Test the Build Your Customer Will Receive

A development server passing its tests does not establish that a production bundle behaves the same way. Build tools can replace environment values, remove code and change asset paths.

When Claude Code changes a deployment-sensitive feature, ask for one check against the compiled output. A scheduled page is a useful example: the check should load the built handler, provide a controlled time and inspect the returned page, not just call the date helper.

Compare that evidence with the actual failure you are trying to prevent. If the browser needs a button to work after hydration, a successful HTML render is only part of the proof. Record the build command and relevant runtime version with the result so another person can reproduce it.

Claude Code documentation.