on the contrary, many good developers do know what to write. They understand what the software does, and why, and they are capable of explaining it. They know what decisions were made, and why they were chosen over other options. Above all, they know where the tricky bits are (because they solved them), which are, for the most part, going to be the tricky bits for anyone following.

Anything you talk to the rubber ducky about probably deserves writing down.