What
The description of the Agent tool was rewritten in the prompt Claude Code sends with its reminder about reading a file that was already read. The Agent tool is how Claude passes work to a subagent, a separate helper copy of Claude.
The new text sets out when not to delegate:
- Do the work directly when it is a handful of tool calls (individual actions such as reading a file) or a lookup whose target is already known.
- Delegate a review only to get an opinion not anchored on Claude's own, and then hand over the code rather than Claude's conclusion.
- Once something is delegated, wait for the result instead of also doing it.
- When in doubt, don't spawn a helper.
Why
This text is part of Claude's own instructions, so the rewrite changes how readily Claude starts helpers. The new wording leans toward Claude doing small tasks itself and avoiding duplicated work.