diff --git a/quantumaudio/schemes/mqsm.py b/quantumaudio/schemes/mqsm.py
index ac43ef0..72d0921 100644
--- a/quantumaudio/schemes/mqsm.py
+++ b/quantumaudio/schemes/mqsm.py
@@ -13,7 +13,7 @@
 # limitations under the License.
 # ==========================================================================
 
-from typing import Optional, Union, Callable, Any, Tuple
+from typing import Optional, Union, Tuple
 
 import numpy as np
 import qiskit
@@ -360,7 +360,7 @@ def decode_counts(
         self,
         counts: Union[dict, qiskit.result.Counts],
         metadata: dict,
-        keep_padding: Tuple[int, int] = (False, False),
+        keep_padding: Tuple[bool, bool] = (False, False),
     ) -> np.ndarray:
         """Given a Qiskit counts object or Dictionary, Extract components and restore the
         conversion did at encoding stage.
@@ -411,7 +411,7 @@ def decode_result(
         self,
         result: qiskit.result.Result,
         metadata: Optional[dict] = None,
-        keep_padding: Tuple[int, int] = (False, False),
+        keep_padding: Tuple[bool, bool] = (False, False),
     ) -> np.ndarray:
         """Given a result object. Extract components and restore the conversion
         did in the encoding stage.
@@ -441,10 +441,8 @@ def decode(
         self,
         circuit: qiskit.QuantumCircuit,
         metadata: Optional[dict] = None,
-        keep_padding: Tuple[int, int] = (False, False),
-        execute_function: Callable[
-            [qiskit.QuantumCircuit, dict], Any
-        ] = utils.execute,
+        keep_padding: Tuple[bool, bool] = (False, False),
+        execute_function: utils.ExecuteFunction = utils.execute,
         **kwargs,
     ) -> np.ndarray:
         """Given a qiskit circuit, decodes and returns the Original Audio Array.
diff --git a/quantumaudio/schemes/msqpam.py b/quantumaudio/schemes/msqpam.py
index 821d7be..5c1de3c 100644
--- a/quantumaudio/schemes/msqpam.py
+++ b/quantumaudio/schemes/msqpam.py
@@ -13,7 +13,7 @@
 # limitations under the License.
 # ==========================================================================
 
-from typing import Optional, Union, Callable, Any, Tuple
+from typing import Optional, Union, Tuple
 
 import numpy as np
 import qiskit
@@ -370,7 +370,7 @@ def decode_counts(
         counts: Union[dict, qiskit.result.Counts],
         metadata: dict,
         inverted: bool = False,
-        keep_padding: Tuple[int, int] = (False, False),
+        keep_padding: Tuple[bool, bool] = (False, False),
     ) -> np.ndarray:
         """Given a Qiskit counts object or Dictionary, Extract components and restore the
         conversion did at encoding stage.
@@ -420,7 +420,7 @@ def decode_result(
         result: qiskit.result.Result,
         metadata: Optional[dict] = None,
         inverted: bool = False,
-        keep_padding: Tuple[int, int] = (False, False),
+        keep_padding: Tuple[bool, bool] = (False, False),
     ) -> np.ndarray:
         """Given a result object. Extract components and restore the conversion
         did in the encoding stage.
@@ -455,10 +455,8 @@ def decode(
         circuit: qiskit.QuantumCircuit,
         metadata: Optional[dict] = None,
         inverted: bool = False,
-        keep_padding: Tuple[int, int] = (False, False),
-        execute_function: Callable[
-            [qiskit.QuantumCircuit, dict], Any
-        ] = utils.execute,
+        keep_padding: Tuple[bool, bool] = (False, False),
+        execute_function: utils.ExecuteFunction = utils.execute,
         **kwargs,
     ) -> np.ndarray:
         """Given a qiskit circuit, decodes and returns the Original Audio Array.
diff --git a/quantumaudio/schemes/qpam.py b/quantumaudio/schemes/qpam.py
index 98122ea..ca31bf0 100644
--- a/quantumaudio/schemes/qpam.py
+++ b/quantumaudio/schemes/qpam.py
@@ -13,7 +13,7 @@
 # limitations under the License.
 # ==========================================================================
 
-from typing import Optional, Union, Callable, Any, Tuple
+from typing import Optional, Union, Tuple
 
 import numpy as np
 import qiskit
@@ -345,9 +345,7 @@ def decode(
         shots: Optional[int] = 8000,
         norm: Optional[float] = None,
         keep_padding: bool = False,
-        execute_function: Callable[
-            [qiskit.QuantumCircuit, dict], Any
-        ] = utils.execute,
+        execute_function: utils.ExecuteFunction = utils.execute,
         **kwargs,
     ) -> np.ndarray:
         """Given a qiskit circuit, decodes and returns back the Original Audio Array.
diff --git a/quantumaudio/schemes/qsm.py b/quantumaudio/schemes/qsm.py
index ca0b037..23dd259 100644
--- a/quantumaudio/schemes/qsm.py
+++ b/quantumaudio/schemes/qsm.py
@@ -13,7 +13,7 @@
 # limitations under the License.
 # ==========================================================================
 
