PREFIX ex: <http://a.example>
PREFIX sx: <http://www.w3.org/ns/shex#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>

[] a sx:Schema ;
    sx:shapes (<http://a.example/S1>) .

<http://a.example/S1> a sx:ShapeDecl ; sx:shapeExpr [ a sx:Shape ;
  sx:expression
    [ a sx:TripleConstraint ;
      sx:predicate <http://a.example/p1> ] ;
  sx:annotation
    ([ a sx:Annotation ;
       sx:predicate <http://a.example/annot1> ;
       sx:object "STRING_LITERAL1" ]) ] .