Implement

Implementation is where a plan meets what is actually there, and what is actually there always differs. The skill is not in the typing. It is in noticing the difference early, while it is still cheap.

Slow is smooth and smooth is fast. One change at a time, each cut deliberate, no thrashing.

Always know where you are

At any moment, be able to answer: what is the last state that was known good, what is being changed right now, and what would show whether it worked.

When those cannot be answered, that is the finding, and it precedes everything else. Work that has drifted from its last verified point is accumulating unverified assumptions, and the cost of discovering a mistake grows with every one added.

The distance to the last checkpoint is the single most useful thing to track. Keep it short. A change verified in three places is three cheap failures; the same change verified once at the end is one expensive one.

Build outward from what holds

Types and the shape of the data first — they are the design, and everything downstream reads them. Then the pure logic that moves between them, which can be checked with literals. Then the effects, the integration, the parts that need a real environment to say anything.

This is not ceremony. It is ordering by feedback speed: establish the things that can be checked in a second before the things that need a deploy.