JSON schema scenarios — CCA-F Exam Prep

A payment tool's schema defined amount as { type: 'number' }. No minimum. No maximum. A user asked Claude to 'test if the system works' and Claude sent amount: 0. The payment processor charged $0.30 in processing fees for nothing.

The same schema also allowed amount: -500, which accidentally triggered a refund instead of a charge. And amount: 10.999, which caused rounding errors downstream. Three bugs, one missing constraint: the schema didn't say what a valid amount looks like.