fix(rate-limit): replace unsupported Bottleneck maxWait with job-level expiration (#1694)

Bottleneck v2.19.5 does not support a `maxWait` limiter/constructor option — it
was silently ignored, causing queued jobs to wait indefinitely when no 429 response
triggered the drop mechanism.

Replace with Bottleneck's supported `expiration` job-schedule option which rejects
any job that waits+executes longer than maxWaitMs. Also log expiration rejections
so they are observable in production.

CHANGELOG.md

@@ -20,6 +20,7 @@
 - **fix(codex):** prevent unexpected protocol leakage and fabricated instructions on bare chat completion requests without tools (#1686)
 - **fix(executors):** truncate tools array to 128 items max in GitHub Copilot and OpenCode executors to mitigate 400 Bad Request errors from upstream (#1687)
 - **fix:** add body-read timeout to prevent stuck pending requests (#1680)
+- **fix(rate-limit):** replace unsupported Bottleneck `maxWait` option with job-level `expiration` to prevent indefinite queue stalls (#1694)
 - **fix:** combo retry loop stops immediately on client disconnect (499) (#1681)
 - **fix(search):** support optional bearer auth for SearXNG (#1683)
 - **fix(vision):** respect native GPT vision support — prevents VisionBridge from intercepting models that already handle images natively (#1678)

open-sse/services/rateLimitManager.ts

@@ -30,7 +30,6 @@ interface LearnedLimitEntry {
 interface LimiterUpdateSettings {
   maxConcurrent?: number | null;
   minTime: number;
-  maxWait?: number | null;
   reservoir?: number | null;
   reservoirRefreshAmount?: number | null;
   reservoirRefreshInterval?: number | null;
@@ -76,7 +75,6 @@ function buildLimiterDefaults() {
     reservoir: currentRequestQueueSettings.requestsPerMinute,
     reservoirRefreshAmount: currentRequestQueueSettings.requestsPerMinute,
     reservoirRefreshInterval: 60 * 1000,
-    maxWait: currentRequestQueueSettings.maxWaitMs,
   };
 }
 
@@ -85,7 +83,6 @@ function updateAllLimiterSettings() {
     limiter.updateSettings({
       maxConcurrent: currentRequestQueueSettings.concurrentRequests,
       minTime: currentRequestQueueSettings.minTimeBetweenRequestsMs,
-      maxWait: currentRequestQueueSettings.maxWaitMs,
       reservoir: currentRequestQueueSettings.requestsPerMinute,
       reservoirRefreshAmount: currentRequestQueueSettings.requestsPerMinute,
       reservoirRefreshInterval: 60 * 1000,
@@ -285,7 +282,21 @@ export async function withRateLimit(provider, connectionId, model, fn) {
   }
 
   const limiter = getLimiter(provider, connectionId, model);
-  return limiter.schedule(fn);
+  const maxWaitMs = currentRequestQueueSettings.maxWaitMs;
+  const scheduleOpts = maxWaitMs && maxWaitMs > 0 ? { expiration: maxWaitMs } : {};
+  try {
+    return await limiter.schedule(scheduleOpts, fn);
+  } catch (err) {
+    // Bottleneck throws when a job exceeds its expiration timeout.
+    // Surface as a clear rate-limit timeout so callers can fallback.
+    if (err?.message?.includes("This job timed out")) {
+      const key = getLimiterKey(provider, connectionId, model);
+      console.log(
+        `⏰ [RATE-LIMIT] ${key} — job expired after ${Math.ceil((maxWaitMs || 0) / 1000)}s in queue, dropping`
+      );
+    }
+    throw err;
+  }
 }
 
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