HiL-Bench (Human-in-Loop Benchmark): Do Agents Know When to Ask for Help? - Mohamed Elfeki; Tu Trinh; Kelvin Luu; Guangze Luo; Nathan Hunt; Ernesto Montoya; Nandan Marwaha; Yannis He; Charles Wang; Fernando Crabedo; Alessa Castilo; Bing Liu (CoRR, 2026)