@@ -241,13 +241,14 @@ export const MuseDriver: ProviderDriver<
         // The probe may have advanced the generation before publishing its new account.
         if (!newer || auth.type === "apiKey" || museUsageAccount(auth) !== account.identity) return;
         const now = yield* DateTime.now;
+        const authLabel = museUsageAuth(auth, usage.tier).label;
         yield* snapshot.applyUsageLimits({
           windows: museUsageWindows(usage, DateTime.toEpochMillis(now)),
           checkedAt: DateTime.formatIso(DateTime.makeUnsafe(usage.observedAtMs)),
           // A report is the account's whole state, so a window that has reset
           // since loses its old reset time instead of keeping it.
-          replace: true,
-          authLabel: museUsageAuth(auth, usage.tier).label,
+          complete: true,
+          ...(authLabel !== undefined ? { authLabel } : {}),
         });
       }, usagePermit.withPermits(1)),
       ...(eventLoggers.native ? { nativeEventLogger: eventLoggers.native } : {}),
 
@@ -182,6 +182,7 @@ describe("Muse usage limits", () => {
     });
     expect(museUsageAccount(apiKey)).toBeUndefined();
     expect(museUsageAuth(login, "tier-1")).toEqual({ ...login, label: "tier-1" });
+    expect(museUsageAuth({ ...login, label: "tier-1" }, " ").label).toBeUndefined();
     const labelOnly = { status: "authenticated", type: "accountLogin", label: "Team A" } as const;
     expect(museUsageAuth(labelOnly, "tier-1")).toBe(labelOnly);
     const other = nextMuseUsageAccount(named, { ...login, email: "[email protected]" });
 
@@ -177,5 +177,5 @@ export function museUsageAuth(
 ): ServerProviderAuth {
   if (auth.type === "accountLogin" && !auth.email) return auth;
   const label = tier?.trim();
-  return label ? { ...auth, label } : auth;
+  return { ...auth, label: label || undefined };
 }
@@ -164,7 +164,7 @@ export const refreshMuseUsage = Effect.fn("MuseUsageProbe.refresh")(function* (i
         latestUsage,
         provider: {
           ...provider,
-          auth: museUsageAuth(provider.auth, latestUsage?.usage.tier),
+          auth: latestUsage ? museUsageAuth(provider.auth, latestUsage.usage.tier) : provider.auth,
           usageLimits,
           ...(message
             ? {
Original file line number	Diff line number	Diff line change
`@@ -177,5 +177,5 @@ export function museUsageAuth(`
`177`	`177`	`): ServerProviderAuth {`
`178`	`178`	`if (auth.type === "accountLogin" && !auth.email) return auth;`
`179`	`179`	`const label = tier?.trim();`
`180`		`- return label ? { ...auth, label } : auth;`
	`180`	`+ return { ...auth, label: label \|\| undefined };`
`181`	`181`	`}`