I looked at just one of those multi-agent-systems, called MAS-ZERO. In its minimal setting, it dispatches 5 concurrent queries to e.g. gpt-5 and loops that 10 times.
Every one of these queries is turned into tens of thousands of tokens by the system prompt, and routinely dispatches secondary queries to 5 other models. So if your initial query was 100 tokens, this turns it into 10,000 x 5 x 50 tokens, so several million.
And that is without even going to "reasoning"
(2/3)