GitHub Copilot Guide 2025: AI Pair Programming for Every Developer

What Is GitHub Copilot?

GitHub Copilot is an AI coding assistant developed by GitHub (Microsoft) in partnership with OpenAI. Unlike Cursor — which is a full IDE fork — Copilot is an extension that integrates into your existing editor. Its four main modes are:

• Ghost Text — multi-line inline suggestions as you type; press Tab to accept
• Copilot Chat — context-aware AI chat panel with slash commands (/explain, /fix, /tests, /doc)
• Copilot Edits — propose and apply changes across multiple files simultaneously
• Copilot CLI — gh copilot suggest and explain terminal commands

Copilot launched in June 2022 and reached 1.8 million paid users by 2024. GitHub also launched a limited free tier in 2024 — 2,000 completions and 50 chat messages per month — making it accessible to nearly every developer.

Setting Up Copilot in VS Code

1. Open VS Code and go to Extensions (Ctrl+Shift+X / Cmd+Shift+X)
2. Search for GitHub Copilot and install it (also install GitHub Copilot Chat)
3. Click the Copilot status bar icon and Sign in to GitHub via OAuth
4. Open any file — Ghost Text suggestions appear inline as you type
5. Press Ctrl+Alt+I (Windows/Linux) or Cmd+I (Mac) to open Copilot Chat

Ghost Text vs Copilot Chat vs Copilot CLI

Using .github/copilot-instructions.md

Create a .github/copilot-instructions.md file in your repository root to set a persistent system prompt for all Copilot Chat sessions in that repo. Copilot injects it automatically — you don't need to paste context every time.

# .github/copilot-instructions.md example
# This file is automatically injected into every Copilot Chat session

You are assisting with a TypeScript + React project.
- Use functional components with typed props interfaces
- Prefer named exports; default export only for pages
- Use Tailwind CSS for all styling — no inline styles
- Write tests with Vitest + React Testing Library
- Never use the `any` type; prefer `unknown` with type guards
- Keep functions under 40 lines; extract helpers when needed

Keep the file concise (under 400 words). Include: language/framework, code style rules, testing library, naming conventions, and any anti-patterns. Avoid duplicating what the IDE already knows (e.g., "we use TypeScript" when the file is .ts).

GitHub Copilot Pricing (2025)

Students, teachers, and maintainers of popular open-source projects can apply for free Individual access at education.github.com. GitHub verifies eligibility with your .edu email or through the GitHub Student Developer Pack.

GitHub Copilot vs Cursor vs Windsurf

Choose Copilot if you use JetBrains IDEs, are embedded in the GitHub ecosystem, or need the lower price point with solid single-file completions. Choose Cursor or Windsurf if you want a more powerful agentic experience with multi-file planning and model choice.

Pro Tips for Better Copilot Results

• Write descriptive comments before the function: Copilot uses comments as intent. Write "// Debounce fn calls, returns promise that resolves on final call" before the function signature for dramatically better suggestions.
• Keep related files open in tabs: Ghost Text draws context from all open editor tabs, not just the current file. Open your types file, related tests, and the API module before writing new code.
• Use /tests with a selected function: Highlight your function, open Copilot Chat, type /tests, and it generates unit tests that match your existing testing patterns. Works best when you have test files already open.
• Add #file references in chat: Instead of pasting code, type #file: src/components/Button.tsx to give Copilot Chat the exact context it needs without leaving the chat box.
• Check Copilot status when suggestions stop: If Ghost Text disappears, check GitHub Copilot status at Prismix before debugging your setup — outages do happen.

Frequently Asked Questions