Plan mode is useful when you need to make changes that are bigger or more complex than small one function changes.

Plan mode makes Claude Code read only. It can only review your files and develop an approach, but it can't edit, run, or change anything until you give approval.

That makes it a safe way to explore a bigger feature before committing.

Here is the existing calculator app. It currently has basic operator functions: add, subtract, multiply, and divide. Let's use plan mode to add something new, a square root function.

I will press shift tab twice and at the bottom there's an indicator that plan mode is on. You could also type “/plan” if you prefer to type it rather than use a shortcut.

Now for the prompt: “Add a square root function to this calculator consistent with the existing functions.”

Claude Code now reads through the calculator file and checks how the other functions are written.

Because we're in plan mode, it can't touch anything yet. It lays out a plan.

Now on the screen is the plan, and it mentions importing math, adding the square root function, and matching the naming and doc style of the other functions, along with other information.

This is the moment to check the plan makes sense before anything else happens. Does it match how you want it done?

If something's off, you can ask Claude to adjust the plan right here before a single line of code changes.

I will hit yes and use the auto mode to approve the plan. Note at the bottom, Claude is in auto mode as plan mode has completed that task.

Now I will lower the terminal and scroll down, and here's the square root function.

That's the value of plan mode. For anything bigger than a one line fix, it lets you see the reasoning and catch an off track approach early, rather than after the fact.

Plan mode

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