docs: improve safety doc

Signed-off-by: reidliu <reid201711@gmail.com>

docs/source/building_applications/safety.md

@@ -3,15 +3,28 @@
 Safety is a critical component of any AI application. Llama Stack provides a Shield system that can be applied at multiple touchpoints:
 
 ```python
+from llama_stack_client import LlamaStackClient
+
+# Replace host and port
+client = LlamaStackClient(base_url=f"http://{HOST}:{PORT}")
+
 # Register a safety shield
 shield_id = "content_safety"
-client.shields.register(shield_id=shield_id, provider_shield_id="llama-guard-basic")
+SHEILD_NAME = "meta-llama/Llama-Guard-3-1B"
+# If no provider specified and multiple providers available, need specify provider_id, e.g. provider_id="llama-guard"
+# Check with `llama model list` for the supported Llama Guard type models
+client.shields.register(shield_id=shield_id, provider_shield_id=SHEILD_NAME)
 
 # Run content through shield
+# To trigger a violation result, try inputting some sensitive content in <User message here>
 response = client.safety.run_shield(
-    shield_id=shield_id, messages=[{"role": "user", "content": "User message here"}]
+    shield_id=SHEILD_NAME,
+    messages=[{"role": "user", "content": "User message here"}],
+    params={},
 )
 
 if response.violation:
     print(f"Safety violation detected: {response.violation.user_message}")
+else:
+    print("The input content does not trigger any violations.")
 ```