Retry logic in AI commerce agents creates structural double-purchase problem

A common failure in AI-driven commerce occurs when an agent retries a purchase tool call, resulting in duplicate valid orders. This is a structural issue arising from three separate but reasonable design choices: agents retrying failed calls, purchase operations not being idempotent, and payment settlement being asynchronous. The problem exists in the gap between systems, as each component behaves correctly within its own boundaries. A proposed solution involves creating a unique commitment identifier generated before any purchase attempt, which all parties can reference to deduplicate retries.