# Cua S1- A family of System One models > Source: > Published: 2026-09-18 19:15:04+00:00 Cua on X: "1/ Introducing CUA-S1: a family of System One Models, small, specialized, and built for computer use. Today we're open-sourcing CUA-S1-FORMS, the first in the family: https://t.co/J1frbEbZTQ" 1/ Introducing CUA-S1: a family of System One Models, small, specialized, and built for computer use. Today we're open-sourcing CUA-S1-FORMS, the first in the family: github.com/trycua/cua 1/ Introducing CUA-S1: a family of System One Models, small, specialized, and built for computer use. Today we're open-sourcing CUA-S1-FORMS, the first in the family: github.com/trycua/cua 2/ A specialist in action. On the left, a small specialist decides how to fill the form in one pass. Cua Driver then carries out the actions in order. On the right, an LLM agent works through the form step by step using Cua Driver. 3/ CUA-S1-FORMS selects from known options: FILL, CHECK, CLICK, or SKIP. Field values come from the supplied document. The application validates and orders the plan: fields, checkboxes, then submit when authorized. 5/ CUA-S1-FORMS is the first specialist in the family. If your company runs repetitive, bounded, high-volume computer workflows, we'd like to hear what CUA-S1 should learn next. [email protected] bro open-sourcing a tiny specialist that fills forms in one pass while the LLM still clicks around when the task is bounded, a small model with a fixed action set beats a chatty generalist.