Setting a GitHub repository variable from Actions

You can use the preinstalled gh tool to set a repository variable from inside a workflow.

run: gh variable set VARIABLE_NAME --body "$VARIABLE_VALUE"
env:
    GH_TOKEN: ${{ secrets.MY_PAT }}

This requires gh to have write access to repository variables. This access is configured through the GH_TOKEN environment variable. Your workflow has access to the github.token variable by default. However, this token does not have the required permissions.

Create a new Personal Access Token on your account and give it write access.

Store this token in your repository’s secrets, and pass it into the action that runs gh.

If the token doesn’t have the right access, you’ll see an error like failed to set variable "VARIABLE_NAME": HTTP 403: Resource not accessible by integration in your action’s logs.