diff --git a/Sources/Services/Feishu/FeishuAuthService.swift b/Sources/Services/Feishu/FeishuAuthService.swift
index 13b3361..f8e6e47 100644
--- a/Sources/Services/Feishu/FeishuAuthService.swift
+++ b/Sources/Services/Feishu/FeishuAuthService.swift
@@ -102,14 +102,13 @@ final class FeishuAuthService {
         var request = URLRequest(url: url)
         request.httpMethod = "POST"
         request.setValue("application/json; charset=utf-8", forHTTPHeaderField: "Content-Type")
-        request.httpBody = try JSONEncoder().encode([
-            "app_id": appId,
-            "app_secret": appSecret
-        ])
+        let body: [String: String] = ["app_id": appId, "app_secret": appSecret]
+        request.httpBody = try JSONEncoder().encode(body)
 
-        let response: FeishuAPIResponse<TenantAccessTokenData> = try await send(request)
-        guard let data = response.data else {
-            throw FeishuError.apiError(code: response.code, message: response.msg)
+        // This endpoint returns code/msg/tenant_access_token/expire all at top level
+        let data: TenantAccessTokenData = try await send(request)
+        guard data.code == 0 else {
+            throw FeishuError.apiError(code: data.code, message: data.msg)
         }
 
         cachedTenantToken = data.tenantAccessToken
diff --git a/Sources/Services/Feishu/FeishuModels.swift b/Sources/Services/Feishu/FeishuModels.swift
index 6d98b5a..f99e18e 100644
--- a/Sources/Services/Feishu/FeishuModels.swift
+++ b/Sources/Services/Feishu/FeishuModels.swift
@@ -40,10 +40,14 @@ struct OAuthTokenData: Decodable {
 }
 
 struct TenantAccessTokenData: Decodable {
+    let code: Int
+    let msg: String
     let tenantAccessToken: String
     let expire: Int
 
     enum CodingKeys: String, CodingKey {
+        case code
+        case msg
         case tenantAccessToken = "tenant_access_token"
         case expire
     }