diff --git a/src/infra/providers/utils.ts b/src/infra/providers/utils.ts
index 7af874b..18ef69e 100644
--- a/src/infra/providers/utils.ts
+++ b/src/infra/providers/utils.ts
@@ -58,8 +58,8 @@ export function normalizeBaseUrl(url: string): string {
 
 export function normalizeOpenAIBaseUrl(url: string): string {
   let normalized = url.replace(/\/+$/, '');
-  // Auto-append /v1 if not present (for OpenAI-compatible APIs)
-  if (!normalized.endsWith('/v1')) {
+  // Auto-append /v1 if no version path detected (e.g., /v1, /v2, /v4)
+  if (!/\/v\d+$/.test(normalized)) {
     normalized += '/v1';
   }
   return normalized;
diff --git a/tests/unit/providers/openai.test.ts b/tests/unit/providers/openai.test.ts
index 0efd3d2..14e94bf 100644
--- a/tests/unit/providers/openai.test.ts
+++ b/tests/unit/providers/openai.test.ts
@@ -10,6 +10,11 @@ runner
     const config = provider.toConfig();
     expect.toEqual(config.baseUrl, 'https://api.openai.com/v1');
   })
+  .test('baseUrl 保留已有版本路径 /v4 (GLM coding endpoint)', async () => {
+    const provider = new OpenAIProvider('test-key', 'any-model', 'https://open.bigmodel.cn/api/coding/paas/v4');
+    const config = provider.toConfig();
+    expect.toEqual(config.baseUrl, 'https://open.bigmodel.cn/api/coding/paas/v4');
+  })
   .test('请求体包含 system 与工具调用结构', async () => {
     const provider = new OpenAIProvider('test-key', 'gpt-4o', 'https://api.openai.com');
     const messages: Message[] = [