GitHub Copilot

GitHub Copilot

Copilot integrates natively with GitHub's directory conventions. It supports multiple instruction mechanisms, including the cross-tool AGENTS.md standard.

File Overview

Category	File	Scope
Instructions	.github/copilot-instructions.md	Repository-wide instructions
Instructions	.github/instructions/*.instructions.md	Path-specific instructions
Instructions	AGENTS.md	Cross-tool instructions (supported by coding agent)
Prompts	.github/prompts/*.prompt.md	Reusable prompt templates (public preview)
Skills	.github/skills/<name>/SKILL.md	Repository-scoped agent skills
Agents	.github/agents/*.agent.md	Custom agent definitions
CLI	~/.copilot/copilot-instructions.md	Local CLI instructions

Repository-Wide Instructions

.github/copilot-instructions.md is the primary instruction file. It applies to all Copilot interactions in the repository.

Path-Specific Instructions

.github/instructions/*.instructions.md files provide scoped rules using YAML frontmatter:

Instruction Frontmatter

---
applyTo: "internal/**/*.go"         # Required. File pattern this instruction applies to
excludeAgent: "code-review"          # Optional. Exclude specific agents
---

Key fields:

• applyTo — determines which files trigger this instruction
• excludeAgent — prevents specific agents (e.g., code-review, coding-agent) from seeing this instruction

AGENTS.md Support

The Copilot coding agent reads AGENTS.md files, including nested ones in subdirectories. This provides cross-tool compatibility with Codex and other tools that use the AGENTS.md convention.

Prompt Files

.github/prompts/*.prompt.md are reusable prompt templates. They serve as the closest equivalent to slash commands in Copilot — explicit-invocation templates for common tasks.

Prompt files are primarily Markdown body content with minimal frontmatter.

Skills

Copilot supports agent skills via SKILL.md files. It also reads skill directories from other tool locations for compatibility.

Skill Frontmatter

---
name: image-convert                              # Required. Skill identifier
description: Converts SVG images to PNG format   # Required. Trigger description
license: MIT                                     # Optional. License declaration
allowed-tools: Bash(convert-svg-to-png.sh)       # Optional. Permitted tools
---

Skill Discovery Paths

Copilot looks for skills in multiple locations:

1. .github/skills/<name>/SKILL.md
2. .claude/skills/<name>/SKILL.md
3. .agents/skills/<name>/SKILL.md

CLI-Specific Configuration

For Copilot CLI usage:

• ~/.copilot/copilot-instructions.md — local instructions
• COPILOT_CUSTOM_INSTRUCTIONS_DIRS — environment variable pointing to additional instruction directories