\documentclass{article}
\usepackage[version=3]{acro}
\RenewAcroCommand\ac{mo}{\UseAcroTemplate{first}{#1}\IfNoValueF{#2}{#2}}
\DeclareAcronym{uc}{
short = UC ,
long = Universal Composability ,
cite = xxx
}
\begin{document}
We use the \ac{uc}[ model] for\dots
\end{document}