Why it matters for your business
Tool calling is the bridge between an AI model and your business systems, so it is where much of the value and much of the risk sit. The model only proposes a call; your code decides whether to run it. That means permissions, input validation and approval steps can be enforced in software rather than left to the prompt. Well-designed tools are narrow and clearly described, such as get_invoice_status rather than run_any_sql_query. Poorly scoped tools are a common source of agent errors and security problems.
Example
A support agent for an online retailer has three tools: look up an order by number, check shipment tracking, and create a return label for orders under 30 days old. When a customer asks where a package is, the model calls the order and tracking tools, then answers. The return tool checks the 30-day rule in code, so the model cannot override it.