diff --git a/src/Network/AWS/Wolf/Act.hs b/src/Network/AWS/Wolf/Act.hs
--- a/src/Network/AWS/Wolf/Act.hs
+++ b/src/Network/AWS/Wolf/Act.hs
@@ -17,6 +17,7 @@
 import Network.AWS.Wolf.SWF
 import Network.AWS.Wolf.Types
 import System.Directory
+import System.Exit
 import System.Process
 
 -- | S3 copy call.
@@ -115,5 +116,7 @@
       conf <- readYaml cf
       runConfCtx conf $
         runConcurrent $ replicate num $ forever $ do
-          boolThrowIO "Quiesce" =<< not <$> check quiesce
+          ok <- check quiesce
+          when ok $
+            liftIO exitSuccess
           act queue nocopy local command
diff --git a/wolf.cabal b/wolf.cabal
--- a/wolf.cabal
+++ b/wolf.cabal
@@ -1,5 +1,5 @@
 name:                  wolf
-version:               0.3.28
+version:               0.3.29
 synopsis:              Amazon Simple Workflow Service Wrapper.
 description:           Wolf is a wrapper around Amazon Simple Workflow Service.
 homepage:              https://github.com/swift-nav/wolf