Sub-Agent Skills (subskills)

Sub-Agent Skills (subskills)

This manual explains the /subskills directory mechanism — a way to attach, discover, and manage skill documents that sub-agents can use.

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1. What is /subskills?

Each skill directory under ~/casabot/skills/ can contain a /subskills subdirectory. This subdirectory holds skill documents intended for sub-agents rather than the base agent.

~/casabot/skills/
├── agent/
│   ├── SKILL.md
│   └── subskills/          ← Skills for sub-agents in this domain
│       ├── python-dev/
│       │   └── SKILL.md
│       └── web-scraper/
│           └── SKILL.md
├── memory/
│   ├── SKILL.md
│   └── subskills/
│       └── vector-search/
│           └── SKILL.md
└── subskills/
    └── SKILL.md             ← This document

Key Concepts

• Base skills (SKILL.md at the skill root) are read by the base agent.
• Subskills (subskills/<name>/SKILL.md) are passed to sub-agents when they are created or delegated tasks.
• Subskill documents follow the same format as regular skills (YAML frontmatter + Markdown body).

2. Who can add subskills?

Agent-driven discovery

The base agent (or a sub-agent) can search for relevant tools, libraries, or techniques and write a new subskill document based on the findings.

# Create a subskill directory
mkdir -p ~/casabot/skills/agent/subskills/python-dev

# Write the subskill document
cat > ~/casabot/skills/agent/subskills/python-dev/SKILL.md << 'EOF'
---
name: Python Development
description: Guidelines and tools for Python-based sub-agents
metadata:
  casabot:
    requires:
      bins: [python3, pip]
---

# Python Development

Instructions for sub-agents working on Python projects...
EOF

User-provided subskills

Users can also place skill documents directly into the /subskills directory of any skill. This is useful for domain-specific instructions or custom tool configurations that the user wants sub-agents to follow.

# User manually adds a subskill
mkdir -p ~/casabot/skills/agent/subskills/my-custom-tool
cat > ~/casabot/skills/agent/subskills/my-custom-tool/SKILL.md << 'EOF'
---
name: My Custom Tool
description: Custom tool usage instructions for sub-agents
metadata:
  casabot:
    requires:
      bins: []
---

# My Custom Tool

(Custom instructions for sub-agents...)
EOF