feat: add LiteLLM as AI gateway provider

src/setup.ts

@@ -240,6 +240,88 @@ async function setupOpenAIKey(): Promise<boolean> {
   }
 }
 
+async function setupLiteLLMProxy(): Promise<boolean> {
+  console.log('');
+  showInfo('LiteLLM is an AI gateway proxy that routes to 100+ LLM providers.');
+  showInfo('Docs: ' + chalk.underline('https://docs.litellm.ai/docs/proxy/quick_start'));
+  console.log('');
+
+  const { baseUrl } = await inquirer.prompt([
+    {
+      type: 'input',
+      name: 'baseUrl',
+      message: 'Enter your LiteLLM proxy base URL:',
+      default: 'http://localhost:4000/v1',
+      validate: (input: string) => {
+        if (!input || !input.startsWith('http')) {
+          return 'Please enter a valid URL (e.g. http://localhost:4000/v1)';
+        }
+        return true;
+      },
+    },
+  ]);
+
+  const { apiKey } = await inquirer.prompt([
+    {
+      type: 'password',
+      name: 'apiKey',
+      message: 'Enter your LiteLLM API key (leave blank if not required):',
+      mask: '*',
+    },
+  ]);
+
+  const { model } = await inquirer.prompt([
+    {
+      type: 'input',
+      name: 'model',
+      message: 'Enter the default model (uses LiteLLM model format, e.g. gpt-4o, anthropic/claude-sonnet-4-6):',
+      default: 'gpt-4o',
+    },
+  ]);
+
+  const spinner = ora('Testing LiteLLM proxy connection...').start();
+
+  try {
+    const llm = new LLMBackbone({
+      provider: 'litellm',
+      model,
+      apiKey: apiKey || undefined,
+      baseUrl,
+      maxTokens: 10,
+      temperature: 0,
+    });
+
+    await llm.prompt('Hello', undefined, { maxTokens: 10 });
+    spinner.succeed('LiteLLM proxy connection successful!');
+
+    config.set('litellm', { baseUrl, defaultModel: model });
+    if (apiKey) setApiKey('litellm', apiKey);
+    showSuccess('LiteLLM proxy configured successfully!');
+
+    return true;
+  } catch (error) {
+    spinner.fail('LiteLLM proxy connection failed');
+    showError(`Error: ${error instanceof Error ? error.message : String(error)}`);
+
+    const { saveAnyway } = await inquirer.prompt([
+      {
+        type: 'confirm',
+        name: 'saveAnyway',
+        message: 'Save the configuration anyway? (proxy may not be running yet)',
+        default: true,
+      },
+    ]);
+
+    if (saveAnyway) {
+      config.set('litellm', { baseUrl, defaultModel: model });
+      if (apiKey) setApiKey('litellm', apiKey);
+      showSuccess('LiteLLM proxy configuration saved.');
+      return true;
+    }
+    return false;
+  }
+}
+
 // =============================================================================
 // MODEL SELECTION
 // =============================================================================
@@ -285,6 +367,7 @@ You'll need an API key from one of these providers:
 • ${chalk.cyan('OpenRouter')} (recommended) - Access multiple models
 • ${chalk.cyan('Anthropic')} - Direct Claude access
 • ${chalk.cyan('OpenAI')} - GPT models
+• ${chalk.cyan('LiteLLM')} - AI gateway proxy (100+ providers)
 
 The setup will guide you through:
 1. Adding your API key(s)
@@ -384,6 +467,10 @@ async function setupApiKeys(): Promise<void> {
           name: `OpenAI ${hasApiKey('openai') ? chalk.green('(configured)') : ''}`,
           value: 'openai',
         },
+        {
+          name: `LiteLLM Proxy ${config.hasLiteLLMProxy() ? chalk.green('(configured)') : chalk.gray('(100+ providers via gateway)')}`,
+          value: 'litellm',
+        },
       ],
     },
   ]);
@@ -402,6 +489,9 @@ async function setupApiKeys(): Promise<void> {
       case 'openai':
         await setupOpenAIKey();
         break;
+      case 'litellm':
+        await setupLiteLLMProxy();
+        break;
     }
   }
 }
@@ -413,6 +503,7 @@ async function setupProvider(): Promise<void> {
   if (hasApiKey('venice')) configuredProviders.push({ name: 'Venice', value: 'venice' });
   if (hasApiKey('anthropic')) configuredProviders.push({ name: 'Anthropic', value: 'anthropic' });
   if (hasApiKey('openai')) configuredProviders.push({ name: 'OpenAI', value: 'openai' });
+  if (config.hasLiteLLMProxy()) configuredProviders.push({ name: 'LiteLLM Proxy', value: 'litellm' });
 
   if (configuredProviders.length === 0) {
     showWarning('No API keys configured. Please add at least one API key first.');