Overview
A pillar is not a practice. It is a property the delivery system has, together with the mechanism that makes it true whether or not anyone remembers to care.
Automation
A check a human runs by hand does not exist to an agent.
Tests
Borrow a frame from systems engineering: the codebase is the plant, and every mechanism that inspects its output is a sensor in a feedback loop. Code review is one such sensor. It is not the only one, and treating it as the default is what breaks when agents enter the system.
Complexity Reduction
Complexity has always been charged to the next person who reads the code. With agents it is charged twice, and the second charge is the one teams miss.