diff --git a/shake-ext.cabal b/shake-ext.cabal
--- a/shake-ext.cabal
+++ b/shake-ext.cabal
@@ -1,5 +1,5 @@
 name:                shake-ext
-version:             0.5.0.4
+version:             1.0.0.0
 synopsis:            Helper functions for linting with shake 
 description:         This package provides several linters out of the box, as well as functionality for building ATS source files with [shake](http://shakebuild.com/).
 homepage:            https://hub.darcs.net/vmchale/shake-ext
@@ -30,6 +30,7 @@
   build-depends:       base >= 4.10 && < 5
                      , shake
                      , language-ats
+                     , mtl
                      , composition-prelude
                      , directory
   default-language:    Haskell2010
diff --git a/src/Development/Shake/ATS.hs b/src/Development/Shake/ATS.hs
--- a/src/Development/Shake/ATS.hs
+++ b/src/Development/Shake/ATS.hs
@@ -14,7 +14,8 @@
                              , Version (..)
                              ) where
 
-import           Control.Monad              (filterM, forM_)
+import           Control.Monad
+import           Control.Monad.IO.Class
 import           Data.Either                (fromRight)
 import           Data.Maybe                 (fromMaybe)
 import           Data.Semigroup             (Semigroup (..))
@@ -51,8 +52,10 @@
 atsBin :: Version -> Bool -> [String] -> String -> String -> Rules ()
 atsBin v gc libs sourceFile out = do
 
-    priority 0.75 $ out %> \_ -> do
-        need [sourceFile]
+    atsDeps
+
+    out %> \_ -> do
+        need [sourceFile]  --sources
         let home = "/usr/local/lib/ats2-postiats-" ++ show v
         cmd_ ["mkdir", "-p", dropDirectory1 out]
         let toLibs = fmap ("-l" <>)
@@ -88,13 +91,16 @@
         need [sourceFile]
         atsCommand version sourceFile out
 
+trim :: String -> String
+trim = init . drop 1
+
 atsDeps :: Rules ()
-atsDeps = priority 0.25 $
+atsDeps =
 
     ["//*.dats", "//*.sats"] |%> \out -> do
         contents <- liftIO $ readFile out
         let ats = fromRight mempty . parseATS . lexATS $ contents
-        deps <- filterM doesFileExist $ getDependencies ats
+        deps <- filterM doesFileExist $ trim <$> getDependencies ats
         need deps
         home <- patsHome
         forM_ deps $ \dep ->