How do you review a 900 line diff from Claude Code when you're not a developer?

What I do, even as a developer:

1. Read the file list first, not the lines. git diff --stat. Does every file make sense for "recurring bookings"? A change in auth/ or middleware.ts is a question to ask.
2. Read migrations and anything with delete/permissions fully. That's where mistakes cost money. UI code you can mostly judge by clicking.
3. Ask a fresh session to review it. New session, prompt: "Review the diff of the last commit against main. List risks, anything not needed for recurring bookings, and anything that could delete or leak data." A fresh context doesn't defend its own work.
4. Test the edges, not the happy path. Booking that repeats past the end of the month, cancel one occurrence, timezone change.

Next time: "Plan this in 4 steps, each step small enough to commit and test separately." Then review 4 x 200 lines.

Adding to Katja: make it write tests for the edge cases before you look at the diff, then run them. You can read a test ("a weekly booking on Jan 31 lands on Feb 28") much easier than the implementation.

Small practical one: stage per file in VS Code source control instead of accepting everything. It forces you to at least open each file once and you can commit the obviously fine ones separately.