Add a simple gpt-oss example (#1440)

This pull request adds a simple gpt-oss example app

Author: seratch

examples/basic/hello_world_gpt_oss.py

@@ -0,0 +1,38 @@
+import asyncio
+import logging
+
+from openai import AsyncOpenAI
+
+from agents import Agent, OpenAIChatCompletionsModel, Runner, set_tracing_disabled
+
+set_tracing_disabled(True)
+logging.basicConfig(level=logging.DEBUG)
+
+# This is an example of how to use gpt-oss with Ollama.
+# Refer to https://cookbook.openai.com/articles/gpt-oss/run-locally-ollama for more details.
+# If you prefer using LM Studio, refer to https://cookbook.openai.com/articles/gpt-oss/run-locally-lmstudio
+gpt_oss_model = OpenAIChatCompletionsModel(
+    model="gpt-oss:20b",
+    openai_client=AsyncOpenAI(
+        base_url="http://localhost:11434/v1",
+        api_key="ollama",
+    ),
+)
+
+
+async def main():
+    # Note that using a custom outputType for an agent may not work well with gpt-oss models.
+    # Consider going with the default "text" outputType.
+    # See also: https://github.com/openai/openai-agents-python/issues/1414
+    agent = Agent(
+        name="Assistant",
+        instructions="You're a helpful assistant. You provide a concise answer to the user's question.",
+        model=gpt_oss_model,
+    )
+
+    result = await Runner.run(agent, "Tell me about recursion in programming.")
+    print(result.final_output)
+
+
+if __name__ == "__main__":
+    asyncio.run(main())