Decide which side branch to checkout from as base_branch when using github issues

[tomerr-ma]

I’m using Claude Code with GitHub Actions in “mention” mode — when I write @ claude in a GitHub issue, it will always takes the main/master default branch as the "base_branch".
Is there a way to tell Claude which side branch to checkout from as the "base_branch" from the "issues" tab in Github?

(I do not want to statically hardcode base_branch in the github action file as it will affect all other developers using this repo.