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Agents / Efficiency & Inference

Optimizing Agent Skill Library Retrieval

Original: SkillZip: Contract-Preserving Graph Compression for Scalable Agent Skill Libraries

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Key Takeaways

  • SkillZip organizes skill libraries into a structured procedural graph to solve the issue of reuse-granularity mismatch.
  • The system uses MotifZip to identify and rewrite recurring subgraphs into reusable macros that preserve procedural contracts.
  • Performance on the SkillsBench benchmark shows a task reward of 33.3 and a Ret@1 improvement from 66.7 to 73.6 compared to SkillDAG.
  • The ReZip module supports incremental library maintenance by updating compressed graphs and addressing performance failures.

Summary & Methodology Analysis

SkillZip addresses the problem of redundant or incomplete execution contexts in large agent skill libraries by implementing a contract-preserving compression framework. The process begins with Sec2Graph, which decomposes source skill packages into typed nodes representing specific procedural units, such as Intent, Operation, and Verifier, before building a dependency-aware graph. This structure allows the system to model the logical relationships between components more effectively than flat storage formats, ensuring that the retrieval of skill segments remains both reliable and contextually accurate.

The core compression mechanism, MotifZip, identifies frequently recurring subgraphs and rewrites them into consolidated macro nodes. These macros are validated against strict criteria, including boundary signatures, dependency closure, and verifier reachability, to ensure that the logic remains sound after compression. At inference time, PathHydrate facilitates query-guided hydration to construct a compact, dependency-closed subgraph that covers specific task anchors while maintaining necessary verifier connectivity. The framework also includes a ReZip component, which handles library evolution by incorporating new skills and refining existing macros based on real-world execution evidence, such as downstream repair costs or verifier failures.

While the system improves retrieval accuracy, it has documented limitations. The compression guarantee is purely structural, focusing on the recovery of interfaces and dependencies rather than the semantic correctness of the verifiers themselves. Furthermore, the framework employs a conflict-aware greedy policy for macro rewriting, which does not guarantee global optimality when dealing with overlapping motifs. These constraints mean that while the system is highly effective for managing large-scale skill sets, engineers should remain aware that the structural integrity of the compressed graph does not automatically imply the logical success of every retrieved agent skill.

Interactive System Flowchart

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Cross-Examination & FAQs

A deeper dive clarifying mechanics, constraints, and baseline evaluations.

Q1. What is the primary problem SkillZip solves?

It solves the reuse-granularity mismatch and redundant or incomplete execution context issues that occur as agent skill libraries grow.

Q2. What is the main advantage of using SkillZip?

It provides a framework for scalable and reliable skill retrieval by using contract-preserving graph compression.

Q3. Does SkillZip support updating the library after initial compression?

Yes, it uses a module called ReZip to perform incremental library maintenance and update the compressed graph with new skills.

Q4. How does SkillZip perform compared to existing methods like SkillDAG?

On the SkillsBench benchmark using MiniMax-M2.7, SkillZip improved Ret@1 from 66.7 in SkillDAG to 73.6.

Q5. Does the system guarantee the correctness of the skills it compresses?

No, the compression guarantee is structural rather than semantic; it ensures the recovery of interfaces and dependencies but does not prove the correctness of verifiers.

Q6. Is the macro rewriting process in MotifZip globally optimal?

No, the conflict-aware greedy policy used for macro rewriting does not guarantee global optimality over all possible overlapping motifs.

Q7. What benchmarks were used to evaluate this research?

The paper evaluated the system on the SkillsBench benchmark.

Q8. What models or datasets are mentioned in the paper?

The paper references SkillsBench, ALFWorld, MiniMax-M2.7, gpt-5.2-codex, Qwen 3.5, Kimi K2.5, Claude Sonnet 4.5, Gemini 3 Pro, BGE-M3, SkillDAG, GoS, Vector Skills, and OpenHands.

Q9. How does PathHydrate work during inference?

It performs query-guided context hydration by constructing a compact, dependency-closed procedural subgraph that covers task anchors while maintaining verifier connectivity.