Security systems often ask operators to trust a black box. Sigma takes the opposite posture: every decision should be explainable, scoped, and reviewable. It is a runtime guardrail layer for environments that have already been inspected and now need policy-aware observation or enforcement during operation.
Sigma is not a universal sandbox or a magic container-escape blocker. Its framing is narrower and stronger: it evaluates defined capability policies, records how a decision was reached, and supports a staged path from observation to action. Teams can start in passive mode, compare decisions with real workload behaviour, and only then decide whether stronger controls make sense.
The useful story is operational maturity. Sigma is built around traces, modes, operator feedback, and local observation. Instead of claiming every threat can be stopped, it asks a more credible question: when the system makes a security-relevant decision, can the operator understand why? Can the policy be reviewed? Can a false positive become part of the next calibration cycle?
That makes Sigma relevant for teams that care about reproducibility, incident review, and gradual adoption. It sits beside existing OS controls, CI gates, and monitoring — a semantic policy layer that does not pretend to replace the rest of the stack.
When the system makes a security decision, can the operator understand why?