Skill SDK Utilities

VerifiedSafe

The Skill SDK Utilities provide core infrastructure for the skill system, including loading skill instructions with caching, registering skills with the Anthropic Agent SDK, and intelligent auto-selection of skills based on queries. This internal toolkit helps manage skill metadata and integration points, reducing disk I/O and enabling seamless skill workflow execution.

Sby Skills Guide Bot
DevelopmentIntermediate
6/2/2026
Claude Code
#sdk#skill-management#caching#auto-selection

Recommended for

Automated summary

This SDK provides core utilities to load, cache, and register skills, with an auto‑selection feature for integration with the agent system.

Strengths

  • Intelligent caching reduces disk I/O by over 90%
  • Auto‑selection algorithm scores skills by name, description, and tool relevance
  • Seamless integration with Anthropic Agent SDK patterns

Limitations

  • Not a user‑facing skill
  • Requires understanding of the skill system to use
  • Cache invalidation is manual
When to use it

Use this SDK when building or extending a skill‑based agent system that needs automated loading, caching, and selection of skills.

When not to use it

Do not use it for direct user interactions or general‑purpose tasks that do not rely on the skill infrastructure.

Security analysis

Safe
Quality score88/100

The SKILL.md is purely documentation describing internal utility modules. It contains no executable code, destruction commands, data exfiltration, or obfuscated payloads. No allowed tools are declared, and the content is informational.

No concerns found

How this analysis is made

Examples

Load skill instructions
Load the skill instructions for the 'rule-auditor' skill.
Auto-select skills for a query
Select relevant skills for auditing code for violations, returning the top 3.
Register a skill manually
Register the skill named 'code-style-validator' with the SDK.

name: sdk description: Skill SDK utilities for loading, registering, and managing skills with caching and auto-selection

Skill SDK

This is not a user-facing skill - it's a utility SDK that provides infrastructure for the skill system.

Purpose

The SDK directory contains core utilities that power the skill system:

  1. skill-loader.mjs: Loads skill instructions and metadata with intelligent caching
  2. skill-registry.mjs: Registers skills and integrates with Anthropic Agent SDK patterns

Components

skill-loader.mjs

Provides functions for loading and caching skill instructions:

  • loadSkillInstructions(skillName, useCache): Load skill instructions from SKILL.md
  • loadSkillMetadata(skillName): Extract YAML frontmatter metadata
  • getAllSkillNames(): Get list of all available skills
  • autoSelectSkills(query, maxResults): Intelligently select skills based on query
  • clearCache(): Clear skill cache
  • getCacheStats(): Get cache statistics

Caching: Skills are cached in .claude/context/cache/skill-cache.json for performance.

skill-registry.mjs

Integrates skills with Anthropic Agent SDK patterns:

  • registerSkill(skillName): Register a skill and parse its metadata
  • getAllSkills(): Get all registered skills
  • getSkill(skillName): Retrieve a registered skill
  • registerSkillWithSDK(skillName): Create SDK-compatible skill object
  • initializeSkills(): Initialize all skills on startup
  • invokeSkill(skillName, input, context): Invoke a skill with context
  • createSDKSkill(skillConfig): Create SDK skill instance

Usage

These utilities are used internally by the skill system and skill-manager. They are not invoked directly by users.

Example (internal use):

import { loadSkillInstructions, autoSelectSkills } from '.claude/skills/sdk/skill-loader.mjs';

// Load specific skill
const instructions = await loadSkillInstructions('rule-auditor');

// Auto-select relevant skills
const skills = await autoSelectSkills('audit code for violations', 3);
// Returns: ['rule-auditor', 'code-style-validator', 'fixing-rule-violations']

Skill Format

All skills must follow this format in their SKILL.md:

---
name: skill-name
description: Brief description
allowed-tools: tool1, tool2
version: 1.0.0
---

# Skill Instructions

Detailed instructions for the skill...

Auto-Selection Algorithm

The auto-selection algorithm scores skills based on:

  1. Name match (10 points): Skill name contains query words
  2. Description match (5 points per word): Description contains query words
  3. Tool match (3 points per word): Allowed tools contain query words

Top N skills by score are returned.

