feat: enhance assistant instructions in chat route

- Added current date to the assistant's system message for context.
- Included guidance on tool usage and user interaction for improved clarity.

app/api/chat/route.ts

@@ -197,9 +197,13 @@ export async function POST(req: Request) {
     model: model.languageModel(selectedModel),
     system: `You are a helpful assistant with access to a variety of tools.
 
+    Today's date is ${new Date().toISOString().split('T')[0]}.
+
     The tools are very powerful, and you can use them to answer the user's question.
     So choose the tool that is most relevant to the user's question.
 
+    If tools are not available, say you don't know or if the user wants a tool they can add one from the server icon in bottom left corner in the sidebar.
+
     You can use multiple tools in a single response.
     Always respond after using the tools for better user experience.
     You can run multiple steps using all the tools!!!!