diff --git a/main/actor.hs b/main/actor.hs
--- a/main/actor.hs
+++ b/main/actor.hs
@@ -16,6 +16,12 @@
     -- ^ Configuration file.
   , quiesce :: Maybe FilePath
     -- ^ Optional quiesce file to stop actor.
+  , domain  :: Maybe Text
+    -- ^ Optional domain to use.
+  , bucket  :: Maybe Text
+    -- ^ Optional bucket to use.
+  , prefix  :: Maybe Text
+    -- ^ Optional prefix to use.
   , queue   :: Text
     -- ^ Queue to listen to act on.
   , num     :: Maybe Int
@@ -38,6 +44,9 @@
   actMain
     (config args)
     (quiesce args)
+    (domain args)
+    (bucket args)
+    (prefix args)
     (queue args)
     (fromMaybe 1 $ num args)
     (nocopy args)
diff --git a/main/counter.hs b/main/counter.hs
--- a/main/counter.hs
+++ b/main/counter.hs
@@ -16,6 +16,8 @@
     -- ^ Configuration file.
   , plan   :: FilePath
     -- ^ Plan file to count on.
+  , domain :: Maybe Text
+    -- ^ Optional domain to use.
   } deriving (Show, Generic)
 
 instance ParseRecord Args
@@ -28,3 +30,4 @@
   countMain
     (config args)
     (plan args)
+    (domain args)
diff --git a/main/decider.hs b/main/decider.hs
--- a/main/decider.hs
+++ b/main/decider.hs
@@ -16,6 +16,8 @@
     -- ^ Configuration file.
   , plan   :: FilePath
     -- ^ Plan file to decide on.
+  , domain :: Maybe Text
+    -- ^ Optional domain to use.
   } deriving (Show, Generic)
 
 instance ParseRecord Args
@@ -28,3 +30,4 @@
   decideMain
     (config args)
     (plan args)
+    (domain args)
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
@@ -105,14 +105,14 @@
               statsIncrement "wolf.act.activity.count" [ "queue" =. queue, "status" =. status ]
               statsHistogram "wolf.act.activity.elapsed" (realToFrac (diffUTCTime t3 t2) :: Double) [ "queue" =. queue ]
 
-
 -- | Run actor from main with config file.
 --
-actMain :: MonadControl m => FilePath -> Maybe FilePath -> Text -> Int -> Bool -> Bool -> String -> m ()
-actMain cf quiesce queue num nocopy local command =
+actMain :: MonadControl m => FilePath -> Maybe FilePath -> Maybe Text -> Maybe Text -> Maybe Text -> Text -> Int -> Bool -> Bool -> String -> m ()
+actMain cf quiesce domain bucket prefix queue num nocopy local command =
   runCtx $ runTop $ do
     conf <- readYaml cf
-    runConfCtx conf $
+    let conf' = override cPrefix prefix $ override cBucket bucket $ override cDomain domain conf
+    runConfCtx conf' $
       runConcurrent $ replicate num $ forever $ do
         ok <- check quiesce
         when ok $
diff --git a/src/Network/AWS/Wolf/Count.hs b/src/Network/AWS/Wolf/Count.hs
--- a/src/Network/AWS/Wolf/Count.hs
+++ b/src/Network/AWS/Wolf/Count.hs
@@ -47,10 +47,11 @@
 
 -- | Run counter from main with config file.
 --
-countMain :: MonadControl m => FilePath -> FilePath -> m ()
-countMain cf pf =
+countMain :: MonadControl m => FilePath -> FilePath -> Maybe Text -> m ()
+countMain cf pf domain =
   runCtx $ runTop $ do
     conf <- readYaml cf
-    runConfCtx conf $ do
+    let conf' = override cDomain domain conf
+    runConfCtx conf' $ do
       plans <- readYaml pf
       mapM_ count (plans :: [Plan])
diff --git a/src/Network/AWS/Wolf/Decide.hs b/src/Network/AWS/Wolf/Decide.hs
--- a/src/Network/AWS/Wolf/Decide.hs
+++ b/src/Network/AWS/Wolf/Decide.hs
@@ -110,11 +110,12 @@
 
 -- | Run decider from main with config file.
 --
-decideMain :: MonadControl m => FilePath -> FilePath -> m ()
-decideMain cf pf =
+decideMain :: MonadControl m => FilePath -> FilePath -> Maybe Text -> m ()
+decideMain cf pf domain  =
   runCtx $ runTop $ do
     conf <- readYaml cf
-    runConfCtx conf $ do
+    let conf' = override cDomain domain conf
+    runConfCtx conf' $ do
       plans <- readYaml pf
       runConcurrent $
         forever . decide <$> plans
diff --git a/src/Network/AWS/Wolf/Prelude.hs b/src/Network/AWS/Wolf/Prelude.hs
--- a/src/Network/AWS/Wolf/Prelude.hs
+++ b/src/Network/AWS/Wolf/Prelude.hs
@@ -7,6 +7,7 @@
 module Network.AWS.Wolf.Prelude
   ( module Exports
   , runConcurrent
+  , override
   ) where
 
 import Control.Concurrent.Async.Lifted
@@ -16,3 +17,8 @@
 --
 runConcurrent :: MonadBaseControl IO m => [m a] -> m ()
 runConcurrent = void . runConcurrently . traverse Concurrently
+
+-- | Override a lens value with a maybe value.
+--
+override :: ASetter s s a b -> Maybe b -> s -> s
+override k v c = maybe c (flip (set k) c) v
diff --git a/wolf.cabal b/wolf.cabal
--- a/wolf.cabal
+++ b/wolf.cabal
@@ -1,5 +1,5 @@
 name:                  wolf
-version:               0.3.38
+version:               0.3.39
 synopsis:              Amazon Simple Workflow Service Wrapper.
 description:           Wolf is a wrapper around Amazon Simple Workflow Service.
 homepage:              https://github.com/swift-nav/wolf