Set add_security_analyzer=False by default and simplify examples (#846)

Co-authored-by: openhands <openhands@all-hands.dev>

Author: xingyaoww

examples/01_standalone_sdk/01_hello_world.py

@@ -18,13 +18,7 @@
     base_url=base_url,
     usage_id="agent",
 )
-
-add_security_analyzer = bool(os.getenv("ADD_SECURITY_ANALYZER", "").strip())
-if add_security_analyzer:
-    print("Agent security analyzer added.")
-agent = get_default_agent(
-    llm=llm, cli_mode=True, add_security_analyzer=add_security_analyzer
-)
+agent = get_default_agent(llm=llm, cli_mode=True)
 
 # Start a conversation and send some messages
 cwd = os.getcwd()

examples/01_standalone_sdk/04_confirmation_mode_example.py

@@ -88,7 +88,10 @@ def run_until_finished(conversation: BaseConversation, confirmer: Callable) -> N
     api_key=SecretStr(api_key),
 )
 
-agent = get_default_agent(llm=llm)
+add_security_analyzer = bool(os.getenv("ADD_SECURITY_ANALYZER", "").strip())
+if add_security_analyzer:
+    print("Agent security analyzer added.")
+agent = get_default_agent(llm=llm, add_security_analyzer=add_security_analyzer)
 conversation = Conversation(agent=agent, workspace=os.getcwd())
 
 # 1) Confirmation mode ON

examples/01_standalone_sdk/23_responses_reasoning.py

@@ -24,10 +24,8 @@
 logger = get_logger(__name__)
 
 
-api_key = os.getenv("LLM_API_KEY")
-if api_key is None:
-    api_key = os.getenv("OPENAI_API_KEY")
-assert api_key is not None, "Set LLM_API_KEY or OPENAI_API_KEY in your environment."
+api_key = os.getenv("LLM_API_KEY") or os.getenv("OPENAI_API_KEY")
+assert api_key, "Set LLM_API_KEY or OPENAI_API_KEY in your environment."
 
 model = os.getenv("LLM_MODEL", "openhands/gpt-5-codex")
 base_url = os.getenv("LLM_BASE_URL")