diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,8 @@
-## [_Unreleased_](https://github.com/freckle/amazonka-mtl/compare/v0.1.0.0...main)
+## [_Unreleased_](https://github.com/freckle/amazonka-mtl/compare/v0.1.1.0...main)
+
+## [v0.1.1.0](https://github.com/freckle/amazonka-mtl/compare/v0.1.0.0...v0.1.1.0)
+
+- Add `withAuth` and `localEnv`
 
 ## [v0.1.0.0](https://github.com/freckle/amazonka-mtl/tree/v0.1.0.0)
 
diff --git a/amazonka-mtl.cabal b/amazonka-mtl.cabal
--- a/amazonka-mtl.cabal
+++ b/amazonka-mtl.cabal
@@ -1,6 +1,6 @@
 cabal-version:      1.18
 name:               amazonka-mtl
-version:            0.1.0.0
+version:            0.1.1.0
 license:            MIT
 license-file:       LICENSE
 maintainer:         Freckle Education
@@ -86,9 +86,10 @@
         TypeApplications TypeFamilies
 
     ghc-options:
-        -Weverything -Wno-missing-exported-signatures
+        -Weverything -Wno-all-missed-specialisations
+        -Wno-missed-specialisations -Wno-missing-exported-signatures
         -Wno-missing-import-lists -Wno-missing-local-signatures
-        -Wno-monomorphism-restriction -Wno-unsafe -Wno-safe
+        -Wno-monomorphism-restriction -Wno-safe -Wno-unsafe
 
     build-depends:
         amazonka,
@@ -122,9 +123,10 @@
         TypeApplications TypeFamilies
 
     ghc-options:
-        -Weverything -Wno-missing-exported-signatures
+        -Weverything -Wno-all-missed-specialisations
+        -Wno-missed-specialisations -Wno-missing-exported-signatures
         -Wno-missing-import-lists -Wno-missing-local-signatures
-        -Wno-monomorphism-restriction -Wno-unsafe -Wno-safe -pgmL
+        -Wno-monomorphism-restriction -Wno-safe -Wno-unsafe -pgmL
         markdown-unlit
 
     build-depends:
@@ -164,9 +166,10 @@
         TypeApplications TypeFamilies
 
     ghc-options:
-        -Weverything -Wno-missing-exported-signatures
+        -Weverything -Wno-all-missed-specialisations
+        -Wno-missed-specialisations -Wno-missing-exported-signatures
         -Wno-missing-import-lists -Wno-missing-local-signatures
-        -Wno-monomorphism-restriction -Wno-unsafe -Wno-safe -threaded
+        -Wno-monomorphism-restriction -Wno-safe -Wno-unsafe -threaded
         -rtsopts -with-rtsopts=-N
 
     build-depends:
diff --git a/library/Control/Monad/AWS.hs b/library/Control/Monad/AWS.hs
--- a/library/Control/Monad/AWS.hs
+++ b/library/Control/Monad/AWS.hs
@@ -26,6 +26,8 @@
 import Data.Typeable (Typeable)
 
 -- | Version of 'Amazonka.send' built on our 'sendEither'
+--
+-- @since 0.1.0.0
 send
   :: ( MonadIO m
      , MonadAWS m
@@ -38,6 +40,8 @@
 send = sendEither >=> hoistEither
 
 -- | Version of 'Amazonka.paginateEither' built on our 'sendEither'
+--
+-- @since 0.1.0.0
 paginateEither
   :: (MonadAWS m, AWSPager a, Typeable a, Typeable (AWSResponse a))
   => a
@@ -52,6 +56,8 @@
         maybe (pure (Right ())) go (Pager.page rq rs)
 
 -- | Version of 'Amazonka.paginate' built on our 'paginateEither'
+--
+-- @since 0.1.0.0
 paginate
   :: ( MonadIO m
      , MonadAWS m
@@ -65,6 +71,8 @@
   paginateEither >=> hoistEither
 
 -- | Version of 'Amazonka.await' built on our 'awaitEither'
+--
+-- @since 0.1.0.0
 await
   :: (MonadIO m, MonadAWS m, AWSRequest a, Typeable a)
   => Waiter.Wait a
diff --git a/library/Control/Monad/AWS/Class.hs b/library/Control/Monad/AWS/Class.hs
--- a/library/Control/Monad/AWS/Class.hs
+++ b/library/Control/Monad/AWS/Class.hs
@@ -5,7 +5,9 @@
 
 import Amazonka.Prelude
 
+import Amazonka (AuthEnv)
 import Amazonka.Core (AWSRequest, AWSResponse, Error)
+import Amazonka.Env (Env)
 import qualified Amazonka.Waiter as Waiter
 import Data.Typeable (Typeable)
 
