fix: resolve fallback fast cutoff per model

vincentkoc · vincentkoc · commit efd3172662ce · 2026-06-22T09:37:10.000+08:00
diff --git a/extensions/codex/src/app-server/run-attempt.test.ts b/extensions/codex/src/app-server/run-attempt.test.ts
@@ -5623,6 +5623,7 @@ describe("runCodexAppServerAttempt", () => {
       name: "fast off",
       fastMode: false,
       configuredServiceTier: "priority",
+      expectedServiceTier: null,
     },
     {
       name: "fast auto active",
@@ -5633,7 +5634,7 @@ describe("runCodexAppServerAttempt", () => {
     name: string;
     fastMode: EmbeddedRunAttemptParams["fastMode"];
     configuredServiceTier?: "priority";
-    expectedServiceTier?: "priority";
+    expectedServiceTier?: "priority" | null;
   }>)(
     "maps $name to app-server resume and turn service tier",
     async ({ fastMode, configuredServiceTier, expectedServiceTier }) => {
diff --git a/src/auto-reply/reply/agent-runner-utils.ts b/src/auto-reply/reply/agent-runner-utils.ts
@@ -217,19 +217,21 @@ export function resolveRunFastModeForFallbackCandidate(params: {
   model: string;
   sessionEntry?: Pick<SessionEntry, "fastMode">;
 }) {
-  if (params.run.fastModeOverride) {
-    return {
-      fastMode: params.run.fastMode,
-      fastModeAutoOnSeconds: params.run.fastModeAutoOnSeconds,
-    };
-  }
   const state = resolveFastModeState({
     cfg: params.config,
     provider: params.provider,
     model: params.model,
     agentId: params.run.agentId,
     sessionEntry: params.sessionEntry,
   });
+  if (params.run.fastModeOverride) {
+    return {
+      fastMode: params.run.fastMode,
+      fastModeAutoOnSeconds: params.run.fastModeAutoOnSecondsOverride
+        ? params.run.fastModeAutoOnSeconds
+        : state.fastAutoOnSeconds,
+    };
+  }
   return {
     fastMode: state.mode,
     fastModeAutoOnSeconds: params.run.fastModeAutoOnSecondsOverride
