Copilot Asset Design Skill

code

✨ SKILL ACTIVATED: copilot-asset-design
   Purpose: Design and validate GitHub Copilot customization assets
   Functionality: Asset architecture patterns, quality criteria, compliance validation, integration strategies
   Output: Asset design specifications and validation checklists
   Scope: Portable across VS Code, CLI, Claude, Cursor, and compatible agents

Purpose

Comprehensive methodology for designing, structuring, and validating GitHub Copilot customization assets. Covers agents, skills, instructions, prompts, and their integration patterns following VS Code and agentskills.io standards.

When to Use This Skill

•Designing new Copilot customization assets
•Validating existing agent/skill/instruction files
•Planning customization architecture
•Auditing asset quality and compliance
•Creating integration strategies between assets
•Establishing customization governance

Asset Types Overview

Asset	Location	Standard	Portability	Purpose
Skills	`.github/skills/*/SKILL.md`	agentskills.io	Cross-platform	Portable capabilities
Agents	`.github/agents/*.agent.md`	VS Code v1.106+	VS Code only	Role-based specialists
Instructions	`.github/instructions/*.instructions.md`	VS Code	VS Code/GitHub	Coding standards
Prompts	`.github/prompts/*.prompt.md`	VS Code	VS Code	Task templates

Decision Framework

When to Create Each Asset Type

Create a Skill when: ✅ Capability should work across multiple AI platforms
✅ Need to include scripts, examples, or resources
✅ Want automatic activation based on user context
✅ Building domain expertise (testing, debugging, deployment)
✅ Knowledge is portable and platform-agnostic

Create an Agent when: ✅ Need VS Code-specific tool access (terminal, files, editor)
✅ Require handoff workflows between multiple agents
✅ Building role-based specialist with strict permissions
✅ Need to control tool approval and security
✅ Creating interactive multi-step workflows

Create Instructions when: ✅ Defining project-wide coding standards
✅ Establishing architectural patterns
✅ Setting code review guidelines
✅ Creating reusable workflows for multiple agents
✅ Specifying file-type-specific rules (glob patterns)

Create a Prompt when: ✅ Building parameterized task templates
✅ Creating reusable slash commands
✅ Defining structured output formats
✅ Batch operations with variables
✅ Quick-access common workflows

Skill Design

Structure

code

.github/skills/
└── skill-name/              # lowercase-with-hyphens
    ├── SKILL.md             # Required
    ├── examples/            # Optional
    │   └── example-01.ts
    ├── scripts/             # Optional
    │   └── helper.sh
    └── resources/           # Optional
        └── templates/

SKILL.md Format

yaml

---
name: skill-name               # Max 64 chars, lowercase-hyphens
description: |                 # Max 1024 chars, specific use cases
  What this skill does and when to use it.
  Include key capabilities and scenarios.
---

# Skill Purpose
[Clear overview of what this accomplishes]

## When to Use This Skill
- [Specific scenario 1]
- [Specific scenario 2]

## Instructions
### Step 1: [Action]
[Detailed procedure]

## Examples
[Code/command examples]

## Resources
- [Link to included files](./scripts/helper.sh)

## Success Criteria
- [ ] [Expected outcome]

Quality Checklist

• Name is lowercase with hyphens (≤64 chars)
• Description is specific and clear (≤1024 chars)
• Description explains WHEN to use
• Instructions are step-by-step
• Examples demonstrate real usage
• Resources use relative paths
• Skill provides domain expertise, not just instructions

Agent Design

Structure

markdown

---
description: 'Clear role description'
model: Auto (copilot)                    # Or specific model
tools: ['search', 'edit', 'terminal']    # Approved tools only
handoffs:                                 # Optional
  - label: 'Next Action'
    agent: 'TargetAgent'
    prompt: 'Context for next agent'
    send: false                           # Manual vs auto handoff
---

## Agent Name (vX.X)

### Role
[Clear description of agent's purpose and capabilities]

### Core Objectives
1. [Objective 1]
2. [Objective 2]

### Workflow
1. [Step 1]
2. [Step 2]

### Reused Instructions
*[Reference to shared instructions]*

Tool Selection

Read-Only Tools (planning, analysis):

•search, search/codebase - Code search
•changes - Git diff viewing
•problems - Diagnostics viewing

Write Tools (implementation):

•edit - File modification
•new - File creation
•terminal - Command execution

Specialized Tools:

•usages - Symbol reference finding
•fetch - Web content retrieval
•githubRepo - GitHub API access

Security Principle: Grant minimum necessary tools for agent role.

