The thing that trips up agents like this in production is ambiguous external API responses. A hotel booking returns "pending" and the agent either stalls or treats it as confirmed - both wrong. Built something similar for scheduling and the fix was explicit state transitions: unconfirmed, confirmed, failed. You define what "done" means for each step, not the model. The model is decent at reasoning about next steps but genuinely bad at catching when "pending" isn't "booked" after 10 chained tool calls. Worth building that state machine early rather than debugging it after the first failed retreat booking.