diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,11 @@
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [PVP versioning](https://pvp.haskell.org/).
 
+## v2.8.1 _(2024-11-29)_
+
+### Added
+- Added instances `Semigroup`, `Monoid` and `Contravariant` for `Debugger`
+
 ## v2.8.0 _(2024-11-28)_
 
 ### Changed
diff --git a/hasmtlib.cabal b/hasmtlib.cabal
--- a/hasmtlib.cabal
+++ b/hasmtlib.cabal
@@ -1,7 +1,7 @@
 cabal-version:         3.0
 
 name:                  hasmtlib
-version:               2.8.0
+version:               2.8.1
 synopsis:              A monad for interfacing with external SMT solvers
 description:           Hasmtlib is a library for generating SMTLib2-problems using a monad.
   It takes care of encoding your problem, marshaling the data to an external solver and parsing and interpreting the result into Haskell types.
@@ -21,6 +21,7 @@
 tested-with:           GHC == 9.4.8
                      , GHC == 9.6.4
                      , GHC == 9.8.2
+                     , GHC == 9.10.1
 
 library
   hs-source-dirs:      src
@@ -60,8 +61,8 @@
   build-depends:       array                        >= 0.5    && < 1
                      , attoparsec                   >= 0.14.4 && < 1
                      , base                         >= 4.17.2 && < 5
-                     , lifted-base                  >= 0.2 && < 0.5
-                     , monad-control                >= 1.0 && < 1.2
+                     , lifted-base                  >= 0.2    && < 0.5
+                     , monad-control                >= 1.0    && < 1.2
                      , bytestring                   >= 0.11.5 && < 1
                      , containers                   >= 0.6.7  && < 1
                      , unordered-containers         >= 0.2.20 && < 0.3
diff --git a/src/Language/Hasmtlib/Type/Debugger.hs b/src/Language/Hasmtlib/Type/Debugger.hs
--- a/src/Language/Hasmtlib/Type/Debugger.hs
+++ b/src/Language/Hasmtlib/Type/Debugger.hs
@@ -19,7 +19,6 @@
   , assertionish
   , incrementalStackish, getValueish
   , responseish
-
   )
 where
 
@@ -34,6 +33,7 @@
 import Data.ByteString.Builder
 import qualified Data.ByteString.Lazy.Char8 as ByteString.Char8
 import Data.Default
+import Data.Functor.Contravariant
 import Control.Lens hiding (op)
 
 -- | A type holding actions for debugging states holding SMT-Problems.
@@ -57,6 +57,33 @@
 
 instance Default (Debugger s) where
   def = verbosely
+
+-- | Concats actions
+instance Semigroup (Debugger s) where
+  x <> y = Debugger
+    (\input -> debugState x input          >> debugState y input)
+    (\input -> debugOption x input         >> debugOption y input)
+    (\input -> debugLogic x input          >> debugLogic y input)
+    (\input -> debugVar x input            >> debugVar y input)
+    (\input -> debugAssert x input         >> debugAssert y input)
+    (\input -> debugPop x input            >> debugPop y input)
+    (\input -> debugCheckSat x input       >> debugCheckSat y input)
+    (\input -> debugGetModel x input       >> debugGetModel y input)
+    (\input -> debugGetValue x input       >> debugGetValue y input)
+    (\input -> debugMinimize x input       >> debugMinimize y input)
+    (\input -> debugMaximize x input       >> debugMaximize y input)
+    (\input -> debugMaximize x input       >> debugMaximize y input)
+    (\input -> debugAssertSoft x input     >> debugAssertSoft y input)
+    (\input -> debugResultResponse x input >> debugResultResponse y input)
+    (\input -> debugModelResponse x input  >> debugModelResponse y input)
+
+instance Monoid (Debugger s) where
+  mempty = silently
+
+instance Contravariant Debugger where
+  contramap f' debugger = debugger { debugState = f . f' }
+    where
+      f = debugState debugger
 
 printer :: Builder -> IO ()
 printer = ByteString.Char8.putStrLn . toLazyByteString