diff --git a/ci/default.yml b/ci/default.yml
index 4a85316030..7c17844fac 100644
--- a/ci/default.yml
+++ b/ci/default.yml
@@ -17,7 +17,7 @@ test_model_stencils:
     # exclude slow test configurations
     - if: $BACKEND == "roundtrip" && $GRID == "icon_grid"
       when: never
-    - when: always
+    - when: on_success
 
 test_tools:
   extends: .test_template
diff --git a/tools/README.md b/tools/README.md
index d6288ad2f7..72132757df 100644
--- a/tools/README.md
+++ b/tools/README.md
@@ -148,6 +148,8 @@ In addition, other optional keyword arguments are the following:
 
 - `copies`: Takes a boolean string input, and controls whether before field copies should be made or not. If set to False only the `#ifdef __DSL_VERIFY` directive is generated. Defaults to true.<br><br>
 
+- `optional_module`: Takes a boolean string input, and controls whether stencils is part of an optional module. Defaults to "None".<br><br>
+
 #### `!$DSL END STENCIL()`
 
 This directive denotes the end of a stencil. The required argument is `name`, which must match the name of the preceding `START STENCIL` directive.
diff --git a/tools/src/icon4pytools/liskov/cli.py b/tools/src/icon4pytools/liskov/cli.py
index a90afbc09e..a118199e4d 100644
--- a/tools/src/icon4pytools/liskov/cli.py
+++ b/tools/src/icon4pytools/liskov/cli.py
@@ -12,6 +12,7 @@
 # SPDX-License-Identifier: GPL-3.0-or-later
 
 import pathlib
+from typing import Optional
 
 import click
 
@@ -27,6 +28,10 @@
 logger = setup_logger(__name__)
 
 
+def split_comma(ctx, param, value) -> Optional[tuple[str]]:
+    return tuple(v.strip() for v in value.split(",")) if value else None
+
+
 @click.group(invoke_without_command=True)
 @click.pass_context
 def main(ctx: click.Context) -> None:
@@ -56,6 +61,11 @@ def main(ctx: click.Context) -> None:
     default=False,
     help="Adds fused or unfused stencils.",
 )
+@click.option(
+    "--optional-modules-to-enable",
+    callback=split_comma,
+    help="Specify a list of comma-separated optional DSL modules to enable.",
+)
 @click.option(
     "--verification/--substitution",
     "-v/-s",
@@ -77,10 +87,13 @@ def integrate(
     verification: bool,
     profile: bool,
     metadatagen: bool,
+    optional_modules_to_enable: Optional[tuple[str]],
 ) -> None:
     mode = "integration"
     iface = parse_fortran_file(input_path, output_path, mode)
-    iface_gt4py = process_stencils(iface, fused)
+    iface_gt4py = process_stencils(
+        iface, fused, optional_modules_to_enable=optional_modules_to_enable
+    )
     run_code_generation(
         input_path,
         output_path,
diff --git a/tools/src/icon4pytools/liskov/codegen/integration/deserialise.py b/tools/src/icon4pytools/liskov/codegen/integration/deserialise.py
index 54e085d685..d669f220c6 100644
--- a/tools/src/icon4pytools/liskov/codegen/integration/deserialise.py
+++ b/tools/src/icon4pytools/liskov/codegen/integration/deserialise.py
@@ -53,6 +53,10 @@
 TOLERANCE_ARGS = ["abs_tol", "rel_tol"]
 DEFAULT_DECLARE_IDENT_TYPE = "REAL(wp)"
 DEFAULT_DECLARE_SUFFIX = "before"
+DEFAULT_STARTSTENCIL_ACC_PRESENT = "true"
+DEFAULT_STARTSTENCIL_MERGECOPY = "false"
+DEFAULT_STARTSTENCIL_COPIES = "true"
+DEFAULT_STARTSTENCIL_OPTIONAL_MODULE = "None"
 
 logger = setup_logger(__name__)
 
