What is cache hit rate?
Cache hit rate is (hits + adapts) ÷ (hits + adapts + compiles) over a window of your runs. Twin computes it per tenant from the mode each run settled in, alongside total credits charged and an estimate of the credits those hits and adapts saved against cold compiles.
Why it matters
It is the metric that tells you whether your agents are re-phrasing the same intents (in which case the cache is compounding) or genuinely doing new things every time (in which case it is not, and that is worth knowing). It is a free read — it does not reserve or charge credits.