The quota display for Codex is a bit interesting.

It shows that this week's quota is already at 0%,
but the current conversation can still continue to work.
Let's not jump to conclusions; it could be several mechanisms stacking together:
The short-term window quota is still active,
the current session has a grace period,
local tool calls don't fully consume the same pool,
UI percentage may be rounded or delayed,
the remote host status is still maintained.
These kinds of details are quite similar to the real complexity of an Agent product:
Users see a chat box,
but behind the scenes, there might be a bunch of quota, session, tools, permissions, host status coordinating.
In the future, when using AI tools, you might really need to learn how to check system status,
and not just focus on that one percentage on the UI.