Most small businesses end up run by “reluctant operators” who never signed up to handle billing, HR, insurance claims and cash flow. Dental practices highlight that gap: US dentists spend hours on paperwork, hiring, training and negotiating with insurers instead of patient care. That work is getting harder to staff and costly when done wrong. Lassie, backed by a16z’s $35 million Series A, aims to automate those tasks using AI agents that plug into a practice’s existing systems and workflows. Founders Steijn Pelle and Frédéric Renken built Lassie after learning the hard way inside Dr. Kwon’s dental office—processing payments by hand to map every step. They then spent months interviewing dentists, primary care doctors and healthcare finance teams before writing any code. Today Lassie reads insurance claims, reconciles payments, posts to ledgers and flags exceptions without leaving the practice team with review work. It’s live in over 700 practices across 49 states, driving $10 million in annualized revenue and saving 250,000 hours of labor each year. Dentists report that Lassie doesn’t just speed up admin—it catches underpayments, denials and missing claims that would otherwise slip through. The startup chose dental first because its workflows are structured and high-value, but the founders believe the same model applies broadly. Every small business juggles scheduling, paperwork, payments, vendor management and exceptions. AI agents shift the value from software tools to delivered labor, handling thousands of recurring workflows end to end. Lassie’s edge isn’t just its AI model, but its integrations and growing knowledge layer. As it completes workflows, it learns business-specific rules, vendor quirks and system details—making it hard for competitors to clone. a16z sees this as a pivotal shift: software that doesn’t just assist but actually runs the work. If you know a dentist owner or want to build this tech, Lassie is hiring.