@@ -21,13 +23,32 @@
 -- - "Control.Monad.AWS.ViaReader"
 -- - "Control.Monad.AWS.ViaMock"
 class Monad m => MonadAWS m where
+  -- | The type-class version of 'Amazonka.sendEither'.
+  --
+  -- @since 0.1.0.0
   sendEither
     :: (AWSRequest a, Typeable a, Typeable (AWSResponse a))
     => a
     -> m (Either Error (AWSResponse a))
 
+  -- | The type-class version of 'Amazonka.awaitEither'.
+  --
+  -- @since 0.1.0.0
   awaitEither
     :: (AWSRequest a, Typeable a)
     => Waiter.Wait a
     -> a
     -> m (Either Error Waiter.Accept)
+
+  -- | Supply the current credentials to the given action.
+  --
+  -- @since 0.1.1.0
+  withAuth :: (AuthEnv -> m a) -> m a
+
+  -- | Run the given action with a modified 'Env'
+  --
+  -- For instances that supply 'Env' via Reader, this should behave like
+  -- 'local'.
+  --
+  -- @since 0.1.1.0
+  localEnv :: (Env -> Env) -> m a -> m a
diff --git a/library/Control/Monad/AWS/EnvT.hs b/library/Control/Monad/AWS/EnvT.hs
--- a/library/Control/Monad/AWS/EnvT.hs
+++ b/library/Control/Monad/AWS/EnvT.hs
@@ -33,6 +33,9 @@
 import Control.Monad.Reader
 import Control.Monad.Trans.Resource
 
+-- |
+--
+-- @since 0.1.0.0
 newtype EnvT m a = EnvT
   { unEnvT :: ReaderT Env (ResourceT m) a
   }
@@ -47,5 +50,8 @@
     )
   deriving (MonadAWS) via (ReaderAWS (EnvT m))
 
+-- |
+--
+-- @since 0.1.0.0
 runEnvT :: MonadUnliftIO m => EnvT m a -> Env -> m a
 runEnvT f = runResourceT . runReaderT (unEnvT f)
diff --git a/library/Control/Monad/AWS/Matchers.hs b/library/Control/Monad/AWS/Matchers.hs
--- a/library/Control/Monad/AWS/Matchers.hs
+++ b/library/Control/Monad/AWS/Matchers.hs
@@ -25,14 +25,18 @@
 
 -- | Define a response to provide for any matched requests
 data Matcher where
-  -- Matches calls to 'send' where the given predicate holds
+  -- | Matches calls to 'send' where the given predicate holds
+  --
+  -- @since 0.1.0.0
   SendMatcher
     :: forall a
      . (AWSRequest a, Typeable a, Typeable (AWSResponse a))
     => (a -> Bool)
     -> Either Error (AWSResponse a)
     -> Matcher
-  -- Matches calls to 'await' where the given predicate holds
+  -- | Matches calls to 'await' where the given predicate holds
+  --
+  -- @since 0.1.0.0
   AwaitMatcher
     :: forall a
      . (AWSRequest a, Typeable a)
@@ -40,25 +44,41 @@
     -> Either Error Waiter.Accept
     -> Matcher
 
+-- |
+--
+-- @since 0.1.0.0
 newtype Matchers = Matchers
   { unMatchers :: [Matcher]
   }
   deriving newtype (Semigroup, Monoid)
 
+-- |
+--
+-- @since 0.1.0.0
 class HasMatchers env where
   matchersL :: Lens' env Matchers
 
+-- |
+--
+-- @since 0.1.0.0
 instance HasMatchers Matchers where
   matchersL = id
 
 -- | Add a 'Matcher' for the duration of the block
+--
+-- @since 0.1.0.0
 withMatcher :: (MonadReader env m, HasMatchers env) => Matcher -> m a -> m a
 withMatcher = withMatchers . pure
 
 -- | Add multiple 'Matcher's for the duration of the block
+--
+-- @since 0.1.0.0
 withMatchers :: (MonadReader env m, HasMatchers env) => [Matcher] -> m a -> m a
 withMatchers ms = local $ matchersL <>~ Matchers ms
 
+-- |
+--
+-- @since 0.1.0.0
 matchSend
   :: forall m env a
    . ( MonadIO m
@@ -77,6 +97,9 @@
       cast resp
     AwaitMatcher {} -> Nothing
 
+-- |
+--
+-- @since 0.1.0.0
 matchAwait
   :: forall m env a
    . (MonadIO m, MonadReader env m, HasMatchers env, Typeable a)
@@ -99,6 +122,9 @@
   matchers <- view matchersL
   pure $ listToMaybe $ mapMaybe f $ unMatchers matchers
 
