Plan Mode: Think Before Editing
The most expensive agent mistake is a confident, sprawling change built on a misunderstanding. Plan mode splits the work into two phases — agree on what to do, then do it — so misunderstandings surface while they are still cheap.
The rule
Plan first when the change is big, unclear or hard to undo.
In plan mode, Claude can read, search and ask you questions, but it does not edit files or run commands that change anything. It comes back with a plan: which files it will touch, in what order, the risks, and the questions it could not answer alone.
To get there, press Shift+Tab until the mode indicator shows plan mode. Recent versions also offer a slash command for it, and you can start a session in plan mode with a permission-mode option at launch. Then you discuss the plan: reply with corrections, cut steps, answer its questions. When you are happy, leave plan mode and ask Claude to carry out the plan, ideally one step at a time.
A good plan is a list of small steps you can check one by one:
Plan: "pause tomorrow" for weekly-plan customers
1. Add paused dates to the subscription record (orders.py).
2. Skip paused dates when building the delivery list.
3. Credit one day's price, ₹90, on the next bill (pricing.py).
4. Tests: a pause removes exactly one delivery; the credit is ₹90.
Open question: until what time can a customer pause tomorrow?The ₹90 is the weekly-plan day rate: ₹100 with 10% off. A plan that shows its numbers is a plan you can check. It is also easy to share: a teammate can review a plan in two minutes, long before there is any code to review.
The shortcut
Ask three questions: Does it touch more than a couple of files? Is the requirement unclear? Would a mistake be hard to undo, as with data migrations, billing or deletions? Any yes: plan first. All no: just ask.
Enter plan mode
Press Shift+Tab until plan mode shows. Ask for a plan for "pause tomorrow", with open questions listed.
The trap is approving a plan you skimmed. The plan is the cheapest place in the whole task to catch a misunderstanding: a wrong line in a plan costs seconds, and the same mistake in code costs an afternoon.
Drills
Answer fast — trust the rule.
What can Claude NOT do in plan mode?
Which task most deserves plan mode first?
The plan lists an open question about the pause cut-off time. What should you do?
Why carry out a plan one step at a time?
Remember
- Plan first when the change is big, unclear or hard to undo.
- Shortcut: many files, a fuzzy requirement or a hard undo; any yes means plan.
- Trap: rubber-stamping a plan you have not read.