Update Strategy in SamplingParams to be a union

llama_stack/distribution/ui/page/playground/chat.py

@@ -95,6 +95,15 @@ if prompt := st.chat_input("Example: What is Llama Stack?"):
         message_placeholder = st.empty()
         full_response = ""
 
+        if temperature > 0.0:
+            strategy = {
+                "type": "top_p",
+                "temperature": temperature,
+                "top_p": top_p,
+            }
+        else:
+            strategy = {"type": "greedy"}
+
         response = llama_stack_api.client.inference.chat_completion(
             messages=[
                 {"role": "system", "content": system_prompt},
@@ -103,8 +112,7 @@ if prompt := st.chat_input("Example: What is Llama Stack?"):
             model_id=selected_model,
             stream=stream,
             sampling_params={
-                "temperature": temperature,
-                "top_p": top_p,
+                "strategy": strategy,
                 "max_tokens": max_tokens,
                 "repetition_penalty": repetition_penalty,
             },

llama_stack/distribution/ui/page/playground/rag.py

@@ -118,13 +118,20 @@ def rag_chat_page():
         with st.chat_message(message["role"]):
             st.markdown(message["content"])
 
+    if temperature > 0.0:
+        strategy = {
+            "type": "top_p",
+            "temperature": temperature,
+            "top_p": top_p,
+        }
+    else:
+        strategy = {"type": "greedy"}
+
     agent_config = AgentConfig(
         model=selected_model,
         instructions=system_prompt,
         sampling_params={
-            "strategy": "greedy",
-            "temperature": temperature,
-            "top_p": top_p,
+            "strategy": strategy,
         },
         tools=[
             {