This is the second post in my Claude Code Tools Deep Dive series. The previous post unpacked AskUserQuestion, a structured tool that lets users choose from concrete options. This time, we're looking at its sibling: EnterPlanMode.
Before reading this post, it may help to read the series prelude on how Claude Code's tool mechanism works. This article follows the same four-layer framework introduced there.
EnterPlanMode
Like AskUserQuestion, EnterPlanMode is a tool you may encounter almost every day. But its design is much heavier. It does not merely ask a question; it switches Claude into an entirely different mode of operation.
What It Does
