Custom instructions for GitHub Copilot

  • https://docs.github.com/en/copilot/how-tos/custom-instructions/adding-repository-custom-instructions-for-github-copilot
MyProject
├── .git
│   ├── branches
│   ├── COMMIT_EDITMSG
│   ...
├── .github
│   ├── copilot-instructions.md
│   └── instructions
│       ├── javascript.instructions.md
│       ├── landing-page.instructions.md
│       ├── markdown.instructions.md
│       ├── mongodb.instructions.md
│       ├── nextjs.instructions.md
│       ├── react.instructions.md
│       └── tailwindcss.instructions.md

Type of instructions files

https://code.visualstudio.com/docs/copilot/customization/custom-instructions#_type-of-instructions-files

VS Code supports multiple types of Markdown-based instructions files. If you have multiple types of instructions files in your project, VS Code combines and adds them to the chat context, no specific order is guaranteed.

  • A single .github/copilot-instructions.md file

    • Automatically applies to all chat requests in the workspace
    • Stored within the workspace

  • One or more .instructions.md files

    • Conditionally apply instructions based on file type or location by using glob patterns
    • Stored in the workspace or user profile

  • One or more AGENTS.md files

    • Useful if you work with multiple AI agents in your workspace
    • Automatically applies to all chat requests in the workspace or to specific subfolders (experimental)
    • Stored in the root of the workspace or in subfolders (experimental)

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 reference specific context in your instructions, such as files or URLs, you can use Markdown links.

Using a single .github/copilot-instructions.md file

Code: .github/copilot-instructions.md
# Mardkdown
When working with markdown files, do the following:
- Use reference link instead of inline link.
- Don't add link in the headers.

Using one or more .instructions.md files

You can split copilot-instructions.md into multiple files. Create a .github/instructions folder and place your instructions files there. GitHub Copilot will automatically load all *.instructions.md files in that folder.

You can name the instructions file anything you like, such as javascript.instructions.md, as long as you place it in the .github/instructions folder.

Important guidelines:

  • Do not reference other files or locations - keep all necessary information within the instructions file itself, since the "pre-prompt" does not collect resources externally.

  • When working with multiple files:

    • Do not duplicate content or list items more than once, as this will cause the AI to malfunction.

    • Do not include conflicting rules; conflicting instructions will lead to unpredictable results.

    • Do keep instructions concise and clear, avoiding ambiguity. Leaving decisions open to the AI can result in unreliable and inconsistent outputs due to inherent randomness.