What is the primary architectural purpose of utilizing a canonical null directive within the four-module modular harness protocol?

In harnesses lacking an explicit planning mechanism, the null planner module emits the canonical null directive unconditionally at every time step.

Explain how the four-module protocol h = (M, P, A, F) accommodates purely reactive architectures like ReAct while preserving modular interface semantics.

Match each symbol or component from the four-module modular harness protocol with its designated role.

By employing a canonical null directive, downstream modules retain identical functional signatures across complex planned workflows and purely ___ architectures.

Evaluate the developer's proposal against the protocol's design principles. What component should be used instead, and what operational advantage does it confer?