AI Papers of the Week
Every paper worth reading in AI, hand-picked one week at a time.
CoAct-1
Researchers from USC, Salesforce, and UW present CoAct-1, a multi-agent system that combines GUI interaction with direct code execution to improve efficiency and robustness in computer-using agents. Unlike prior GUI-only frameworks, CoAct-1’s Orchestrator delegates subtasks to either a GUI Operator (vision-language action model) or a Programmer (Python/Bash execution), enabling agents to bypass brittle, multi-click sequences for tasks better handled via scripts.
Medical Reasoning in the Era of LLMs
This review categorizes techniques for enhancing LLM medical reasoning into training-time (e.g., fine-tuning, RL) and test-time (e.g., prompt engineering, multi-agent systems) approaches, applied across modalities and clinical tasks. It highlights advances in evaluation methods, key challenges like the faithfulness–plausibility gap, and the need for native multimodal reasoning in future medical AI.
Geometric-Mean Policy Optimization
Introduces a stabilized alternative to Group Relative Policy Optimization (GRPO), which is widely used to improve reasoning capabilities in large language models via reinforcement learning. GRPO optimizes the arithmetic mean of token-level rewards but suffers from training instability due to extreme importance sampling ratios. GMPO addresses this by instead maximizing the geometric mean of token-level rewards, leading to more stable updates.
Apple Intelligence Foundation Language Models
Apple introduces two multilingual, multimodal foundation models: a 3B-parameter on-device model optimized for Apple silicon and a scalable server model using a novel PT-MoE transformer architecture. Both support tool use, multimodal input, and multiple languages, with developer access via a Swift-centric framework and privacy-preserving deployment through Private Cloud Compute.
AI4Research
This survey offers the first unified and comprehensive framework for understanding how AI is transforming the full lifecycle of scientific research. The paper identifies five core areas: Scientific Comprehension, Academic Survey, Scientific Discovery, Academic Writing, and Academic Peer Review, and presents a detailed taxonomy and modeling approach for each.
Threats in LLM-Powered AI Agents Workflows
This work presents the first comprehensive, end-to-end threat model for LLM-powered agent ecosystems. As LLM agents gain the ability to orchestrate multi-step workflows and interact via protocols like MCP, ANP, and A2A, this paper surveys over 30 attack techniques spanning the entire stack, from input manipulation to inter-agent protocol exploits.
Deep Research Agents
Provides the most comprehensive survey to date of Deep Research (DR) agents, LLM-powered systems built for autonomous, multi-step informational research. The paper defines DR agents as AI systems that tightly integrate dynamic reasoning, adaptive long-horizon planning, tool use, retrieval, and structured report generation. It establishes a taxonomy of DR architectures, evaluates recent advances, and outlines the limitations of current systems and benchmarks.
Visual Structures Help Visual Reasoning
This study shows that adding simple spatial structures (like horizontal lines) to images significantly boosts GPT-4o’s visual reasoning by improving feature binding. This visual input tweak outperforms textual strategies alone, yielding large gains in visual search (+25%), counting (+26.8%), and spatial understanding (+9.5%).
DeepRare
Introduces DeepRare, a modular agentic system powered by LLMs to aid rare disease diagnosis from multimodal clinical inputs (text, HPO terms, VCFs). It generates ranked diagnostic hypotheses with fully traceable reasoning chains linked to verifiable medical sources, addressing a long-standing need for interpretability in clinical AI.
AlphaGenome
Google DeepMind introduces AlphaGenome, a powerful AI model designed to predict how genetic variants affect gene regulation by modeling up to 1 million DNA base pairs at single-base resolution. Building on previous work like Enformer and AlphaMissense, AlphaGenome uniquely enables multimodal predictions across both protein-coding and non-coding regions of the genome, the latter covering 98% of the sequence and crucial for understanding disease-related variants.
Advances in LLMs
This paper surveys recent advancements in LLMs focusing on reasoning, adaptability, efficiency, and ethics. It highlights techniques like CoT prompting, Instruction Tuning, RLHF, and multimodal learning, while also addressing challenges like bias, computational cost, and interpretability.
