Real-time decoding proved essential once I tried applying a non-Clifford gate via magic state injection on a surface code patch. Without feeding the decoder output back before the gate, the pending Pauli corrections got conjugated incorrectly and the logical operator no longer matched the intended circuit. I walked through the commutation relations in a small lattice simulation and the failure mode appeared exactly where the literature predicts for T gates. A useful reference is the treatment in arXiv:2007.07303 on lattice surgery with feed-forward.