A construction AI startup went from two agents to more than ten, and caught a $4M change order on a $100M job

Trunk Tools, founded by former carpenter Sarah Buchner, runs AI agents over the fragmented document set on a construction project — contracts, drawings, specifications, submittals, bids — and flags inconsistencies plus downstream impacts. Reported 13 August 2026: roughly $70M raised including a $40M Series B in 2025 at a $325M valuation, more than 100 staff, over ten live agents against two a year ago, revenue up fourfold last year and a projected 3.5x this year. In one case it showed a requested change would add nearly $4M to a roughly $100M project, and the owner dropped it.

What it means The value here is not document search but second- and third-order impact analysis across connected documents — the shape of agent work that is hard for a person and cheap for a machine.