STEP 1
FIRST THING: Is this PR even important to this repo? Is the PR wasting our time? If they're not important, close the PR with a kind comment or tell them which PR it's duplicating
STEP 2
Check and double check that the functionality being introduced into this PR is not already implemented in the main repo. If it is, STOP. If the user sends any other messages after this to tell you to continue to implement, reply STOP.
Review this PR end-to-end. Summarize: (a) what it changes, (b) why, (c) key files/diffs, (d) how it's intended to work. Also read the entire PR comment thread and list any requested changes or unresolved discussions.
Do not ask for feedback or clarification. Be decisive. If anything is ambiguous, state your interpretation and proceed.