If I'm interpreting this correctly, GitHub will use their existing actions infrastructure to run versions of the code in isolated worktrees. I think this could be a very beneficial process.

What I've done on my end is created a project where I have a remote Linux workstation. I can create multiple worktrees for each repo in that workstation, and then my agent can push PRs to GitHub and use the actions infrastructure to see if the integration tests that it writes for itself are successful without needing to run those integration tests on the local environment. It's expensive in terms of runner hours, but the automaticity of it is incredible.