diff --git a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/CredentialCaches.kt b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/CredentialCaches.kt
index 03f22cb21f6a1ad1bc8560e0ec8ffd500b433f8c..5aaaeab950644c30307371e0c78a4316898a2dea 100644
--- a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/CredentialCaches.kt
+++ b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/CredentialCaches.kt
@@ -15,10 +15,10 @@ import software.amazon.smithy.rust.codegen.core.rustlang.rust
 import software.amazon.smithy.rust.codegen.core.rustlang.rustTemplate
 import software.amazon.smithy.rust.codegen.core.rustlang.writable
 import software.amazon.smithy.rust.codegen.core.smithy.RuntimeConfig
-import software.amazon.smithy.rust.codegen.core.smithy.customize.AdHocSection
+import software.amazon.smithy.rust.codegen.core.smithy.customize.AdHocCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.customize.OperationCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.customize.OperationSection
-import software.amazon.smithy.rust.codegen.core.smithy.customize.Section
+import software.amazon.smithy.rust.codegen.core.smithy.customize.adhocCustomization
 
 class CredentialsCacheDecorator : ClientCodegenDecorator {
     override val name: String = "CredentialsCache"
@@ -38,12 +38,10 @@ class CredentialsCacheDecorator : ClientCodegenDecorator {
         return baseCustomizations + CredentialsCacheFeature(codegenContext.runtimeConfig)
     }
 
-    override fun extraSections(codegenContext: ClientCodegenContext): List<Pair<AdHocSection<*>, (Section) -> Writable>> =
+    override fun extraSections(codegenContext: ClientCodegenContext): List<AdHocCustomization> =
         listOf(
-            SdkConfigSection.create { section ->
-                writable {
-                    rust("${section.serviceConfigBuilder}.set_credentials_cache(${section.sdkConfig}.credentials_cache().cloned());")
-                }
+            adhocCustomization<SdkConfigSection.CopySdkConfigToClientConfig> { section ->
+                rust("${section.serviceConfigBuilder}.set_credentials_cache(${section.sdkConfig}.credentials_cache().cloned());")
             },
         )
 }
diff --git a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/CredentialProviders.kt b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/CredentialProviders.kt
index dc6f8e9d0ae3b898a6a256c5946a3901ec41c528..c9499c39203d8d33524f8ec0fe8ad5d1a99487a7 100644
--- a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/CredentialProviders.kt
+++ b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/CredentialProviders.kt
@@ -17,8 +17,8 @@ import software.amazon.smithy.rust.codegen.core.rustlang.writable
 import software.amazon.smithy.rust.codegen.core.smithy.RuntimeConfig
 import software.amazon.smithy.rust.codegen.core.smithy.RuntimeType
 import software.amazon.smithy.rust.codegen.core.smithy.RustCrate
-import software.amazon.smithy.rust.codegen.core.smithy.customize.AdHocSection
-import software.amazon.smithy.rust.codegen.core.smithy.customize.Section
+import software.amazon.smithy.rust.codegen.core.smithy.customize.AdHocCustomization
+import software.amazon.smithy.rust.codegen.core.smithy.customize.adhocCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.generators.LibRsCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.generators.LibRsSection
 
@@ -40,12 +40,10 @@ class CredentialsProviderDecorator : ClientCodegenDecorator {
         return baseCustomizations + PubUseCredentials(codegenContext.runtimeConfig)
     }
 
-    override fun extraSections(codegenContext: ClientCodegenContext): List<Pair<AdHocSection<*>, (Section) -> Writable>> =
+    override fun extraSections(codegenContext: ClientCodegenContext): List<AdHocCustomization> =
         listOf(
-            SdkConfigSection.create { section ->
-                writable {
-                    rust("${section.serviceConfigBuilder}.set_credentials_provider(${section.sdkConfig}.credentials_provider().cloned());")
-                }
+            adhocCustomization<SdkConfigSection.CopySdkConfigToClientConfig> { section ->
+                rust("${section.serviceConfigBuilder}.set_credentials_provider(${section.sdkConfig}.credentials_provider().cloned());")
             },
         )
 
