At least for the sake of this demo, the costs are actually pretty small, especially given that many of the ... even at $1.75/1M tokens you'd have to have 2 megabytes of text across all users before this even broke $1...
The unit price looks low but the cost driver in these apps is usually the context window. You have to re-send the full history every turn to maintain state, so you end up paying for the same tokens dozens of times. By the end of a long session the cost per interaction is significantly higher than at the start since you're re-processing the entire game log for every new command.
It ran for a while when I gave it instructions to do a depth-first search of the known map, while observing any atypical features of every new location and also picking up anything of note. A few times, it asked me if I wanted to continue the search, but I finally told it not to interrupt the search until it had exhausted all new options, which made it run until it said it had reached the maximum number of tool calls (15).
