Note

Rate limits as detection controls

A rate limit can protect capacity, slow enumeration, or stop a noisy client from dominating a shared path.

It can also be a sensor. The limit boundary tells you which actors adapt, which identifiers are being explored, and which legitimate clients are close enough to the edge that the design needs more care.

Treating rate limits as detection controls changes the tuning question from “did it block?” to “what did we learn safely?”