structured requests to execute specific tools when they need capabilities beyond their training Extends capabilities - Enables real-time data access, performing actions, and running computations the LLM can't do alone Common examples - Web search, calculators, APIs, databases, code execution, email, and calendar systems Makes LLMs current and actionable - No longer limited to training data; can fetch live information and complete multi-step tasks Excursion – Tool/Function Calling From Copilot to Autopilot Integrating AI Assistants into Modern Software Engineering Practices