agent-customization
**WORKFLOW SKILL** — Create, update, review, fix, or debug VS Code agent customization files (.instructions.md, .prompt.md, .agent.md, SKILL.md, copilot-instructions.md, AGENTS.md). USE FOR: saving coding preferences; troubleshooting why instructions/skills/agents are ignored or not invoked; configuring applyTo patterns; defining tool restrictions; creating custom agent modes or specialized workflows; packaging domain knowledge; fixing YAML frontmatter syntax. DO NOT USE FOR: general coding questions (use default agent); runtime debugging or error diagnosis; MCP server configuration (use MCP docs directly); VS Code extension development. INVOKES: file system tools (read/write customization files), ask-questions tool (interview user for requirements), subagents for codebase exploration. FOR SINGLE OPERATIONS: For quick YAML frontmatter fixes or creating a single file from a known pattern, edit the file directly — no skill needed.
Install
Install this Claude and Codex skill with the command below. The command stays visible even when copy support is unavailable.
git clone https://github.com/microsoft/vscode /tmp/vscode && ln -s /tmp/vscode/extensions/copilot/assets/prompts/skills/agent-customization ~/.claude/skills/agent-customizationFrom README
Agent Customization Decision Flow | Primitive | When to Use | |-----------|-------------| | agent instructions | Always-on, applies everywhere in the project | | File Instructions | Explicit via applyTo patterns, or on-demand via description | | MCP | Integrates external systems, APIs, or data | | Hooks | Deterministic shell commands at agent lifecycle points (block tools, auto-format, inject context) | | Custom Agents | Subagents for context isolation, or multi-stage workflows with tool restrictions | | Prompts | Single focused task with parameterized inputs | | Skills | On-demand workflow with bundled assets (scripts/templates) | Quick Reference Consult the reference docs for templates, domain examples, advanced frontmatter options, asset organization, anti-patterns, and creation checklists. If the references are not enough, load the official documentation links for each primitive.