RULESHow it works
Do ChatGPT Work and Codex share usage limits?
On some plans they share an agentic allowance and credits. Your account and workspace settings show the exact rules.
Full answer and how it works
On plans with a shared allowance or credits, Codex, ChatGPT Work and some Workspace Agents can draw from the same pool.
The model, task complexity, context, reasoning effort, speed and tools all affect how much each request uses, so "number of messages" isn't a reliable unit.