diff --git a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/testutil/CodegenIntegrationTest.kt b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/testutil/CodegenIntegrationTest.kt
index 817af1e09a..8a09ccc09e 100644
--- a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/testutil/CodegenIntegrationTest.kt
+++ b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/testutil/CodegenIntegrationTest.kt
@@ -40,97 +40,73 @@ data class IntegrationTestParams(
  *     model,
  *     IntegrationTestParams(
  *         additionalSettings =
- *             ServerAdditionalSettings.builder()
- *                 .generateCodegenComments()
- *                 .publicConstrainedTypes()
+ *             ServerAdditionalSettings()
+ *                 .generateCodegenComments(true)
+ *                 .publicConstrainedTypes(true)
  *                 .toObjectNode()
  * )),
  * ```
  */
-sealed class AdditionalSettings {
-    abstract fun toObjectNode(): ObjectNode
-
-    abstract class CoreAdditionalSettings protected constructor(val settings: List<AdditionalSettings>) : AdditionalSettings() {
-        override fun toObjectNode(): ObjectNode {
-            val merged =
-                settings.map { it.toObjectNode() }
-                    .reduce { acc, next -> acc.merge(next) }
-
-            return ObjectNode.builder()
-                .withMember("codegen", merged)
-                .build()
-        }
-
-        abstract class Builder<T : CoreAdditionalSettings> : AdditionalSettings() {
-            protected val settings = mutableListOf<AdditionalSettings>()
-
-            fun generateCodegenComments(debugMode: Boolean = true): Builder<T> {
-                settings.add(GenerateCodegenComments(debugMode))
-                return this
-            }
-
-            abstract fun build(): T
-
-            override fun toObjectNode(): ObjectNode = build().toObjectNode()
+open class AdditionalSettings<T : AdditionalSettings<T>> {
+    private val codegenBuilderDelegate =
+        lazy {
+            ObjectNode.builder()
         }
+    private val codegenBuilder: ObjectNode.Builder by codegenBuilderDelegate
 
-        // Core settings that are common to both Servers and Clients should be defined here.
-        data class GenerateCodegenComments(val debugMode: Boolean) : AdditionalSettings() {
-            override fun toObjectNode(): ObjectNode =
-                ObjectNode.builder()
-                    .withMember("debugMode", debugMode)
-                    .build()
+    fun build(): ObjectNode {
+        return if (codegenBuilderDelegate.isInitialized()) {
+            ObjectNode.builder()
+                .withMember("codegen", codegenBuilder.build())
+                .build()
+        } else {
+            ObjectNode.builder().build()
         }
     }
-}
-
-class ClientAdditionalSettings private constructor(settings: List<AdditionalSettings>) :
-    AdditionalSettings.CoreAdditionalSettings(settings) {
-        class Builder : CoreAdditionalSettings.Builder<ClientAdditionalSettings>() {
-            override fun build(): ClientAdditionalSettings = ClientAdditionalSettings(settings)
-        }
 
-        // Additional settings that are specific to client generation should be defined here.
-
-        companion object {
-            fun builder() = Builder()
-        }
+    @Suppress("UNCHECKED_CAST")
+    open fun generateCodegenComments(debugMode: Boolean = true): T {
+        codegenBuilder.withMember("debugMode", debugMode)
+        return this as T
     }
 
-class ServerAdditionalSettings private constructor(settings: List<AdditionalSettings>) :
-    AdditionalSettings.CoreAdditionalSettings(settings) {
-        class Builder : CoreAdditionalSettings.Builder<ServerAdditionalSettings>() {
-            fun publicConstrainedTypes(enabled: Boolean = true): Builder {
-                settings.add(PublicConstrainedTypes(enabled))
-                return this
-            }
+    @Suppress("UNCHECKED_CAST")
+    protected fun withCodegenMember(
+        key: String,
+        value: Boolean,
+    ): T {
+        codegenBuilder.withMember(key, value)
+        return this as T
+    }
 
-            fun addValidationExceptionToConstrainedOperations(enabled: Boolean = true): Builder {
-                settings.add(AddValidationExceptionToConstrainedOperations(enabled))
-                return this
-            }
+    @Suppress("UNCHECKED_CAST")
+    protected fun withCodegenMember(
+        key: String,
+        value: String,
+    ): T {
+        codegenBuilder.withMember(key, value)
+        return this as T
+    }
 
-            override fun build(): ServerAdditionalSettings = ServerAdditionalSettings(settings)
-        }
+    @Suppress("UNCHECKED_CAST")
+    protected fun withCodegenMember(
+        key: String,
+        value: Number,
+    ): T {
+        codegenBuilder.withMember(key, value)
+        return this as T
+    }
+}
 
-        private data class PublicConstrainedTypes(val enabled: Boolean) : AdditionalSettings() {
-            override fun toObjectNode(): ObjectNode =
-                ObjectNode.builder()
-                    .withMember("publicConstrainedTypes", enabled)
-                    .build()
-        }
+class ServerAdditionalSettings : AdditionalSettings<ServerAdditionalSettings>() {
+    fun publicConstrainedTypes(enabled: Boolean = true): ServerAdditionalSettings =
+        withCodegenMember("publicConstrainedTypes", enabled)
 
-        private data class AddValidationExceptionToConstrainedOperations(val enabled: Boolean) : AdditionalSettings() {
-            override fun toObjectNode(): ObjectNode =
-                ObjectNode.builder()
-                    .withMember("addValidationExceptionToConstrainedOperations", enabled)
-                    .build()
-        }
+    fun addValidationExceptionToConstrainedOperations(enabled: Boolean = true) =
+        withCodegenMember("addValidationExceptionToConstrainedOperations", enabled)
 
-        companion object {
-            fun builder() = Builder()
-        }
-    }
+    fun ignoreUnsupportedConstraints() = withCodegenMember("ignoreUnsupportedConstraints", true)
+}
 
 /**
  * Run cargo test on a true, end-to-end, codegen product of a given model.
