diff --git a/registry.cabal b/registry.cabal
--- a/registry.cabal
+++ b/registry.cabal
@@ -4,10 +4,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 9a42dc0b45e4a76624b48f457789494c6d57502a863d3397c88a28a0e85d57cf
+-- hash: dc7abb1b0160688b046f2210abaffa3b985df621f1d47126e9920b573485fdb8
 
 name:           registry
-version:        0.1.3.0
+version:        0.1.3.1
 synopsis:       data structure for assembling components
 description:    This library provides a "Registry" which is a data structure containing a list of functions and values representing dependencies in a directed acyclic graph. A `make` function can then be used to create a value of a specific type out of the registry.
                 You can start with the [README](https://github.com/etorreborre/registry/blob/master/README.md) for a full description of the library.
diff --git a/src/Data/Registry/Internal/Dynamic.hs b/src/Data/Registry/Internal/Dynamic.hs
--- a/src/Data/Registry/Internal/Dynamic.hs
+++ b/src/Data/Registry/Internal/Dynamic.hs
@@ -31,6 +31,17 @@
 
      pure $ makeCreatedValue created description dependencies
 
+-- | Apply a function modifying a single value and keeping its type
+--   to be used with Modifiers
+applyModification ::
+     Function           -- ^ function
+  -> Value              -- ^ inputs
+  -> Either Text Value  -- ^ result
+applyModification function value =
+  do created <- applyFunctionDyn (funDyn function) [valueDyn value]
+     let description  = ValueDescription (_outputType . funDescription $ function) Nothing
+     pure $ CreatedValue created description (specializationContext value) (usedSpecialization  value) (valDependencies value)
+
 -- | Apply a Dynamic function to a list of Dynamic values
 applyFunctionDyn ::
      Dynamic             -- ^ function
diff --git a/src/Data/Registry/Internal/Registry.hs b/src/Data/Registry/Internal/Registry.hs
--- a/src/Data/Registry/Internal/Registry.hs
+++ b/src/Data/Registry/Internal/Registry.hs
@@ -126,5 +126,5 @@
     modifyValue :: Value -> [(SomeTypeRep, Function)] -> Stack Value
     modifyValue v [] = pure v
     modifyValue v ((_, f) : rest) = do
-      applied <- lift $ applyFunction f [v]
+      applied <- lift $ applyModification f v
       modifyValue applied rest
diff --git a/src/Data/Registry/Internal/Statistics.hs b/src/Data/Registry/Internal/Statistics.hs
--- a/src/Data/Registry/Internal/Statistics.hs
+++ b/src/Data/Registry/Internal/Statistics.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE AllowAmbiguousTypes #-}
+
 {-
   This module provides a set of statistics over the execution
   of the registry. This allows to get better insights over the execution
@@ -7,6 +9,7 @@
 
 import           Data.Registry.Internal.Types
 import           Protolude
+import           Type.Reflection
 
 -- * DATA TYPES
 
@@ -69,3 +72,7 @@
   (v :) <$> valuePaths d
 
 valuePaths _ = []
+
+-- | Find the most recently created value of a given type
+findMostRecentValue :: forall a . (Typeable a) => Statistics -> Maybe Value
+findMostRecentValue stats = find (\v -> valueDynTypeRep v == someTypeRep (Proxy :: Proxy a)) $ unValues (values stats)
diff --git a/test/Test/Data/Registry/Make/TweakingSpec.hs b/test/Test/Data/Registry/Make/TweakingSpec.hs
--- a/test/Test/Data/Registry/Make/TweakingSpec.hs
+++ b/test/Test/Data/Registry/Make/TweakingSpec.hs
@@ -1,9 +1,10 @@
-{-# LANGUAGE DataKinds        #-}
+{-# LANGUAGE DataKinds #-}
 {-# OPTIONS_GHC -fno-warn-missing-signatures #-}
 
 module Test.Data.Registry.Make.TweakingSpec where
 
 import           Data.Registry
+import           Data.Registry.Internal.Types
 import           Protolude
 import           Test.Tasty.Extensions
 
@@ -26,3 +27,30 @@
 
 newtype UseConfig1 = UseConfig1 { printConfig1 :: Config }
 newUseConfig1 config = UseConfig1 { printConfig1 = config }
+
+-- * =========
+
+test_tweak_non_lossy = test "a modified value must not lose its context, specialization or dependencies" $ do
+  (a, stats) <- liftIO $
+    do let r =    val (C 1)
+               +: fun B
+               +: fun A
+               +: end
+       let r' = specialize @A @C (C 2) r
+       let r'' = tweak (\(B (C _)) -> B (C 3)) r'
+       pure (make @A r'', makeStatistics @A r'')
+
+  -- The specialized value was 2 but after tweaking it is 3
+  a === A (B (C 3))
+
+  -- Get the value for the type C
+  let cValue = findMostRecentValue @C stats
+  isJust (specializationContext =<< cValue) === True
+  isJust (usedSpecialization =<< cValue) === True
+
+  -- this seems weird but a value is in the list of its dependencies
+  (not . null) (valDependencies <$> cValue) === True
+
+newtype A = A B   deriving (Eq, Show)
+newtype B = B C   deriving (Eq, Show)
+newtype C = C Int deriving (Eq, Show)