Visual Studio Code's Copilot Chat architecture enables extension authors to integrate with the GitHub Copilot Chat experience. A chat extension is a VS Code extension that uses the Chat extension API by contributing a Chat participant. Chat participants are domain experts that can answer user queries within a specific domain.

The Language Model API enables you to use the Language Model and integrate AI-powered features and natural language processing in your Visual Studio Code extension.

When an extension uses the Chat or the Language Model API, we call it a GitHub Copilot Extension, since GitHub Copilot is the provider of the Chat and the Language Model experience.

This GitHub Copilot Extension sample shows:

How to contribute a chat participant to the GitHub Copilot Chat view.
How to use the Language Model API to request access to the Language Model (gpt-4o, gpt-3.5-turbo, gpt-4).

Documentation can be found here:

Running the Sample

Run npm install in terminal to install dependencies
Run the Run Extension target in the Debug View. This will:
- Start a task npm: watch to compile the code
- Run the extension in a new VS Code window
- You will see the @cat chat participant show in the GitHub Copilot Chat view