Hey I'm looking for some advice on a common use case: handling calls for returning customers. My goal is to load a digest of a previous conversation right at the beginning of a new call to give the assistant some context. My current approach uses two separate assistants - one for new and one for returning users. Both are configured with a tool to fetch the conversation digest from my backend. The issue is that the tool only triggers when the user explicitly asks for it. My goal is to have it fire automatically at the start of the call. Ideally, I'd like to simplify this by using a single assistant and dynamically changing its system context or greeting based on the user's history. Is this possible with the Vapi API? I've also experimented with using Vapi Workflows for this. They seem like a good fit for this kind of logic, but I found the prompts within them to be more limited compared to a standard Assistant. This made it difficult to provide the full context I wanted. If workflows are the best way to handle this, I'm willing to use them and find a way to simplify the context. But before I go down that path, I wanted to ask if I'm missing a simpler method. What's the best practice for this? Is there a way to get a standard Assistant to automatically trigger a tool at the beginning of a call? Any guidance would be greatly appreciated. Thanks!