github-copilot-customizer

name

github-copilot-customizer

description

Comprehensive guide for customizing GitHub Copilot through workspace instructions, custom agents, prompts, and conditional instruction files. Use when: creating copilot-instructions.md, setting up custom agents, building reusable prompts, configuring file-specific instructions, organizing .github/copilot folder structure, or any GitHub Copilot customization task. Triggers on: "customize copilot", "copilot instructions", "create agent", "prompt file", "instruction file", ".github setup". Use when this capability is needed.

GitHub Copilot Customizer

Tailor GitHub Copilot through six customization methods. This skill provides navigation to detailed guides.

When to Use This Skill

Use this when you need to:

• Create or modify .github/copilot-instructions.md
• Build custom agents (.agent.md), prompts (.prompt.md), or instruction files (.instructions.md)
• Configure MCP servers for external tool access
• Choose the right customization method for your needs
• Set up the .github/ folder structure

Quick Decision Guide

Need to...
├─ Apply rule to ALL code? → copilot-instructions.md
├─ Apply rule to specific file types? → .instructions.md  
├─ Create reusable workflow? → .agent.md
├─ Template a common task? → .prompt.md
├─ Package domain knowledge? → SKILL.md
└─ Add external tools? → mcp.json (+ MCP server)

Six Customization Methods

Method	Extension	When to Use	Details
Workspace Instructions	.github/copilot-instructions.md	Project-wide baseline rules	Guide
Agents	.agent.md	Task-specific workflows with tools	Guide · Examples
Prompts	.prompt.md	Reusable task templates	Guide
Instructions	.instructions.md	File-type conditional rules	Guide · Examples
Skills	SKILL.md	Domain knowledge packages	Guide
MCP Servers	.vscode/mcp.json	External tool integration	Setup Guide

Critical: Use exact file extensions or detection fails.

Prerequisites

• VS Code with GitHub Copilot extension
• Enable instruction files in settings:

  {
    "github.copilot.chat.codeGeneration.useInstructionFiles": true,
    "chat.agent.enabled": true
  }
  

Directory Structure

.github/
├── copilot-instructions.md
├── agents/
│   ├── planner.agent.md
│   └── reviewer.agent.md
├── prompts/
│   └── generate-component.prompt.md
├── instructions/
│   ├── python-coding.instructions.md
│   └── typescript-coding.instructions.md
└── skills/
    └── <skill-name>/SKILL.md

.vscode/
└── mcp.json  # VS Code only

Quick Start

1. Create workspace baseline: Copy template to .github/copilot-instructions.md
2. Add custom agent: Use template → save as .github/agents/<name>.agent.md
3. Create prompt: Use template → save as .github/prompts/<name>.prompt.md
4. Add instruction file: Use template → save as .github/instructions/<name>.instructions.md
5. Configure MCP: See MCP Setup Guide

Details and Examples

Complete Guides

• Detailed Guides - In-depth information on all methods
  • Agent frontmatter properties (9 properties with handoffs)
  • Available models and tools
  • Prompt file properties
  • Glob patterns for instruction files
  • Skills vs Instructions comparison
  • Combining methods patterns
• Agent Examples - Common patterns (Planner, Implementer, Reviewer)
• Instruction Examples - Language/framework specific
• Chat Tools Reference - Complete list of 47+ tools and tool sets
• VS Code Settings - Essential Copilot settings organized by category
• MCP Setup - Complete MCP server configuration guide with stdio/HTTP types

Templates

• Agent Template - Generic .agent.md starter
• Prompt Template - Generic .prompt.md starter
• Instructions Template - Generic .instructions.md starter
• Copilot Instructions Template - Workspace baseline starter

Troubleshooting

Issue	Solution
Instructions not applied	Enable useInstructionFiles in settings
Agent not visible	Check .agent.md extension, verify YAML syntax
Prompt not appearing	Ensure .prompt.md extension
Instruction file ignored	Verify .instructions.md extension, test glob pattern
MCP server not starting	Check command/args, view MCP output logs
Tool not available	Verify tool in agent's tools list or MCP server running

External Resources

• Custom Agents Documentation
• Agent Skills Documentation
• Custom Instructions
• Prompt Files
• Chat Tools Reference
• MCP Servers
• Agent Skills Standard

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Source: DJ2695/custom-copilot — distributed by TomeVault.