fix: add customize anthropic baseURL (#28)

* fix: add custom anthropic baseURL

* feat: add baseURL support for all AI providers

- Add GOOGLE_BASE_URL for Google Generative AI
- Add AZURE_BASE_URL for Azure OpenAI
- Add OLLAMA_BASE_URL support (was documented but not implemented)
- Add OPENROUTER_BASE_URL for OpenRouter
- Fix missing semicolon in Anthropic case
- Update env.example with new environment variables

Closes #20

---------

Co-authored-by: dayuan.jiang <jdy.toh@gmail.com>

env.example

@@ -20,16 +20,20 @@ AI_MODEL=global.anthropic.claude-sonnet-4-5-20250929-v1:0
 
 # Anthropic (Direct) Configuration
 # ANTHROPIC_API_KEY=sk-ant-...
+# ANTHROPIC_BASE_URL=https://your-custom-anthropic/v1
 
 # Google Generative AI Configuration
 # GOOGLE_GENERATIVE_AI_API_KEY=...
+# GOOGLE_BASE_URL=https://generativelanguage.googleapis.com/v1beta  # Optional: Custom endpoint
 
 # Azure OpenAI Configuration
 # AZURE_RESOURCE_NAME=your-resource-name
 # AZURE_API_KEY=...
+# AZURE_BASE_URL=https://your-resource.openai.azure.com  # Optional: Custom endpoint (overrides resourceName)
 
 # Ollama (Local) Configuration
 # OLLAMA_BASE_URL=http://localhost:11434/api  # Optional, defaults to localhost
 
 # OpenRouter Configuration
 # OPENROUTER_API_KEY=sk-or-v1-...
+# OPENROUTER_BASE_URL=https://openrouter.ai/api/v1  # Optional: Custom endpoint

lib/ai-providers.ts

@@ -1,9 +1,9 @@
 import { bedrock } from '@ai-sdk/amazon-bedrock';
 import { openai, createOpenAI } from '@ai-sdk/openai';
-import { anthropic } from '@ai-sdk/anthropic';
+import { createAnthropic } from '@ai-sdk/anthropic';
-import { google } from '@ai-sdk/google';
+import { google, createGoogleGenerativeAI } from '@ai-sdk/google';
-import { azure } from '@ai-sdk/azure';
+import { azure, createAzure } from '@ai-sdk/azure';
-import { ollama } from 'ollama-ai-provider-v2';
+import { ollama, createOllama } from 'ollama-ai-provider-v2';
 import { createOpenRouter } from '@openrouter/ai-sdk-provider';
 
 export type ProviderName =
@@ -115,26 +115,55 @@ export function getAIModel(): ModelConfig {
       break;
 
     case 'anthropic':
-      model = anthropic(modelId);
+      const customProvider = createAnthropic({
+        apiKey: process.env.ANTHROPIC_API_KEY,
+        baseURL: process.env.ANTHROPIC_BASE_URL || 'https://api.anthropic.com/v1',
+        headers: ANTHROPIC_BETA_HEADERS,
+      });
+      model = customProvider(modelId);
       // Add beta headers for fine-grained tool streaming
       headers = ANTHROPIC_BETA_HEADERS;
       break;
 
     case 'google':
-      model = google(modelId);
+      if (process.env.GOOGLE_BASE_URL) {
+        const customGoogle = createGoogleGenerativeAI({
+          apiKey: process.env.GOOGLE_GENERATIVE_AI_API_KEY,
+          baseURL: process.env.GOOGLE_BASE_URL,
+        });
+        model = customGoogle(modelId);
+      } else {
+        model = google(modelId);
+      }
       break;
 
     case 'azure':
-      model = azure(modelId);
+      if (process.env.AZURE_BASE_URL) {
+        const customAzure = createAzure({
+          apiKey: process.env.AZURE_API_KEY,
+          baseURL: process.env.AZURE_BASE_URL,
+        });
+        model = customAzure(modelId);
+      } else {
+        model = azure(modelId);
+      }
       break;
 
     case 'ollama':
-      model = ollama(modelId);
+      if (process.env.OLLAMA_BASE_URL) {
+        const customOllama = createOllama({
+          baseURL: process.env.OLLAMA_BASE_URL,
+        });
+        model = customOllama(modelId);
+      } else {
+        model = ollama(modelId);
+      }
       break;
 
     case 'openrouter':
       const openrouter = createOpenRouter({
         apiKey: process.env.OPENROUTER_API_KEY,
+        ...(process.env.OPENROUTER_BASE_URL && { baseURL: process.env.OPENROUTER_BASE_URL }),
       });
       model = openrouter(modelId);
       break;