Credits are consumed by the blocks that get generated, not by the agents themselves. Some blocks are cheaper than others. A simple prompt or image block is a single model call, while browser use or deliverable blocks like documents and spreadsheets run models in a loop and cost more. Blocks also cost more when they have more blocks connected to them (more input tokens).
In the demo video I shared, the task cost about ~7,000 credits since it ran around 10 BrowserUse blocks and produced multiple deliverables.
If you want to fix a specific block (or set of blocks), you can select them and the chat will scope itself to primarily work on those. In that case fewer blocks run, so it's cheaper.
7000 credits, ouch. The tool is really cool, I do think it's super useful. I also like the swarm particle animations in the backround.