@@ -286,12 +290,13 @@ def create_stencil_data(
         for i, directive in enumerate(directives):
             named_args = parsed["content"][directive_cls.__name__][i]
             additional_attrs = self._pop_additional_attributes(dtype, named_args)
-            acc_present = string_to_bool(pop_item_from_dict(named_args, "accpresent", "true"))
+            acc_present = string_to_bool(
+                pop_item_from_dict(named_args, "accpresent", DEFAULT_STARTSTENCIL_ACC_PRESENT)
+            )
             stencil_name = _extract_stencil_name(named_args, directive)
             bounds = self._make_bounds(named_args)
             fields = self._make_fields(named_args, field_dimensions)
             fields_w_tolerance = self._update_tolerances(named_args, fields)
-
             deserialised.append(
                 dtype(
                     name=stencil_name,
@@ -305,14 +310,27 @@ def create_stencil_data(
         return deserialised
 
     def _pop_additional_attributes(
-        self, dtype: Type[StartStencilData | StartFusedStencilData], named_args: dict[str, Any]
+        self,
+        dtype: Type[StartStencilData | StartFusedStencilData],
+        named_args: dict[str, Any],
     ) -> dict:
         """Pop and return additional attributes specific to StartStencilData."""
         additional_attrs = {}
         if dtype == StartStencilData:
-            mergecopy = string_to_bool(pop_item_from_dict(named_args, "mergecopy", "false"))
-            copies = string_to_bool(pop_item_from_dict(named_args, "copies", "true"))
-            additional_attrs = {"mergecopy": mergecopy, "copies": copies}
+            mergecopy = string_to_bool(
+                pop_item_from_dict(named_args, "mergecopy", DEFAULT_STARTSTENCIL_MERGECOPY)
+            )
+            copies = string_to_bool(
+                pop_item_from_dict(named_args, "copies", DEFAULT_STARTSTENCIL_COPIES)
+            )
+            optional_module = pop_item_from_dict(
+                named_args, "optional_module", DEFAULT_STARTSTENCIL_OPTIONAL_MODULE
+            )
+            additional_attrs = {
+                "mergecopy": mergecopy,
+                "copies": copies,
+                "optional_module": optional_module,
+            }
         return additional_attrs
 
     @staticmethod
diff --git a/tools/src/icon4pytools/liskov/codegen/integration/generate.py b/tools/src/icon4pytools/liskov/codegen/integration/generate.py
index 077e6f437d..fb8bd5ccd4 100644
--- a/tools/src/icon4pytools/liskov/codegen/integration/generate.py
+++ b/tools/src/icon4pytools/liskov/codegen/integration/generate.py
@@ -146,6 +146,7 @@ def _generate_start_stencil(self) -> None:
                     acc_present=stencil.acc_present,
                     mergecopy=stencil.mergecopy,
                     copies=stencil.copies,
+                    optional_module=stencil.optional_module,
                 )
                 i += 2
 
diff --git a/tools/src/icon4pytools/liskov/codegen/integration/interface.py b/tools/src/icon4pytools/liskov/codegen/integration/interface.py
index 93903cab78..07cb43872e 100644
--- a/tools/src/icon4pytools/liskov/codegen/integration/interface.py
+++ b/tools/src/icon4pytools/liskov/codegen/integration/interface.py
@@ -89,6 +89,7 @@ class BaseStartStencilData(CodeGenInput):
 class StartStencilData(BaseStartStencilData):
     mergecopy: Optional[bool]
     copies: Optional[bool]
+    optional_module: Optional[str]
 
 
 @dataclass
diff --git a/tools/src/icon4pytools/liskov/codegen/serialisation/deserialise.py b/tools/src/icon4pytools/liskov/codegen/serialisation/deserialise.py
index 6860b455f5..f550b4fd09 100644
--- a/tools/src/icon4pytools/liskov/codegen/serialisation/deserialise.py
+++ b/tools/src/icon4pytools/liskov/codegen/serialisation/deserialise.py
@@ -40,6 +40,7 @@
     "accpresent",
     "mergecopy",
     "copies",
+    "optional_module",
     "horizontal_lower",
     "horizontal_upper",
     "vertical_lower",
diff --git a/tools/src/icon4pytools/liskov/parsing/transform.py b/tools/src/icon4pytools/liskov/parsing/transform.py
index e6a0bd8ef8..ed1c8ad93b 100644
--- a/tools/src/icon4pytools/liskov/parsing/transform.py
+++ b/tools/src/icon4pytools/liskov/parsing/transform.py
@@ -10,9 +10,10 @@
 # distribution for a copy of the license or check <https://www.gnu.org/licenses/>.
 #
 # SPDX-License-Identifier: GPL-3.0-or-later
-from typing import Any
+from typing import Any, Optional
 
 from icon4pytools.common.logger import setup_logger
+from icon4pytools.liskov.codegen.integration.deserialise import DEFAULT_STARTSTENCIL_OPTIONAL_MODULE
 from icon4pytools.liskov.codegen.integration.interface import (
     EndDeleteData,
     EndFusedStencilData,
@@ -30,7 +31,18 @@
 logger = setup_logger(__name__)
 