+-- |
+--
+-- @since 0.1.0.0
 newtype UnmatchedRequestError = UnmatchedRequestError
   { unmatchedRequestType :: String
   }
@@ -108,6 +134,8 @@
 -- representation (derived is best), and displayException is where you make it
 -- human-readable. Sadly, too many tools (*cough* hspec) use show instead of
 -- displayException, and we want it to look nice there. Sigh.
+--
+-- https://github.com/hspec/hspec/issues/289
 instance Show UnmatchedRequestError where
   show ex =
     "Unexpected AWS request made within MockT: "
diff --git a/library/Control/Monad/AWS/MockT.hs b/library/Control/Monad/AWS/MockT.hs
--- a/library/Control/Monad/AWS/MockT.hs
+++ b/library/Control/Monad/AWS/MockT.hs
@@ -45,6 +45,9 @@
 import Control.Monad.IO.Unlift
 import Control.Monad.Reader
 
+-- |
+--
+-- @since 0.1.0.0
 newtype MockT m a = MockT
   { unMockT :: ReaderT Matchers m a
   }
@@ -58,5 +61,8 @@
     )
   deriving (MonadAWS) via (MockAWS (MockT m))
 
+-- |
+--
+-- @since 0.1.0.0
 runMockT :: MockT m a -> m a
 runMockT f = runReaderT (unMockT f) mempty
diff --git a/library/Control/Monad/AWS/ViaMock.hs b/library/Control/Monad/AWS/ViaMock.hs
--- a/library/Control/Monad/AWS/ViaMock.hs
+++ b/library/Control/Monad/AWS/ViaMock.hs
@@ -57,11 +57,15 @@
 
 import Prelude
 
+import Amazonka (AuthEnv (..))
 import Control.Monad.AWS.Class
 import Control.Monad.AWS.Matchers
 import Control.Monad.IO.Class (MonadIO)
 import Control.Monad.Reader (MonadReader (..))
 
+-- |
+--
+-- @since 0.1.0.0
 newtype MockAWS m a = MockAWS
   { unMockAWS :: m a
   }
@@ -76,3 +80,14 @@
 instance (MonadIO m, MonadReader env m, HasMatchers env) => MonadAWS (MockAWS m) where
   sendEither = matchSend
   awaitEither = matchAwait
+  withAuth = ($ fakeAuthEnv)
+  localEnv _ = id
+
+fakeAuthEnv :: AuthEnv
+fakeAuthEnv =
+  AuthEnv
+    { accessKeyId = "mock-aws-access-key-id"
+    , secretAccessKey = "mock-aws-secret-key"
+    , sessionToken = Just "mock-aws-sessin-token"
+    , expiration = Nothing
+    }
diff --git a/library/Control/Monad/AWS/ViaReader.hs b/library/Control/Monad/AWS/ViaReader.hs
--- a/library/Control/Monad/AWS/ViaReader.hs
+++ b/library/Control/Monad/AWS/ViaReader.hs
@@ -69,19 +69,30 @@
 
 import Prelude
 
+import qualified Amazonka.Auth as Amazonka
 import Amazonka.Env
 import qualified Amazonka.Send as Amazonka
-import Control.Lens (Lens', view)
+import Control.Lens (Lens', to, view, (%~))
 import Control.Monad.AWS.Class
 import Control.Monad.Reader
 import Control.Monad.Trans.Resource (MonadResource)
+import Data.Functor.Identity (runIdentity)
 
+-- |
+--
+-- @since 0.1.0.0
 class HasEnv env where
   envL :: Lens' env Env
 
+-- |
+--
+-- @since 0.1.0.0
 instance HasEnv Env where
   envL = id
 
+-- |
+--
+-- @since 0.1.0.0
 newtype ReaderAWS m a = ReaderAWS
   { unReaderAWS :: m a
   }
@@ -102,3 +113,9 @@
   awaitEither w a = do
     env <- view envL
     Amazonka.awaitEither env w a
+
+  withAuth f = do
+    auth <- view $ envL . env_auth . to runIdentity
+    Amazonka.withAuth auth f
+
+  localEnv f = local $ envL %~ f
diff --git a/package.yaml b/package.yaml
--- a/package.yaml
+++ b/package.yaml
@@ -1,5 +1,5 @@
 name: amazonka-mtl
-version: 0.1.0.0
+version: 0.1.1.0
 maintainer: Freckle Education
 category: Utils
 github: freckle/amazonka-mtl
@@ -58,12 +58,14 @@
 
 ghc-options:
   - -Weverything
+  - -Wno-all-missed-specialisations
+  - -Wno-missed-specialisations
   - -Wno-missing-exported-signatures # re-enables missing-signatures
   - -Wno-missing-import-lists
   - -Wno-missing-local-signatures
   - -Wno-monomorphism-restriction
-  - -Wno-unsafe
   - -Wno-safe
+  - -Wno-unsafe
 
 when:
   - condition: "impl(ghc >= 9.2)"