diff --git a/README-EN.md b/README-EN.md
index 78a350b..e017e09 100644
--- a/README-EN.md
+++ b/README-EN.md
@@ -123,6 +123,10 @@ This project consists of three core files, each with its own specific function:
     ```bash
     node gemini-api-server.js --oauth-creds-file "/path/to/your/oauth_creds.json"
     ```
+*   **Start with Specified Project ID** (e.g., for multi-project environments)
+    ```bash
+    node gemini-api-server.js --project-id your-gcp-project-id
+    ```
 
 #### 💻 Call the API (Default API Key: `123456`)
 *   **List Models**
diff --git a/README.md b/README.md
index ab15bbc..301e47a 100644
--- a/README.md
+++ b/README.md
@@ -123,6 +123,10 @@
     ```bash
     node gemini-api-server.js --oauth-creds-file "/path/to/your/oauth_creds.json"
     ```
+*   **通过指定项目ID启动** (例如，用于多项目环境)
+    ```bash
+    node gemini-api-server.js --project-id your-gcp-project-id
+    ```
 
 #### 💻 调用 API (默认 API Key: `123456`)
 *   **列出模型**
diff --git a/gemini-api-server.js b/gemini-api-server.js
index 08e2165..581b940 100644
--- a/gemini-api-server.js
+++ b/gemini-api-server.js
@@ -57,6 +57,9 @@
  *    // 通过指定凭证文件路径启动 (例如，用于自定义凭证位置)
  *    node gemini-api-server.js --oauth-creds-file "/path/to/your/oauth_creds.json"
  *
+ *    // 通过指定项目ID启动 (例如，用于多项目环境)
+ *    node gemini-api-server.js --project-id your-gcp-project-id
+ *
  * 3. 调用 API 接口 (默认 API Key: 123456):
  *
  *    // a) 列出可用模型 (GET 请求，密钥在 URL 参数中)
@@ -106,6 +109,7 @@ let REQUIRED_API_KEY = '123456'; // Default API Key
 let SERVER_PORT = 3000; // Default Port
 let OAUTH_CREDS_BASE64 = null; // New variable for base64 encoded OAuth credentials
 let OAUTH_CREDS_FILE_PATH = null; // New variable for OAuth credentials file path
+let PROJECT_ID = null; // New variable for project ID
 
 const args = process.argv.slice(2);
 const remainingArgs = [];
@@ -151,6 +155,13 @@ for (let i = 0; i < args.length; i++) {
         } else {
             console.warn(`[Config Warning] --oauth-creds-file flag requires a value.`);
         }
+    } else if (args[i] === '--project-id') { // New argument for project ID
+        if (i + 1 < args.length) {
+            PROJECT_ID = args[i + 1];
+            i++; // Skip the value
+        } else {
+            console.warn(`[Config Warning] --project-id flag requires a value.`);
+        }
     } else {
         remainingArgs.push(args[i]);
     }
@@ -186,7 +197,7 @@ function isAuthorized(req, requestUrl) {
 let apiServiceInstance = null;
 async function getApiService() {
     if (!apiServiceInstance) {
-        apiServiceInstance = new GeminiApiService(HOST, OAUTH_CREDS_BASE64, OAUTH_CREDS_FILE_PATH);
+        apiServiceInstance = new GeminiApiService(HOST, OAUTH_CREDS_BASE64, OAUTH_CREDS_FILE_PATH, PROJECT_ID);
         await apiServiceInstance.initialize();
     } else if (!apiServiceInstance.isInitialized) {
         await apiServiceInstance.initialize();
@@ -291,6 +302,7 @@ server.listen(SERVER_PORT, HOST, () => {
     console.log(`  Required API Key: ${REQUIRED_API_KEY}`);
     console.log(`  Prompt Logging: ${PROMPT_LOG_MODE}${PROMPT_LOG_MODE === 'file' ? ` (to ${PROMPT_LOG_FILENAME})` : ''}`);
     console.log(`  OAuth Creds File Path: ${OAUTH_CREDS_FILE_PATH || 'Default'}`);
+    console.log(`  Project ID: ${PROJECT_ID || 'Auto-discovered'}`); // Log the project ID
     console.log(`--------------------------`);
     console.log(`\nGemini API Server (Final) running on http://${HOST}:${SERVER_PORT}`);
     console.log('Initializing service... This may take a moment.');
diff --git a/gemini-core.js b/gemini-core.js
index 01ace83..f75dabe 100644
--- a/gemini-core.js
+++ b/gemini-core.js
@@ -124,9 +124,9 @@ export async function getRequestBody(req) {
 
 // --- Main Service Class ---
 export class GeminiApiService {
-    constructor(host = 'localhost', oauthCredsBase64 = null, oauthCredsFilePath = null) {
+    constructor(host = 'localhost', oauthCredsBase64 = null, oauthCredsFilePath = null, projectId = null) {
         this.authClient = new OAuth2Client(OAUTH_CLIENT_ID, OAUTH_CLIENT_SECRET);
-        this.projectId = null;
+        this.projectId = projectId; // Set projectId from constructor argument
         this.availableModels = [];
         this.isInitialized = false;
         this.host = host;
@@ -138,7 +138,15 @@ export class GeminiApiService {
         if (this.isInitialized) return;
         console.log('[Service] Initializing Gemini API Service...');
         await this.initializeAuth();
-        this.projectId = await this.discoverProjectAndModels();
+        // Only discover project ID if it's not already provided
+        if (!this.projectId) {
+            this.projectId = await this.discoverProjectAndModels();
+        } else {
+            console.log(`[Service] Using provided Project ID: ${this.projectId}`);
+            // Still need to ensure models are set up even if project ID is provided
+            this.availableModels = ['gemini-2.5-pro', 'gemini-2.5-flash'];
+            console.log(`[Service] Using fixed models: [${this.availableModels.join(', ')}]`);
+        }
         this.isInitialized = true;
         console.log(`[Service] Initialization complete. Project ID: ${this.projectId}`);
     }
@@ -239,7 +247,12 @@ export class GeminiApiService {
     }
 