 
-class StencilTransformer(Step):
+def _remove_stencils(
+    parsed: IntegrationCodeInterface, stencils_to_remove: list[CodeGenInput]
+) -> None:
+    attributes_to_modify = ["StartStencil", "EndStencil"]
+
+    for attr_name in attributes_to_modify:
+        current_stencil_list = getattr(parsed, attr_name)
+        modified_stencil_list = [_ for _ in current_stencil_list if _ not in stencils_to_remove]
+        setattr(parsed, attr_name, modified_stencil_list)
+
+
+class FusedStencilTransformer(Step):
     def __init__(self, parsed: IntegrationCodeInterface, fused: bool) -> None:
         self.parsed = parsed
         self.fused = fused
@@ -71,7 +83,7 @@ def _process_stencils_for_deletion(self) -> None:
                     self._create_delete_directives(start_single, end_single)
                     stencils_to_remove += [start_single, end_single]
 
-        self._remove_stencils(stencils_to_remove)
+        _remove_stencils(self.parsed, stencils_to_remove)
 
     def _stencil_is_removable(
         self,
@@ -105,14 +117,6 @@ def _create_delete_directives(
             directive.append(cls(startln=param.startln))
             setattr(self.parsed, attr, directive)
 
-    def _remove_stencils(self, stencils_to_remove: list[CodeGenInput]) -> None:
-        attributes_to_modify = ["StartStencil", "EndStencil"]
-
-        for attr_name in attributes_to_modify:
-            current_stencil_list = getattr(self.parsed, attr_name)
-            modified_stencil_list = [_ for _ in current_stencil_list if _ not in stencils_to_remove]
-            setattr(self.parsed, attr_name, modified_stencil_list)
-
     def _remove_fused_stencils(self) -> None:
         self.parsed.StartFusedStencil = []
         self.parsed.EndFusedStencil = []
@@ -120,3 +124,52 @@ def _remove_fused_stencils(self) -> None:
     def _remove_delete(self) -> None:
         self.parsed.StartDelete = []
         self.parsed.EndDelete = []
+
+
+class OptionalModulesTransformer(Step):
+    def __init__(
+        self, parsed: IntegrationCodeInterface, optional_modules_to_enable: Optional[tuple[str]]
+    ) -> None:
+        self.parsed = parsed
+        self.optional_modules_to_enable = optional_modules_to_enable
+
+    def __call__(self, data: Any = None) -> IntegrationCodeInterface:
+        """Transform stencils in the parse tree based on 'optional_modules_to_enable', either enabling specific modules or removing them.
+
+        Args:
+            data (Any): Optional data to be passed. Defaults to None.
+
+        Returns:
+            IntegrationCodeInterface: The modified interface object.
+        """
+        if self.optional_modules_to_enable is not None:
+            action = "enabling"
+        else:
+            action = "removing"
+        logger.info(f"Transforming stencils by {action} optional modules.")
+        self._transform_stencils()
+
+        return self.parsed
+
+    def _transform_stencils(self) -> None:
+        """Identify stencils to transform based on 'optional_modules_to_enable' and applies necessary changes."""
+        stencils_to_remove = []
+        for start_stencil, end_stencil in zip(
+            self.parsed.StartStencil, self.parsed.EndStencil, strict=False
+        ):
+            if self._should_remove_stencil(start_stencil):
+                stencils_to_remove.extend([start_stencil, end_stencil])
+
+        _remove_stencils(self.parsed, stencils_to_remove)
+
+    def _should_remove_stencil(self, stencil: StartStencilData) -> bool:
+        """Determine if a stencil should be removed based on 'optional_modules_to_enable'.
+
+        Returns:
+            bool: True if the stencil should be removed, False otherwise.
+        """
+        if stencil.optional_module == DEFAULT_STARTSTENCIL_OPTIONAL_MODULE:
+            return False
+        if self.optional_modules_to_enable is None:
+            return True
+        return stencil.optional_module not in self.optional_modules_to_enable
diff --git a/tools/src/icon4pytools/liskov/pipeline/collection.py b/tools/src/icon4pytools/liskov/pipeline/collection.py
index 4d458ad1cc..8b924926b3 100644
--- a/tools/src/icon4pytools/liskov/pipeline/collection.py
+++ b/tools/src/icon4pytools/liskov/pipeline/collection.py
@@ -11,7 +11,7 @@
 #
 # SPDX-License-Identifier: GPL-3.0-or-later
 from pathlib import Path
-from typing import Any
+from typing import Any, Optional
 
