diff --git a/Sources/CodexBarCore/Resources/Plugins/openrouter.js b/Sources/CodexBarCore/Resources/Plugins/openrouter.js
index 5e2a0f83f4..e28b05eed9 100644
--- a/Sources/CodexBarCore/Resources/Plugins/openrouter.js
+++ b/Sources/CodexBarCore/Resources/Plugins/openrouter.js
@@ -112,26 +112,27 @@ defineProvider({
     } else
       try {
         const now = ctx.date.now();
-        const today = now.toISOString().slice(0, 10);
-        const cutoffDate = new Date(now.getTime() - 29 * 24 * 60 * 60 * 1000);
+        const latestCompletedDate = new Date(now.getTime() - 24 * 60 * 60 * 1000);
+        const latestCompleted = latestCompletedDate.toISOString().slice(0, 10);
+        const cutoffDate = new Date(latestCompletedDate.getTime() - 29 * 24 * 60 * 60 * 1000);
         const cutoff = cutoffDate.toISOString().slice(0, 10);
         // A management credential must never follow the user-configurable API base to a proxy.
         const activityURL = "https://openrouter.ai/api/v1/activity";
-        const [historyResponse, todayResponse] = await Promise.all([
+        const [historyResponse, latestCompletedResponse] = await Promise.all([
           ctx.http.get(activityURL, {
             timeoutSeconds: optionalRequestTimeoutSeconds,
             openRouterManagementAuth: true,
           }),
-          ctx.http.get(`${activityURL}?date=${encodeURIComponent(today)}`, {
+          ctx.http.get(`${activityURL}?date=${encodeURIComponent(latestCompleted)}`, {
             timeoutSeconds: optionalRequestTimeoutSeconds,
             openRouterManagementAuth: true,
           }),
         ]);
-        if (historyResponse.status !== 200 || todayResponse.status !== 200) {
-          const failed = historyResponse.status !== 200 ? historyResponse : todayResponse;
+        if (historyResponse.status !== 200 || latestCompletedResponse.status !== 200) {
+          const failed = historyResponse.status !== 200 ? historyResponse : latestCompletedResponse;
           activityDegradation = activityDegradationReason(failed.status);
         } else {
-          const payloads = [historyResponse, todayResponse].map((response) => JSON.parse(response.bodyText));
+          const payloads = [historyResponse, latestCompletedResponse].map((response) => JSON.parse(response.bodyText));
           const rows = payloads.flatMap((payload) => {
             if (!payload || !Array.isArray(payload.data)) throw new TypeError("activity.data must be an array");
             return payload.data;
@@ -157,7 +158,9 @@ defineProvider({
             if (!Number.isFinite(parsedDate.getTime()) || parsedDate.toISOString().slice(0, 10) !== date) {
               throw new TypeError(`activity.data[${index}].date must be a real calendar date`);
             }
-            if (date > today) throw new TypeError(`activity.data[${index}].date must not be in the future`);
+            if (date > latestCompleted) {
+              throw new TypeError(`activity.data[${index}].date must be a completed UTC day`);
+            }
             if (date < cutoff) continue;
             const rawModel = row.model_permaslug ?? row.model;
             const model = typeof rawModel === "string" && rawModel.trim() ? rawModel.trim() : null;
@@ -246,7 +249,7 @@ defineProvider({
             currency: "USD",
             historyDays: 30,
             historyLabel: "Last 30 days (UTC)",
-            windowEnd: today,
+            windowEnd: latestCompleted,
             entries,
           };
         }
diff --git a/Tests/CodexBarTests/OpenRouterUsageStatsTests.swift b/Tests/CodexBarTests/OpenRouterUsageStatsTests.swift
index b3270bc418..0b27166ac8 100644
--- a/Tests/CodexBarTests/OpenRouterUsageStatsTests.swift
+++ b/Tests/CodexBarTests/OpenRouterUsageStatsTests.swift
@@ -149,6 +149,75 @@ struct OpenRouterPluginGoldenTests {
         #expect(ordinary.allSatisfy { $0.value(forHTTPHeaderField: "Authorization") == "Bearer standard-key" })
     }
 
+    @Test
+    func `activity requests the latest completed UTC day`() async throws {
+        let requests = OpenRouterRequestRecorder()
+        let activityBody = #"""
+        {"data":[
+          {
+            "date":"2026-08-17",
+            "model":"openai/gpt-5.6",
+            "prompt_tokens":10,
+            "completion_tokens":5,
+            "reasoning_tokens":2,
+            "requests":1,
+            "usage":1
+          },
+          {
+            "date":"2026-07-19",
+            "model":"x-ai/grok-4",
+            "prompt_tokens":4,
+            "completion_tokens":1,
+            "reasoning_tokens":0,
+            "requests":1,
+            "usage":1
+          }
+        ]}
+        """#
+        let runtime = try ProviderPluginRuntime(
+            bundledPlugin: "openrouter",
+            transport: ProviderHTTPTransportHandler { request in
+                await requests.append(request)
+                let path = request.url?.path ?? ""
+                if path.hasSuffix("/activity") {
+                    let date = request.url
+                        .flatMap { URLComponents(url: $0, resolvingAgainstBaseURL: false) }?
+                        .queryItems?
+                        .first { $0.name == "date" }?
+                        .value
+                    if date == "2026-08-18" {
+                        return try Self.response(
+                            request,
+                            body: #"{"error":{"message":"Date must be within the last 30 (completed) UTC days"}}"#,
+                            statusCode: 400)
+                    }
+                    return try Self.response(request, body: activityBody)
+                }
+                if path.hasSuffix("/key") {
+                    return try Self.response(request, body: #"{"data":{"limit":20,"usage":5}}"#)
+                }
+                return try Self.response(request, body: Self.defaultCreditsBody)
+            })
+        let now = Date(timeIntervalSince1970: 1_787_079_600) // 2026-08-18T12:00:00Z; stable injected clock.
+
+        let usage = try await runtime.fetchUsage(
+            secrets: [
+                OpenRouterSettingsReader.envKey: "fixture-key",
+                OpenRouterSettingsReader.managementAPIKeyEnvironmentKey: "fixture-management-key",
+            ],
+            now: now)
+        let recorded = await requests.requests
+        let datedRequest = try #require(recorded.first { $0.url?.query != nil })
+        let date = datedRequest.url
+            .flatMap { URLComponents(url: $0, resolvingAgainstBaseURL: false) }?
+            .queryItems?
+            .first { $0.name == "date" }?
+            .value
+
+        #expect(date == "2026-08-17")
+        #expect(usage.costUsage?.last30DaysCostUSD == 2)
+    }
+
     @Test
     func `server remaining drives monthly quota golden`() async throws {
         let usage = try await Self.fetch(keyBody: #"""