diff --git a/build_artifact.py b/build_artifact.py
index 15540e3..78f1baa 100755
--- a/build_artifact.py
+++ b/build_artifact.py
@@ -198,6 +198,7 @@
 
     # If the marker is missing, it's definitely not staged.
     if not os.path.exists(marker_file):
+      self._Log('No marker file, %s is not staged.', self)
       return False
 
     # We want to ensure that every file listed in the marker is actually there.
@@ -213,8 +214,10 @@
                   'All' if len(files) == len(missing_files) else 'Some',
                   marker_file, '\n'.join(missing_files))
         os.remove(marker_file)
+        self._Log('Missing files, %s is not staged.', self)
         return False
 
+    self._Log('ArtifactStaged() -> yes, %s is staged.', self)
     return True
 
   def _MarkArtifactStaged(self):
diff --git a/devserver.py b/devserver.py
index 1338345..a3511a5 100755
--- a/devserver.py
+++ b/devserver.py
@@ -666,7 +666,9 @@
             artifacts=autotest,test_suites
     """
     dl, factory = _get_downloader_and_factory(kwargs)
-    return str(dl.IsStaged(factory))
+    response = str(dl.IsStaged(factory))
+    _Log('Responding to is_staged %s request with %r', kwargs, response)
+    return response
 
   @cherrypy.expose
   def list_image_dir(self, **kwargs):