Long helper runs stay quick because old tool output is set aside
Helpers working in the background now drop the bulky output of old tool calls, so each step gets lighter instead of slower.
A helper that worked for a long time kept every large result it had ever seen, and with Claude Code each new step had to carry all of it again. Steps got slower and cost more the longer the helper ran.
Helpers now do what your main chat already did: once old results are big enough to matter, they are replaced by a short note saying where the full text is kept. The newest results stay in full, and nothing is lost from the saved history.