Chapter 6: Skill System

Skills are the cuttlefish's specialties. Hermes Agent comes with 100+ built-in skills covering programming, writing, DevOps, creative work, and more. You can also teach it new skills — it will remember and use them next time.

What is a Skill?

A Skill is a lazily-loaded knowledge document. It's not a plugin, not a code package — it's a set of instructions telling the Agent how to behave in specific scenarios.

Key characteristics:

• Lazy loading: Only read when relevant, doesn't waste tokens
• Progressive expansion: Shows summary first, loads full content when needed
• Auto-evolution: After completing complex tasks, the Agent can automatically save them as Skills
• Open standard: Compatible with agentskills.io standard

All Skills are stored in the ~/.hermes/skills/ directory.

Three Ways to Use Skills

1. Slash Commands

Each installed Skill automatically becomes a slash command:

/plan Implement a user registration feature
/review Check recent code changes

2. Natural Language Trigger

Just talk normally — the Agent automatically matches relevant Skills:

You: Help me write a Python script to process CSV files
Hermes: [Auto-loads python-related skill...] Sure, let me help...

3. Manual Loading

/skill-load skill-name

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Built-in Skill Categories

Hermes Agent includes 100+ built-in skills, organized by category:

Category	Representative Skills	Description
Software Development	plan, test-driven-development, systematic-debugging	Planning, TDD, debugging
GitHub	github-pr-workflow, github-code-review, github-issues	PR, review, issue management
Creative	ascii-art, excalidraw, p5js, songwriting	ASCII art, diagrams, music
Media	youtube-content, gif-search, heartmula	YouTube, GIF, music generation
Research	arxiv, llm-wiki, web-content-fetch	Papers, knowledge base, web scraping
Productivity	notion, google-workspace, powerpoint, nano-pdf	Notion, Google, PPT, PDF
DevOps	webhook-subscriptions	Webhook management
Data Science	jupyter-live-kernel	Jupyter interactive analysis
MLOps	gguf, llama-cpp, vllm, unsloth, trl-fine-tuning	Model training, inference, quantization
Apple	apple-notes, apple-reminders, imessage	macOS/iOS automation
Email	himalaya	Email management
Gaming	minecraft-modpack-server, pokemon-player	Minecraft, Pokemon

Platform Limitations

Some Skills have platform restrictions. For example, the apple-* series is only available on macOS. If the current platform is incompatible, the Skill is automatically hidden.

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SKILL.md Format

Each Skill is a directory with a SKILL.md file at its core:

~/.hermes/skills/my-skill/
├── SKILL.md          # Skill definition (required)
├── references/       # Reference documents
├── templates/        # Template files
├── scripts/          # Scripts
└── assets/           # Asset files

Basic structure of SKILL.md:

---
name: my-skill
description: One-sentence description of what this skill does
platforms: [macos, linux]        # Optional: restrict platform
fallback_for_toolsets: [web]     # Optional: fallback condition
env:                             # Optional: required environment variables
  - MY_API_KEY
settings:                        # Optional: configuration items
  - key: output_dir
    description: Output directory
    default: ~/output
---

# Skill Title

Detailed instructions...

Key Field Descriptions

Field	Required	Description
name	✅	Skill identifier, lowercase + hyphens
description	✅	One-sentence description
platforms	❌	Restrict to specific OS
fallback_for_toolsets	❌	Only show when specified toolset is unavailable
env	❌	Required environment variables (keys, etc.)
settings	❌	Non-secret configuration items, stored in config.yaml

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Managing Skills

View Installed Skills

/skills

Or ask in conversation:

You: What skills do you have?
Hermes: [Lists all available skills...]

Install Skills

From Skills Hub:

hermes skills install <skill-name>

Agent-Created Skills

When you complete a complex task, the Agent can automatically save it as a Skill:

You: Save this workflow as a skill
Hermes: [Automatically calls skill_manage to create SKILL.md]

The Agent automatically creates Skills in these scenarios:

• Completed a complex task with 5+ tool invocations
• Resolved a tricky bug
• User corrected the Agent's approach

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External Skill Directories

If you have a shared skill directory used by multiple AI tools (e.g., ~/.agents/skills/), you can have Hermes scan it too:

# ~/.hermes/config.yaml
skills:
  external_dirs:
    - ~/.agents/skills
    - ~/my-custom-skills

Paths support ~ expansion and ${VAR} environment variable substitution.

TIP

If both local and external directories have a Skill with the same name, the local version takes priority (shadow mechanism).

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Skill Configuration (Settings)

Skills can declare non-secret configuration items, stored under skills.config in config.yaml:

# ~/.hermes/config.yaml
skills:
  config:
    my-skill:
      output_dir: ~/output
      language: zh-CN

Configuration values are automatically injected into the Agent's context when the Skill is loaded.

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Conditional Activation (Fallback Mechanism)

A Skill can be set as a fallback for a specific toolset:

# Example: built-in duckduckgo-search skill
fallback_for_toolsets: [web]

This means:

• If you set FIRECRAWL_API_KEY, the web toolset is available → use web_search, DuckDuckGo skill is hidden
• If you don't set an API Key → DuckDuckGo skill automatically appears as an alternative

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Hands-On: Installing a Custom Skill

Let's install defuddle (web content extraction) as an example:

# Method 1: Via Skills Hub
hermes skills install defuddle

# Method 2: Manual creation
mkdir -p ~/.hermes/skills/defuddle
# Write SKILL.md...

After installation, you can use it:

You: Help me extract the content from this webpage https://example.com/article
Hermes: [Auto-loads defuddle skill] [Runs defuddle parse...] Done!

Further Reading

• Official docs: Skills System
• Skills development guide: Working with Skills
• Skill standard: agentskills.io — Open skill standard and specification
• Skill marketplace: skills.sh · skillhub.cn — Browse and share community skills

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