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Custom chat modes in Github Copilot

Out of the box, you get 3 modes in VS Code as explained in the documentation:

Chat mode Description
Ask mode Ask mode is optimized for answering questions about your codebase, coding, and general technology concepts. Use ask mode to understand how a piece of code works, brainstorm software design ideas, or explore new technologies.
Edit mode Edit mode is optimized for making code edits across multiple files in your project. VS Code directly applies the code changes in the editor, where you can review them in-place. Use edit mode for coding tasks when you have a good understanding of the changes that you want to make, and which files you want to edit.
Agent mode Agent mode is optimized for making autonomous edits across multiple files in your project. Use agent mode for coding tasks when you have a less well-defined task that might also require running terminal commands and tools.

While these 3 modes provide solid general-purpose functionality, custom chat modes unlock the potential to create highly specialized AI assistants tailored to your specific workflows.

What are custom chat modes?

Custom chat modes are predefined configurations that combine specific instructions with curated tool sets to create focused AI assistants within VS Code. Think of them as specialized personas that your AI can adopt for different tasks - whether you're planning new features, conducting code reviews, or researching implementation approaches.

Each custom chat mode consists of:

  • Description: A brief description of the chat mode.
  • Instructions: Detailed prompts that guide the AI's behavior and responses
  • Tools: A curated set of available tools (codebase search, file operations, etc.)
  • Model selection: Choose which AI model to use for optimal results

Custom chat modes are defined using Markdown files with a .chatmode.md extension. The structure is elegantly simple:

Real world example: Beast mode

If you are looking for a real world example, I would recommend to have a look at the Beast chat mode created by Burke Holland: Introducing Beast Mode 3.1 · Burke Holland

Beast Mode builds on OpenAI’s official 4.1 cookbook coding agent example and layers in a highly opinionated workflow that is modeled after how an actual developer might work to solve a problem, implement a feature, etc. It is specifically designed to be used with GPT 4.1. Burk created this mode to fix the lack of agency and accuracy he encountered while using GPT 4.1.

You can find his markdown file here: Beast Mode

Creating your own custom chat mode

Creating your own custom chat mode is easy:

  • Open the Github Copilot Chat view

  • Select Configure Modes in the list of modes

 

  • Choose "Create new custom chat mode file"

 

  • Decide on location:
    • Workspace: Stored in .github/chatmodes/ (great for team sharing)
    • User profile: Personal modes that sync across devices

 

  • Name your mode

 

  • Start customizing…

Some example chat modes

Code Review Assistant

Create a mode focused on security, performance, and maintainability checks:

Documentation Generator

Build a mode specialized in creating comprehensive documentation:

Debugging Detective

Create a troubleshooting-focused assistant:

More information

Use chat modes in VS Code

Introducing Beast Mode 3.1 · Burke Holland

Beast Mode

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