error-boundary

An error-boundary is a design boundary that separates a system component from its environment such that failures occurring outside the boundary cannot propagate across it. Parameters: (1) containment — errors on one side are intercepted and do not cross to the other side; (2) fallback — when a failure is contained, a degraded or alternative state is maintained on the protected side; (3) visibility — the boundary reports errors across itself for monitoring without allowing them to cross. It persists through code conventions, architectural documentation, and implementation in frameworks (e.g., try-catch blocks, circuit breakers, compartmentalization patterns). [formal: terminatio | substrate: behavior | horizon: a moment | explicit: yes | epoch: 0.01]