Handoff Patterns

Manual Handoff (user approval):

yaml

handoffs:
  - label: 'Execute Plan'
    agent: 'ChangeExecutor'
    prompt: 'Implement the plan above.'
    send: false    # User must click button

Automatic Handoff (workflow continuation):

yaml

handoffs:
  - label: 'Validate Changes'
    agent: 'VerificationAgent'
    prompt: 'Verify changes meet requirements.'
    send: true     # Auto-submit

Quality Gate Placement:

•Before destructive operations (editing, deleting)
•After analysis/planning phases
•Before external tool execution
•When user decision needed

Quality Checklist

• Description is clear and concise
• Tools list matches agent responsibilities
• Handoffs have appropriate send: true/false
• Instructions referenced for reusable patterns
• No hardcoded paths or secrets
• Schema compliance (YAML + Markdown structure)

Instruction Design

Structure

markdown

# Instruction Title

## Purpose
[What this instruction set accomplishes]

## When to Apply
[Scenarios where these instructions are relevant]

## Guidelines

### Section 1
[Specific rules and patterns]

### Section 2
[More rules and examples]

## Examples
[Code examples demonstrating patterns]

## Anti-Patterns
[What NOT to do]

---
**ApplyTo**: `**/*.{ts,js}`  # Glob pattern for file types

Metadata

yaml

# At top of file or in frontmatter
applyTo: '**/*.ts'        # Required for auto-application
description: 'Purpose'     # Optional but recommended

Quality Checklist

• applyTo glob pattern specified
• Clear guidelines with examples
• Anti-patterns documented
• Reusable across multiple agents
• Not duplicating agent-specific logic

Prompt Design

Structure

markdown

---
agent: AgentName                # Optional: specific agent to use
description: 'What this prompt does'
instructions:                   # Optional: instructions to apply
  - InstructionFile.instructions.md
mode: ask                       # ask/agent/generate
---

# Prompt Title

## Purpose
[What this prompt accomplishes]

## Parameters
- **PARAM_NAME** (required): [Description]
- **OPTIONAL_PARAM** (optional): [Description]

## Usage Example

/PromptName PARAM_NAME: "value", OPTIONAL_PARAM: "value"

code


## Workflow
1. [Step 1]
2. [Step 2]

## Output
[What the prompt generates/returns]

Variables

Built-in Variables:

•#file - Current file path
•#selection - Current selection
•#editor - Editor content

Custom Variables:

markdown

## Parameters
- **TARGET_PATH** (required): "{Absolute path}"
- **INCLUDE_TESTS** (optional): "true/false"

Quality Checklist

• Description is clear
• Parameters documented with types
• Usage examples provided
• Expected output described
• Agent/mode specified if needed
• Instructions referenced appropriately

Orchestration Decision Framework

When to Create Each System Type

Approach	When to Use	Agent Count	Coordination
Standalone Agent	Single-purpose task, no coordination needed	1	None
Handoff Chain	Linear workflow, sequential steps (plan → implement → review)	2-4	Sequential handoffs
Orchestra System	Structured multi-phase projects, TDD required, quality gates needed	3-5	Conductor-managed
Atlas System	Large codebases (50+ files), parallel work opportunities, context conservation critical	5-10	Conductor + parallel

Pattern Selection Matrix

Criteria	Standalone	Handoff Chain	Lightweight Conductor	Orchestra	Atlas
Agent count	1	2	3+	4-5	6-10
Files affected	<10	<20	<50	<50	50+
TDD enforcement	Manual	Per-agent	Simplified	Per-phase	Per-phase + parallel
Quality gates	None	Optional	2-3	3+ mandatory	3+ mandatory
Parallel execution	No	No	No	No	Yes
Plan file tracking	No	No	Yes (simplified)	Yes	Yes
Context conservation	N/A	Prompt transfer	Plan file	Plan file	Plan file + scoped
Complexity	Low	Low-Medium	Medium	Medium-High	High

Decision Flow

code

Q1: Does the task need multiple specialized roles?
  → NO: Create a standalone agent
  → YES: Go to Q2

Q2: Is the workflow strictly sequential (A → B → C) with only 2 agents?
  → YES: Create a handoff chain
  → NO: Go to Q2b

Q2b (Bootstrap context): Are 3+ agents being generated?
  → YES: Auto-include lightweight conductor (minimum orchestration tier)
  → NO: Standalone agent or handoff chain

Q3: Does the project need TDD enforcement, quality gates, or plan tracking?
  → YES: Go to Q4
  → NO: Lightweight conductor is sufficient

Q4: Does the codebase have 50+ files or need parallel execution?
  → YES: Create an Atlas system (spec inline; /NewOrchestratedSystem for advanced customization only)
  → NO: Create an Orchestra system (spec inline; /NewOrchestratedSystem for advanced customization only)

Orchestrated System Integration

code

Orchestrated System
├── Conductor (.agent.md) — manages phases, quality gates, plan files
├── Subagents (.agent.md) — specialized roles (planner, implementer, reviewer)
├── Plan Files (plans/) — PLAN.md, phase completion records
└── VS Code Config (.vscode/settings.json) — enables subagent invocation

Reference: multi-agent-orchestration skill for complete methodology

Integration Patterns

Skills + Agents

Pattern: Skill provides methodology, Agent uses VS Code tools to execute

yaml

# In agent file
---
description: 'Testing specialist that uses test-automation skill'
tools: ['terminal', 'edit', 'new']
---

Use the `test-automation` skill for test structure patterns,
then execute tests using terminal tools.

