When it matters most

Plan mode earns its extra step most clearly on changes where the right approach genuinely is not obvious yet before you have seen the full shape of it: a refactor touching several files in ways that depend on each other, a bug with more than one plausible cause.

It is equally useful for a feature where the natural place to add it only becomes clear once you have actually looked at how similar things are already structured elsewhere in the codebase, rather than being obvious from the request alone.

Rather than approving the first edit and hoping the rest follows sensibly from there, plan mode lets the entire shape of the change get worked out and reviewed as a whole before any of it actually lands.

It is equally worth reaching for on a change to something genuinely sensitive, authentication logic, a payment path, anything where a subtly wrong first attempt would be costly to have shipped even briefly, regardless of how well-understood the change otherwise seems.

Conversely, a request you could describe completely and unambiguously in one sentence rarely benefits from plan mode; the extra review step adds friction without adding real insight when there was never much ambiguity to resolve in the first place.