Refactor safety response handling in guardrails.mdx for js

Author: mcavdar

src/oss/langchain/guardrails.mdx

@@ -531,13 +531,7 @@ def safety_guardrail(state: AgentState, runtime: Runtime) -> dict[str, Any] | No
     result = safety_model.invoke([{"role": "user", "content": safety_prompt}])
 
     if "UNSAFE" in result.content:
-        return {
-            "messages": [{
-                "role": "assistant",
-                "content": "I cannot provide that response. Please rephrase your request."
-            }],
-            "jump_to": "end"
-        }
+        last_message.content = "I cannot provide that response. Please rephrase your request."
 
     return None
 
@@ -590,14 +584,7 @@ const safetyGuardrailMiddleware = () => {
       ]);
 
       if (result.content.toString().includes("UNSAFE")) {
-        return {
-          messages: [
-            new AIMessage(
-              "I cannot provide that response. Please rephrase your request."
-            )
-          ],
-          jumpTo: "end",
-        };
+        lastMessage.content = "I cannot provide that response. Please rephrase your request.";
       }
 
       return;