Cache Management

  • Cache Location: .claude/context/cache/skill-cache.json
  • Cache Contents: Skill instructions and metadata
  • Cache Invalidation: Manual via clearCache() or by deleting cache file
  • Performance: 90%+ reduction in disk I/O for repeated skill loads

Integration Points

The SDK is used by:

  • skill-manager: Managing and validating all skills
  • Skill tool invocations: Loading skill instructions when invoked
  • Auto-selection: Finding relevant skills for user queries
  • Workflow execution: Loading skills for workflow steps

Notes

  • This is infrastructure code, not a user-facing skill
  • Do not invoke this skill directly
  • Do not create prompts or commands that reference this skill
  • This directory should contain only utility modules for the skill system

From the file to a first result

The download contains exactly the content displayed on this page. This copy may differ from the latest version in the source repository.

View the source and supporting files

This download contains SKILL.md only. Any scripts, references, templates and dependencies are not included. Get the required files from the source, preserving their directory structure, before continuing.

1. Download the file

Download SKILL.md

From the root of a test project, save the file as .skill-downloads/skill-sdk-utilities-mm78nneh/SKILL.md, or use the command below. This folder is for inspecting the skill before installation.

Command for macOS/Linux or WSL: requires a POSIX shell and curl. On Windows without WSL, use the download button and create the folder manually.

mkdir -p '.skill-downloads/skill-sdk-utilities-mm78nneh' && curl --fail --show-error --location 'https://skills-guides.com/api/skills/skill-sdk-utilities-mm78nneh/download' --output '.skill-downloads/skill-sdk-utilities-mm78nneh/SKILL.md.part' && mv '.skill-downloads/skill-sdk-utilities-mm78nneh/SKILL.md.part' '.skill-downloads/skill-sdk-utilities-mm78nneh/SKILL.md'

2. Check prerequisites

Read SKILL.md before using it. If it references scripts or external services, inspect them and prepare the required access in your test environment.

No recognized prerequisites section in this file. This does not mean it is self-contained: libraries, tools and access requirements may be mentioned elsewhere in the content or source repository.

The platforms on this page are catalog indications. The paths below follow tool documentation; they do not prove this skill has been run in those tools. No minimum tool version is confirmed for this listing.

3. Load the skill

After inspection, copy the complete folder into your project using one of the commands below, then open a new tool session. The command stops if a folder with the same name already exists: compare the files before replacing it.

Claude Code
test -f '.skill-downloads/skill-sdk-utilities-mm78nneh/SKILL.md' && test -s '.skill-downloads/skill-sdk-utilities-mm78nneh/SKILL.md' && mkdir -p '.claude/skills' && test ! -e '.claude/skills/sdk' && cp -R '.skill-downloads/skill-sdk-utilities-mm78nneh' '.claude/skills/sdk'

OpenSkills

OpenSkills must already be installed. The local install/read procedure is checked with OpenSkills 1.5.0, which requires Node.js ≥ 20.6.0. Catalog slugs are not resolved automatically.

Official OpenSkills installation
openskills install './.skill-downloads/skill-sdk-utilities-mm78nneh'

openskills read 'skill-sdk-utilities-mm78nneh'

Reading should display the installed file content and its base directory. It does not run the skill or install its dependencies.

For an agent that reads AGENTS.md, then sync the index. This command changes AGENTS.md: review the diff before using it.

openskills sync

Manual method or another tool: attach SKILL.md to a conversation, or open it in an agent that can read files. Include any required supporting resources. No universal folder is recognized by every tool.

4. Try a first task

Use a short, synthetic input: an API endpoint, a small document or an interface brief. In a new conversation, attach the file or give the agent its path, then adapt this request:

Read .skill-downloads/skill-sdk-utilities-mm78nneh/SKILL.md and apply its instructions to this example: [describe a test input]. Identify any missing files, dependencies or access. Produce the result requested by the skill without inventing data or running unreviewed scripts.

Expected result: output matching the skill instructions, or a precise list of missing prerequisites. A read confirmation alone does not validate a first use. If an external resource is unavailable, that path remains untested.

Related skills