Copilot Prompting

Introduction

GitHub Copilot (and Copilot Chat) responds to inline comments + structured chat prompts. Strong at code; weaker at long docs.

Beginner analogy: Like pair programming with someone who finishes your sentences — give clear context, get clean code.

Understanding the topic

Core concepts to understand:

• Inline: write a clear comment, Copilot completes the code.
• Chat: use slash commands (/explain, /fix, /tests).
• Provide function signatures + types for best completions.
• Use Workspace mode for multi-file edits.
• Custom instructions in .github/copilot-instructions.md.

Syntax reference

Visual workflow / architecture:

// Function that validates an email and returns
// a typed result with reason on failure.
function validateEmail(input: string): Result {
  // → Copilot completes here
}

Real-world use

Used by 1M+ developers daily; cuts coding time 30%+ when prompts (comments) are clear.

Best practices

• Write the comment as if briefing a junior dev.
• Provide types and examples in code above.
• Use Workspace for cross-file refactors.

Hands-on exercise

Interview preparation — practice these questions:

• Q1. How prompt Copilot inline?
• Q2. What are Copilot slash commands?
• Q3. How customise repo-wide?
• Q4. Copilot vs Cursor — differences?