\documentclass{article}

\usepackage{agda}

\begin{document}

100\% postulated: \begin{code}%
\>[0]\AgdaKeyword{postulate}\AgdaSpace{}%
\AgdaPostulate{A}\AgdaSpace{}%
\AgdaSymbol{:}\AgdaSpace{}%
\AgdaPrimitiveType{Set}\<%
\end{code}

\end{document}
