Is that cruft or past conversation history / subagent history and observability logs?

Just garbage. Temp files, worktrees that weren't removed after subagents finished, build files... all kinds of things.

But that's agent behavior, and not harness responsibility...?

	▲	klodolph 2 hours ago \| parent [-]
		Harnesses should be responsible IMO for managing lifecycle stuff, including worktrees and temp files. It’s simple, deterministic stuff. At least most of the time.