 from icon4pytools.liskov.codegen.integration.deserialise import IntegrationCodeDeserialiser
 from icon4pytools.liskov.codegen.integration.generate import IntegrationCodeGenerator
@@ -22,7 +22,10 @@
 from icon4pytools.liskov.external.gt4py import UpdateFieldsWithGt4PyStencils
 from icon4pytools.liskov.parsing.parse import DirectivesParser
 from icon4pytools.liskov.parsing.scan import DirectivesScanner
-from icon4pytools.liskov.parsing.transform import StencilTransformer
+from icon4pytools.liskov.parsing.transform import (
+    FusedStencilTransformer,
+    OptionalModulesTransformer,
+)
 from icon4pytools.liskov.pipeline.definition import Step, linear_pipeline
 
 
@@ -70,21 +73,28 @@ def parse_fortran_file(
 
 
 @linear_pipeline
-def process_stencils(parsed: IntegrationCodeInterface, fused: bool) -> list[Step]:
+def process_stencils(
+    parsed: IntegrationCodeInterface, fused: bool, optional_modules_to_enable: Optional[tuple[str]]
+) -> list[Step]:
     """Execute a linear pipeline to transform stencils and produce either fused or unfused execution.
 
     This function takes an input `parsed` object of type `IntegrationCodeInterface` and a `fused` boolean flag.
-    It then executes a linear pipeline, consisting of two steps: transformation of stencils for fusion or unfusion,
-    and updating fields with information from GT4Py stencils.
+    It then executes a linear pipeline, consisting of three steps: transformation of stencils for fusion or unfusion,
+    enabling optional modules, and updating fields with information from GT4Py stencils.
 
     Args:
         parsed (IntegrationCodeInterface): The input object containing parsed integration code.
         fused (bool): A boolean flag indicating whether to produce fused (True) or unfused (False) execution.
+        optional_modules_to_enable (Optional[tuple[str]]): A tuple of optional modules to enable.
 
     Returns:
-        The updated and transformed object with fields containing information from GT4Py stencils.
+        The updated and transformed IntegrationCodeInterface object.
     """
-    return [StencilTransformer(parsed, fused), UpdateFieldsWithGt4PyStencils(parsed)]
+    return [
+        FusedStencilTransformer(parsed, fused),
+        OptionalModulesTransformer(parsed, optional_modules_to_enable),
+        UpdateFieldsWithGt4PyStencils(parsed),
+    ]
 
 
 @linear_pipeline
diff --git a/tools/tests/liskov/test_external.py b/tools/tests/liskov/test_external.py
index 55f2e5f3b2..454d01e428 100644
--- a/tools/tests/liskov/test_external.py
+++ b/tools/tests/liskov/test_external.py
@@ -77,6 +77,7 @@ def test_stencil_collector_invalid_member():
             acc_present=False,
             mergecopy=False,
             copies=True,
+            optional_module="None",
         )
     ],
     Imports=None,
diff --git a/tools/tests/liskov/test_generation.py b/tools/tests/liskov/test_generation.py
index 46b7f43dae..b715f6b643 100644
--- a/tools/tests/liskov/test_generation.py
+++ b/tools/tests/liskov/test_generation.py
@@ -79,6 +79,7 @@ def integration_code_interface():
         acc_present=False,
         mergecopy=False,
         copies=True,
+        optional_module="None",
     )
     end_stencil_data = EndStencilData(
         name="stencil1", startln=3, noendif=False, noprofile=False, noaccenddata=False
diff --git a/tools/tests/liskov/test_serialisation_deserialiser.py b/tools/tests/liskov/test_serialisation_deserialiser.py
index 0431086beb..518029af3a 100644
--- a/tools/tests/liskov/test_serialisation_deserialiser.py
+++ b/tools/tests/liskov/test_serialisation_deserialiser.py
@@ -105,6 +105,7 @@ def parsed_dict():
                     "horizontal_lower": "i_startidx",
                     "horizontal_upper": "i_endidx",
                     "accpresent": "True",
+                    "optional_module": "advection",
                 }
             ],
             "StartProfile": [{"name": "apply_nabla2_to_vn_in_lateral_boundary"}],
@@ -127,5 +128,7 @@ def test_savepoint_data_factory(parsed_dict):
     savepoints = SavepointDataFactory()(parsed_dict)
     assert len(savepoints) == 2
     assert any([isinstance(sp, SavepointData) for sp in savepoints])
+    # check that unnecessary keys have been removed
+    assert not any(f.variable == "optional_module" for sp in savepoints for f in sp.fields)
     assert any([isinstance(f, FieldSerialisationData) for f in savepoints[0].fields])
     assert any([isinstance(m, Metadata) for m in savepoints[0].metadata])
diff --git a/tools/tests/liskov/test_transform.py b/tools/tests/liskov/test_transform.py
index 4c2a60454c..1ac5a2bcbb 100644
--- a/tools/tests/liskov/test_transform.py
+++ b/tools/tests/liskov/test_transform.py
@@ -33,7 +33,10 @@
     StartProfileData,
     StartStencilData,
 )
-from icon4pytools.liskov.parsing.transform import StencilTransformer
+from icon4pytools.liskov.parsing.transform import (
+    FusedStencilTransformer,
+    OptionalModulesTransformer,
+)
 
