The 'AI-First Law Firm' Just Got a Business Model: What Mid-Market Firms Should Steal From Carta Law, Avantia, and Harvey in 2026

May 2026 has been the month the AI-first law firm became a business model, not a thesis. Carta acquired ALSP Avantia and launched Carta Law. Harvey is at an $11B valuation. Legora raised $600M. The mid-market lesson isn't to copy the brand — it's to copy the operating architecture that makes AI compoundable: a unified backbone, native trust accounting, and AI applied to the workflow, not bolted next to it.