Approving & Requesting Changes

Option C is the model approval. It tells the author exactly what you verified (tested locally, existing tests, the specific edge cases), which builds confidence that the review was thorough. It also ends with genuine praise.

"LGTM" has become a shorthand that can mean anything from "I read every line carefully" to "I glanced at the diff". It's fine in a pinch for small changes among close collaborators, but for significant PRs, more detail signals real engagement.

Approval comments should answer: What did you verify? Did you test it? Are there open questions? A 2-sentence approval is always better than a one-word one.

Option B works because it: (1) signals due diligence ("reviewed this thoroughly"); (2) frames the outcome clearly ("need to be addressed before merge"); (3) offers collaboration ("happy to discuss"). This is the standard opening for a change-request review in professional environments.

Key vocabulary: "Before we can merge" is the standard phrase for blocking feedback. Compare: "blocking issue", "must be addressed", "required change" (all blocking) vs. "nit", "optional", "consider" (non-blocking suggestions).

Option A is hostile and vague. Option C and D leave the author with no context or path forward.

Option B demonstrates mature team communication. It: (1) gives a scoped approval ("from a backend logic perspective") — you're not blocking the PR, but clarifying the scope of your review; (2) flags the specific concern (authentication flow); (3) makes a concrete recommendation (loop in security); (4) specifies the threshold (before merging to production).

This pattern is called a conditional approval or scoped approval — common in organisations with separate security and compliance review processes. Option C is a hard block without explanation. Option D gives false assurance on a security-sensitive change.