diff --git a/backend/src/common/utils/ai-caller.ts b/backend/src/common/utils/ai-caller.ts
index 13f80e8..d3b14a4 100644
--- a/backend/src/common/utils/ai-caller.ts
+++ b/backend/src/common/utils/ai-caller.ts
@@ -37,7 +37,12 @@ export async function callOpenAICompatible(params: AICallerParams): Promise<AICa
   const https = await import('https');
 
   const aiResult = await new Promise<{ status: number; body: string }>((resolve, reject) => {
-    const url = new URL(`${apiUrl}/chat/completions`);
+    // Normalize: strip trailing slash and /chat/completions if user included it
+    let baseUrl = apiUrl.replace(/\/+$/, '');
+    if (baseUrl.endsWith('/chat/completions')) {
+      baseUrl = baseUrl.slice(0, -'/chat/completions'.length);
+    }
+    const url = new URL(`${baseUrl}/chat/completions`);
 
     const options = {
       hostname: url.hostname,
diff --git a/frontend/src/pages/admin/AdminShadowAiPage.tsx b/frontend/src/pages/admin/AdminShadowAiPage.tsx
index 996a7f8..70ca42a 100644
--- a/frontend/src/pages/admin/AdminShadowAiPage.tsx
+++ b/frontend/src/pages/admin/AdminShadowAiPage.tsx
@@ -194,7 +194,7 @@ function ModelSlotCard({ slot, model, isLoading }: { slot: string; model?: Shado
         </Group>
         <Divider />
         <TextInput label="Display Name" placeholder="e.g. GPT-4o" value={name} onChange={(e) => setName(e.target.value)} size="sm" />
-        <TextInput label="API URL" placeholder="https://api.openai.com/v1" value={apiUrl} onChange={(e) => setApiUrl(e.target.value)} size="sm" />
+        <TextInput label="API URL" description="Base URL only — /chat/completions is added automatically" placeholder="https://openrouter.ai/api/v1" value={apiUrl} onChange={(e) => setApiUrl(e.target.value)} size="sm" />
         <PasswordInput label="API Key" placeholder="sk-..." value={apiKey} onChange={(e) => setApiKey(e.target.value)} size="sm" />
         <TextInput label="Model Name" placeholder="gpt-4o" value={modelName} onChange={(e) => setModelName(e.target.value)} size="sm" />
         <Switch label="Active" checked={isActive} onChange={(e) => setIsActive(e.currentTarget.checked)} />