A rationality-bounding condition is formulated: when jointly solving control, communication, and computing problems (С ), an optimal solution (control action) can be impossible to find due to real-time requirements, and almost optimal solutions have to be used instead (the best ones found under the existing constraints on the search procedure). This condition interconnects common concepts in control and optimization such as requisite variety, bounded rationality, analytical complexity, heuristics, and records in real-time optimization, demonstrating their unity and deep relationship. For the institutional control of organizational and technical systems, several applications-relevant problems are solved: minimizing the error or complexity, finding a critical capacity of a communication channel and a critical rate of computing, and determining the maximum number of controlled subsystems.