diff --git a/metafacture-io/src/main/java/org/metafacture/io/ObjectFileWriter.java b/metafacture-io/src/main/java/org/metafacture/io/ObjectFileWriter.java
index 36d45426..0504f246 100644
--- a/metafacture-io/src/main/java/org/metafacture/io/ObjectFileWriter.java
+++ b/metafacture-io/src/main/java/org/metafacture/io/ObjectFileWriter.java
@@ -36,7 +36,9 @@
  * @author Christoph Böhme
  *
  */
+@Description("Writes objects to one (or more) file(s)")
 @In(Object.class)
+@In(Void.class)
 @FluxCommand("write-files")
 public final class ObjectFileWriter<T> extends AbstractObjectWriter<T>  {
 
diff --git a/metafacture-io/src/main/java/org/metafacture/io/ObjectStdoutWriter.java b/metafacture-io/src/main/java/org/metafacture/io/ObjectStdoutWriter.java
index 5394b26a..f799cb65 100644
--- a/metafacture-io/src/main/java/org/metafacture/io/ObjectStdoutWriter.java
+++ b/metafacture-io/src/main/java/org/metafacture/io/ObjectStdoutWriter.java
@@ -31,6 +31,7 @@
 
 @Description("Writes objects to stdout")
 @In(Object.class)
+@Out(Void.class)
 @FluxCommand("print")
 public final class ObjectStdoutWriter<T> extends AbstractObjectWriter<T>  {