V-JEPA 2
Meta AI introduces V-JEPA 2, a scalable joint-embedding predictive architecture for self-supervised video learning, targeting the goal of building a generalist world model capable of understanding, predicting, and planning in the physical world. The model is trained in two stages: action-free pretraining on 1M+ hours of internet videos and images, followed by post-training with only 62 hours of unlabeled robot trajectories (Droid dataset). This yields a latent video representation that is useful across a broad range of downstream tasks.
Magistral
Mistral introduces Magistral, its first reasoning-focused LLM line, alongside a custom RL training stack that enables pure reinforcement learning from scratch. In contrast to prior approaches that rely on distillation from teacher models, Magistral trains directly using online RL with text-only data and custom reward shaping. The work yields two open models: Magistral Medium (based on Mistral Medium 3) and the open-sourced Magistral Small (24B), which is bootstrapped via SFT on Medium’s outputs, followed by RL. Key insights:
Coding Agents with Multimodal Browsing
Introduces OpenHands-Versa, a unified agent designed to perform strongly across diverse domains, coding, web browsing, and multimodal information access, by equipping a single agent with three general capabilities: code execution, multimodal web browsing, and file/search access. In contrast to specialist or multi-agent systems optimized for narrow domains, OpenHands-Versa aims to solve a wide variety of real-world tasks with minimal architectural complexity. Key highlights:
Visual Planning
Proposes a novel reasoning paradigm that replaces language-based planning with image-based reasoning. The authors argue that language is not always the optimal medium for tasks involving spatial or physical reasoning. They introduce Visual Planning, where reasoning is executed as a sequence of visual states (images) without any text mediation, allowing models to “think” directly in images. This is realized through a reinforcement learning framework called VPRL (Visual Planning via Reinforcement Learning), which trains a vision-only model (LVM-3B) to plan using images. Key contributions and findings:
EfficientLLM
Introduces the first large-scale, empirical benchmark for evaluating efficiency trade-offs in LLMs across architecture, fine-tuning, and inference. Conducted on a high-performance cluster (48×GH200, 8×H200 GPUs), the study evaluates over 100 model–technique pairs spanning 0.5B–72B parameters, using six metrics: memory utilization, compute utilization, latency, throughput, energy consumption, and compression rate. Key insights include:
Kimi-Audio
Kimi-Audio is a new open-source audio foundation model built for universal audio understanding, generation, and speech conversation. The model architecture uses a hybrid of discrete semantic audio tokens and continuous Whisper-derived acoustic features. It is initialized from a pre-trained LLM and trained on 13M+ hours of audio, spanning speech, sound, and music. It also supports a streaming detokenizer with chunk-wise decoding and a novel look-ahead mechanism for smoother audio generation. Extensive benchmarking shows that Kimi-Audio outperforms other audio LLMs across multiple modalities and tasks. Key highlights:
Describe Anything
Introduces DAM, a model that generates fine-grained, region-specific captions in both images and videos. The authors address key limitations in prior vision-language models—namely, the inability to preserve local detail and the lack of suitable datasets and benchmarks for detailed localized captioning (DLC). Key contributions:
UXAgent
Introduces a novel framework, UXAgent, for simulating large-scale usability testing using LLM-driven agents. The system empowers UX researchers to test and iterate web design and study protocols before engaging real users. This is achieved through the orchestration of simulated agents with diverse personas interacting in real web environments, providing both behavioral and reasoning data. Key highlights:
The AI Scientist V2
The AI Scientist-v2 refines and extends its predecessor to achieve a new milestone: autonomously generating a workshop-accepted research manuscript. The system removes dependencies on human-authored code templates, incorporates agentic tree-search methods for deeper exploration, uses Vision-Language Models to refine figures, and demonstrates impressive real-world outcomes by passing the peer-review bar.
