diff --git a/src/features/quota/quotaTimelineModel.ts b/src/features/quota/quotaTimelineModel.ts
index 58b8d3ba..c9012a76 100644
--- a/src/features/quota/quotaTimelineModel.ts
+++ b/src/features/quota/quotaTimelineModel.ts
@@ -268,6 +268,7 @@ export function laneHasWindow(lane: TimelineLane): boolean {
 
 /** Shape the lane builder reads. Deliberately structural — see the note below. */
 interface WindowLike {
+  id?: string;
   label?: string;
   usedPercent?: number | null;
   resetAtMs?: number | null;
@@ -352,7 +353,25 @@ export function buildTimelineLane(input: TimelineLaneInput): TimelineLane {
     const windows = ((quota as { windows?: WindowLike[] }).windows ?? []).filter(
       (window) => typeof window.resetAtMs === 'number'
     );
-    const chosen = pickLaneWindow(windows, maxPeriodHours);
+    const preferredCodexId =
+      maxPeriodHours !== undefined && maxPeriodHours <= SESSION_PERIOD_HOURS
+        ? 'five-hour'
+        : 'weekly';
+    // Codex can report model-scoped windows with the same period as the account
+    // window (for example GPT-5.3-Codex-Spark weekly). A reset-time tie-break
+    // would make the lane silently switch to that model's quota. Keep the lane
+    // anchored to the standard account window whenever it fits this view.
+    const preferredCodexWindow =
+      provider === 'codex'
+        ? windows.find(
+            (window) =>
+              window.id === preferredCodexId &&
+              typeof window.periodHours === 'number' &&
+              window.periodHours > 0 &&
+              (maxPeriodHours === undefined || window.periodHours <= maxPeriodHours)
+          )
+        : undefined;
+    const chosen = preferredCodexWindow ?? pickLaneWindow(windows, maxPeriodHours);
     if (!chosen) return empty;
 
     const resetCredits =
diff --git a/tests/quotaTimeline.test.ts b/tests/quotaTimeline.test.ts
index 8ee6d29e..a8433542 100644
--- a/tests/quotaTimeline.test.ts
+++ b/tests/quotaTimeline.test.ts
@@ -281,6 +281,39 @@ describe('buildTimelineLane', () => {
     ]);
   });
 
+  test('codex: keeps the weekly lane on the account quota instead of Spark quota', () => {
+    const accountReset = at(2026, 7, 1, 20);
+    const sparkReset = at(2026, 6, 29, 20);
+    const lane = buildTimelineLane({
+      ...base,
+      provider: 'codex',
+      quota: {
+        status: 'success',
+        windows: [
+          {
+            id: 'weekly',
+            label: 'Weekly limit',
+            usedPercent: 70,
+            resetAtMs: accountReset,
+            periodHours: 168,
+          },
+          {
+            id: 'gpt-5-3-codex-spark-weekly-0',
+            label: 'GPT-5.3-Codex-Spark weekly limit',
+            usedPercent: 2,
+            resetAtMs: sparkReset,
+            periodHours: 168,
+          },
+        ],
+      },
+      maxPeriodHours: 14 * 24,
+    });
+
+    expect(lane.anchorMs).toBe(accountReset);
+    expect(lane.periodHours).toBe(168);
+    expect(lane.remaining).toBe(30);
+  });
+
   test('codex: includes available reset credits with parseable expiry dates', () => {
     const expiresAt = '2026-08-02T12:00:00Z';
     const lane = buildTimelineLane({