All of that was about what to build. Now the how, which is where people start to disagree.
Plan
The steps an agent intends to take, written before it takes them: which files, in what order, what it will check, and what it isn't sure about.
It is the cheapest place to find out the agent misunderstood you. It is also a guess that nothing has tested yet, and polishing one can feel like progress while no knowledge is being added. Skip it when the change is small and the approach is obvious.
Say it to your agent
“/plan Add idempotency to apply(). Read src/webhooks/ first. Give me the files you would change, the test you would write first, and what you are unsure about. If it is one file and obvious, say so and skip the plan.”