Reading and Reviewing Code You Did Not Write

Reading diffs and unfamiliar code critically: what to check first, where agent changes typically go wrong, and how to review more code than you could ever write.

Topics

Reading Unfamiliar Code

Tracing entry points, data flow and side effects in code you did not write.

Reading Diffs

Reading a change in the context of the code around it, including what it deletes, what it renames and what it quietly leaves untouched.

A Review Checklist for Agent Changes

Scope, error paths, security, data changes, new dependencies and duplicated logic, checked in a fixed order.

Reviewing Tests First

Checking that the tests encode the right behavior before trusting the code that passes them.

Risk-Based Review

Spending attention where mistakes are costly, such as security, money, data and migrations, and less where they are cheap.

Automated Reviewers and Shared Blind Spots

Using model reviewers for coverage while remembering that two models can be wrong in the same way.