diff --git a/frontend/src/app/ApiContext.tsx b/frontend/src/app/ApiContext.tsx
index 901ccc5..d7abd48 100644
--- a/frontend/src/app/ApiContext.tsx
+++ b/frontend/src/app/ApiContext.tsx
@@ -6,7 +6,7 @@ type HttpClient = typeof httpClient;
 
 interface ApiContextValue {
   client: HttpClient;
-  setAuthToken: (token?: string | null) => void;
+  setAuthToken: (token: string) => void;
   clearAuthToken: () => void;
 }
 
diff --git a/frontend/src/lib/apiClient.ts b/frontend/src/lib/apiClient.ts
index 93f0df1..672e718 100644
--- a/frontend/src/lib/apiClient.ts
+++ b/frontend/src/lib/apiClient.ts
@@ -281,12 +281,8 @@ export const listTenants = async (): Promise<TenantSnippet[]> => {
   return Array.isArray(data?.tenants) ? data.tenants : [];
 };
 
-export const setAuthToken = (token?: string | null) => {
-  if (token) {
-    api.defaults.headers.common.Authorization = `Bearer ${token}`;
-  } else {
-    delete api.defaults.headers.common.Authorization;
-  }
+export const setAuthToken = (token: string) => {
+  api.defaults.headers.common.Authorization = `Bearer ${token}`;
 };
 
 export const clearAuthToken = () => {