Figure 1: Overview of STRIDE. From K initial samples, STRIDE selects a champion and refines it
for t rounds. Each round performs evolutionary refinement and agent state update through dual-route
evaluation: the verifier scores candidate images against the rubrics, while the perceptor provides vi-
sual grounding of the observed failures. The lead editor then analyzes the agent state and refinement
trajectory to route the champion to either the composer for global redraw or the retoucher for local
editing. The generated candidates are then re-evaluated, and the champion is updated only when a
candidate improves the verifier score. Repeating this process yields the final champion.