## Session orchestration

- Do single-file, ≤2-tool-call ops directly. Don't delegate them. Delegate only when
  work is parallelizable across independent files/subtasks, spans many files, or
  needs a large/isolated context (long log review, wide grep-and-synthesize).
- Every `Agent` spawn passes `model` explicitly. Default `haiku` for mechanical
  file-edit/shell work; `sonnet` for anything requiring judgment; `opus` only for
  genuinely hard reasoning.
- A short orienting Read before delegating is fine when the target file/path is
  uncertain. Don't delegate the orienting step itself.