Your code seems to be correct, so I assume there might be something wrong with how you're calling the flow.

In my environment, your code is working for both the Dev UI and curl POST.

• Dev UI (run genkit start -o)

• curl

$ curl -X POST -H "Content-Type: application/json" -d '{"data": {"question": "What is the menu suggestion for today?"}}' http://[your_firebase_function_url]/menuSuggestionFlow
{"result":{"answer":"This is the answer to your question: What is the menu suggestion for today?"}}