Instruction Files & Agents

The guardrail system: what each file covers, when it activates, and how agents review your code.

How Auto-Loading Works

Each instruction file has an applyTo glob pattern in its YAML frontmatter. When you edit a file matching that pattern, the instruction auto-loads into the AI's context. No manual action needed — it's the difference between drowning the AI in every rule you have and having the right guidance whisper only when it's relevant. (For full details on writing your own applyTo patterns, see Chapter 8.)

---
description: Security best practices — input validation, auth, secrets
applyTo: "**/auth/**,**/security/**,**/middleware/**"
---
# Security Rules
- Parameterized queries only — never string interpolation in SQL
- Input validation at system boundaries
- No secrets in code — use environment variables or secret managers
...

Universal Files (All Presets)

These four files ship with every preset — they form the universal baseline:

Domain Instruction Files (Per Preset)

Each preset installs 17 domain-specific instruction files. They auto-load based on what you're editing:

As of v2.18, every instruction file includes Temper Guards (shortcut prevention tables) and Warning Signs (observable anti-patterns). These help agents avoid common quality erosion and help reviewers detect violations.

Agents

19 agents organized in three categories. Agents are read-only — they audit code but can't edit files.

Stack-Specific Agents (6)

Vary by preset — examples for dotnet:

Cross-Stack Agents (8)

Shared across all presets — same expertise regardless of language:

Pipeline Agents (6)

Drive the 7-step pipeline with handoff buttons between stages:

Skills

12 slash commands per app preset. Skills do work — they can read, write, and run terminal commands:

Lifecycle Hooks

Hooks run automatically during agent sessions — no manual activation:

📄 Full reference: capabilities.md, COPILOT-VSCODE-GUIDE.md