Add OpenRouter provider support for unified LLM API access

src/config/manager.ts

@@ -10,6 +10,7 @@ import { Logger } from '../utils/logger';
 
 export class ConfigurationManager {
   private static config: MCPServerConfig | null = null;
+  private static readonly VALID_LLM_PROVIDERS = ['gemini', 'claude', 'openai', 'openrouter'] as const;
 
   static async loadConfiguration(): Promise<MCPServerConfig> {
     Logger.debug('Loading configuration from environment variables...');
@@ -27,7 +28,8 @@ export class ConfigurationManager {
         ...(process.env.CONTEXT_OPT_LLM_MODEL && { model: process.env.CONTEXT_OPT_LLM_MODEL }),
         ...(process.env.CONTEXT_OPT_GEMINI_KEY && { geminiKey: process.env.CONTEXT_OPT_GEMINI_KEY }),
         ...(process.env.CONTEXT_OPT_CLAUDE_KEY && { claudeKey: process.env.CONTEXT_OPT_CLAUDE_KEY }),
-        ...(process.env.CONTEXT_OPT_OPENAI_KEY && { openaiKey: process.env.CONTEXT_OPT_OPENAI_KEY })
+        ...(process.env.CONTEXT_OPT_OPENAI_KEY && { openaiKey: process.env.CONTEXT_OPT_OPENAI_KEY }),
+        ...(process.env.CONTEXT_OPT_OPENROUTER_KEY && { openrouterKey: process.env.CONTEXT_OPT_OPENROUTER_KEY })
       },
       research: {
         ...(process.env.CONTEXT_OPT_EXA_KEY && { exaKey: process.env.CONTEXT_OPT_EXA_KEY })
@@ -50,18 +52,18 @@ export class ConfigurationManager {
     return config;
   }
 
-  private static getLLMProvider(): 'gemini' | 'claude' | 'openai' {
+  private static getLLMProvider(): 'gemini' | 'claude' | 'openai' | 'openrouter' {
     const provider = process.env.CONTEXT_OPT_LLM_PROVIDER?.toLowerCase();
 
     if (!provider) {
-      throw new Error('CONTEXT_OPT_LLM_PROVIDER environment variable is required. Set to "gemini", "claude", or "openai"');
+      throw new Error(`CONTEXT_OPT_LLM_PROVIDER environment variable is required. Set to ${this.VALID_LLM_PROVIDERS.map(p => `"${p}"`).join(', ')}`);
     }
 
-    if (!['gemini', 'claude', 'openai'].includes(provider)) {
-      throw new Error(`Invalid CONTEXT_OPT_LLM_PROVIDER: ${provider}. Must be "gemini", "claude", or "openai"`);
+    if (!this.VALID_LLM_PROVIDERS.includes(provider as any)) {
+      throw new Error(`Invalid CONTEXT_OPT_LLM_PROVIDER: ${provider}. Must be ${this.VALID_LLM_PROVIDERS.map(p => `"${p}"`).join(', ')}`);
     }
 
-    return provider as 'gemini' | 'claude' | 'openai';
+    return provider as 'gemini' | 'claude' | 'openai' | 'openrouter';
   }
 
   private static parseAllowedBasePaths(): string[] {
@@ -108,7 +110,7 @@ export class ConfigurationManager {
       throw new Error('Configuration error: llm.provider is required');
     }
 
-    const validProviders = ['gemini', 'claude', 'openai'];
+    const validProviders = [...this.VALID_LLM_PROVIDERS];
     if (!validProviders.includes(config.llm.provider)) {
       throw new Error(`Configuration error: llm.provider must be one of: ${validProviders.join(', ')}`);
     }
@@ -210,7 +212,8 @@ export class ConfigurationManager {
         model: config.llm.model,
         hasGeminiKey: !!config.llm.geminiKey,
         hasClaudeKey: !!config.llm.claudeKey,
-        hasOpenaiKey: !!config.llm.openaiKey
+        hasOpenaiKey: !!config.llm.openaiKey,
+        hasOpenrouterKey: !!config.llm.openrouterKey
       },
       research: {
         hasExaKey: !!config.research.exaKey

src/config/schema.ts

@@ -15,11 +15,12 @@ export interface MCPServerConfig {
 
   // LLM providers
   llm: {
-    provider: 'gemini' | 'claude' | 'openai';
+    provider: 'gemini' | 'claude' | 'openai' | 'openrouter';
     model?: string;                    // Optional custom model
     geminiKey?: string;
     claudeKey?: string;
     openaiKey?: string;
+    openrouterKey?: string;
   };
 
