- _budget_notice no longer names the cite tool after prepare_tools has
withdrawn it; the post-grace state gets the plain no-tools text back.
- Split search-budget rejections from any failed tool call: the code tool
raises ToolFailed for every error in model-written Python, so
budget_spent was true for a ZeroDivisionError.
- docs/capabilities/rag.md described the old single-turn removal.
- Drop the rationale clause from the CHANGELOG entry.
50 executions across 40 cases in an 822-case run died on
'_io.TextIOWrapper' object is not iterable, and those cases scored 37.5%
judged against 60.1% and cited 12.5% against 55.2%.