-from typing import Optional, Union, Callable, Any, Tuple
+from typing import Optional, Union, Tuple
 
 import numpy as np
 import qiskit
@@ -361,9 +361,7 @@ def decode(
         circuit: qiskit.QuantumCircuit,
         metadata: Optional[dict] = None,
         keep_padding: bool = False,
-        execute_function: Callable[
-            [qiskit.QuantumCircuit, dict], Any
-        ] = utils.execute,
+        execute_function: utils.ExecuteFunction = utils.execute,
         **kwargs,
     ) -> np.ndarray:
         """Given a qiskit circuit, decodes and returns back the Original Audio Array.
diff --git a/quantumaudio/schemes/sqpam.py b/quantumaudio/schemes/sqpam.py
index e127f98..e2de8d4 100644
--- a/quantumaudio/schemes/sqpam.py
+++ b/quantumaudio/schemes/sqpam.py
@@ -13,7 +13,7 @@
 # limitations under the License.
 # ==========================================================================
 
-from typing import Optional, Union, Callable, Any, Tuple
+from typing import Optional, Union, Tuple
 
 import numpy as np
 import qiskit
@@ -378,9 +378,7 @@ def decode(
         metadata: Optional[dict] = None,
         inverted: bool = False,
         keep_padding: bool = False,
-        execute_function: Callable[
-            [qiskit.QuantumCircuit, dict], Any
-        ] = utils.execute,
+        execute_function: utils.ExecuteFunction = utils.execute,
         **kwargs,
     ) -> np.ndarray:
         """Given a qiskit circuit, decodes and returns back the Original Audio Array.
diff --git a/quantumaudio/utils/execute.py b/quantumaudio/utils/execute.py
index e23afed..f23e71e 100644
--- a/quantumaudio/utils/execute.py
+++ b/quantumaudio/utils/execute.py
@@ -15,9 +15,27 @@
 
 import qiskit_aer
 from qiskit.transpiler.preset_passmanagers import generate_preset_pass_manager
-from typing import Type, Any
+from typing import Type, Any, Protocol
 import importlib
 
+import qiskit
+
+
+class ExecuteFunction(Protocol):
+    """Callable protocol for circuit execution backends used by scheme decoders.
+
+    An execute function takes a ``circuit`` argument and may accept
+    any number of additional keyword arguments (e.g. ``shots``, ``backend``).
+    It returns a result object compatible with
+    :func:`quantumaudio.utils.results.get_counts` and
+    :func:`quantumaudio.utils.results.get_metadata`.
+    """
+
+    def __call__(
+        self, circuit: qiskit.QuantumCircuit, **kwargs: Any
+    ) -> Any: ...
+
+
 # Optional Import if exists
 _Sampler = (
     getattr(importlib.import_module("qiskit_ibm_runtime"), "SamplerV2", None)
@@ -37,6 +55,7 @@ def execute(
     backend: Any = None,
     keep_memory: bool = False,
     optimization_level: int = 3,
+    **kwargs: Any,
 ):
     """
     Executes a quantum circuit on a given backend and return the results.
@@ -47,6 +66,9 @@ def execute(
         shots: Total number of times the quantum circuit is measured.
         keep_memory: Whether to return the memory (quantum state) of each shot.
         optimization_level: Optimization level for transpiling the circuit.
+        **kwargs: Accepted for compatibility with the :class:`ExecuteFunction`
+            protocol (additional keyword arguments forwarded by scheme
+            ``decode`` calls); ignored by this implementation.
 
     Returns:
         Result: The result of the execution, containing the counts and other metadata.
@@ -74,6 +96,7 @@ def execute_with_sampler(
     backend: Any = None,
     shots: int = 8000,
     optimization_level: int = 3,
+    **kwargs: Any,
 ):
     """
     Executes a quantum circuit on a given backend using `Sampler Primitive` and return the results.
@@ -83,6 +106,9 @@ def execute_with_sampler(
         backend: The backend on which to run the circuit. If None, the default backend `qiskit_aer.AerSimulator()` is used.
         shots: Total number of times the quantum circuit is measured.
         optimization_level: Optimization level for transpiling the circuit.
+        **kwargs: Accepted for compatibility with the :class:`ExecuteFunction`
+            protocol (additional keyword arguments forwarded by scheme
+            ``decode`` calls); ignored by this implementation.
 
     Returns:
         Result: The result of the execution, containing the counts and other metadata.