diff --git a/taskflow/engines/action_engine/engine.py b/taskflow/engines/action_engine/engine.py
index 68bd3458..e7763068 100644
--- a/taskflow/engines/action_engine/engine.py
+++ b/taskflow/engines/action_engine/engine.py
@@ -19,6 +19,7 @@ import contextlib
 import threading
 
 from concurrent import futures
+import networkx as nx
 from oslo_utils import excutils
 from oslo_utils import strutils
 import six
@@ -28,12 +29,15 @@ from taskflow.engines.action_engine import executor
 from taskflow.engines.action_engine import runtime
 from taskflow.engines import base
 from taskflow import exceptions as exc
+from taskflow import logging
 from taskflow import states
 from taskflow import storage
 from taskflow.types import failure
 from taskflow.utils import lock_utils
 from taskflow.utils import misc
 
+LOG = logging.getLogger(__name__)
+
 
 @contextlib.contextmanager
 def _start_stop(executor):
@@ -213,9 +217,16 @@ class ActionEngine(base.Engine):
         # flow/task provided or storage provided, if there are still missing
         # dependencies then this flow will fail at runtime (which we can avoid
         # by failing at validation time).
+        execution_graph = self._compilation.execution_graph
+        if LOG.isEnabledFor(logging.BLATHER):
+            LOG.blather("Validating scoping and argument visibility for"
+                        " execution graph with %s nodes and %s edges with"
+                        " density %0.3f", execution_graph.number_of_nodes(),
+                        execution_graph.number_of_edges(),
+                        nx.density(execution_graph))
         missing = set()
         fetch = self.storage.fetch_unsatisfied_args
-        for node in self._compilation.execution_graph.nodes_iter():
+        for node in execution_graph.nodes_iter():
             missing.update(fetch(node.name, node.rebind,
                                  optional_args=node.optional))
         if missing: