I spend a significant amount of time (a) curating the test suite, and making sure it matches my notion of correctness and (b) forcing the agent to make PNG visuals (which Claude Code can see, by the way, and presumably also Gemini CLI, and maybe Aider?, etc)

I'd have to do this anyways, if I was writing the code myself, so this is not "time above what I'd normally spend"

The visuals it makes for me I can inspect and easily tell if it is on the right path, or wrong. The test suite is a sharper notion of "this is right, this is wrong" -- more sharp than just visual feedback and my directions.

The basic idea is to setup a feedback loop for the agent, and then keep the agent in the loop, and observe what it is doing. The visuals are absolutely critical -- as a compressed representation of the behavior of the codebase, which I can quickly and easily parse and recognize if there are issues.