Why does Tessary check every trace instead of sampling?

Because sampling is built to measure a rate, and by the time an agent is mature, nearly everything left to catch is rare, exactly what a sample misses. Tessary checks every trace because the checks are cheap enough to afford it.

Sampling is a rate instrument: accurate and cheap for telling you how often something happens, nearly useless for catching one instance of something uncommon. The failures a team already fixed are the frequent ones, so what’s left as an agent matures is low-probability by construction.

What matters is what one check has to cost before reading everything is affordable. Deep judgment on every trace isn’t that. Tessary’s built-in classifiers are built to that constraint, with per-trace costs small enough to run against all of the traffic, so coverage follows failure modes rather than a slice of it.