SKIM: Adaptive soft-token compression for procedural skills in LLM workflows
Researchers introduce SKIM (SKIll coMpression), a multi-resolution soft token compression framework targeting procedural knowledge (skills/workflows) rather than factual documents. SKIM compresses reusable natural language skills to 30–60% of their original token length while preserving task performance, reducing prefill cost and latency when skills are repeatedly invoked. The method adapts compression depth to skill complexity and supports offline compression for frequently updated community skills.
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SkillWeaver: Compositional Skill Routing for LLM Agents via Decompose-Retrieve-Compose
Researchers introduce SkillWeaver, a framework for compositional skill routing in LLM agents that decomposes complex queries into atomic sub-tasks, retrieves matching skills from a large library, and composes an executable DAG plan. The paper formalizes the Compositional Skill Routing problem and introduces CompSkillBench, a benchmark of 300 compositional queries over 2,209 real MCP server skills across 24 categories. A key finding is that task decomposition quality is the primary bottleneck, with standard LLM decomposition reaching only 34.2% category recall; the proposed Iterative Skill-Aware Decomposition (SAD) method improves decomposition accuracy from 51.0% to 67.7% in a single iteration. The framework also reduces context window consumption by over 99% compared to naive skill-stuffing approaches.
SkillOpt: Systematic Text-Space Optimizer for Self-Evolving Agent Skills
SkillOpt introduces a principled optimization framework for agent skills, treating the skill document as an external trainable state analogous to model weights. A separate optimizer model converts scored rollouts into bounded edits (add/delete/replace) on a skill document, accepting only edits that improve held-out validation scores. Evaluated across six benchmarks, seven target models, and three execution harnesses (direct chat, Codex, Claude Code), SkillOpt achieves best or tied performance on all 52 evaluated cells, lifting GPT-5.5 no-skill accuracy by up to +24.8 points inside the Codex agentic loop. Optimized skill artifacts also transfer across model scales and execution environments without further optimization.
Adaptive asymmetric token compression accelerates time series language models up to 7.68×
A new arXiv preprint proposes an adaptive token budgeting framework for time series (TS) language models that compresses TS tokens using frequency-domain structure and progressively prunes prompt tokens across model layers. The authors demonstrate up to 7.68× inference acceleration with performance improvements in 78% of evaluated settings across forecasting, classification, imputation, and anomaly detection tasks. The work is motivated by the observation that TS tokens have uneven spectral contributions and prompt-token influence attenuates with model depth, making uniform token processing wasteful.
SkillKit: Portable Skills Layer for AI Coding Agents
SkillKit is an open-source TypeScript project that provides a portable skills abstraction for AI coding agents, enabling installation, translation, and sharing of skills across tools like Claude Code, Cursor, Codex, GitHub Copilot, and 40+ others. The project has accumulated 1,112 stars with 32 added today, indicating moderate community traction. It targets the interoperability gap between the growing ecosystem of AI coding assistants.
ReuseRL: Skill Reuse as Compression in Agentic RL via MDL Principle
ReuseRL formalizes agentic reinforcement learning through the Minimum Description Length (MDL) principle, extracting a shared skill dictionary from successful trajectories and augmenting the RL objective with a segmentation cost that penalizes idiosyncratic, non-reusable behaviors. The authors prove a PAC-Bayes generalization bound for this compression penalty. Evaluated on ALFWorld, TextWorld-Cooking, and Countdown-Stepwise, ReuseRL outperforms vanilla GRPO and round-length baselines on both in-distribution and out-of-distribution tasks.
SubFit: Submodule-Level Fitted Residual Replacement for LLM Compression
SubFit introduces a post-training LLM compression method that operates at the submodule level (Attention and FeedForward separately) rather than full layers, and selects components non-contiguously. The approach replaces removed submodules with lightweight fitted residual bypasses calibrated on small data. Evaluated across ten LLMs at sparsity levels from 12.5% to 37.5%, SubFit retains 84.6% of dense downstream accuracy at 25% sparsity versus 81.6% for the strongest baseline, while reducing perplexity degradation from 4.34x to 2.42x and delivering measurable inference speedup and KV-cache savings.
Latent Context Language Models (LCLMs) achieve competitive encoder-decoder KV cache compression at scale
Researchers introduce Latent Context Language Models (LCLMs), a family of encoder-decoder compressors that map long token sequences to shorter latent embeddings consumed by a decoder, targeting the KV cache memory bottleneck in long-context inference. The authors conduct architecture search and continually pre-train 0.6B-encoder/4B-decoder models on over 350B tokens at compression ratios of 1:4, 1:8, and 1:16. LCLMs improve the Pareto frontier across general-task performance, compression speed, and peak memory, and are demonstrated as efficient backbones for long-horizon agents that can skim compressed context and expand relevant segments on demand. The work closes a previously noted gap between encoder-decoder approaches and KV cache compression methods on the accuracy-efficiency frontier.
SkillGenBench: Benchmarking Skill Generation Pipelines for LLM Agents
SkillGenBench is a new benchmark designed to evaluate the ability of LLM agents to generate correct, reusable, and executable skills from raw repositories and documents, rather than merely using pre-provided skills. It covers two generation regimes (task-conditioned and task-agnostic) and two procedural sources (repository-grounded and document-grounded), with standardized execution-based evaluation protocols. Experiments across multiple skill-generation methods reveal substantial performance variation and distinct failure modes depending on source type. The benchmark aims to establish skill generation as an independent research problem within agent systems.