     async discoverProjectAndModels() {
-        if (this.projectId) return this.projectId;
+        // If projectId is already set, return it directly
+        if (this.projectId) {
+            console.log(`[Service] Using pre-configured Project ID: ${this.projectId}`);
+            return this.projectId;
+        }
+
         console.log('[Service] Discovering Project ID...');
         this.availableModels = ['gemini-2.5-pro', 'gemini-2.5-flash'];
         console.log(`[Service] Using fixed models: [${this.availableModels.join(', ')}]`);
@@ -249,7 +262,7 @@ export class GeminiApiService {
                 return loadResponse.cloudaicompanionProject;
             }
             const defaultTier = loadResponse.allowedTiers?.find(tier => tier.isDefault);
-            const onboardRequest = { tierId: defaultTier?.id || 'free-tier', metadata: { pluginType: 'GEMINI' } };
+            const onboardRequest = { tierId: defaultTier?.id || 'free-tier', metadata: { pluginType: 'GEMINI' } , cloudaicompanionProject: 'default',};
             let lro = await this.callApi('onboardUser', onboardRequest);
             while (!lro.done) {
                 await new Promise(resolve => setTimeout(resolve, 2000));
@@ -278,11 +291,14 @@ export class GeminiApiService {
 
     async callApi(method, body, isRetry = false) {
         try {
+            console.log(`${CODE_ASSIST_ENDPOINT}/${CODE_ASSIST_API_VERSION}:${method}`);
+            console.log(body);
             const res = await this.authClient.request({
                 url: `${CODE_ASSIST_ENDPOINT}/${CODE_ASSIST_API_VERSION}:${method}`,
                 method: "POST", headers: { "Content-Type": "application/json" },
                 responseType: "json", body: JSON.stringify(body),
             });
+            console.log(res.data);
             return res.data;
         } catch (error) {
             if (error.response?.status === 401 && !isRetry) {
diff --git a/openai-api-server.js b/openai-api-server.js
index 95b1230..d3a7e95 100644
--- a/openai-api-server.js
+++ b/openai-api-server.js
@@ -71,6 +71,11 @@
  *      node openai-api-server.js --oauth-creds-file "/path/to/your/oauth_creds.json"
  *      ```
  *
+ *    - **通过指定项目ID启动** (例如，用于多项目环境)
+ *      ```bash
+ *      node openai-api-server.js --project-id your-gcp-project-id
+ *      ```
+ *
  * 4. 调用 API 接口 (假设 API Key: `your_secret_key`, 服务运行在 `localhost:8000`):
  *
  *    - **a) 列出可用模型**
@@ -127,6 +132,7 @@ let REQUIRED_API_KEY = '123456'; // Default API Key
 let SERVER_PORT = 8000; // Default Port
 let OAUTH_CREDS_BASE64 = null; // New variable for base64 encoded OAuth credentials
 let OAUTH_CREDS_FILE_PATH = null; // New variable for OAuth credentials file path
+let PROJECT_ID = null; // New variable for project ID
 
 const args = process.argv.slice(2);
 const remainingArgs = [];
@@ -172,6 +178,13 @@ for (let i = 0; i < args.length; i++) {
         } else {
             console.warn(`[Config Warning] --oauth-creds-file flag requires a value.`);
         }
+    } else if (args[i] === '--project-id') { // New argument for project ID
+        if (i + 1 < args.length) {
+            PROJECT_ID = args[i + 1];
+            i++; // Skip the value
+        } else {
+            console.warn(`[Config Warning] --project-id flag requires a value.`);
+        }
     } else {
         remainingArgs.push(args[i]);
     }
@@ -398,7 +411,7 @@ function isAuthorized(req, requestUrl) {
 let apiServiceInstance = null;
 async function getApiService() {
     if (!apiServiceInstance) {
-        apiServiceInstance = new GeminiApiService(HOST, OAUTH_CREDS_BASE64, OAUTH_CREDS_FILE_PATH);
+        apiServiceInstance = new GeminiApiService(HOST, OAUTH_CREDS_BASE64, OAUTH_CREDS_FILE_PATH, PROJECT_ID);
         await apiServiceInstance.initialize();
     } else if (!apiServiceInstance.isInitialized) { // Ensure re-initialization if not already initialized
         await apiServiceInstance.initialize();
@@ -522,6 +535,7 @@ server.listen(SERVER_PORT, HOST, () => {
     console.log(`  Required API Key: ${REQUIRED_API_KEY}`);
     console.log(`  Prompt Logging: ${PROMPT_LOG_MODE}${PROMPT_LOG_MODE === 'file' ? ` (to ${PROMPT_LOG_FILENAME})` : ''}`);
     console.log(`  OAuth Creds File Path: ${OAUTH_CREDS_FILE_PATH || 'Default'}`);
+    console.log(`  Project ID: ${PROJECT_ID || 'Auto-discovered'}`); // Log the project ID
     console.log(`---------------------------------------------`);
     console.log(`\nServer running on http://${HOST}:${SERVER_PORT}`);
     console.log('Initializing backend service... This may take a moment.');