/admin/debug/correlation read every incident ever created, sorted them in Python and kept 20, and separately pulled every call in the orphan window with no cap. That worked while the collections were small. They are not small now: Firestore kills an unbounded scan with a 503 and the request never returns, so the debug view simply spins -- which is also what made the org backfill script fail earlier tonight, same cause, different caller. Incidents now come back pre-sorted from Firestore with a limit, and the orphan scan is capped at 3000 documents. Both queries order on the single field they already filter or sort by (updated_at, ended_at), so neither needs a composite index -- worth preserving, since the index file from the tenancy work has not been deployed. Capping introduces a way to be wrong quietly: a truncated window looks exactly like a quiet night. The payload now carries incidents_window_exhausted and orphan_scan_truncated so a short result announces itself instead of being read as a correlation improvement. The AI-system filter still runs in Python, so the incident window is 10x the requested limit rather than the limit itself. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>