Prompts.

In this article, you’ll learn how prompt files and repository instructions shape GitHub Copilot interactions without replacing review and verification. That matters because useful AI integration depends as much on explicit trust and verification as it does on model capability.

Summary

This post explains what prompts are in the context of GitHub Copilot Chat, how to create reusable prompts in the .github/prompts directory, and how to automatically include them in Copilot Chat using the github.copilot.chat.codeGeneration.instructions setting. An example and useful references are provided.

For more tips on writing effective prompts and using Copilot efficiently, see the Best Practices for Using GitHub Copilot.

Understanding Prompts in GitHub Copilot Chat

Prompts are instructions or context you provide to GitHub Copilot Chat to guide its code generation or responses. Well-crafted prompts help Copilot understand your intent, resulting in more accurate and relevant suggestions.

Creating Custom Prompts

You can create reusable prompts by adding .prompt.md files in your repository’s .github/prompts directory. Each file should contain a specific instruction or context you want Copilot to use.

Steps:

1. Create a .github/prompts directory in your repository if it doesn’t exist.
2. Add a Markdown file (e.g., readme.prompt.md) with your prompt content.

Example (.github/prompts/readme.prompt.md):

Always use 2 spaces for indentation and single quotes for strings.

Automatically Including Prompts in Copilot Chat (User or Workspace settings)

To have Copilot Chat automatically use your custom prompts, configure the github.copilot.chat.codeGeneration.instructions setting in your workspace settings:

{
  "github.copilot.chat.codeGeneration.instructions": [
    {
      "file": "readme.prompt.md"
    }
  ]
}

Automatically Include Prompts in Copilot Chat (Folder settings)

To have Copilot Chat automatically use your custom prompts, configure the github.copilot.chat.codeGeneration.instructions setting in your Folder settings (has highest priority and will override both User and Workspace settings):

{
  "github.copilot.chat.codeGeneration.instructions": [
    {
      "file": ".github/prompts/readme.prompt.md"
    }
  ]
}

This tells Copilot Chat to include the content of readme.prompt.md as context for each request.

Example

Suppose you want Copilot to always follow your project’s code style. Create .github/prompts/codestyle.prompt.md:

Always use 2 spaces for indentation and single quotes for strings.

Then, update .vscode/settings.json:

{
  "github.copilot.chat.codeGeneration.instructions": [
    { "file": ".github/prompts/codestyle.prompt.md" }
  ]
}

Now, Copilot Chat will automatically consider your code style instructions.

Custom instructions settings

• github.copilot.chat.codeGeneration.useInstructionFiles: controls whether code instructions from .github/copilot-instructions.md are added to Copilot requests.
• github.copilot.chat.codeGeneration.instructions (Experimental): set of instructions that will be added to Copilot requests that generate code.
• github.copilot.chat.testGeneration.instructions (Experimental): set of instructions that will be added to Copilot requests that generate tests.
• github.copilot.chat.reviewSelection.instructions (Preview): set of instructions that will be added to Copilot requests for reviewing the current editor selection.
• github.copilot.chat.commitMessageGeneration.instructions (Experimental): set of instructions that will be added to Copilot requests that generate commit messages.
• github.copilot.chat.pullRequestDescriptionGeneration.instructions (Experimental): set of instructions that will be added to Copilot requests that generate pull request titles and descriptions.

2026 technical review

2026 update: prompt files are not instruction files

The settings-based code-generation and test-generation instruction mechanism described below is deprecated in current VS Code. Use file-based custom instructions instead:

• .github/copilot-instructions.md for repository-wide, always-on guidance;
• .github/instructions/*.instructions.md with applyTo patterns for file- or task-specific guidance; and
• .github/prompts/*.prompt.md for reusable prompts that a user invokes for a particular task.

A prompt file is an on-demand workflow and can declare inputs, tools, and model preferences. It is not automatically attached to every chat merely because it sits in the prompts directory. Keep instructions concise, explain non-obvious reasons, and use examples for conventions that a formatter cannot enforce.

Instructions influence model behavior; they are not policy enforcement. Back important requirements with compilation, tests, linters, security controls, and human review. Treat instructions from dependencies, copied issues, and tool output as untrusted context when they conflict with repository or user intent.

References

• GitHub Copilot Chat Cookbook
• GitHub Copilot Tips and Tricks
• Customise Copilot Chat
• Best Practices for Using GitHub Copilot
• VS Code custom instructions
• VS Code prompt files

Closing thought

A prompt file can make intent repeatable, but only tests, tools, and review can turn that repeated intent into dependable software.