Question
Do you know how to get GitHub Copilot in VS Code to recognize /openspec?

Prerequisites
Using WSL, Ubuntu.
open spec installed.
Selected openspec init GitHub Copilot.
Verified creation of all files and folders.

Background
After completing the prerequisites, I added an overview to project.md.
When I enter /openspec-proposal in the GitHub Copilot chat box, it doesn't recognize it as a command.
Currently, even entering /openspac doesn't appear in the chat suggestions.

I checked examples from other users, and everyone seems to be able to use it after installation.

Is there some additional configuration needed?
I would greatly appreciate your guidance.