Agent Skills: copilot-cli-agent-customization

**WORKFLOW SKILL** — Create, update, review, fix, or debug Copilot CLI customization files (`copilot-instructions.md`, `AGENTS.md`, `*.instructions.md`, `*.agent.md`, `SKILL.md`, hook JSON, `plugin.json`, and plugin command files). USE FOR: authoring terminal-first customization workflows; troubleshooting why CLI instructions, skills, agents, hooks, or plugins are ignored; configuring `applyTo` and `excludeAgent`; defining CLI tool restrictions; creating custom agents or command packs; packaging reusable CLI customizations. DO NOT USE FOR: general coding questions; non-customization runtime debugging; Copilot in VS Code customization (use `copilot-vscode-agent-customization` instead); MCP server configuration; VS Code prompt files or extension development. INVOKES: file system tools, ask-questions tool, subagents for codebase exploration. FOR SINGLE OPERATIONS: For quick YAML or JSON fixes, or for creating one known file from a clear pattern, edit directly instead of loading the full skill.