diff --git a/src/services/modelService.ts b/src/services/modelService.ts
index 75663c6..e4d3591 100644
--- a/src/services/modelService.ts
+++ b/src/services/modelService.ts
@@ -40,21 +40,23 @@ const stripKnownSuffix = (baseUrl: string) =>
     .replace(/\/(?:v1beta|v1)\/models$/i, '')
     .replace(/\/models$/i, '');
 
-const endpointCandidates = (provider: ModelProvider, baseUrl: string): string[] => {
+export const modelEndpointCandidates = (provider: ModelProvider, baseUrl: string): string[] => {
   const resolvedBaseUrl = baseUrl.trim()
     || (provider === 'gemini'
       ? DEFAULT_GEMINI_BASE_URL
       : provider === 'claude'
         ? DEFAULT_CLAUDE_BASE_URL
         : '');
-  const base = stripKnownSuffix(resolvedBaseUrl);
-  if (!base) return [];
+  const normalized = normalizeBaseUrl(resolvedBaseUrl);
+  if (!normalized) return [];
+  if (provider === 'openai') {
+    return [/\/models$/i.test(normalized) ? normalized : `${normalized}/models`];
+  }
+  const base = stripKnownSuffix(normalized);
   const withoutVersion = base.replace(/\/(?:v1beta|v1)$/i, '');
   if (provider === 'gemini') return [`${withoutVersion}/v1beta/models`];
   if (provider === 'claude') return [`${withoutVersion}/v1/models`];
-  const first = /\/v1$/i.test(base) ? `${base}/models` : `${base}/v1/models`;
-  const fallback = `${base}/models`;
-  return first === fallback ? [first] : [first, fallback];
+  return [/\/v1$/i.test(base) ? `${base}/models` : `${base}/v1/models`];
 };
 
 const normalizeModelList = (payload: unknown): ModelOption[] => {
@@ -95,7 +97,7 @@ export async function fetchModels(
   timeoutMs?: number,
 ): Promise<ModelOption[]> {
   const normalized = baseUrl.trim() ? normalizeBaseUrl(baseUrl) : '';
-  const candidates = endpointCandidates(provider, normalized);
+  const candidates = modelEndpointCandidates(provider, normalized);
   if (candidates.length === 0) throw new Error(modelText('model.error.baseUrlRequired'));
   const headers: Record<string, string> = { ...customHeaders };
   const hasHeader = (name: string) =>
diff --git a/src/services/providerHealthCheck.ts b/src/services/providerHealthCheck.ts
index 7b88e27..d6efdba 100644
--- a/src/services/providerHealthCheck.ts
+++ b/src/services/providerHealthCheck.ts
@@ -44,6 +44,12 @@ const endpointRoot = (provider: ModelProvider, baseUrl: string) => {
   return normalized.replace(/\/(?:v1beta|v1)$/i, '');
 };
 
+const openAIChatCompletionsEndpoint = (baseUrl: string) => {
+  const normalized = normalizeBaseUrl(baseUrl);
+  if (!normalized) return '';
+  return `${normalized}/chat/completions`;
+};
+
 const hasHeader = (headers: Record<string, string>, name: string) =>
   Object.keys(headers).some((key) => key.toLowerCase() === name.toLowerCase());
 
@@ -148,7 +154,7 @@ export function buildProviderHealthProbe(
   }
 
   return {
-    url: `${root}/v1/chat/completions`,
+    url: openAIChatCompletionsEndpoint(baseUrl),
     header: headers,
     protocol: 'openai-chat',
     data: JSON.stringify({
diff --git a/tests/providerHealthCheck.test.ts b/tests/providerHealthCheck.test.ts
index 42650a9..35bd9da 100644
--- a/tests/providerHealthCheck.test.ts
+++ b/tests/providerHealthCheck.test.ts
@@ -5,6 +5,7 @@ import {
   primaryProviderHealthCredential,
   runProviderModelHealthChecks,
 } from '../src/services/providerHealthCheck';
+import { modelEndpointCandidates } from '../src/services/modelService';
 
 describe('API 接入健康检测', () => {
   it('健康检测只保留已勾选模型，并使用发现结果补充模型信息', () => {
@@ -59,6 +60,51 @@ describe('API 接入健康检测', () => {
     expect(probe.protocol).toBe('openai-chat');
   });
 
+  it('为非 v1 的 OpenAI 兼容版本前缀保留原始版本号', () => {
+    const probe = buildProviderHealthProbe(
+      'openai',
+      'https://open.bigmodel.cn/api/coding/paas/v4',
+      'glm-test',
+      'secret-key',
+    );
+
+    expect(probe.url).toBe(
+      'https://open.bigmodel.cn/api/coding/paas/v4/chat/completions',
+    );
+    expect(modelEndpointCandidates(
+      'openai',
+      'https://open.bigmodel.cn/api/coding/paas/v4',
+    )).toEqual([
+      'https://open.bigmodel.cn/api/coding/paas/v4/models',
+    ]);
+  });
+
+  it('把不含版本号的中转地址视为完整 API 路径前缀', () => {
+    const baseUrl = 'https://relay.example/custom/openai';
+    const probe = buildProviderHealthProbe(
+      'openai',
+      baseUrl,
+      'mapped-model',
+      'secret-key',
+    );
+
+    expect(probe.url).toBe(
+      'https://relay.example/custom/openai/chat/completions',
+    );
+    expect(modelEndpointCandidates('openai', baseUrl)).toEqual([
+      'https://relay.example/custom/openai/models',
+    ]);
+    expect(modelEndpointCandidates(
+      'openai',
+      'https://relay.example/custom/openai/v1/models',
+    )).toEqual([
+      'https://relay.example/custom/openai/v1/models',
+    ]);
+    expect(modelEndpointCandidates('codex', 'https://codex.example')).toEqual([
+      'https://codex.example/v1/models',
+    ]);
+  });
+
   it('不会覆盖供应商已有的自定义认证头', () => {
     const probe = buildProviderHealthProbe(
       'claude',