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Overview

Skills are folders of instructions, scripts, and resources that agents load dynamically to improve performance on specialized tasks. The agent first sees only a skill’s name and short description. When the task matches, it loads the full SKILL.md and can execute commands the skill references.

How Skills Work

  1. Starts light - Agent discovers skills by name/description only
  2. Loads on demand - Pulls full instructions from SKILL.md when relevant
  3. Executes safely - Runs skill-driven commands in isolated environment

Skill Structure

A skill is a directory with this layout:

SKILL.md Format

The SKILL.md file contains YAML frontmatter and markdown content:

Notes

  • Slack prefers GIFs under 1MB
  • 480px width is optimal
  • 10 fps is usually sufficient

Skill Attributes

Using Skills with Agents

Pass skill paths to the agent constructor (src/agentor/core/agent.py:182):

Multiple Skills

Provide multiple skills for different capabilities:

Skill Injection

Skills are injected into the agent’s system prompt as XML (src/agentor/core/agent.py:227):

XML Format

Skills are serialized to XML (src/agentor/skills.py:34):
The agent sees this in its system prompt and can load the full skill content when needed.

Example: GIF Creator Skill

From the README example:
The agent:
  1. Sees the skill name and description in its prompt
  2. Recognizes the task matches the skill
  3. Loads full instructions from .skills/slack-gif-creator/SKILL.md
  4. Uses ShellTool to execute ffmpeg commands from the skill
  5. Creates an optimized GIF for Slack

Creating Custom Skills

1. Create Directory Structure

2. Write SKILL.md

Tips

  • Important tip 1
  • Important tip 2

4. Add Resources (Optional)

Place templates or reference files:

Skill Best Practices

Clear Descriptions

Write concise descriptions that help the agent decide when to use the skill:

Step-by-Step Instructions

Provide clear, ordered steps:

Include Examples

Show concrete examples the agent can follow:

Tool Integration

Skills work best with tools that can execute their instructions:

Shell Tool

For command execution:

File Tools

For file manipulation:

JSON Serialization

Export skills to JSON (src/agentor/skills.py:43):
Output:

Error Handling

The loader validates skill structure (src/agentor/skills.py:14):

Skill Discovery

Agents see skill summaries in their system prompt:
The agent can then request the full content when needed.

Next Steps

Tools

Learn about tools that execute skill instructions

Agents

Understand agent architecture and lifecycle

Examples

See example skills and implementations
Last modified on May 5, 2026