diff --git a/codegen-server/src/test/kotlin/software/amazon/smithy/rust/codegen/server/smithy/ConstraintsTest.kt b/codegen-server/src/test/kotlin/software/amazon/smithy/rust/codegen/server/smithy/ConstraintsTest.kt
index 36e30230c6..8087b3e08e 100644
--- a/codegen-server/src/test/kotlin/software/amazon/smithy/rust/codegen/server/smithy/ConstraintsTest.kt
+++ b/codegen-server/src/test/kotlin/software/amazon/smithy/rust/codegen/server/smithy/ConstraintsTest.kt
@@ -242,9 +242,9 @@ class ConstraintsTest {
             IntegrationTestParams(
                 service = "test#SampleService",
                 additionalSettings =
-                    ServerAdditionalSettings.builder()
+                    ServerAdditionalSettings()
                         .publicConstrainedTypes(pubConstraints)
-                        .toObjectNode(),
+                        .build(),
                 overrideTestDir = dir,
             ),
             test = test,
diff --git a/codegen-server/src/test/kotlin/software/amazon/smithy/rust/codegen/server/smithy/customizations/AddValidationExceptionToConstrainedOperationsTest.kt b/codegen-server/src/test/kotlin/software/amazon/smithy/rust/codegen/server/smithy/customizations/AddValidationExceptionToConstrainedOperationsTest.kt
index d56dd5c6f2..b15a424f34 100644
--- a/codegen-server/src/test/kotlin/software/amazon/smithy/rust/codegen/server/smithy/customizations/AddValidationExceptionToConstrainedOperationsTest.kt
+++ b/codegen-server/src/test/kotlin/software/amazon/smithy/rust/codegen/server/smithy/customizations/AddValidationExceptionToConstrainedOperationsTest.kt
@@ -76,9 +76,10 @@ internal class AddValidationExceptionToConstrainedOperationsTest {
             testModelWithValidationExceptionImported,
             IntegrationTestParams(
                 additionalSettings =
-                    ServerAdditionalSettings.builder()
+                    ServerAdditionalSettings()
+                        .generateCodegenComments(true)
                         .addValidationExceptionToConstrainedOperations()
-                        .toObjectNode(),
+                        .build(),
             ),
         )
     }
diff --git a/codegen-server/src/test/kotlin/software/amazon/smithy/rust/codegen/server/smithy/protocols/serialize/CborConstraintsIntegrationTest.kt b/codegen-server/src/test/kotlin/software/amazon/smithy/rust/codegen/server/smithy/protocols/serialize/CborConstraintsIntegrationTest.kt
index 0a80a125d6..3c18d765a8 100644
--- a/codegen-server/src/test/kotlin/software/amazon/smithy/rust/codegen/server/smithy/protocols/serialize/CborConstraintsIntegrationTest.kt
+++ b/codegen-server/src/test/kotlin/software/amazon/smithy/rust/codegen/server/smithy/protocols/serialize/CborConstraintsIntegrationTest.kt
@@ -6,7 +6,6 @@ package software.amazon.smithy.rust.codegen.server.smithy.protocols.serialize
 
 import org.junit.jupiter.api.Test
 import software.amazon.smithy.rust.codegen.core.testutil.IntegrationTestParams
-import software.amazon.smithy.rust.codegen.core.testutil.ServerAdditionalSettings
 import software.amazon.smithy.rust.codegen.server.smithy.ModelProtocol
 import software.amazon.smithy.rust.codegen.server.smithy.loadSmithyConstraintsModelForProtocol
 import software.amazon.smithy.rust.codegen.server.smithy.testutil.serverIntegrationTest
@@ -20,7 +19,6 @@ class CborConstraintsIntegrationTest {
             model,
             IntegrationTestParams(
                 service = serviceShape.toString(),
-                additionalSettings = ServerAdditionalSettings.builder().generateCodegenComments().toObjectNode(),
             ),
         ) { _, _ ->
         }