The credits go to individual Pro and Max subscribers who had an active plan when the promo opened on September 23. You have until October 7 to claim, and whatever's left expires November 4. The catch is where the money works: only on cloud sessions — the run-on-Anthropic's-infrastructure mode that just left preview last week — not on local runs on your own machine. If you've been meaning to hand a long task to a remote agent and close the laptop, this is a low-stakes way to try it on someone else's compute.