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Agent Skills is a lightweight, markdown-based framework introduced by Anthropic for defining modular, reusable agent capabilities. Skills enable you to specialize agents without modifying code by loading skill definitions from simple SKILL.md files.

What are Agent Skills?

Agent Skills are:
  • Markdown-based: Written in simple Markdown format with YAML frontmatter
  • Modular: Each skill is a self-contained capability
  • Reusable: Skills can be shared across agents and projects
  • Context-aware: Automatically loaded based on task similarity
  • Code-free: No code changes needed to add new capabilities

Skills Directory Structure

SKILL.md Format

Basic Structure

Each SKILL.md file has two parts:
  1. YAML Frontmatter: Metadata about the skill
  2. Markdown Content: Instructions and methodology

Example: Financial Analysis Skill

Using Agent Skills

Dynamic Loading (Task-Based, Automatic)

Setting skills_dir on an agent enables dynamic, task-based skill loading automatically. Every call to agent.run(task) loads only the skills whose description is similar enough to the current task (cosine similarity over term-frequency vectors, threshold 0.3 by default) and appends them to the system prompt for that run. There is no separate “load everything” mode triggered by run() — this dynamic path is what fires whenever skills_dir is set.

Static Loading (Load All Skills)

To force-load every skill in skills_dir regardless of task similarity, call handle_skills() directly with no task argument (e.g. right after construction, before run()):

Creating Custom Skills

Step 1: Create Directory

Step 2: Write SKILL.md

Step 3: Use the Skill

Skill Examples

Data Visualization Skill

Dynamic Skills Loader

Best Practices

1. Keep Skills Focused

2. Include Examples

Always provide concrete examples in your skills:

3. Use Clear Instructions

4. Provide Guidelines

Sharing Skills

Skills can be easily shared across projects and teams:

Next Steps

Structured Outputs

Get structured responses from agents

Creating Agents

Learn how to create agents

Reference

  • Skills handling: swarms/structs/agent.py (handle_skills, a short delegate) plus swarms/agents/skills_manager.py (SkillsManager._static_prompt, SkillsManager._dynamic_prompt) for the tiered static/dynamic loading logic
  • Dynamic skills loader: swarms/structs/dynamic_skills_loader.py
  • Example skills: examples/single_agent/agent_skill_examples/
  • Anthropic Agent Skills: Agent Skills announcement