Why: Streaming tool arguments looked like a frozen cursor, and a failed run folded the only narration into the collapsed process block.
Evidence: npx vitest run in modules/frontend, 13 files, 66 passed. npx tsc -b reports only a pre-existing missing docx-preview module.
Impact: Live tools move composing to running to done with arguments and output; finished runs lift the last narration; same-run errors and duplicate files collapse into the reply.
Refs: feature/stream-display-overhaul
Co-authored-by: Cursor <cursoragent@cursor.com>