diff --git a/README.md b/README.md
index 1a9145c..ae1caf3 100644
--- a/README.md
+++ b/README.md
@@ -35,13 +35,28 @@ After setup and installing dependencies, you can run the proxy in either of thes
 ### 1. Recommended: Run via the CLI/main entrypoint
 
 ```bash
-# Run as module:
+# Run as module with environment variables:
 python -m claudex.main --host 0.0.0.0 --port 8082 --reload
 
-# Or (if installed as a script):
-claudex --host 0.0.0.0 --port 8082 --reload
+# Or with command line arguments:
+python -m claudex.main --target-api-base https://api.openrouter.ai/v1 --big-model openai/gpt-4.1 --small-model openai/gpt-4.1-mini --log-level INFO
+
+# Or if installed as a script:
+claudex --host 0.0.0.0 --port 8082 --target-api-base https://api.openrouter.ai/v1 --big-model openai/gpt-4.1 --small-model openai/gpt-4.1-mini
 ```
 
+#### CLI Options
+
+- `--host` - Host to bind (default: 0.0.0.0)
+- `--port` - Port to bind (default: 8082)
+- `--reload` - Enable live-reload for development
+- `--target-api-base` - Base URL for target OpenAI-compatible API
+- `--big-model` - Target model for Claude Sonnet/larger models
+- `--small-model` - Target model for Claude Haiku/smaller models
+- `--log-level` - Logging level (DEBUG, INFO, WARNING, ERROR)
+
+Note: The API key must still be provided via the TARGET_API_KEY environment variable for security reasons.
+
 ### 2. Alternative: Run directly with Uvicorn
 
 ```bash
diff --git a/claudex/main.py b/claudex/main.py
index 4efc435..8142200 100644
--- a/claudex/main.py
+++ b/claudex/main.py
@@ -1,4 +1,5 @@
 import uvicorn
+import os
 from .proxy import app
 
 def main():
@@ -7,8 +8,22 @@ def main():
     parser.add_argument('--host', default='0.0.0.0', help='Host to bind (default: 0.0.0.0)')
     parser.add_argument('--port', type=int, default=8082, help='Port to bind (default: 8082)')
     parser.add_argument('--reload', action='store_true', help='Enable live-reload (for development)')
+    parser.add_argument('--target-api-base', help='Base URL for target OpenAI-compatible API (default: from TARGET_API_BASE env)')
+    parser.add_argument('--big-model', help='Target model for Claude Sonnet/larger models (default: from BIG_MODEL_TARGET env)')
+    parser.add_argument('--small-model', help='Target model for Claude Haiku/smaller models (default: from SMALL_MODEL_TARGET env)')
+    parser.add_argument('--log-level', choices=['DEBUG', 'INFO', 'WARNING', 'ERROR'], default=None, help='Logging level (default: from LOG_LEVEL env)')
     args = parser.parse_args()
 
+    # Set environment variables from CLI arguments if provided
+    if args.target_api_base:
+        os.environ['TARGET_API_BASE'] = args.target_api_base
+    if args.big_model:
+        os.environ['BIG_MODEL_TARGET'] = args.big_model
+    if args.small_model:
+        os.environ['SMALL_MODEL_TARGET'] = args.small_model
+    if args.log_level:
+        os.environ['LOG_LEVEL'] = args.log_level
+
     uvicorn.run("claudex.proxy:app", host=args.host, port=args.port, reload=args.reload)
 
 if __name__ == "__main__":