 
 @pytest.fixture
@@ -94,6 +97,7 @@ def integration_code_interface():
         acc_present=False,
         mergecopy=False,
         copies=True,
+        optional_module="None",
     )
     end_stencil_data1 = EndStencilData(
         name="stencil1", startln=3, noendif=False, noprofile=False, noaccenddata=False
@@ -126,6 +130,7 @@ def integration_code_interface():
         acc_present=False,
         mergecopy=False,
         copies=True,
+        optional_module="advection",
     )
     end_stencil_data2 = EndStencilData(
         name="stencil2", startln=6, noendif=False, noprofile=False, noaccenddata=False
@@ -165,20 +170,32 @@ def integration_code_interface():
 
 
 @pytest.fixture
-def stencil_transform_fused(integration_code_interface):
-    return StencilTransformer(integration_code_interface, fused=True)
+def fused_stencil_transform_fused(integration_code_interface):
+    return FusedStencilTransformer(integration_code_interface, fused=True)
 
 
 @pytest.fixture
-def stencil_transform_unfused(integration_code_interface):
-    return StencilTransformer(integration_code_interface, fused=False)
+def fused_stencil_transform_unfused(integration_code_interface):
+    return FusedStencilTransformer(integration_code_interface, fused=False)
+
+
+@pytest.fixture
+def optional_modules_transform_enabled(integration_code_interface):
+    return OptionalModulesTransformer(
+        integration_code_interface, optional_modules_to_enable=["advection"]
+    )
+
+
+@pytest.fixture
+def optional_modules_transform_disabled(integration_code_interface):
+    return OptionalModulesTransformer(integration_code_interface, optional_modules_to_enable=None)
 
 
 def test_transform_fused(
-    stencil_transform_fused,
+    fused_stencil_transform_fused,
 ):
     # Check that the transformed interface is as expected
-    transformed = stencil_transform_fused()
+    transformed = fused_stencil_transform_fused()
     assert len(transformed.StartFusedStencil) == 1
     assert len(transformed.EndFusedStencil) == 1
     assert len(transformed.StartStencil) == 1
@@ -188,10 +205,10 @@ def test_transform_fused(
 
 
 def test_transform_unfused(
-    stencil_transform_unfused,
+    fused_stencil_transform_unfused,
 ):
     # Check that the transformed interface is as expected
-    transformed = stencil_transform_unfused()
+    transformed = fused_stencil_transform_unfused()
 
     assert not transformed.StartFusedStencil
     assert not transformed.EndFusedStencil
@@ -199,3 +216,30 @@ def test_transform_unfused(
     assert len(transformed.EndStencil) == 2
     assert not transformed.StartDelete
     assert not transformed.EndDelete
+
+
+def test_transform_optional_enabled(
+    optional_modules_transform_enabled,
+):
+    # Check that the transformed interface is as expected
+    transformed = optional_modules_transform_enabled()
+    assert len(transformed.StartFusedStencil) == 1
+    assert len(transformed.EndFusedStencil) == 1
+    assert len(transformed.StartStencil) == 2
+    assert len(transformed.EndStencil) == 2
+    assert len(transformed.StartDelete) == 1
+    assert len(transformed.EndDelete) == 1
+
+
+def test_transform_optional_disabled(
+    optional_modules_transform_disabled,
+):
+    # Check that the transformed interface is as expected
+    transformed = optional_modules_transform_disabled()
+
+    assert len(transformed.StartFusedStencil) == 1
+    assert len(transformed.EndFusedStencil) == 1
+    assert len(transformed.StartStencil) == 1
+    assert len(transformed.EndStencil) == 1
+    assert len(transformed.StartDelete) == 1
+    assert len(transformed.EndDelete) == 1