    \documentclass{article}

    \usepackage{agda}

    % Make sure that cluster counting is activated.
    \begin{code}[hide]
      {-# OPTIONS --count-clusters #-}
    \end{code}

    \begin{document}

    \AgdaPostulate{A} and \AgdaPostulate{B} should be aligned:
    \begin{code}
      postulate
        +̲+̲+̲+̲+̲+̲  A
                B : Set
    \end{code}

    The two \AgdaKeyword{field} keywords should not be aligned:
    \begin{code}
      record +̲ : Set₁ where  field C : Set
                              field D : Set
    \end{code}

    \end{document}