Customize chat responses and set context

You can ask GitHub Copilot Chat to give you code suggestions, explain code, generate unit tests, and suggest code fixes. Chat in Visual Studio can give you responses and generate code that matches your coding practices and project requirements, if you give it the right context. Instead of repeatedly adding this information in every chat prompt, you can store this context in files and automatically include it in every chat request.

In this article, you learn how to get better answers by providing more information to Copilot Chat:

• Use slash commands to quickly specify common tasks like /explain to get code explanations
• Use the guided chat experience to refine context
• Use custom instructions and prompt files to customize responses

Learn more about AI-assisted development in Visual Studio and how to use Copilot Chat in Visual Studio.

Prerequisites

To get started using GitHub Copilot Chat in Visual Studio, you need:

• Visual Studio 2022 version 17.10 or later
• Sign in to Visual Studio using a GitHub account with Copilot access
  ^** You can sign up for GitHub Copilot for Free.

Support for GitHub Copilot Chat is provided by GitHub and can be reached at https://support.github.com.

Prompting guidance

The guided chat experience in Visual Studio 17.12 and later helps refine your prompts to clarify context for better answers. GitHub Copilot Chat now guides you with clarifying questions when context is unclear.

Use custom instructions

The custom instructions feature enables you to automatically add prespecified contextual details to your chat questions. Copilot Chat uses these instructions tailored to your specific context, such as, the way your team works, the tools you use, or the specifics of your project, when generating responses.

Use a .github/copilot-instructions.md file

To use a .github/copilot-instructions.md file:

1. Create/add a custom instructions file .github/copilot-instructions.md in the root of your repository.

Custom instructions aren't visible in the Chat view or inline chat. However, when used by Copilot, the.github/copilot-instructions.md file is listed in the References list of a response.

Use .instructions.md files

Instead of using a single instructions file that applies to all chat requests, you can create multiple *.instructions.md files that apply to specific file types or tasks. For example, you can create instructions files for different programming languages, frameworks, or project types.

To use a .github/instructions/*.instructions.md file:

1. Create the .github/instructions directory if it does not already exist.

2. Add one or more .github/instructions/*.instructions.md files.

3. Add the applyTo property in the frontmatter section of the instructions file. Use glob syntax to specify what files or folders the instructions apply to.

4. Enable the feature in Visual Studio.

   In the Tools > Options pane, expand the All Settings > GitHub > Copilot > Copilot Chat section and select the Enable custom instructions to be loaded from .github/copilot-instructions.md files and added to requests checkbox.

   In the Tools > Options dialog, expand the GitHub > Copilot section. In the Copilot Chat group, select the Enable custom instructions to be loaded from .github/copilot-instructions.md files and added to requests checkbox.

Instructions file format

Targeted instruction files use the .instructions.md extension and have this structure:

• Header (optional): YAML frontmatter
  • description: Description shown on hover in Chat view
  • applyTo: Glob pattern that matches the files or folders you want the instructions to apply to
• Body: Instructions in Markdown format

Example

Here's an example C# custom instruction:

## C# Instructions
---
applyTo: `**/*.cs`
---

- Write clear and concise comments for each function.
- Use PascalCase for component names, method names, and public members.
- Use camelCase for private fields and local variables.
- Add a newline before the opening curly brace of any code block  
  (such as after `if`, `for`, `while`, `foreach`, `using`, `try`, etc.).
- Ensure that the final `return` statement of a method is on its own line.

Copy these instructions into your .github/instructions/*.instructions.md file to use and automatically apply to Copilot behavior.

For more examples of custom instructions, see the list of instruction samples on GitHub.

How instruction files work

When you start working with Copilot, it automatically detects which instruction files are relevant to your current context and attaches them as references. This ensures Copilot’s suggestions are always aligned with your project’s rules no matter where you’re working in your codebase.

The instruction files used by Copilot are listed in the References list of the response.

Use prompt files

You can now create reusable prompt files in your repository to run or share your frequently used prompts.

To create a prompt file:

1. Write your prompts as you normally would in the prompt box, using # references to include specific information from your solution, such as methods, classes, and files. You can even reference other prompt files for shared instructions.
2. Copy the prompt into a markdown file, and save it with the .prompt.md extension in the .github/prompts folder at the root of your repository.

To use a prompt file:

1. Type #prompt: in chat input to reference any prompt files from your .github/prompts folder, or click the ➕ icon in the chat input to add it as context.
2. Add any extra details, or simply enter the prompt as is.

Use slash commands to set context for common tasks

Slash commands in Copilot Chat help you set the intent quickly for common development tasks. By using specific slash commands to form your question, you can get better answers without having to write out long questions.

You can use slash commands in a chat window, or directly inline in the code that you're looking to modify, using inline code assistance. Commands that help modify or add to the code file you have open in the editor work both in the inline code assistant and the chat windows whereas commands for more general coding questions work only in the chat pane.

With Visual Studio 2022 version 17.13, as the user types a slash command, the command expands out the prompt in natural language to display the context for the command.

Next steps

• GitHub Copilot experience for Visual Studio
• GitHub Copilot Chat experience for Visual Studio
• GitHub Copilot Trust Center
• Send us suggestions, feedback, and issues
• Support for GitHub Copilot Chat
• How to use GitHub Copilot: Prompts, tips, and use cases