Adding repository custom instructions for GitHub Copilot

Create a file in a repository that gives Copilot additional context for the work it does in that repository.

In this article

Note

This feature is currently in public preview and is subject to change.

This version of this article is for using repository custom instructions on the GitHub website. Click the tabs above for information on using custom instructions in other environments.

About repository custom instructions for Copilot

Repository custom instructions are currently supported for:

  • Copilot Chat in Visual Studio, VS Code and on the GitHub website
  • Copilot coding agent
  • Copilot code review

You can configure GitHub Copilot to generate responses that are tailored to the way your team works, the tools you use, or the specifics of your project. You can do this by creating a file in your repository that provides Copilot with the contextual information it needs to generate higher quality responses.

The custom instructions file is used for chat responses, for code review, and also by Copilot when you assign it to an issue or ask it to create a pull request. Instructions included in this file can help Copilot to work on files in a way that matches your team's working practices and conforms to coding standards for your project. See About Copilot coding agent.

Example

This example of a .github/copilot-instructions.md file contains three instructions for Copilot.

We use Bazel for managing our Java dependencies, not Maven, so when talking about Java packages, always give me instructions and code samples that use Bazel.

We always write JavaScript with double quotes and tabs for indentation, so when your responses include JavaScript code, please follow those conventions.

Our team uses Jira for tracking items of work.

For examples of custom instructions used to configure Copilot code review, see Using GitHub Copilot code review.

Prerequisites for repository custom instructions

  • You must have a custom instructions file (see the instructions below).

Creating a repository custom instructions file

  1. In the root of your repository, create a file named .github/copilot-instructions.md.

    Create the .github directory if it does not already exist.

  2. Add natural language instructions to the file, in Markdown format.

    Whitespace between instructions is ignored, so the instructions can be written as a single paragraph, each on a new line, or separated by blank lines for legibility.

To see your instructions in action, go to https://github.com/copilot, attach the repository containing the instructions file, and start a conversation.

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Writing effective repository custom instructions

The instructions you add to the .github/copilot-instructions.md file should be short, self-contained statements provide Copilot with relevant information to help it work in this repository.

You should also consider the size and complexity of your repository. The following types of instructions may work for a small repository with only a few contributors, but for a large and diverse repository, these may cause problems:

  • Requests to refer to external resources when formulating a response
  • Instructions to answer in a particular style
  • Requests to always respond with a certain level of detail

For example, the following instructions may not have the intended results:

Always conform to the coding styles defined in styleguide.md in repo my-org/my-repo when generating code.

Use @terminal when answering questions about Git.

Answer all questions in the style of a friendly colleague, using informal language.

Answer all questions in less than 1000 characters, and words of no more than 12 characters.

Repository custom instructions in use

The instructions in the .github/copilot-instructions.md file are available for use by Copilot Chat as soon as you save the file. The complete set of instructions will be automatically added to requests that you submit to Copilot in the context of that repository. For example, they are added to the prompt you submit to Copilot Chat.

In Copilot Chat's immersive view (github.com/copilot), you can start a conversation that uses repository custom instructions by adding, as an attachment, the repository that contains the instructions file.

Whenever repository custom instructions are used by Copilot Chat, the instructions file is added as a reference for the response that's generated. To find out whether repository custom instructions were used, expand the list of references at the top of a chat response in the Chat panel and check whether the .github/copilot-instructions.md file is listed.

Screenshot of an expanded References list, showing the 'copilot-instructions.md' file highlighted with a dark orange outline.

You can click the reference to open the file.

Note

  • It is possible for multiple types of custom instructions to apply to a conversation. Personal instructions take the highest priority, followed by repository instructions, with organization instructions prioritized last. However, all sets of relevant instructions are still combined and provided to Copilot Chat.
  • Whenever possible, you should avoid providing conflicting sets of instructions. If you are concerned about response quality, you can also choose to temporarily disable repository instructions. See Adding repository custom instructions for GitHub Copilot.

Enabling or disabling repository custom instructions

You can choose whether or not you want Copilot to use repository-based custom instructions.

Enabling or disabling custom instructions for Copilot Chat

Custom instructions are enabled for Copilot Chat by default but you can disable, or re-enable, them at any time. This applies to your own use of Copilot Chat and does not affect other users.

  1. On GitHub.com, do one of the following:

    • Go to a repository with a custom instructions file and open the assistive chat panel.
    • Go to the immersive view of Copilot Chat (github.com/copilot) and attach a repository that contains a custom instructions file.

  2. Click the button at the top of the Chat panel, or the top right of the immersive page.

  3. Click Disable custom instructions or Enable custom instructions.

    Note

    You will only see these options in the context of a repository that contains a custom instructions file.

Your choice persists, for all repositories containing a custom instructions file, until you change it.

Enabling or disabling custom instructions for Copilot code review

Custom instructions are enabled for Copilot code review by default but you can disable, or re-enable, them in the repository settings on GitHub.com. This applies to Copilot's use of custom instructions for all code reviews it performs in this repository.

  1. On GitHub, navigate to the main page of the repository.

  2. Under your repository name, click Settings. If you cannot see the "Settings" tab, select the dropdown menu, then click Settings.

    Screenshot of a repository header showing the tabs. The "Settings" tab is highlighted by a dark orange outline.

  3. In the "Code & automation" section of the sidebar, click Copilot, then Code review.

  4. Toggle the “Use custom instructions when reviewing pull requests” option on or off.