diff --git a/src/coordinax/_src/vectors/api.py b/src/coordinax/_src/vectors/api.py
index bce9be86..0b2ec8ae 100644
--- a/src/coordinax/_src/vectors/api.py
+++ b/src/coordinax/_src/vectors/api.py
@@ -15,7 +15,13 @@
 def vconvert(target: type[Any], /, *args: Any, **kwargs: Any) -> Any:
     """Transform the current vector to the target vector.
 
-    See the dispatch implementations for more details.
+    See the dispatch implementations for more details. Not all transformations
+    result in the target vector type, for example
+    ``vconvert(type[Cartesian3DPos], FourVector)`` will return a
+    `coordinax.vecs.FourVector` with the spatial part in Cartesian coordinates.
+    Likewise, `coordinax.vconvert` on `coordinax.Coordinate` instances will
+    transform the contained vectors to the target type, returning a
+    `coordinax.Coordinate` instance.
 
     """
     raise NotImplementedError  # pragma: no cover