reducing variance. Furthermore, we show that a top-k approximation of the baseline further lowers cost without compromising performance. Across mathematical and scientific reasoning benchmarks, vOPD consistently outperforms vanilla OPD and matches the most expensive full-vocabulary baseline, offering an efficient stabilization of On-Policy Distillation through principled RL variance reduction.

World models enable prediction, planning, and decision-making by learning internal simulators of environment dynamics. Although substantial progress has been made in world models from pixel-based observations, many physical systems are instead observed through vector-based measurements that are noisy and only partially informative of the underlying state. We introduce K-PWM, a Koopman-structured probabilistic world model for prediction and control under partial observation. K-PWM combines a parameterized Koopman-structured state-space model with a nonlinear observation decoder, and performs probabilistic latent-state inference directly through the learned model parameters rather than through a separately trained inference network. We train K-PWM using a generalized expectation conditional maximization (GECM) procedure with principled initialization. Across Gymnasium MuJoCo tasks, K-PWM improves sample efficiency, yields reliable long-horizon predictions, and supports downstream control through model predictive path integral (MPPI) control. These results suggest that structured probabilistic latent dynamics provide a useful route toward data-efficient world modeling and control in partially observable vector-valued settings.

Mixed-precision quantization improves the accuracy-efficiency trade-off by assigning different bit-widths across a network. Since bit-width selection is a combinatorial problem, existing methods often optimize additive surrogate losses instead of directly evaluating task losses in all configurations. We show that these surrogates can suffer from surrogate-task mismatch, especially when many layers are changed simultaneously from a reference configuration. We further observe that, although allowing more layers to change improves the surrogate objective, the evaluated task loss can be minimized at an intermediate limit on the number of changed layers. Based on this observation, we propose Iterative Integer Linear Programming (I2LP), which iteratively refines a reference bit configuration. At each refinement step, I2LP solves multiple ILPs with different limits on how many layers may change from the current reference, and accepts the best candidate only when it reduces the task loss. I2LP applies to both post-training quantization and quantization-aware training, and consistently outperforms uniform-precision baselines and existing mixed-precision methods. Code will be released.

Search-based planning is a powerful policy improvement paradigm in reinforcement learning, with milestone successes on discrete-action domains through the AlphaZero and MuZero families. Extending it to continuous control, however, faces a structural mismatch between the search operator and the policy class: search at each state evaluates a finite candidate set and returns a discrete distribution, while the parametric Gaussian policy commonly used in continuous control is a continuous density. We prove that distilling the search output into a Gaussian induces a non-vanishing projection error that inflates policy variance and produces a return gap that persists even when the policy mean is locally optimal, and is not closed by additional search compute or data. Inspired by the iterative refinement of MPPI in continuous control, we propose \textbf{Iterative Gumbel Planning (IGP)}, which adapts this principle to a discrete policy class. IGP represents the policy as a per-dimension factorized categorical distribution aligned with the search support, eliminating the projection error and reducing the residual approximation to a bounded discretization error controllable by the grid resolution. Joint candidates are drawn by Gumbel Top-$K$ sampling without replacement, avoiding the $V^{|A|}$ combinatorial explosion of joint discretization, and search-refine iteration runs for multiple rounds at the same state. On DMControl and HumanoidBench, IGP achieves state-of-the-art performance, with improved sample efficiency and lower temporal action variance at evaluation.

Humanoid teleoperation datasets are growing rapidly, with operator demonstrations retargeted onto a shared robot skeleton to train whole-body controllers and foundation models. We report a surprising property of this pipeline: retargeting normalizes body proportions but preserves operator movement dynamics (joint velocity profiles, ranges of motion, and coordination patterns shaped by the operator's physiology). On BONES-SEED (522 operators, 142K sequences), retargeted Unitree G1 trajectories support gender classification at 96.0% and operator re-identification at 97.2% Top-1; on operators never seen during training, gender holds at 83.4% and age and height regress within ±4.2 yr and ±5.7 cm. Partial correlation analysis reveals emergent, biomechanically interpretable structure: the signals are task-invariant across activity categories and hold across retargeting implementations. We introduce UNVEIL, a skeleton-aware spatiotemporal graph network to measure and interpret this effect, take initial steps toward operator anonymization, and ask the community: as teleoperation datasets scale, what should our data practices be? Code, models, and anonymized trajectories are at our project website https://project-unveil.github.io.