tl;dr: Claude Code silently burns ~15-20% of user tokens (mostly on Opus) by having each background agent summarize its own transcript every ~30 seconds into a 3-5 word status line that never leaves the agents panel. There's no official setting to disable it, so the author ships an ~80-line Bun preload hook that wraps setTimeout/setInterval and suppresses the summarizer timer by matching its callback source text. Tested on Linux across Claude Code 2.1.257–2.1.312; it may silently fail after updates, so re-verification via OpenTelemetry is recommended.