AI Papers of the Week
Every paper worth reading in AI, hand-picked one week at a time.

Is Grep All You Need?
The paper evaluates grep-style text search against embedding-based retrieval inside coding agents. When wrapped in a suitable agent harness, grep matches or exceeds embedding retrieval on coding-agent tasks. The study isolates the contribution of the harness from the contribution of the retrieval primitive, and finds that harness design accounts for most of the performance differential typically attributed to embeddings.

δ-mem
δ-mem augments a frozen full-attention model with a compact online associative-memory state. The state is a fixed-size matrix updated by delta-rule learning during generation, and its readout produces low-rank corrections to the backbone's attention output. There is no fine-tuning, no backbone swap, and no context extension.

Beyond Individual Intelligence
A multi-agent systems survey covering 200+ papers, organized along three axes: collaboration mechanisms, failure attribution, and self-evolution. Each axis is treated as a distinct research line. The self-evolution chapter maps how memory, meta-learning, and procedure-editing approaches intersect.

AutoTTS
AutoTTS reframes test-time scaling as a search problem. Instead of designing branching, pruning, and stopping heuristics directly, the user constructs a discovery environment in which TTS strategies are searched automatically. Width-depth TTS is recast as controller synthesis over pre-collected reasoning trajectories and probe signals, so candidate controllers can be evaluated without repeated LLM calls.

AEvo
AEvo separates the iterative self-improvement loop into two roles: a candidate-proposer that generates the next attempt, and a meta-agent that observes traces and edits the procedure used to propose future candidates. Past runs (candidates, feedback, traces, failures) function as memory the meta-agent reads from when revising the procedure. AEvo reports a 26% relative gain over the strongest evolution baseline on agentic and reasoning benchmarks, and SOTA on three open-ended optimization tasks under the same iteration budget. The work demonstrates one way to operationalize accumulated agentic search logs as input to procedure-level updates rather than discarding them after each run.

HeavySkill
One of the cleaner takes on agentic harness design released this year. The paper argues that what actually drives harness performance is not the orchestration code, but a single inner skill: parallel reasoning followed by deliberation. Internalize that pattern into the model and most of the surrounding scaffolding becomes optional. HeavySkill systematizes the idea as a two-stage pipeline you can run beneath any harness, then trains it as a learnable skill via RLVR. The result is a harness win that looks more like a model win.

Conductor
Sakana AI's ICLR 2026 paper introduces a 7B Conductor model that hits SOTA on GPQA-Diamond and LiveCodeBench by orchestrating other LLMs instead of solving problems itself. The Conductor is trained with RL to do two things simultaneously: design communication topologies between worker agents (open or closed source) and prompt-engineer focused instructions to each worker so it leverages individual strengths. The orchestrator becomes a learnable policy, not a wrapper around one.

Connect Four AlphaZero from Scratch
This paper proposes a new way to evaluate coding agents: hand them a minimal task description, give them a tight budget, and ask them to autonomously rebuild a famous ML breakthrough end-to-end. Connect Four plus AlphaZero is the first instance. It is small enough to run on a laptop and hard enough to require a real research engineering loop. Claude Opus 4.7 implemented the full pipeline (MCTS, neural value and policy nets, self-play, training schedule) in three hours on consumer hardware, then beat the Pascal Pons solver 7 of 8 as first-mover. No other frontier coding agent tested cleared 2 of 8.

Coordination as Architecture
Multi-agent LLM systems fail in production at rates between 41% and 87%, and the majority of those failures are coordination defects, not base-model capability. Most published comparisons of multi-agent architectures cannot even tell you whether the gain came from coordination or from one configuration just having more context. This paper argues coordination should be treated as a configurable architectural layer, separable from agent logic and information access, then backs the position with an information-controlled experiment.

1,000 Synthetic Computers
Microsoft Research builds 1,000 synthetic computers, each with realistic directory structures, documents, and artifacts, then runs long-horizon simulations on top of them. One agent plays the user and sets productivity goals; another executes the work. Each simulation runs over 8 hours of agent runtime and 2,000+ turns on average, roughly a month of human work compressed into one trace. Training on this experiential data drives significant improvements on both in-domain and out-of-domain productivity evaluations.

Agentic-imodels
The entire interpretability literature is built around human readers. As more analysis gets delegated to agents, the right target of interpretability shifts. Microsoft Research introduces Agentic-imodels, an autoresearch loop where a coding agent (Claude Code, Codex) iteratively evolves scikit-learn-compatible regressors that are simultaneously accurate AND readable by other LLMs. Interpretability is measured by whether a small LLM can simulate the fitted model's behavior just by reading its string representation, predictions, feature effects, and counterfactuals from the __str__ output alone. Across 65 tabular datasets, the discovered models push the Pareto frontier past every classical interpretable baseline (decision trees, GAMs, sparse linear), and improve four downstream agentic data-science systems on the BLADE benchmark by 8% to 73%.

Agentic World Modeling
A massive 40-author survey lands the cleanest taxonomy of world models in agent research released so far. The paper proposes a "levels by laws" framework spanning three capability levels and four law regimes, then synthesizes 400+ works and 100+ representative systems across model-based RL, video generation, web and GUI agents, multi-agent simulation, and scientific discovery. As agents shift from chatbots to goal-accomplishers, the bottleneck moves from language to environment, and this is the first paper that gives builders a shared vocabulary across communities that have been working in isolation.

