Claude Code: switch to manual mode and read the diff before approving

The guide is built around a small practice folder holding a CSV of holidays and a short Python script that counts them by month, managed with Git, with screenshots taken from a session on October 12, 2026. Its starting point is the mode the tool launches in: in the captured environment the lower-left display read "auto mode on", meaning it proceeds without confirmation, and a single Shift+Tab changed that to "manual mode on".

The suggested sequence moves from low-risk to higher-risk work. A read-only request comes first, and Claude Code asks for confirmation before running the command that inspects file contents. A small write follows, with the advice to state what to do, where, and under what policy — for example, asking for a README.md describing the folder and how to run count_holidays.py — rather than vague instructions like "fix it" or "write tests".

The remaining discipline is about the approval screen itself: the content to be written is shown with line numbers, and the reader chooses "Yes", "Yes" (auto-approving edits for the rest of the session), or "No". The three checks before approving are the added lines, any removed lines that should not disappear, and whether unrequested files are in scope. The guide notes you can ask for an explanation of a change on the spot, and that a diff too large to read is a sign to split the request into smaller ones.