No because your agent will hallucinate. Code is truth.
Yes you do. Definitely not in the excruciating detail we used to. But an agent on itself typically catches only (relatively) superficial issues. It hasn't ever occurred to me to get a higher-level disagreement on the changes of the PR by an agent.
E.g. why re-implement the oauth workflow instead of using the established package of the ecosystem? Why monkeypatch an existing python method for all code instead of implementing and using where needed a context manager?
The agent can give you an assessment on such alternative approaches if you ask it, but I haven't seen it taking the initiative to radically steer a PR.
P.S. Have a feeling this will get down-voted but posting since I am interested in counter-arguments for this approach.