Codeuteronomy
Design is settled before code is written
Redirecting a plan costs a sentence. Redirecting a diff costs an afternoon.
Let an agent start coding and it commits, in seconds, to a dozen decisions you never saw made: a data shape, an error strategy, where the module lives, what the caller expects. Each one is free to change while it's a line in a plan and expensive once three hundred lines depend on it. Plan mode matters more with an agent than the same discipline did with humans because the gap between “wrong approach” and “wrong approach, implemented” is seconds.
Settle the approach first. Make the agent state how: the files, the shape, the tradeoff chosen. Correct it at that altitude, before approving the plan. Once the plan is right, implementation is the cheap part; hand it over and let it run. You own the design. The agent owns the typing.
How to practice it
Live in plan mode.
Enter it (Shift+Tab) for anything past a trivial edit, and actually read the plan before approving it.
Reject underspecified plans.
One that lists tasks but no decisions has settled nothing. Send it back until it commits to how, not just what.
Hand it over cleanly.
“Follow the plan. You are the implementer” is a strong, low-friction mode once the approach is agreed.
Capture a good planning routine as a skill
you invoke, instead of re-describing it every session.