>Barter involves agreeing on a specific exchange rate
This does not match with any definition that I've seen. Graeber debunks a parable used by Adam Smith and economists used to explain why money is more efficient than barter. The problem is that the central thesis of the parable still stands: trade is more efficient with through a medium of exchange.
Graeber's examples of early debt are reciprocal. Otherwise, there would be no need to record them. Sure, it's not as transactional as money is, but it's a transaction nonetheless. I'll admit it's not immediate, but I don't think that's a particularly meaningful distinction. It's not particularly difficult to trust a farmer within your community when they say they'll offer you grain in the future during harvest season. They'd risk ostracization if they break their promise, which is close to a death sentence in that era.
I remember several examples of qualitative generosity and not quantitative reciprocity, but it was a while since I read the book, so I accept that I might remember incorrectly.
This does not match with any definition that I've seen. Graeber debunks a parable used by Adam Smith and economists used to explain why money is more efficient than barter. The problem is that the central thesis of the parable still stands: trade is more efficient with through a medium of exchange.