The recent study by B. De Bruyne, S. N. Majumdar, H. Orland and G. Schehr [arXiv:2110.07573], concerning the conditioning of Brownian motion random walks on global dynamical constraints over a finite time-window $T$, is reformulated as general framework for 'microcanonical conditioning' Markov processes time-additive observables. This formalism applied to various types processes, namely discret...