GitHub Copilot Chat Commands: A Cheat Sheet With Examples

GitHub Copilot Chat has three kinds of commands. Slash commands (/) run a common task like /tests or /fix. Chat variables (#) attach context such as #file or #selection. Chat participants (@) hand your question to a specialist such as @terminal or @vscode.

Which ones you get depends on where you use Chat: the GitHub website, Visual Studio Code, Visual Studio, JetBrains or Xcode. GitHub's docs say the available slash commands vary with your environment and the context of the chat. Type / in the prompt box to see the live list for your setup.

GitHub Copilot Chat commands at a glance#

The @ symbol does two jobs depending on the environment. On the GitHub website it attaches items such as discussions, extensions, files, issues, pull requests and repositories. In VS Code it picks a participant.

Copilot Chat slash commands list by environment#

Slash commands exist so you don't have to write a long prompt for a routine job. Type / followed by the command name. Here is what the official cheat sheet lists for each environment.

Visual Studio Code#

Visual Studio#

JetBrains#

The last three only apply if you run interactive Copilot CLI sessions inside JetBrains.

Xcode#

GitHub website#

Notice that /new and /clear mean different things on the website and in VS Code. On the website /new starts a new conversation. In VS Code it creates a new project. Check the table for your environment before you rely on a name you remember from somewhere else.

Which slash command for which job#

The list is short, so picking is mostly about matching the task to the verb.

• You don't understand a block of code. Use /explain. Select the code first or keep the file active in the editor.
• Something is broken in a selection. Use /fix. It proposes a fix for problems in the selected code.
• A test is red. In VS Code, /fixTestFailure is aimed at exactly that: find and fix a failing test.
• You need tests. /tests generates unit tests for the selected code. That answers the common search for a slash command to generate unit tests. It's listed in VS Code, Visual Studio, JetBrains and Xcode.
• Code is slow. In Visual Studio, /optimize analyzes and improves the running time of the selected code.
• Undocumented symbol. /doc works in Visual Studio and Xcode.
• Too much code. /simplify is Xcode only in this cheat sheet.

A habit I'd recommend: select the exact code first, then type the command. The test and fix descriptions both say "selected code", so a precise selection gives the command less to guess at.

You can still add your own words after a command. Something like /tests followed by a sentence about which cases you care about is a normal way to steer it. The cheat sheet doesn't document specific arguments, so treat that as a plain prompt addition, not a formal syntax.

Chat variables: add context with#

Chat variables put specific context into your prompt. Type # in the prompt box, then the variable. These are the ones the cheat sheet lists for VS Code:

Pick the narrowest one that still contains what the question needs. If you're asking about one method, #function says so more precisely than #file. A few examples:

Why would #function return null here?
Summarize what #class is responsible for.
What does #selection do when the input is empty?

References in Visual Studio#

Visual Studio uses # differently. By default Chat references the file you have open or the code you selected, and you can add # followed by a file name, file name with line numbers, or solution:

Where are the tests in #MyFile.cs?
How are these files related #MyFile.cs #MyFile2.cs
Explain this function #MyFile.cs: 66-72
Is there a delete method in this #solution?

The file-and-lines form is useful when a file is long and only one range matters.

Chat participants: pick a specialist with @#

Participants are described as domain experts. Type @ in the prompt box to see which are available. The cheat sheet lists these for VS Code:

@terminal how do I list files larger than 100 MB?
@vscode how do I change the default formatter?

This is the nearest thing to a "Copilot chat command line" question the pack answers: @terminal helps you write and debug shell commands, but it's a participant in the editor chat, not a separate CLI. Copilot CLI sessions appear in the pack only through the JetBrains commands above.

Mentions and MCP skills on the GitHub website#

On github.com, @ attaches context to the conversation: discussions, extensions, files, issues, pull requests and repositories. That's handy when you want to ask about a particular pull request without pasting it.

The cheat sheet also lists MCP skills such as create_branch, push_files, merge_pull_request, get_me and search_users. You don't type the skill name. You describe the task and Copilot Chat picks the skill, for example:

Create a new branch called [BRANCH-NAME] in the repository [USERNAME/REPO-NAME].

Be careful with prompts that write or merge. merge_pull_request really does what it says, so read the PR number twice before you send it.

Custom commands and what the docs don't cover#

People search for custom slash commands a lot. The cheat sheet only documents the built-in ones, so I won't describe a setup for custom commands here. Check the current GitHub Copilot documentation on docs.github.com for what your editor supports. Options change quickly.

Try it: check a command against your environment#

This small script holds the cheat sheet data and tells you where a command is listed. Edit the ask array to try your own.

const commands = {
  'VS Code': ['clear', 'explain', 'fix', 'fixTestFailure', 'help', 'new', 'tests'],
  'Visual Studio': ['doc', 'explain', 'fix', 'help', 'optimize', 'tests'],
  'JetBrains': ['chronicle', 'compact', 'explain', 'fix', 'help', 'remote', 'tests'],
  'Xcode': ['doc', 'explain', 'fix', 'simplify', 'tests'],
  'GitHub website': ['clear', 'delete', 'new', 'rename'],
};

const ask = ['tests', 'optimize', 'simplify', 'new', 'refactor'];

for (const name of ask) {
  const where = Object.entries(commands)
    .filter(([, list]) => list.includes(name))
    .map(([env]) => env);
  console.log(`/${name}: ${where.length ? where.join(', ') : 'not in the cheat sheet'}`);
}

And a quick check that the # variables in a prompt are ones the VS Code list knows:

const known = ['block', 'class', 'comment', 'file', 'function', 'line', 'path', 'project', 'selection', 'sym'];
const prompt = 'Explain #function and compare it with #selection and #scope';

for (const match of prompt.matchAll(/#(\w+)/g)) {
  const ok = known.includes(match[1]);
  console.log(`#${match[1]}: ${ok ? 'listed' : 'not in the VS Code list'}`);
}

Common mistakes and gotchas#

• Assuming a command exists everywhere. /optimize is listed only for Visual Studio, /simplify only for Xcode, /fixTestFailure only for VS Code. If a command is missing, type / and read the live list.
• Same name, different meaning. /new and /clear behave differently on the website and in VS Code, as covered above.
• Forgetting the selection. /fix and /tests act on selected code. Without a selection you're leaving the scope to chance.
• Over-attaching context. #file when you only mean #function adds noise to the prompt.
• Mixing up @. On the website it attaches items. In VS Code it picks a participant.
• Trusting a cached cheat sheet. Command lists change. The source below is the place to confirm.

Quick reference checklist#

1. Type / to see the commands your environment actually offers.
2. Select the code, then run /explain, /fix or /tests.
3. Add #function, #selection or #file when the default context isn't enough.
4. Type @ to pick a participant (VS Code) or attach an item (GitHub website).
5. On the website, use /new, /rename, /delete and /clear to manage conversations.
6. Re-check the official Copilot Chat cheat sheet before you build habits around a command.

Quick answers