diff --git a/adala/runtimes/_litellm.py b/adala/runtimes/_litellm.py
index c5975f16..535861c7 100644
--- a/adala/runtimes/_litellm.py
+++ b/adala/runtimes/_litellm.py
@@ -134,6 +134,7 @@ class LiteLLMChatRuntime(Runtime):
                  with the provider of your specified model.
         base_url (Optional[str]): Base URL, optional. If provided, will be used to talk to an OpenAI-compatible API provider besides OpenAI.
         api_version (Optional[str]): API version, optional except for Azure.
+        extra_headers (Optional[Dict[str, str]]): Extra headers to be sent with the request.
         timeout: Timeout in seconds.
     """
 
@@ -303,6 +304,7 @@ class AsyncLiteLLMChatRuntime(AsyncRuntime):
                  with the provider of your specified model.
         base_url (Optional[str]): Base URL, optional. If provided, will be used to talk to an OpenAI-compatible API provider besides OpenAI.
         api_version (Optional[str]): API version, optional except for Azure.
+        extra_headers (Optional[Dict[str, str]]): Extra headers to be sent with the request.
         timeout: Timeout in seconds.
     """
 
diff --git a/tests/manual_test_scripts/auth_proxy_server.py b/tests/manual_test_scripts/auth_proxy_server.py
new file mode 100644
index 00000000..efec5414
--- /dev/null
+++ b/tests/manual_test_scripts/auth_proxy_server.py
@@ -0,0 +1,75 @@
+import os
+import httpx
+from loguru import logger
+from fastapi import FastAPI, Request, HTTPException
+from fastapi.responses import StreamingResponse
+
+"""
+This script is a simple HTTP proxy server that forwards requests to a target URL.
+It requires the TARGET_URL environment variable to be set to the target URL.
+It also requires the EXPECTED_HEADER environment variable to be set to the expected Authorization header value.
+
+To install the dependencies, run the following command:
+```
+pip install fastapi httpx loguru
+```
+
+To run the server:
+```
+TARGET_URL=https://example.com EXPECTED_HEADER=secret uvicorn auth_proxy_server:app
+```
+
+This will forward all requests to `https://example.com` and check for the `Authorization` header to be equal to `secret`.
+"""
+app = FastAPI()
+
+TARGET_URL = os.getenv('TARGET_URL')
+EXPECTED_HEADER = os.getenv('EXPECTED_HEADER')
+
+
+async def proxy_request(request: Request):
+    # Check for authentication header
+    auth_header = request.headers.get("Authorization")
+    if not auth_header:
+        raise HTTPException(status_code=401, detail="Authorization header missing")
+    if EXPECTED_HEADER and auth_header != EXPECTED_HEADER:
+        raise HTTPException(status_code=403, detail=f"Invalid Authorization header."
+                                                    f" Provided: {auth_header}. Required: {EXPECTED_HEADER}")
+
+    # Prepare the URL for the proxied request
+    path = request.url.path
+    if request.url.query:
+        path += f"?{request.url.query}"
+    url = f"{TARGET_URL}{path}"
+
+    # Prepare headers
+    headers = dict(request.headers)
+    headers["host"] = TARGET_URL.split("://")[1]
+
+    logger.info(f"Forwarding request to {url}, headers: {headers}")
+
+    # Create httpx client
+    async with httpx.AsyncClient(timeout=60) as client:
+        # Forward the request
+        response = await client.request(
+            method=request.method,
+            url=url,
+            headers=headers,
+            content=await request.body()
+        )
+
+    # Stream the response back to the client
+    return StreamingResponse(
+        response.aiter_bytes(),
+        status_code=response.status_code,
+        headers=response.headers
+    )
+
+
+@app.api_route("/{path:path}", methods=["GET", "POST", "PUT", "DELETE", "OPTIONS", "HEAD", "PATCH", "TRACE"])
+async def catch_all(request: Request, path: str):
+    return await proxy_request(request)
+
+if __name__ == "__main__":
+    import uvicorn
+    uvicorn.run(app, host="0.0.0.0", port=8010)
\ No newline at end of file
diff --git a/tests/test_agent_custom_model.py b/tests/test_agent_custom_model.py
new file mode 100644
index 00000000..ce1a552f
--- /dev/null
+++ b/tests/test_agent_custom_model.py
@@ -0,0 +1,47 @@
+import pytest
+import pandas as pd
+import responses
+import asyncio
+
+
+@responses.activate
+def test_agent_with_custom_base_url():
+    from adala.agents import Agent  # type: ignore
+
+    agent_json = {
+        "skills": [
+            {
+                "type": "ClassificationSkill",
+                "name": "ClassificationResult",
+                "instructions": "",
+                "input_template": "Classify sentiment of the input text: {input}",
+                "field_schema": {
+                    "output": {
+                        "type": "string",
+                        "enum": ["positive", "negative", "neutral"],
+                    }
+                },
+            }
+        ],
+        "runtimes": {
+            "default": {
+                "type": "AsyncLiteLLMChatRuntime",
+                "api_version": "v1",
+                "max_tokens": 4096,
+                "model": "openai/llama3.1",
+                "temperature": 0,
+                "batch_size": 100,
+                "timeout": 120,
+                "verbose": False,
+                "base_url": "http://localhost:11434/v1/",
+                "api_key": "ollama",
+                "auth_token": "SECRET-TEST-TOKEN",
+            }
+        },
+    }
+    agent = Agent(**agent_json)
+
+    df = pd.DataFrame([["I'm happy"], ["I'm sad"], ["I'm neutral"]], columns=["input"])
+
+    results = asyncio.run(agent.arun(input=df))
+    print(results)