fix(chat): resolve llm client endpoint conflicts with model base urls

Author: juhuaxia

apps/webuiapps/src/lib/__tests__/llmClient.test.ts

@@ -345,6 +345,16 @@ describe('chat()', () => {
       expect(headers['Authorization']).toBe('Bearer sk-test-key');
     });
 
+    it('uses v1/chat/completions when baseUrl has no version suffix', async () => {
+      const mockFetch = vi.fn().mockResolvedValueOnce(makeOpenAIResponse('ok'));
+      globalThis.fetch = mockFetch;
+
+      await chat(MOCK_MESSAGES, [], MOCK_OPENAI_CONFIG);
+
+      const headers = mockFetch.mock.calls[0][1].headers as Record<string, string>;
+      expect(headers['X-LLM-Target-URL']).toBe('https://api.openai.com/v1/chat/completions');
+    });
+
     it('includes tools in body when tools array is non-empty', async () => {
       const mockFetch = vi.fn().mockResolvedValueOnce(makeOpenAIResponse('ok'));
       globalThis.fetch = mockFetch;
@@ -421,6 +431,20 @@ describe('chat()', () => {
       expect(headers['x-api-key']).toBe('ant-test-key');
     });
 
+    it('uses /messages when baseUrl already includes /v1', async () => {
+      const mockFetch = vi.fn().mockResolvedValueOnce(makeAnthropicResponse('Anthropic response'));
+      globalThis.fetch = mockFetch;
+
+      const configWithVersion: LLMConfig = {
+        ...MOCK_ANTHROPIC_CONFIG,
+        baseUrl: 'https://api.anthropic.com/v1',
+      };
+      await chat(MOCK_MESSAGES, [], configWithVersion);
+
+      const headers = mockFetch.mock.calls[0][1].headers as Record<string, string>;
+      expect(headers['X-LLM-Target-URL']).toBe('https://api.anthropic.com/v1/messages');
+    });
+
     it('extracts system message to top-level system field', async () => {
       const messages: ChatMessage[] = [
         { role: 'system', content: 'You are helpful.' },

apps/webuiapps/src/lib/llmClient.ts

@@ -94,6 +94,22 @@ interface LLMResponse {
   toolCalls: ToolCall[];
 }
 
+function hasVersionSuffix(url: string): boolean {
+  return /\/v\d+\/?$/.test(url);
+}
+
+function joinUrl(baseUrl: string, path: string): string {
+  return `${baseUrl.replace(/\/+$/, '')}/${path.replace(/^\/+/, '')}`;
+}
+
+function getOpenAICompletionsPath(baseUrl: string): string {
+  return hasVersionSuffix(baseUrl) ? 'chat/completions' : 'v1/chat/completions';
+}
+
+function getAnthropicMessagesPath(baseUrl: string): string {
+  return hasVersionSuffix(baseUrl) ? 'messages' : 'v1/messages';
+}
+
 function parseCustomHeaders(raw?: string): Record<string, string> {
   if (!raw) return {};
   const headers: Record<string, string> = {};
@@ -143,7 +159,7 @@ async function chatOpenAI(
     body.tools = tools;
   }
 
-  const targetUrl = `${config.baseUrl}/chat/completions`;
+  const targetUrl = joinUrl(config.baseUrl, getOpenAICompletionsPath(config.baseUrl));
   const toolNames = Array.isArray(tools) ? tools.map((t) => t.function?.name).filter(Boolean) : [];
   logger.info('ToolLog', 'LLM Request: toolCount=', tools.length, 'toolNames=', toolNames);
   logger.info('LLM', 'Request:', {
@@ -250,7 +266,7 @@ async function chatAnthropic(
     'toolNames=',
     anthropicToolNames,
   );
-  const targetUrl = `${config.baseUrl}/v1/messages`;
+  const targetUrl = joinUrl(config.baseUrl, getAnthropicMessagesPath(config.baseUrl));
   logger.info('LLM', 'Anthropic Request:', {
     targetUrl,
     model: config.model,