Installing the extension gives you the @fabric participant immediately.
If you also want Fabric UX agents and skills to appear in Copilot Chat, run the command palette action Fabric UX: Install Copilot Chat Assets To Workspace. That copies the packaged assets into:
.github/agents/
.github/skills/
Those workspace files are the surface Copilot Chat can discover from the active repository. The extension packages and installs them for you.
Local Development
cd fabric-ux-devkit/vscode-extension
npm install
npm run build
npm run install:local
Packaging
npm run package
# Creates fabric-ux-vscode-devkit-0.2.0.vsix
The package step bundles the Fabric UX skills, agent files, and LICENSE into the .vsix.