Unseen AI: what Europe’s public sector buys, and what its procurement registers cannot show (v1.2.1)

White paper (version 1.2, October 2026) measuring how much of the artificial intelligence that Europe’s public sector buys is visible in its procurement registers, and what the registers cannot show. The review sheets and gold-standard samples are at https://doi.org/10.6084/m9.figshare.34912959; the code is available from the author on request. Read the paper and explore the data at https://arquestra.dev/research