I see. Well, we have to consider that copilot/chatgpt hallucinates quite a bit.
What it probably meant was to build a python backend using Agents SDK, which doesn’t require any special access (it can even use other LLMs), and use C# to build the frontend.
Agent SDK however, doesn’t provide an API. It is just an orchestrator.
You would have still have to build the microservice to wire up the requests/authentication with the agents, and returning the results to your frontend. Which might be an overkill.
If you are still curious about agents sdk, I suggest trying to run it with python, even if your main language is C#, just to experience what “agents” are like at least once. Basically you just need to install python, set up an environment variable with your OpenAI API key and run a small example like in this quick start guide. Also have a look at the examples here.
Another option you might consider, is to see if deep research doesn’t match your needs. It is available in the API and provides a more sophisticated result (for a higher cost), and you can easily refer to the curl examples to build your own REST request directly from C#: