diff --git a/include/artifacts.h b/include/artifacts.h
index e58636f18..969f87eb9 100644
--- a/include/artifacts.h
+++ b/include/artifacts.h
@@ -193,7 +193,7 @@ G_GNUC_WARN_UNUSED_RESULT;
  *
  * @param artifact RArtifact to activate
  * @param parent NULL or name of the parent slot
- * @param error a GError, or NULL
+ * @param[out] error Return location for a GError, or NULL
  */
 void r_artifact_activate(const RArtifact *artifact, const gchar *parent);