diff --git a/src/inspector/entry_point.h b/src/inspector/entry_point.h
index 167702d641..a97cc67cce 100644
--- a/src/inspector/entry_point.h
+++ b/src/inspector/entry_point.h
@@ -122,8 +122,12 @@ struct EntryPoint {
   std::vector<StageVariable> output_variables;
   /// List of the pipeline overridable constants accessed via this entry point.
   std::vector<OverridableConstant> overridable_constants;
-  /// Does the entry point use the sample_mask builtin
-  bool sample_mask_used = false;
+  /// Does the entry point use the sample_mask builtin as an input builtin
+  /// variable.
+  bool input_sample_mask_used = false;
+  /// Does the entry point use the sample_mask builtin as an output builtin
+  /// variable.
+  bool output_sample_mask_used = false;
   /// Does the entry point use the position builtin as an input builtin
   /// variable.
   bool input_position_used = false;
diff --git a/src/inspector/inspector.cc b/src/inspector/inspector.cc
index 91ef6211ff..dc057c6e29 100644
--- a/src/inspector/inspector.cc
+++ b/src/inspector/inspector.cc
@@ -170,6 +170,9 @@ std::vector<EntryPoint> Inspector::GetEntryPoints() {
       entry_point.sample_index_used |=
           ContainsBuiltin(ast::Builtin::kSampleIndex, param->Type(),
                           param->Declaration()->decorations());
+      entry_point.input_sample_mask_used |=
+          ContainsBuiltin(ast::Builtin::kSampleMask, param->Type(),
+                          param->Declaration()->decorations());
     }
 
     if (!sem->ReturnType()->Is<sem::Void>()) {
@@ -177,7 +180,7 @@ std::vector<EntryPoint> Inspector::GetEntryPoints() {
                                   func->return_type_decorations(),
                                   entry_point.output_variables);
 
-      entry_point.sample_mask_used =
+      entry_point.output_sample_mask_used =
           ContainsBuiltin(ast::Builtin::kSampleMask, sem->ReturnType(),
                           func->return_type_decorations());
     }
diff --git a/src/inspector/inspector_test.cc b/src/inspector/inspector_test.cc
index 6a8c946acc..488d928685 100644
--- a/src/inspector/inspector_test.cc
+++ b/src/inspector/inspector_test.cc
@@ -637,13 +637,46 @@ TEST_F(InspectorGetEntryPointTest, BuiltinNotReferenced) {
   auto result = inspector.GetEntryPoints();
 
   ASSERT_EQ(1u, result.size());
-  EXPECT_FALSE(result[0].sample_mask_used);
+  EXPECT_FALSE(result[0].input_sample_mask_used);
+  EXPECT_FALSE(result[0].output_sample_mask_used);
   EXPECT_FALSE(result[0].input_position_used);
   EXPECT_FALSE(result[0].front_facing_used);
   EXPECT_FALSE(result[0].sample_index_used);
 }
 
-TEST_F(InspectorGetEntryPointTest, SampleMaskSimpleReferenced) {
+TEST_F(InspectorGetEntryPointTest, InputSampleMaskSimpleReferenced) {
+  auto* in_var =
+      Param("in_var", ty.u32(), {Builtin(ast::Builtin::kSampleMask)});
+  Func("ep_func", {in_var}, ty.void_(), {Return()},
+       {Stage(ast::PipelineStage::kFragment)}, {});
+
+  Inspector& inspector = Build();
+
+  auto result = inspector.GetEntryPoints();
+
+  ASSERT_EQ(1u, result.size());
+  EXPECT_TRUE(result[0].input_sample_mask_used);
+}
+
+TEST_F(InspectorGetEntryPointTest, InputSampleMaskStructReferenced) {
+  ast::StructMemberList members;
+  members.push_back(
+      Member("inner_position", ty.u32(), {Builtin(ast::Builtin::kSampleMask)}));
+  Structure("in_struct", members, {});
+  auto* in_var = Param("in_var", ty.type_name("in_struct"), {});
+
+  Func("ep_func", {in_var}, ty.void_(), {Return()},
+       {Stage(ast::PipelineStage::kFragment)}, {});
+
+  Inspector& inspector = Build();
+
+  auto result = inspector.GetEntryPoints();
+
+  ASSERT_EQ(1u, result.size());
+  EXPECT_TRUE(result[0].input_sample_mask_used);
+}
+
+TEST_F(InspectorGetEntryPointTest, OutputSampleMaskSimpleReferenced) {
   auto* in_var =
       Param("in_var", ty.u32(), {Builtin(ast::Builtin::kSampleMask)});
   Func("ep_func", {in_var}, ty.u32(), {Return("in_var")},
@@ -655,10 +688,10 @@ TEST_F(InspectorGetEntryPointTest, SampleMaskSimpleReferenced) {
   auto result = inspector.GetEntryPoints();
 
   ASSERT_EQ(1u, result.size());
-  EXPECT_TRUE(result[0].sample_mask_used);
+  EXPECT_TRUE(result[0].output_sample_mask_used);
 }
 
-TEST_F(InspectorGetEntryPointTest, SampleMaskStructReferenced) {
+TEST_F(InspectorGetEntryPointTest, OutputSampleMaskStructReferenced) {
   ast::StructMemberList members;
   members.push_back(Member("inner_sample_mask", ty.u32(),
                            {Builtin(ast::Builtin::kSampleMask)}));
@@ -673,7 +706,7 @@ TEST_F(InspectorGetEntryPointTest, SampleMaskStructReferenced) {
   auto result = inspector.GetEntryPoints();
 
   ASSERT_EQ(1u, result.size());
-  EXPECT_TRUE(result[0].sample_mask_used);
+  EXPECT_TRUE(result[0].output_sample_mask_used);
 }
 
 TEST_F(InspectorGetEntryPointTest, InputPositionSimpleReferenced) {