Tool design scenarios — CCA-F Exam Prep

An agent was given a payment tool with one parameter: 'details' (string). It charged a customer $50.00 USD. Then it charged another customer 'fifty dollars.' The server crashed.

When the tool accepts a free-text string for the amount, the agent can pass '$50', '50.00', 'fifty dollars', or '-50' (which accidentally triggers a refund). Tool design isn't about what works in the demo. It's about what can't go wrong in production.