diff --git a/metricflow/model/semantics/metric_lookup.py b/metricflow/model/semantics/metric_lookup.py
index f43348821d..b39ec0324e 100644
--- a/metricflow/model/semantics/metric_lookup.py
+++ b/metricflow/model/semantics/metric_lookup.py
@@ -106,14 +106,9 @@ def add_metric(self, metric: Metric) -> None:
                 )
         self._metrics[metric_reference] = metric
 
-    def configured_input_measure_for_metric(self, metric_reference: MetricReference) -> Optional[MetricInputMeasure]:
-        """Get input measure defined in the original metric config, if exists.
-
-        When SemanticModel is constructed, input measures from input metrics are added to the list of input measures
-        for a metric. Here, use rules about metric types to determine which input measures were defined in the config:
-        - Simple & cumulative metrics require one input measure, and can't take any input metrics.
-        - Derived & ratio metrics take no input measures, only input metrics.
-        """
+    def configured_input_measure_for_metric(  # noqa: D
+        self, metric_reference: MetricReference
+    ) -> Optional[MetricInputMeasure]:
         metric = self.get_metric(metric_reference=metric_reference)
         if metric.type is MetricType.CUMULATIVE or metric.type is MetricType.SIMPLE:
             assert len(metric.input_measures) == 1, "Simple and cumulative metrics should have one input measure."
diff --git a/metricflow/protocols/semantics.py b/metricflow/protocols/semantics.py
index 6fc4e00a39..004a88324a 100644
--- a/metricflow/protocols/semantics.py
+++ b/metricflow/protocols/semantics.py
@@ -14,7 +14,7 @@
 from dbt_semantic_interfaces.protocols.dimension import Dimension
 from dbt_semantic_interfaces.protocols.entity import Entity
 from dbt_semantic_interfaces.protocols.measure import Measure
-from dbt_semantic_interfaces.protocols.metric import Metric
+from dbt_semantic_interfaces.protocols.metric import Metric, MetricInputMeasure
 from dbt_semantic_interfaces.protocols.semantic_model import SemanticModel
 from dbt_semantic_interfaces.references import (
     DimensionReference,
@@ -187,3 +187,14 @@ def metric_input_specs_for_metric(
     ) -> Sequence[MetricSpec]:
         """Returns the metric input specs required to compute the metric."""
         raise NotImplementedError
+
+    @abstractmethod
+    def configured_input_measure_for_metric(self, metric_reference: MetricReference) -> Optional[MetricInputMeasure]:
+        """Get input measure defined in the original metric config, if exists.
+
+        When SemanticModel is constructed, input measures from input metrics are added to the list of input measures
+        for a metric. Here, use rules about metric types to determine which input measures were defined in the config:
+        - Simple & cumulative metrics require one input measure, and can't take any input metrics.
+        - Derived & ratio metrics take no input measures, only input metrics.
+        """
+        raise NotImplementedError