diff --git a/spacy/pipeline/spancat.py b/spacy/pipeline/spancat.py
index eb5f0bbb3..6fb26fa41 100644
--- a/spacy/pipeline/spancat.py
+++ b/spacy/pipeline/spancat.py
@@ -227,6 +227,19 @@ class SpanCategorizer(TrainablePipe):
         """
         return str(self.cfg["spans_key"])
 
+    def _allow_extra_label(self) -> None:
+        """Raise an error if the component can not add any more labels."""
+        nO = None
+        # fmt: off
+        if self.model.has_dim("nO"):
+            nO = self.model.get_dim("nO")
+        elif self.model.has_ref("output_layer") and self.model.get_ref("output_layer").has_dim("nO"):
+            nO = self.model.get_ref("output_layer").get_dim("nO")
+        if nO is not None and nO == self._n_labels:
+            if not self.is_resizable:
+                raise ValueError(Errors.E922.format(name=self.name, nO=self.model.get_dim("nO")))
+        # fmt: on
+
     def add_label(self, label: str) -> int:
         """Add a new label to the pipe.