What should I do when Claude Code creates a 3,000-line PR?

When a coding agent such as Claude Code opens a 3,000-line pull request, do not start at the top of the diff. First find out what the change is, then decide where to spend your attention. DiffGuardian shortens that first step: it breaks the pull request into the features it ships and lets you read it, hear it or see it.

#Steps, without any tool

1. Read what the agent says it did. The description and any plan it wrote tell you the intent.
2. List the files and group them. Routes, migrations, tests and config are different kinds of change. Three kinds of files usually means at least three changes.
3. Separate mechanical changes from behaviour changes. Renames, formatting and generated files can be skimmed once you confirm that is all they are.
4. Follow one feature end to end before moving on to the next.
5. Check the callers of anything the agent changed the shape of.
6. Look for scope creep: files changed that the task never mentioned.

#How DiffGuardian helps

• Break it into features. DiffGuardian reads the pull request against the whole repository and splits it into what it actually ships, so step 2 is done for you.
• Read it. Trace It (Pro) follows one feature across every file it touches, in the order the code runs.
• Hear it. Talk to your pull request (Pro): ask what it does and hear the walkthrough while the code is highlighted. Ask "what did the agent change that I wasn't expecting?"
• See it. The blast radius graph shows what the change touches before you read any code.

The same steps apply to any coding agent, not only Claude Code.

DiffGuardian is a desktop app for macOS, Windows and Linux, and works with pull requests on GitHub, GitLab and Bitbucket.

#Limits

• DiffGuardian explains and maps the change. Whether it is correct, safe and wanted is still your call, and it never merges anything.
• Trace It and voice are Pro features. The blast radius graph works on every plan.