DECIDER use case: prevent model acting like it accesses tools

[slobentanzer]

If you ask "how many patients are in the database" without selecting KG RAG, the model may respond "let me look in the graph", but not actually acting on it (because it can't). We may need to instruct the model that it should expect tool input (or "no result") simultaneously with the user asking a question that involves tool input; informing the user that they need to select a tool if they seem to want to do that.