Lab 086: Customize Copilot: Instructions, Prompt Files, Custom Agents, and Skills¶
Free-first design
Complete the guided exercise with Copilot Free or the included simulation. Paid features are optional and explicitly labeled.
AI Credit impact
Low for guided work; medium/high for agentic or repeated runs. Prefer automatic model selection, plan before acting, keep context focused, and avoid unnecessary parallel sessions.
What You'll Learn¶
- Choose the correct customization artifact
- Scope path-specific instructions with applyTo
- Design reusable prompt files, agents, and SKILL.md packages
- Avoid duplicated or contradictory guidance
GH-300 alignment¶
Use Copilot features (25–30%). This mapping follows the GH-300 curriculum snapshot dated 2026-08-07. The official outline may retain older product wording such as “Copilot Edits”; this lab teaches the current product experience and calls out that difference.
Concept Map¶
flowchart TD
R[Always-on repository rule] --> I[copilot-instructions.md]
P[Path-specific rule] --> PI[*.instructions.md + applyTo]
W[Reusable user workflow] --> PF[Prompt file]
A[Specialist persona] --> AG[*.agent.md]
K[Portable capability] --> SK[SKILL.md]
Hands-on Exercise¶
Step 1: Create repository instructions¶
Add .github/copilot-instructions.md with the invariant rules every contribution must follow. Keep it short, testable, and repository-specific.
Step 2: Add scoped instructions¶
Create .github/instructions/python.instructions.md with frontmatter applyTo: "**/*.py". Put language-specific rules here instead of the global file.
Step 3: Package repeatable work¶
Use a prompt file for a user-invoked workflow, a *.agent.md file for a specialist persona with tools, and SKILL.md for a portable capability with examples and resources.
Step 4: Resolve precedence¶
Inspect AGENTS.md and every matching instruction file. Remove duplicates, state conflicts explicitly, and keep tool permissions least-privileged.
Supporting kit¶
The site build generates stable PDF and ZIP downloads. The ZIP contains the lab guide and every supporting file declared for this lab.