Idempotent Claude Code Skills

Claude Code is good at creating skills. Say "create a skill that does X" and it makes one. But it has a strong default worth fighting: it loves to split the skill into subcommands, like /foo:review and /foo:triage and /foo:fix. I don't want a menu. The whole point is automation.

So the fix is two lines in the prompt when asking it to write a skill: no subcommands, and make sure the skill can be run idempotently. Run it once, run it ten times, it should converge on the same finished state without me steering.

Idempotence is the part that matters more than it sounds. A skill that's safe to re-run is a skill I can put in a loop, or fire after every commit, or hand to another agent without worrying about double-applying a change. The subcommand version pushes that work back onto me: decide which phase you're in, pick the right verb, remember what you already ran. That's the opposite of automation.

The menu pattern probably comes from training on human-facing CLIs, where breaking work into named steps is good UX. For a skill that an agent is going to invoke, it's the wrong shape. One entry point, idempotent, done when it says it's done.