RecursiveMAS
Multi-agent systems usually pass full text messages between agents at every step, which causes token bloat, latency, and context dilution that all grow with team size. RecursiveMAS asks a different question: what if agents collaborated through recursive computation in a shared latent space instead of through text? The system treats a multi-agent team as a recursive computation where each agent acts like an RLM layer, iteratively passing latent representations to the next and forming a looped interaction process. Less talking, more thinking.

From Skill Text to Skill Structure
SKILL.md files entangle invocation interface, execution flow, and tool side effects in a single blob of natural language. That makes downstream discovery and risk review brittle as skill registries scale. This paper proposes SSL, a three-layer typed JSON representation drawn from Schank and Abelson's classical work on scripts, MOPs, and conceptual dependency. An LLM-based normalizer converts existing SKILL.md files into the structure, so adoption does not require rewriting registries by hand.

When to Retrieve During Reasoning
Most RAG systems retrieve once, before the model starts reasoning. Large reasoning models like o1 and R1 do not work that way. They generate 12k to 25k token chains of thought and hit knowledge gaps mid-inference, long after the retrieval window closed. ReaLM-Retrieve is a reasoning-aware retrieval framework that injects evidence during multi-step inference, detects uncertainty at reasoning-step granularity, and learns a policy for when external evidence actually helps. It achieves +10.1% absolute F1 over standard RAG across MuSiQue, HotpotQA, and 2WikiMultiHopQA, with 47% fewer retrieval calls than fixed-interval IRCoT, and hits 71.2% F1 on 2-4 hop MuSiQue with only 1.8 retrieval calls per question.

DeepSeek V4
DeepSeek V4 is the first open model family built from the ground up around million-token contexts as a default rather than a bolt-on feature. The release includes DeepSeek-V4-Pro (1.6T total / 49B active) and DeepSeek-V4-Flash (284B total / 13B active), both trained natively at 1M context length. The tech report details a hybrid attention architecture, new training stability techniques, and a domain-specialist post-training pipeline that together push the open-source frontier much closer to GPT-5.2 and Gemini 3.0-Pro at a fraction of the cost.

Attention to Mamba
Apple proposes a two-stage recipe for cross-architecture distillation from Transformers into Mamba. Naive distillation collapses teacher performance because a Mamba student cannot directly imitate softmax attention. The fix is to distill the transformer into a linearized-attention student using a kernel adaptation first, then transfer that student into a pure Mamba with no attention blocks. On a 1B model trained on 10B tokens, the Mamba student hits 14.11 perplexity against a 13.86 Pythia-1B teacher, nearly matching quality at linear-time inference cost.

Skill-RAG
Most RAG systems retrieve on every query, whether the model needs help or not. This is wasteful when the model already knows the answer and often too late when it does not. This paper introduces Skill-RAG, a failure-state-aware retrieval system that uses hidden-state probing to detect when an LLM is approaching a knowledge failure, then routes the query to a specialized retrieval strategy matched to the gap.

Self-Generated World Knowledge
How far are we from agents that can self-generate world knowledge? This paper proposes an outcome-based reward that measures how much an agent's self-generated world knowledge actually improves its task success rate, then trains with that signal and removes the external guidance at inference. The result is a 14B model that surpasses Gemini-2.5-Flash on web navigation and gains +20% on WebVoyager and WebWalker benchmarks.

Self-Evolving Logic Synthesis
EDA tools like ABC have been hand-tuned by humans for decades. NVIDIA shows they can evolve themselves. This work introduces the first self-evolving logic synthesis framework, a multi-agent LLM system that autonomously refines the entire ABC codebase, generates and tests candidate optimization sequences against standard benchmark circuits, then merges improvements back into the base tool. No human engineer in the loop.

Stateless Decision Memory
Most interesting AI agent papers right now are about capability. This one is about plumbing, and it is probably more important than it looks. Stateful agents do not scale horizontally. The moment you need thousands of concurrent agent instances running across containers, persistent per-agent state becomes the bottleneck. This paper proposes replacing active memory with immutable decision logs using event-sourcing principles from distributed systems.

Diversity Collapse in Multi-Agent LLMs
Every multi-agent system pitch assumes agents explore different solutions, but this paper shows they converge on near-identical outputs over time, even across different architectures and different starting prompts. The authors call it diversity collapse. The cause is structural coupling: shared context, shared task descriptions, and mutual feedback pull every agent toward the same attractor. They measure it formally with metrics like the Vendi score, and the homogenization is real. The practical consequence is that multi-agent setups for brainstorming, hypothesis generation, and ideation only work if teams explicitly engineer isolated reasoning phases, decoupled evaluation, and heterogeneous starting conditions.

AiScientist
Long-horizon AI research agents are mostly a state-management problem. Reasoning well for the next turn is not enough when ML research demands task setup, implementation, experiments, debugging, and evidence tracking over hours or days. This paper introduces AiScientist, a system for autonomous long-horizon engineering built around the principle of thin control and thick state. A top-level orchestrator manages stage-level progress while specialized agents repeatedly ground themselves in durable workspace artifacts.

AlphaEval
Agent evaluations are drifting away from production reality. Most benchmarks use clean tasks, well-specified requirements, deterministic metrics, and retrospective curation. Production work is messier, with implicit constraints, fragmented multimodal inputs, undeclared domain knowledge, long-horizon deliverables, and expert judgment that evolves over time. This paper introduces AlphaEval, a production-grounded benchmark evaluating agents as complete products rather than model APIs.