GZCLP uses three tiers: T1 (5×3+, the main strength lift), T2 (3×10+, a secondary lift for volume), T3 (3×15+, accessories). You alternate Workout A and B three times per week.
The program's own rule is that when you fail a T1 lift twice, it moves down to T2 and a new lift takes the T1 slot. That regression is part of GZCLP itself — worth being precise here: RepRoute does not automate it for you, and it does not trigger a deload off failed sets. You follow the program's rule; RepRoute tracks the numbers.
What RepRoute layers on top is equipment substitution, injury-aware removal, PR detection, and a deload banner when your recent training says you've earned one. The core program runs unchanged.