Compute Agent Arena
Computer Agent Arena is a new open platform for benchmarking LLM and VLM-based agents on real-world computer-use tasks, like coding, editing, and web navigation, using a virtual desktop environment. Initial results show that OpenAI and Anthropic are leading with modest success rates, while the platform aims to grow through crowdsourced tasks, agent submissions, and open-sourcing of its infrastructure. [Report](https://arena.xlang.ai/blog/computer-agent-arena)
One-Minute Video Generation with Test-Time Training
One-Minute Video Generation with Test-Time Training introduces TTT layers, a novel sequence modeling component where hidden states are neural networks updated via self-supervised loss at test time. By integrating these into a pre-trained diffusion model, the authors enable single-shot generation of one-minute, multi-scene videos from storyboards, achieving 34 Elo points higher than strong baselines like Mamba 2 and DeltaNet in human evaluations
Self-Evolving Multi-Agent Simulations for Realistic Clinical Interactions
Presents MedAgentSim is a fully automated, open-source hospital simulation where LLM-powered agents simulate doctor-patient interactions in dynamic diagnostic settings. Unlike previous static QA benchmarks, MedAgentSim mimics real-world clinical workflows with multi-turn dialogue, test requests, and self-improvement. More about this paper: ● Active doctor agents – MedAgentSim requires LLM doctor agents to engage in multi-turn consultations, request labs and imaging (e.g., ECG, X-ray), and iteratively refine diagnoses, making it far more realistic than pre-filled medical QA datasets. ● Self-improvement via memory + reflection – The system maintains buffers of successful and failed diagnoses. It uses retrieved past cases (via kNN), chain-of-thought reasoning, and ensembling to improve performance over time. Misdiagnoses trigger a reflection phase before inclusion in memory. ● Fully autonomous or human-in-the-loop – Users can optionally take control of the doctor or patient agents. Simulation assets are built using a 2D game engine (Phaser), and the agents can navigate, converse, and interact with virtual medical tools. ● Big performance boost across benchmarks – On NEJM, MedQA, and MIMIC-IV, MedAgentSim (with LLaMA 3.3) outperforms baseline setups by +6–37%, especially in vision-language tasks using LLaVA for interpreting medical images. ● Bias analysis & fairness focus – The team studied diagnostic accuracy under cognitive and implicit bias conditions. Models like GPT-4o and LLaMA proved more robust than Mixtral/Mistral, highlighting the importance of bias-aware evaluation.
Qwen2.5-Omni
Qwen2.5-Omni is a single end-to-end multimodal model that can perceive and understand text, audio, image, and video, and generate both text and speech in real time. It introduces architectural and training innovations that push the boundaries of streaming, multi-signal intelligence. Highlights: ● Thinker-Talker architecture – Inspired by the human brain and mouth, Qwen2.5-Omni separates reasoning (Thinker) and speech generation (Talker). Thinker (a transformer decoder) handles all perception and text generation. Talker (a dual-track autoregressive decoder) generates speech by consuming both text and hidden states from Thinker. Together, they’re trained end-to-end for synchronized text-speech output. ● Streaming-first design – To support real-time interaction, Qwen2.5-Omni implements block-wise encoders (for audio and vision) and a sliding-window codec generator for streaming audio. The model introduces TMRoPE (Time-aligned Multimodal RoPE), a 3D positional encoding system that aligns video and audio inputs to the same time axis. ● Pretraining scale & alignment – Trained on over 1.2 trillion tokens of diverse multimodal data, including 300B audio and 100B video-audio tokens. Uses instruction-tuned ChatML formatting and performs multi-stage post-training for both Thinker and Talker. Talker undergoes RL fine-tuning (DPO) and multi-speaker adaptation to ensure natural, stable speech output. ● SOTA across modalities – Qwen2.5-Omni achieves state-of-the-art on OmniBench, surpasses Qwen2-Audio in ASR/S2TT, and matches or beats Qwen2.5-VL in image and video tasks. On SEED zero-shot TTS, it outperforms CosyVoice 2 and F5-TTS in naturalness and stability, with low WER and high speaker similarity. ● Closes the voice-text gap – On a voice-instruction benchmark (converted from MMLU, GSM8K, etc.), Qwen2.5-Omni nearly matches its own text-instructed sibling Qwen2-7B, showing dramatic improvements in speech-based instruction following.