What is GitHub Copilot
GitHub Copilot is an AI pair programmer built into your code editor. It watches what you type and suggests code completions - ranging from a single word to entire functions. It is powered by a model trained on billions of lines of public code.
It launched in 2022 and quickly became the tool that made the entire category of AI coding assistants mainstream. Over 1.8 million developers use it today.
Acceptance rate reality check: Copilot suggests code constantly, but developers accept about 30% of suggestions on first offer. That sounds low, but consider: you are skipping the typing for 30% of your code. That is significant over an 8-hour day.
Source: GitHub Copilot research, 2024
What Copilot does well:
- Boilerplate and repetitive code (extremely good)
- Unit test generation (very good)
- Code documentation (very good)
- Language translations (good - converts between similar languages)
- Explaining unfamiliar code (good, via Chat)
What it does less well: complex novel algorithms, understanding business logic it has not seen, debugging deeply nested state issues. For those, you still need a real developer brain.
Installation and Setup
Getting Copilot running is straightforward. Here is the full process for VS Code and JetBrains:
- Get a subscription - Go to github.com/features/copilot. Students and open-source maintainers get it free. Everyone else pays $10/month. Start your 30-day trial.
- Install the VS Code extension - Open VS Code, go to Extensions (Ctrl+Shift+X), search "GitHub Copilot". Install both "GitHub Copilot" and "GitHub Copilot Chat".
- Sign in with GitHub - VS Code will prompt you to authenticate. Complete the OAuth flow in your browser.
- Verify it is working - Open any code file. Start typing a function. You should see gray suggestion text appear within a second. Press Tab to accept.
- Learn the keyboard shortcuts - Tab to accept a suggestion. Escape to dismiss. Alt+] and Alt+[ to cycle through alternative suggestions. Ctrl+Enter to see a panel with 10 suggestions.
For JetBrains (IntelliJ, WebStorm, PyCharm, etc.): go to Settings - Plugins - search "GitHub Copilot" - install the official plugin - restart the IDE - sign in with GitHub. Same experience as VS Code.
Getting Better Suggestions
Most people install Copilot and start typing. They get okay suggestions. Then they wonder if it is really that impressive. The difference between mediocre and great Copilot suggestions comes down to context - specifically, how much context you give it.
The Comment Trick
Write a comment describing what your function should do before writing any code. Be specific. The more detail you put in the comment, the better the suggestion.
Example: Vague vs. Specific Comments
Vague: // get user data
Specific: // Fetch user profile by ID, return null if not found, include lastLoginAt timestamp
The specific comment produces dramatically better function suggestions - correct parameter types, return type, error handling, and variable naming.
Naming Matters More Than You Think
Function names and variable names are context signals. getUserById(id) gets better suggestions than getUser(x). TypeScript types are extremely powerful context signals - a fully typed function signature gets much better body suggestions than an untyped one.
Keep Relevant Code Visible
Copilot uses the code in your currently open files as context. If you are writing a function that processes User objects, keep the User type definition visible in an adjacent open tab. Copilot will use it.
Context window fact: Copilot suggests 46% of code in enabled repositories when developers write detailed comments and use typed function signatures. With minimal context, that drops significantly.
Source: GitHub engineering blog, 2024
Copilot Chat Features
Copilot Chat is the conversational layer. It is separate from inline completions - you open it in a sidebar and have a back-and-forth conversation about your code. This is where Copilot gets genuinely powerful for less experienced developers.
Things Chat is excellent at:
- Explaining code - Select any code, open Chat, type "explain this". It gives a plain-English walkthrough.
- Generating tests - Select a function, type "/tests". It generates unit tests for all the obvious cases - and some you would have missed.
- Fixing bugs - Paste an error message and select the relevant code. Chat often identifies the problem and suggests a fix on the first try.
- Refactoring - "Refactor this function to use async/await" or "extract this into a separate helper" work surprisingly well.
Chat Slash Commands
In VS Code's Copilot Chat, these slash commands trigger specific behaviors:
/explain- Explain selected code in plain English/fix- Suggest fixes for problems in selected code/tests- Generate unit tests for selected code/doc- Generate documentation comments/simplify- Suggest a simpler version of selected code
Workspace Commands
The @workspace participant in Copilot Chat understands your entire project - not just the current file. This is where Copilot closes the gap with Cursor for many use cases.
Try these workspace queries:
@workspace Where is the user authentication logic?@workspace How does the payment processing work?@workspace What tests are missing for the cart module?
Copilot will search your workspace files, find relevant code, and give you a contextual answer with file references. This is extremely useful when you are new to a codebase or returning to old code.
New to a Codebase?
Use @workspace Explain the overall architecture of this project as your first message. Copilot will give you a surprisingly accurate overview based on the file structure and code it finds. It is faster than reading the README for most projects.
Language-Specific Tips
Copilot performs differently across languages. Here are practical tips for the most common stacks:
Python
Add type hints to function signatures. Copilot's Python suggestions improve dramatically with typed parameters and return types. Use docstrings with parameter descriptions for even better results.
JavaScript and TypeScript
TypeScript gets far better suggestions than plain JavaScript. If you are not using TypeScript, consider at least adding JSDoc type comments. Define interfaces and types clearly - Copilot uses them as context for all suggestions throughout the file.
Go
Write descriptive function names (Go convention). Add comments above functions - Go convention and Copilot both respond well to this. Error handling patterns are well-learned by Copilot for Go.
SQL
Copilot is surprisingly good at SQL. Describe your query in a comment and it often generates the full JOIN query. Works best when your column/table names are descriptive.
Team and Enterprise Features
Copilot Business ($19/user/month) and Enterprise ($39/user/month) add features that matter for professional teams.
| Feature | Individual ($10) | Business ($19) | Enterprise ($39) |
|---|---|---|---|
| Code completion | Yes | Yes | Yes |
| Chat | Yes | Yes | Yes |
| No training on your code | Opt-out | Default off | Default off |
| Custom model fine-tuning | No | No | Yes |
| Codebase indexing | Limited | Yes | Yes |
| Policy controls | No | Yes | Yes |
For teams, the key Business feature is centralized management - you can enable/disable Copilot per user, set policies on which repositories it is active in, and ensure code snippet training is off by default. Enterprise adds custom model fine-tuning on your codebase.
Copilot vs Alternatives
Copilot wins on: ecosystem integration, trust, VS Code depth, JetBrains support, and the strongest track record.
Cursor wins on: multi-file changes, codebase-wide context, and overall suggestion quality for complex tasks. If you write full-stack apps and you are willing to switch IDEs, Cursor is worth trying.
Codeium wins on: price (free) and no limits for individuals. If budget matters, start here.