I find copilot to be much more straightforward, and I can track per request against my credits. Here is the explanation of what a request is:
https://docs.github.com/en/copilot/concepts/billing/copilot-...
https://docs.github.com/en/copilot/concepts/billing/copilot-...
This clearly isn't true for agentic mode though. This document is extremely misleading. VSCode has the `chat.agent.maxRequests` option which lets you define how many requests an agent can use before it asks if you want to continue iterating, and the default is not one. A long running session (say, implementing an openspec proposal) can easily eat through dozens of requests. I have a prompt that I use for security scanning and with a single input/request (`/prompt`) it will use anywhere between 17 and 25 premium requests without any user input.