I run /code-review to spin up multiple independent reviewers that each examine your code from a different angle. Add --comment and the feedback posts directly on the open PR.
The writer/reviewer pattern gets you the most from this: implement in Session A, then open a fresh Session B to review the output. Fresh context means Claude reviews the result, not every implementation decision that led there.
Run /install-github-app to wire this into your PR workflow automatically so every push gets reviewed without you initiating it.