Skills + Instructions

Pattern: Skill references project-specific instructions

markdown

# In SKILL.md
## Project Integration
Follow coding standards defined in [standards.instructions.md](../instructions/CodingStandards.instructions.md)

Agent + Instructions

Pattern: Agent reuses shared instruction workflows

markdown

# In agent file
### Reused Instructions
*Framework: [CopilotFramework.instructions.md](../instructions/CopilotFramework.instructions.md)*

Prompt + Agent

Pattern: Prompt targets specific agent for execution

yaml

# In prompt file
---
agent: APIExpert
description: 'Generate API endpoint using APIExpert agent'
---

Workflow Chain

Pattern: Multiple agents with handoffs

code

PlannerAgent (analysis)
  ↓ handoff: send=false (user approval)
ExecutorAgent (implementation)
  ↓ handoff: send=true (automatic)
ValidatorAgent (verification)

Validation Methodology

Schema Validation

Agent Files:

yaml

Required:
  - description field (YAML frontmatter)
  - Markdown body with instructions

Optional but recommended:
  - tools array
  - handoffs array
  - model specification

Skill Files:

yaml

Required:
  - name (≤64 chars, lowercase-hyphens)
  - description (≤1024 chars)
  - Markdown body with instructions

Directory Structure:
  - SKILL.md is required
  - examples/, scripts/, resources/ are optional

Instruction Files:

yaml

Recommended:
  - applyTo glob pattern
  - Clear section structure
  - Examples included

Not required but improves usability

Quality Dimensions

Completeness:

• All required fields present
• Examples provided
• Documentation clear

Correctness:

• YAML valid
• Glob patterns work
• Tool names are valid

Consistency:

• Naming conventions followed
• Structure matches patterns
• Cross-references valid

Maintainability:

• No duplication
• Clear organization
• Version noted

Cross-Reference Validation

Check for:

•Broken file references
•Invalid agent names in handoffs
•Missing instruction files
•Circular dependencies in handoffs

Tools:

bash

# Find broken Markdown links
grep -r '\[.*\](.*\.md)' .github/

# Validate handoff targets
grep -A5 'handoffs:' .github/agents/*.agent.md

Common Patterns

Testing Assets

code

Skill: test-automation (patterns, methodology)
Agent: TestOrchestrator (executes tests, creates files)
Instructions: TestingStandards (project-specific rules)
Prompt: GenerateTests (quick test generation)

API Development

code

Skill: api-development (REST patterns)
Agent: APIExpert (endpoint creation)
Instructions: APIPatterns (project conventions)
Prompt: NewEndpoint (scaffold endpoint)

Security Review

code

Skill: security-audit (review methodology)
Agent: SecurityReviewer (analysis + reporting)
Instructions: SecurityPatterns (requirements)
Prompt: SecurityScan (trigger review)

Best Practices

Design Principles

•Single Responsibility: One asset = one focused purpose
•DRY: Share common patterns via instructions
•Progressive Disclosure: Skills load resources on-demand
•Least Privilege: Grant minimum necessary tools
•Clear Handoffs: Explicit workflow transitions

Naming Conventions

code

Skills:        lowercase-with-hyphens (api-testing)
Agents:        PascalCase (APIExpert, TestOrchestrator)
Instructions:  PascalCase (CodingStandards, APIPatterns)
Prompts:       PascalCase (GenerateEndpoint, NewAgent)

Documentation Standards

•Start with purpose and when-to-use
•Provide concrete examples
•Document integration points
•Include success criteria
•Note any prerequisites

Security Considerations

•Validate tool permissions
•Review terminal command approvals
•Audit external API access
•Check for hardcoded secrets
•Verify input sanitization

Success Criteria

Well-designed Copilot customization provides:

•✅ Clear asset roles and boundaries
•✅ Appropriate tool permissions
•✅ Smooth integration between assets
•✅ Cross-platform portability (where applicable)
•✅ Comprehensive validation coverage
•✅ Maintainable architecture

Skill Type: Architecture and Design
Complexity: High
Typical Duration: Varies by scope
Prerequisites: Understanding of VS Code Copilot customization, agentskills.io standard

Cross-Platform: Design methodology works across all platforms; validation requires VS Code for agent testing.