Image-generation agents stop merely retrying: failure experience passes a counterfactual check before entering the skill library, reaching 86.1 on GenEval2
Agentic image-generation pipelines have largely been read-only generate-verify-rewrite loops that discard repair experience or admit ungated updates into a skill library. VEvo-Harness expands each failed verdict into a hierarchical verification tree to locate root causes, then admits only causally valid skill patches through counterfactual dual-arm image replay, with memory organized into working, experience and pattern tiers. On the Qwen-Image-2512 backend it reaches 86.1 on GenEval2, 14.5 points above GenRouter, while continuing to evolve.