diff --git a/README.md b/README.md
index 9ad879a1..3a9678e7 100644
--- a/README.md
+++ b/README.md
@@ -59,7 +59,7 @@ TradingAgentsX 支援業界領先的多家 LLM 提供商，並為每個模型配
 | 提供商             | 支援模型                                                                                         | Base URL                                                  | 是否支援自訂端點 |
 | ------------------ | ------------------------------------------------------------------------------------------------ | --------------------------------------------------------- | ---------------- |
 | **OpenAI**         | GPT-5.1, GPT-5 Mini/Nano, GPT-4.1 Mini/Nano, o4-mini                                             | `https://api.openai.com/v1`                               | ✅ 是            |
-| **Anthropic**      | Claude Haiku 4.5, Claude Sonnet 4.5/4.0, Claude 3.5 Haiku, Claude 3 Haiku                        | `https://api.anthropic.com`                               | ✅ 是            |
+| **Anthropic**      | Claude Haiku 4.5, Claude Sonnet 4.5/4.0, Claude 3.5 Haiku, Claude 3 Haiku                        | `https://api.anthropic.com/v1`                               | ✅ 是            |
 | **Gemini**         | Gemini 2.5 Pro, Gemini 2.5 Flash, Gemini 2.5 Flash Lite, Gemini 2.0 Flash, Gemini 2.0 Flash Lite | `https://generativelanguage.googleapis.com/v1beta/openai` | ✅ 是            |
 | **Grok (xAI)**     | Grok-4.1 Fast, Grok-4 Fast, Grok-4, Grok-3, Grok-3 Mini                                          | `https://api.x.ai/v1`                                     | ✅ 是            |
 | **DeepSeek**       | DeepSeek Reasoner, DeepSeek Chat                                                                 | `https://api.deepseek.com/v1`                             | ✅ 是            |
@@ -481,7 +481,7 @@ docker compose down -v
    快速思維 API Key: sk-your-openai-key
 
    深層思維模型: claude-sonnet-4-5
-   深層思維 Base URL: https://api.anthropic.com
+   深層思維 Base URL: https://api.anthropic.com/v1
    深層思維 API Key: sk-ant-your-claude-key
 
    嵌入模型 Base URL: 自訂 → https://api.your-embedding-service.com/v1
@@ -569,7 +569,7 @@ curl -X POST http://localhost:8000/api/analyze \
     "quick_think_llm": "gpt-5-mini-2025-08-07",
     "analysts": ["market", "sentiment", "news", "fundamental"],
     "quick_think_base_url": "https://api.openai.com/v1",
-    "deep_think_base_url": "https://api.anthropic.com",
+    "deep_think_base_url": "https://api.anthropic.com/v1",
     "embedding_base_url": "https://api.openai.com/v1",
     "quick_think_api_key": "sk-your-openai-key",
     "deep_think_api_key": "sk-ant-your-claude-key",
diff --git a/cli/utils.py b/cli/utils.py
index df4af437..36d0bf1d 100644
--- a/cli/utils.py
+++ b/cli/utils.py
@@ -430,7 +430,7 @@ def select_llm_provider() -> tuple[str, str]:
     # 定義 LLM 供應商及其 API 基礎 URL
     BASE_URLS = [
         ("OpenAI", "https://api.openai.com/v1"),
-        ("Anthropic", "https://api.anthropic.com"),
+        ("Anthropic", "https://api.anthropic.com/v1"),
         ("Google", "https://generativelanguage.googleapis.com/v1beta/openai"),
         ("Grok", "https://api.x.ai/v1"),
         ("DeepSeek", "https://api.deepseek.com/v1"),
diff --git a/frontend/lib/api-helpers.ts b/frontend/lib/api-helpers.ts
index fee532a4..0ad5c341 100644
--- a/frontend/lib/api-helpers.ts
+++ b/frontend/lib/api-helpers.ts
@@ -9,12 +9,7 @@ import { ApiSettings } from "./storage";
  * If custom_base_url is set, it takes precedence
  */
 export function getBaseUrlForModel(model: string, customBaseUrl?: string): string {
-  // If custom base URL is provided, use it
-  if (customBaseUrl && customBaseUrl.trim() !== "") {
-    return customBaseUrl;
-  }
-
-  // OpenAI models
+  // OpenAI models - always use OpenAI API
   if (
     model.startsWith("gpt-") ||
     model.startsWith("o4-") ||
@@ -23,31 +18,36 @@ export function getBaseUrlForModel(model: string, customBaseUrl?: string): strin
     return "https://api.openai.com/v1";
   }
 
-  // Anthropic models
+  // Anthropic models - always use Anthropic API
   if (model.startsWith("claude-")) {
-    return "https://api.anthropic.com";
+    return "https://api.anthropic.com/v1";
   }
 
-  // Google models
+  // Google models - always use Google API
   if (model.startsWith("gemini-")) {
     return "https://generativelanguage.googleapis.com/v1beta/openai";
   }
 
-  // Grok models
+  // Grok models - always use Grok API
   if (model.startsWith("grok-")) {
     return "https://api.x.ai/v1";
   }
 
-  // DeepSeek models
+  // DeepSeek models - always use DeepSeek API
   if (model.startsWith("deepseek-")) {
     return "https://api.deepseek.com/v1";
   }
 
-  // Qwen models
+  // Qwen models - always use Qwen API
   if (model.startsWith("qwen")) {
     return "https://dashscope-intl.aliyuncs.com/compatible-mode/v1";
   }
 
+  // For "custom" or unknown models, use custom_base_url if provided
+  if (customBaseUrl && customBaseUrl.trim() !== "") {
+    return customBaseUrl;
+  }
+
   // Default to OpenAI
   return "https://api.openai.com/v1";
 }
@@ -60,14 +60,7 @@ export function getApiKeyForModel(
   model: string,
   settings: ApiSettings
 ): string {
-  // If custom base URL is configured and has a key, use the custom key
-  if (settings.custom_base_url && settings.custom_base_url.trim() !== "") {
-    if (settings.custom_api_key && settings.custom_api_key.trim() !== "") {
-      return settings.custom_api_key;
-    }
-  }
-
-  // OpenAI models
+  // OpenAI models - always use OpenAI API key
   if (
     model.startsWith("gpt-") ||
     model.startsWith("o4-") ||
@@ -76,31 +69,36 @@ export function getApiKeyForModel(
     return settings.openai_api_key;
   }
 
-  // Anthropic models
+  // Anthropic models - always use Anthropic API key
   if (model.startsWith("claude-")) {
     return settings.anthropic_api_key || "";
   }
 
-  // Google models
+  // Google models - always use Google API key
   if (model.startsWith("gemini-")) {
     return settings.google_api_key || "";
   }
 
-  // Grok models
+  // Grok models - always use Grok API key
   if (model.startsWith("grok-")) {
     return settings.grok_api_key || "";
   }
 
-  // DeepSeek models
+  // DeepSeek models - always use DeepSeek API key
   if (model.startsWith("deepseek-")) {
     return settings.deepseek_api_key || "";
   }
 
-  // Qwen models
+  // Qwen models - always use Qwen API key
   if (model.startsWith("qwen")) {
     return settings.qwen_api_key || "";
   }
 
+  // For "custom" or unknown models, use custom_api_key if provided
+  if (settings.custom_api_key && settings.custom_api_key.trim() !== "") {
+    return settings.custom_api_key;
+  }
+
   // Default to OpenAI
   return settings.openai_api_key;
 }