fix(usage): refresh usage snapshot on window focus

apps/code/src/main/di/container.ts

@@ -111,7 +111,10 @@ import { DEV_HOST_ACTIONS_SERVICE } from "@posthog/platform/dev-host-actions";
 import { DIALOG_SERVICE } from "@posthog/platform/dialog";
 import { FILE_ICON_SERVICE } from "@posthog/platform/file-icon";
 import { IMAGE_PROCESSOR_SERVICE } from "@posthog/platform/image-processor";
-import { MAIN_WINDOW_SERVICE } from "@posthog/platform/main-window";
+import {
+  type IMainWindow,
+  MAIN_WINDOW_SERVICE,
+} from "@posthog/platform/main-window";
 import { NOTIFIER_SERVICE } from "@posthog/platform/notifier";
 import { POWER_MANAGER_SERVICE } from "@posthog/platform/power-manager";
 import { SECURE_STORAGE_SERVICE } from "@posthog/platform/secure-storage";
@@ -680,6 +683,8 @@ container.bind(MAIN_UPDATES_SERVICE).toService(UPDATES_SERVICE);
 container.load(usageMonitorModule);
 container.bind(USAGE_HOST).toDynamicValue((ctx) => {
   const agent = () => ctx.get<AgentService>(AGENT_SERVICE);
+  const mainWindow = () => ctx.get<IMainWindow>(MAIN_WINDOW_SERVICE);
+  const windowFocusUnsubscribers = new WeakMap<() => void, () => void>();
   return {
     fetchUsage: () =>
       ctx.get<LlmGatewayService>(MAIN_LLM_GATEWAY_SERVICE).fetchUsage(),
@@ -688,6 +693,10 @@ container.bind(USAGE_HOST).toDynamicValue((ctx) => {
     offLlmActivity: (listener: () => void) =>
       agent().off(AgentServiceEvent.LlmActivity, listener),
     hasActiveSessions: () => agent().hasActiveSessions(),
+    onWindowFocus: (listener: () => void) =>
+      windowFocusUnsubscribers.set(listener, mainWindow().onFocus(listener)),
+    offWindowFocus: (listener: () => void) =>
+      windowFocusUnsubscribers.get(listener)?.(),
     getThresholdsSeen: () => electronUsageThresholdStore.getThresholdsSeen(),
     setThresholdsSeen: (value: Record<string, string>) =>
       electronUsageThresholdStore.setThresholdsSeen(value),

packages/core/src/usage/identifiers.ts

@@ -12,6 +12,13 @@ export interface UsageHost {
   offLlmActivity(listener: () => void): void;
   hasActiveSessions(): boolean;
 
+  // Refreshes usage as soon as the user looks at the window again — the only
+  // in-app signal is LLM activity, so usage consumed elsewhere (the website,
+  // another device, a teammate) would otherwise sit stale for up to the
+  // 30-minute backstop while the window was unfocused.
+  onWindowFocus(listener: () => void): void;
+  offWindowFocus(listener: () => void): void;
+
   getThresholdsSeen(): Record<string, string>;
   setThresholdsSeen(value: Record<string, string>): void;
 }

packages/core/src/usage/usage-monitor.test.ts

@@ -7,24 +7,35 @@ import { UsageMonitorService } from "./usage-monitor";
 
 type ActivitySlice = Pick<
   UsageHost,
-  "onLlmActivity" | "offLlmActivity" | "hasActiveSessions"
+  | "onLlmActivity"
+  | "offLlmActivity"
+  | "hasActiveSessions"
+  | "onWindowFocus"
+  | "offWindowFocus"
 >;
 
 interface MockActivityMonitor extends ActivitySlice {
   fireLlmActivity(): void;
+  fireWindowFocus(): void;
 }
 
 function makeActivityMonitor(opts?: {
   hasActiveSessions?: boolean;
 }): MockActivityMonitor {
   const listeners = new Set<() => void>();
+  const focusListeners = new Set<() => void>();
   return {
     onLlmActivity: (l) => listeners.add(l),
     offLlmActivity: (l) => listeners.delete(l),
     hasActiveSessions: () => opts?.hasActiveSessions ?? false,
+    onWindowFocus: (l) => focusListeners.add(l),
+    offWindowFocus: (l) => focusListeners.delete(l),
     fireLlmActivity: () => {
       for (const l of [...listeners]) l();
     },
+    fireWindowFocus: () => {
+      for (const l of [...focusListeners]) l();
+    },
   };
 }
 
@@ -432,4 +443,32 @@ describe("UsageMonitorService", () => {
     await vi.advanceTimersByTimeAsync(10_000);
     expect(gateway.fetchUsage).toHaveBeenCalledTimes(baseline);
   });
+
+  it("refreshes when the window regains focus, not just on LLM activity", async () => {
+    const gateway = mockGateway(makeUsage({ burstPercent: 10 }));
+    const agent = makeActivityMonitor();
+    service = makeService(gateway, agent);
+    service.init();
+    await vi.advanceTimersByTimeAsync(0);
+    expect(gateway.fetchUsage).toHaveBeenCalledTimes(1);
+
+    agent.fireWindowFocus();
+    await vi.advanceTimersByTimeAsync(5_000);
+    expect(gateway.fetchUsage).toHaveBeenCalledTimes(2);
+  });
+
+  it("unsubscribes from window focus events on stop()", async () => {
+    const gateway = mockGateway(makeUsage({ burstPercent: 10 }));
+    const agent = makeActivityMonitor();
+    service = makeService(gateway, agent);
+    service.init();
+    await vi.advanceTimersByTimeAsync(0);
+    const baseline = (gateway.fetchUsage as ReturnType<typeof vi.fn>).mock.calls
+      .length;
+
+    service.stop();
+    agent.fireWindowFocus();
+    await vi.advanceTimersByTimeAsync(10_000);
+    expect(gateway.fetchUsage).toHaveBeenCalledTimes(baseline);
+  });
 });

packages/core/src/usage/usage-monitor.ts

@@ -31,6 +31,7 @@ export class UsageMonitorService extends TypedEventEmitter<UsageMonitorEvents> {
   private latestUsage: UsageOutput | null = null;
 
   private readonly onLlmActivity = (): void => this.requestRefresh();
+  private readonly onWindowFocus = (): void => this.requestRefresh();
 
   constructor(
     @inject(USAGE_HOST)
@@ -83,13 +84,15 @@ export class UsageMonitorService extends TypedEventEmitter<UsageMonitorEvents> {
   init(): void {
     this.pruneStaleEntries();
     this.host.onLlmActivity(this.onLlmActivity);
+    this.host.onWindowFocus(this.onWindowFocus);
     void this.fetchOnce();
     this.scheduleBackstop();
   }
 
   @preDestroy()
   stop(): void {
     this.host.offLlmActivity(this.onLlmActivity);
+    this.host.offWindowFocus(this.onWindowFocus);
     if (this.backstopTimeoutId) {
       clearTimeout(this.backstopTimeoutId);
       this.backstopTimeoutId = null;