   // Research tools

src/providers/factory.ts

@@ -8,6 +8,7 @@ import { BaseLLMProvider, LLMResponse } from './base';
 import { GeminiProvider } from './gemini';
 import { ClaudeProvider } from './claude';
 import { OpenAIProvider } from './openai';
+import { OpenRouterProvider } from './openrouter';
 
 export interface LLMProvider {
   processRequest(prompt: string, model?: string, apiKey?: string): Promise<LLMResponse>;
@@ -29,6 +30,9 @@ export class LLMProviderFactory {
         case 'openai':
           this.providers.set(providerName, new OpenAIProvider());
           break;
+        case 'openrouter':
+          this.providers.set(providerName, new OpenRouterProvider());
+          break;
         default:
           throw new Error(`Unknown provider: ${providerName}`);
       }

src/providers/openrouter.ts

@@ -0,0 +1,62 @@
+/**
+ * OpenRouter provider implementation
+ */
+
+import { BaseLLMProvider, LLMResponse } from './base';
+
+export class OpenRouterProvider extends BaseLLMProvider {
+  readonly name = 'OpenRouter';
+  readonly defaultModel = 'openai/gpt-4o-mini';
+  readonly apiKeyUrl = 'https://openrouter.ai/';
+  readonly apiKeyPrefix = undefined; // Not standardized
+
+  async processRequest(prompt: string, model?: string, apiKey?: string): Promise<LLMResponse> {
+    if (!apiKey) {
+      return this.createErrorResponse('OpenRouter API key not configured');
+    }
+
+    try {
+      const body = this.createStandardRequest(prompt, model || this.defaultModel);
+      const headers: Record<string, string> = {
+        'Authorization': `Bearer ${apiKey}`,
+        'Content-Type': 'application/json'
+      };
+
+      // Add optional branding headers if environment variables are present
+      if (process.env.CONTEXT_OPT_APP_URL) {
+        headers['HTTP-Referer'] = process.env.CONTEXT_OPT_APP_URL;
+      }
+      if (process.env.CONTEXT_OPT_APP_NAME) {
+        headers['X-Title'] = process.env.CONTEXT_OPT_APP_NAME;
+      }
+
+      const response = await fetch('https://openrouter.ai/api/v1/chat/completions', {
+        method: 'POST',
+        headers,
+        body: JSON.stringify(body)
+      });
+
+      if (!response.ok) {
+        let errorMsg = `HTTP ${response.status}`;
+        try {
+          const errorJson: any = await response.json();
+          errorMsg = errorJson?.error?.message || errorMsg;
+        } catch {
+          // Ignore JSON parsing errors, use HTTP status
+        }
+        return this.createErrorResponse(`OpenRouter request failed: ${errorMsg}`);
+      }
+
+      const json: any = await response.json();
+      const content = json?.choices?.[0]?.message?.content;
+      if (!content) {
+        return this.createErrorResponse('No response from OpenRouter');
+      }
+
+      return this.createSuccessResponse(content);
+    } catch (error: unknown) {
+      const errorMessage = error instanceof Error ? error.message : 'Unknown error';
+      return this.createErrorResponse(`OpenRouter processing failed: ${errorMessage}`);
+    }
+  }
+}

