The loop-breaker's runaway backstop counted per-tool-type call totals and
tripped whenever any tool was used >=15 times — treating 15+ DISTINCT calls
to one tool as a stuck loop. A real batch (e.g. "add these 18 birthdays to my
calendar" emits 18 distinct manage_calendar create_event calls in one round)
got flagged "calling manage_calendar over and over", the calls were discarded
(next round tools_sent=0), and 0 events were created.
Count IDENTICAL repeated call signatures instead (same tool AND args), via a
small, unit-testable _detect_runaway_call() helper. Genuine batches pass; a
model truly stuck repeating one call still trips the backstop. Adds a
regression test.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>