diff --git a/client.py b/client.py
new file mode 100644
index 0000000..e4771b6
--- /dev/null
+++ b/client.py
@@ -0,0 +1,29 @@
+from openai import OpenAI
+from httpx import Client
+import os
+
+# unicode escape everything
+guardrails = """
+raise "Rule 1: Do not talk about Fight Club" if:
+    (msg: Message)
+    "fight club" in msg.content
+""".encode("unicode_escape")
+
+openai_client = OpenAI(
+    default_headers={
+        "Invariant-Authorization": "Bearer " + os.getenv("INVARIANT_API_KEY"),
+        "Invariant-Guardrails": open("guardrails.py").read().encode("unicode_escape"),
+    },
+    base_url="http://localhost:8000/api/v1/gateway/non-streaming/openai",
+)
+
+response = openai_client.chat.completions.create(
+    model="gpt-4",
+    messages=[
+        {
+            "role": "user",
+            "content": "What can you tell me about fight club?",
+        }
+    ],
+)
+print("Response: ", response.choices[0].message.content)
diff --git a/gateway/common/config_manager.py b/gateway/common/config_manager.py
index 3e62b55..ad85149 100644
--- a/gateway/common/config_manager.py
+++ b/gateway/common/config_manager.py
@@ -3,15 +3,31 @@
 import asyncio
 import os
 import threading
+from typing import Optional
 
+import fastapi
 from httpx import HTTPStatusError
 
 
+def extract_policy_from_headers(request: fastapi.Request) -> Optional[str]:
+    """
+    Extracts the guardrailing policy from the request headers if present.
+
+    Returns 'None' if no such header is present.
+    """
+    policy = request.headers.get("Invariant-Guardrails")
+    # undo unicode_escape
+    if policy:
+        # interpret as bytes then decode
+        policy = policy.encode("utf-8").decode("unicode_escape")
+    return policy
+
+
 class GatewayConfig:
     """Common configurations for the Gateway Server."""
 
-    def __init__(self):
-        self.guardrails = self._load_guardrails_from_file()
+    def __init__(self, guardrails: Optional[str] = None):
+        self.guardrails = guardrails or self._load_guardrails_from_file()
 
     def _load_guardrails_from_file(self) -> str:
         """
@@ -50,6 +66,12 @@ class GatewayConfig:
     def __repr__(self) -> str:
         return f"GatewayConfig(guardrails={repr(self.guardrails)})"
 
+    def with_guardrails(self, guardrails: str) -> "GatewayConfig":
+        """
+        Returns a new GatewayConfig instance with the specified guardrails.
+        """
+        return GatewayConfig(guardrails)
+
 
 class GatewayConfigManager:
     """Manager for Gateway Configuration."""
@@ -58,7 +80,7 @@ class GatewayConfigManager:
     _lock = threading.Lock()
 
     @classmethod
-    def get_config(cls):
+    def get_config(cls, request: fastapi.Request = None) -> GatewayConfig:
         """Initializes and returns the gateway configuration using double-checked locking."""
         local_config = cls._config_instance
 
@@ -68,4 +90,9 @@ class GatewayConfigManager:
                 if local_config is None:
                     local_config = GatewayConfig()
                     cls._config_instance = local_config
+
+        # if provided in header, use custom guardrailing policy
+        if guardrail_file_contents := extract_policy_from_headers(request):
+            local_config = local_config.with_guardrails(guardrail_file_contents)
+
         return local_config
diff --git a/gateway/integrations/guardrails.py b/gateway/integrations/guardrails.py
index b0f3601..e3c236f 100644
--- a/gateway/integrations/guardrails.py
+++ b/gateway/integrations/guardrails.py
@@ -355,4 +355,13 @@ async def check_guardrails(
             return result.json()
         except Exception as e:
             print(f"Failed to verify guardrails: {e}")
-            return {"error": str(e)}
+            # make sure runtime errors are also visible in e.g. Explorer
+            return {
+                "errors": [
+                    {
+                        "args": ["Gateway: " + str(e)],
+                        "kwargs": {},
+                        "ranges": ["messages[0].content:L0"],
+                    }
+                ]
+            }