test/openrouter.test.ts

@@ -0,0 +1,224 @@
+/**
+ * Tests for OpenRouter provider
+ */
+
+import { OpenRouterProvider } from '../src/providers/openrouter';
+
+// Mock global fetch
+const mockFetch = jest.fn();
+(global as any).fetch = mockFetch;
+
+describe('OpenRouterProvider', () => {
+  let provider: OpenRouterProvider;
+
+  beforeEach(() => {
+    provider = new OpenRouterProvider();
+    jest.clearAllMocks();
+  });
+
+  afterEach(() => {
+    jest.restoreAllMocks();
+  });
+
+  describe('Provider properties', () => {
+    it('should have correct provider properties', () => {
+      expect(provider.name).toBe('OpenRouter');
+      expect(provider.defaultModel).toBe('openai/gpt-4o-mini');
+      expect(provider.apiKeyUrl).toBe('https://openrouter.ai/');
+      expect(provider.apiKeyPrefix).toBeUndefined();
+    });
+  });
+
+  describe('processRequest', () => {
+    it('should return error when API key is not provided', async () => {
+      const result = await provider.processRequest('test prompt');
+
+      expect(result.success).toBe(false);
+      expect(result.error).toBe('OpenRouter API key not configured');
+      expect(result.content).toBe('');
+    });
+
+    it('should make successful request and return content', async () => {
+      const mockResponse = {
+        ok: true,
+        json: jest.fn().mockResolvedValue({
+          choices: [
+            {
+              message: {
+                content: 'Test response from OpenRouter'
+              }
+            }
+          ]
+        })
+      };
+      mockFetch.mockResolvedValue(mockResponse);
+
+      const result = await provider.processRequest('test prompt', 'test-model', 'test-api-key');
+
+      expect(result.success).toBe(true);
+      expect(result.content).toBe('Test response from OpenRouter');
+      expect(result.error).toBeUndefined();
+
+      expect(mockFetch).toHaveBeenCalledWith(
+        'https://openrouter.ai/api/v1/chat/completions',
+        {
+          method: 'POST',
+          headers: {
+            'Authorization': 'Bearer test-api-key',
+            'Content-Type': 'application/json'
+          },
+          body: JSON.stringify({
+            model: 'test-model',
+            temperature: 0.1,
+            max_tokens: 4000,
+            messages: [{ role: 'user', content: 'test prompt' }]
+          })
+        }
+      );
+    });
+
+    it('should use default model when model is not specified', async () => {
+      const mockResponse = {
+        ok: true,
+        json: jest.fn().mockResolvedValue({
+          choices: [
+            {
+              message: {
+                content: 'Response with default model'
+              }
+            }
+          ]
+        })
+      };
+      mockFetch.mockResolvedValue(mockResponse);
+
+      const result = await provider.processRequest('test prompt', undefined, 'test-api-key');
+
+      expect(result.success).toBe(true);
+      expect(mockFetch).toHaveBeenCalledWith(
+        expect.any(String),
+        expect.objectContaining({
+          body: expect.stringContaining('"model":"openai/gpt-4o-mini"')
+        })
+      );
+    });
+
+    it('should include optional branding headers when environment variables are set', async () => {
+      // Set environment variables
+      process.env.CONTEXT_OPT_APP_URL = 'https://example.com';
+      process.env.CONTEXT_OPT_APP_NAME = 'Test App';
+
+      const mockResponse = {
+        ok: true,
+        json: jest.fn().mockResolvedValue({
+          choices: [{ message: { content: 'Test response' } }]
+        })
+      };
+      mockFetch.mockResolvedValue(mockResponse);
+
+      await provider.processRequest('test prompt', undefined, 'test-api-key');
+
+      expect(mockFetch).toHaveBeenCalledWith(
+        expect.any(String),
+        expect.objectContaining({
+          headers: expect.objectContaining({
+            'Authorization': 'Bearer test-api-key',
+            'Content-Type': 'application/json',
+            'HTTP-Referer': 'https://example.com',
+            'X-Title': 'Test App'
+          })
+        })
+      );
+
+      // Clean up environment variables
+      delete process.env.CONTEXT_OPT_APP_URL;
+      delete process.env.CONTEXT_OPT_APP_NAME;
+    });
+
+    it('should handle HTTP error responses', async () => {
+      const mockResponse = {
+        ok: false,
+        status: 400,
+        json: jest.fn().mockResolvedValue({
+          error: {
+            message: 'Bad Request - Invalid model'
+          }
+        })
+      };
+      mockFetch.mockResolvedValue(mockResponse);
+
+      const result = await provider.processRequest('test prompt', undefined, 'test-api-key');
+
+      expect(result.success).toBe(false);
+      expect(result.error).toBe('OpenRouter request failed: Bad Request - Invalid model');
+      expect(result.content).toBe('');
+    });
+
+    it('should handle HTTP error without error JSON', async () => {
+      const mockResponse = {
+        ok: false,
+        status: 500,
+        json: jest.fn().mockRejectedValue(new Error('Invalid JSON'))
+      };
+      mockFetch.mockResolvedValue(mockResponse);
+
+      const result = await provider.processRequest('test prompt', undefined, 'test-api-key');
+
+      expect(result.success).toBe(false);
+      expect(result.error).toBe('OpenRouter request failed: HTTP 500');
+      expect(result.content).toBe('');
+    });
+
+    it('should handle malformed response (no choices)', async () => {
+      const mockResponse = {
+        ok: true,
+        json: jest.fn().mockResolvedValue({
+          // Missing choices array
+        })
+      };
+      mockFetch.mockResolvedValue(mockResponse);
+
+      const result = await provider.processRequest('test prompt', undefined, 'test-api-key');
+
+      expect(result.success).toBe(false);
+      expect(result.error).toBe('No response from OpenRouter');
+      expect(result.content).toBe('');
+    });
+
+    it('should handle malformed response (empty choices)', async () => {
+      const mockResponse = {
+        ok: true,
+        json: jest.fn().mockResolvedValue({
+          choices: []
+        })
+      };
+      mockFetch.mockResolvedValue(mockResponse);
+
+      const result = await provider.processRequest('test prompt', undefined, 'test-api-key');
+
+      expect(result.success).toBe(false);
+      expect(result.error).toBe('No response from OpenRouter');
+      expect(result.content).toBe('');
+    });
+
+    it('should handle fetch network errors', async () => {
+      mockFetch.mockRejectedValue(new Error('Network error'));
+
+      const result = await provider.processRequest('test prompt', undefined, 'test-api-key');
+
+      expect(result.success).toBe(false);
+      expect(result.error).toBe('OpenRouter processing failed: Network error');
+      expect(result.content).toBe('');
+    });
+
+    it('should handle unknown errors', async () => {
+      mockFetch.mockRejectedValue('Unknown error type');
+
+      const result = await provider.processRequest('test prompt', undefined, 'test-api-key');
+
+      expect(result.success).toBe(false);
+      expect(result.error).toBe('OpenRouter processing failed: Unknown error');
+      expect(result.content).toBe('');
+    });
+  });
+});

tsconfig.json

@@ -17,7 +17,8 @@
     "noImplicitReturns": true,
     "noFallthroughCasesInSwitch": true,
     "noUncheckedIndexedAccess": true,
-    "exactOptionalPropertyTypes": true
+    "exactOptionalPropertyTypes": true,
+    "types": ["node"]
   },
   "include": ["src/**/*"],
   "exclude": ["node_modules", "dist", "**/*.test.ts", "**/*.spec.ts"]