This looks similar to my workflow. I tend to stage my files regularly and then look at diff --staged. Really wish cursor would have an option for that as I often find myself doing diff --staged > diff.txt and then using @diff.txt to discuss the changes.
BTW I do this for quite a bit more than just commit comments. I have found that when working with Cursor or other ai coding tools it is super helpful to produce design docs that are designed to provide context for the ai. I use cursor to help me write the docs–often referring to previous commits for context–and then commit them to my repo and use them as the PR context. This allows the LLM prompts to get way more done correctly with fewer unplanned passes.