Create Agent Skill

Purpose

Standardize the creation of new Agent Skills to ensure they are consistent, discoverable, and follow best practices.

When to Create a Skill

• Complex Tooling: When an agent needs to run a sequence of scripts or commands that are too long for the main agent prompt.
• Shared Capabilities: When multiple agents need the same capability (e.g., "Run UAT" used by UAT Tester and Quality Engineer).
• Strict Procedures: When a process requires exact adherence to a checklist or script (e.g., Release process).

Hard Rules

Must

• Create the skill in .github/skills/<skill-name>/.
• Use kebab-case for the skill name.
• Ensure the skill name matches the parent directory name exactly.
• Ensure name is 1–64 characters, lowercase letters/numbers/hyphens only.
• Ensure name does not start or end with - and does not contain consecutive hyphens (--).
• Include a SKILL.md with valid YAML frontmatter.
• Include a description in the frontmatter (max 1024 chars).
• Create scripts/ and templates/ subdirectories only if needed.
• Use the provided template for SKILL.md.
• Update docs/agents.md to register the new skill in the "Available Skills" table.

Must Not

• Create skills in the root .github/ directory.
• Use spaces or special characters in the skill name.
• Leave the description empty.

Best Practices

• Self-Contained: A skill should include all necessary scripts and templates within its folder.
• Progressive Disclosure: Copilot only loads the skill body when the description matches the user's intent. Keep descriptions specific.
• Verification: Test skills by asking Copilot "How do I ?" and verifying it loads the skill.
• Approval Minimization: Design skills to reduce the number of Maintainer approval prompts (terminal command approvals) so agents can execute workflows with minimal interruptions.
  • Prefer a small number of stable wrapper commands over many one-off commands.
  • Batch related operations into a single command where practical (and safe).
  • Prefer tool-based reads (editor tools) over shell commands for read-only actions when available.
  • Reuse existing repo scripts (e.g., scripts/uat-*.sh) instead of duplicating multi-step command sequences.
  • If a workflow is inherently risky (force-push, merge, deleting branches), keep it explicit and gated, but still consolidate the surrounding steps.

Actions

1. Gather Information

Ask the user for:

• Skill Name: Short, descriptive, kebab-case (e.g., run-uat, deploy-docs).
• Description: One sentence explaining what the skill does and when Copilot should load it.
• Purpose: Detailed explanation of the skill's goal.
• Approval Plan: Which commands will run, and how to structure them to minimize approvals (prefer a small number of stable wrappers).

2. Create Directory Structure

Run the following command to create the skill directory:

mkdir -p .github/skills/<skill-name>

If your skill includes scripts or templates, add those directories explicitly:

mkdir -p .github/skills/<skill-name>/scripts
mkdir -p .github/skills/<skill-name>/templates

3. Create SKILL.md

Read the template from .github/skills/create-agent-skill/templates/SKILL.md and create the new SKILL.md file:

cp .github/skills/create-agent-skill/templates/SKILL.md .github/skills/<skill-name>/SKILL.md

Then, edit the file to replace the placeholders ({{skill-name}}, {{description}}, {{purpose}}) with the gathered information.

4. Update Documentation

Add the new skill to the "Available Skills" table in docs/agents.md.

5. Verify

Check that the file structure looks like this:

.github/skills/<skill-name>/
├── SKILL.md
├── scripts/
└── templates/

References

Specifications & Documentation

Resource	What You'll Find
VS Code Agent Skills	Official documentation: SKILL.md format, YAML frontmatter fields, progressive disclosure architecture, and complete examples.
Agent Skills Standard	The open specification: formal schema, interoperability with other AI tools (Claude, Cursor, OpenAI Codex), and integration guides.
Agent Skills Specification	Detailed field definitions, validation rules, and edge cases for SKILL.md files.

Example Repositories

Repository	What You'll Find
anthropics/skills	Reference skills from Anthropic: well-structured examples covering common patterns like debugging, documentation, and code review.
github/awesome-copilot	Community collection of skills, custom agents, instructions, and prompts. Good source of real-world patterns.

Practical Guides

Resource	What You'll Find
Teaching AI Your Repository Patterns	Hands-on tutorial: real-world example (Selenium testing), key components that work (Clear Rules, Golden Examples, Templates), and verification tips.
GitHub Changelog Announcement	Feature overview, availability across VS Code/CLI/coding agent, and links to community resources.