Nota:
CLI de GitHub Copilot extensions are currently an experimental feature and are subject to change.
An extension lets you add your own capabilities to CLI de Copilot. Each extension is a small Node.js module that runs as a separate process alongside your interactive session and connects back to it. Through that connection an extension can add:
- Tools that Copilot can call while it works on your behalf.
- Slash commands that you run yourself.
Because an extension runs real code on your machine, you can add capabilities the built-in tools don't have. For example, an extension can watch what happens in a session and keep a running total across tool calls, which a one-off shell command can't do.
This article explains how extensions work and how CLI de Copilot handles them. For a hands-on guide to building your own extensions, see Creating extensions for CLI de GitHub Copilot.
Advertencia
Extensions execute on your computer with your privileges. Only load extension code that you trust, in the same way you would only run any other script you didn't write yourself.
How extensions are discovered
When CLI de Copilot starts, it looks for extensions in several locations. Each extension lives in its own subdirectory, and that subdirectory must contain an entry file named extension.mjs, extension.cjs, or extension.js. These are all JavaScript files: the CLI de Copilot runs the entry file directly with Node.js, so an extension must be written in JavaScript—TypeScript and other languages are currently not supported.
The name of the subdirectory becomes the name of the extension.
| Source | Location | Availability |
|---|---|---|
| Project | .github/ in the current repository | Available to anyone working in that repository. |
| User | ~/ | Available in all your CLI sessions, in every directory. |
| Plugin | An installed plugin | Available wherever the plugin is enabled. |
Choosing where an extension lives
Where you put the extension directory determines who can use it:
- Put it in
.github/extensions/in a repository when the extension is specific to that project and you want to share it with everyone who works there. - Put it in
~/.copilot/extensions/when you want the extension available in all of your own sessions, regardless of which directory you start the CLI in.
The two locations follow exactly the same structure—a named subdirectory containing an extension.mjs file—so you can move an extension from one to the other simply by relocating its folder.
Enabling extensions
Extensions are currently an experimental feature, so you need to turn on experimental features. You can do this by doing either of the following:
- Start the CLI with the
--experimentalflag. - Run the
/experimental onslash command inside an interactive session.
Changing how the CLI handles extensions
You can limit Copilot's access to extensions, or turn them off entirely, by using the /extensions mode command. When you use this command you get three options:
- Load & Augment (the default)—the CLI runs your extensions, and Copilot can manage them.
- Load Only—the CLI runs your extensions, but Copilot cannot manage them.
- Disabled—extensions are turned off entirely in the current session and will remain disabled in future sessions until you switch to one of the other two settings. Other current sessions are not affected.
Any change you make takes effect immediately in the current session:
- Switching to Disabled stops any extensions that are currently running. Their processes are shut down and their tools are no longer available.
- Switching from Disabled to either of the other settings starts your extensions.
- Switching between Load Only and Load & Augment just changes whether Copilot can manage your extensions.
What "managing extensions" means
In Load & Augment mode, Copilot is given a small set of extra tools that let it work on the extension system directly, as part of carrying out your requests. Using these tools, Copilot can:
- List the extensions it has discovered and see their status.
- Inspect an extension, including a tail of its log file, to help diagnose one that has failed or is misbehaving.
- Scaffold a new extension—generate a starter
extension.mjsfile for you to build on. - Reload extensions, so that code it (or you) has just written takes effect without restarting the session.
This is what makes it possible for you to ask Copilot to build an extension for you. Copilot can create the file, write the code, and reload it, all without leaving the session.
Choose Load Only when you want to keep a known, trusted set of extensions running but don't want Copilot creating, reloading, or otherwise changing extension code—which runs on your machine—as a side effect of its work. Your existing extensions still run, and Copilot can still call the tools they provide; it simply can't manage the extensions themselves.
Extensions compared with plugins
Both extensions and plugins add functionality to CLI de Copilot, but they serve different purposes:
- An extension is a single JavaScript module that you write to add tools and slash commands, backed by code that runs in your session.
- A plugin is an installable package that bundles reusable components—such as agents, skills, hooks, and integrations—and can be distributed through a marketplace.
For more information about plugins, see Información sobre GitHub Copilot complementos.