diff --git a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/EndpointBuiltInsDecorator.kt b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/EndpointBuiltInsDecorator.kt
index 0b869e7c6f54d7ccff8dcb1e2d3f4b87799ff2ac..1ac83c10ca2ce837415fdf710d59bcf813185d82 100644
--- a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/EndpointBuiltInsDecorator.kt
+++ b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/EndpointBuiltInsDecorator.kt
@@ -29,8 +29,7 @@ import software.amazon.smithy.rust.codegen.core.rustlang.rust
 import software.amazon.smithy.rust.codegen.core.rustlang.rustTemplate
 import software.amazon.smithy.rust.codegen.core.rustlang.writable
 import software.amazon.smithy.rust.codegen.core.smithy.RuntimeType
-import software.amazon.smithy.rust.codegen.core.smithy.customize.AdHocSection
-import software.amazon.smithy.rust.codegen.core.smithy.customize.Section
+import software.amazon.smithy.rust.codegen.core.smithy.customize.AdHocCustomization
 import software.amazon.smithy.rust.codegen.core.util.PANIC
 import software.amazon.smithy.rust.codegen.core.util.dq
 import software.amazon.smithy.rust.codegen.core.util.extendIf
@@ -71,7 +70,7 @@ fun Model.sdkConfigSetter(
     serviceId: ShapeId,
     builtInSrc: Parameter,
     configParameterNameOverride: String?,
-): Pair<AdHocSection<*>, (Section) -> Writable>? {
+): AdHocCustomization? {
     val builtIn = loadBuiltIn(serviceId, builtInSrc) ?: return null
     val fieldName = configParameterNameOverride ?: builtIn.name.rustName()
 
@@ -79,7 +78,7 @@ fun Model.sdkConfigSetter(
         ParameterType.STRING -> writable { rust("|s|s.to_string()") }
         ParameterType.BOOLEAN -> null
     }
-    return SdkConfigSection.copyField(fieldName, map)
+    return SdkConfigCustomization.copyField(fieldName, map)
 }
 
 /**
@@ -99,7 +98,7 @@ fun decoratorForBuiltIn(
         private fun rulesetContainsBuiltIn(codegenContext: ClientCodegenContext) =
             codegenContext.getBuiltIn(builtIn) != null
 
-        override fun extraSections(codegenContext: ClientCodegenContext): List<Pair<AdHocSection<*>, (Section) -> Writable>> {
+        override fun extraSections(codegenContext: ClientCodegenContext): List<AdHocCustomization> {
             return listOfNotNull(
                 codegenContext.model.sdkConfigSetter(codegenContext.serviceShape.id, builtIn, clientParam?.name),
             )
diff --git a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/RegionDecorator.kt b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/RegionDecorator.kt
index fef37957bb8accc6c4ce1fec9f1f416874898ab1..70775e2cda4f94aa7465cb48764ac2f512b3f4d7 100644
--- a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/RegionDecorator.kt
+++ b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/RegionDecorator.kt
@@ -20,10 +20,10 @@ import software.amazon.smithy.rust.codegen.core.rustlang.rustTemplate
 import software.amazon.smithy.rust.codegen.core.rustlang.writable
 import software.amazon.smithy.rust.codegen.core.smithy.CodegenContext
 import software.amazon.smithy.rust.codegen.core.smithy.RuntimeConfig
-import software.amazon.smithy.rust.codegen.core.smithy.customize.AdHocSection
+import software.amazon.smithy.rust.codegen.core.smithy.customize.AdHocCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.customize.OperationCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.customize.OperationSection
-import software.amazon.smithy.rust.codegen.core.smithy.customize.Section
+import software.amazon.smithy.rust.codegen.core.smithy.customize.adhocCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.generators.LibRsCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.generators.LibRsSection
 import software.amazon.smithy.rust.codegen.core.util.dq
@@ -108,17 +108,15 @@ class RegionDecorator : ClientCodegenDecorator {
         return baseCustomizations.extendIf(usesRegion(codegenContext)) { PubUseRegion(codegenContext.runtimeConfig) }
     }
 
-    override fun extraSections(codegenContext: ClientCodegenContext): List<Pair<AdHocSection<*>, (Section) -> Writable>> {
+    override fun extraSections(codegenContext: ClientCodegenContext): List<AdHocCustomization> {
         return usesRegion(codegenContext).thenSingletonListOf {
-            SdkConfigSection.create { section ->
-                {
-                    rust(
-                        """
-                        ${section.serviceConfigBuilder} =
-                             ${section.serviceConfigBuilder}.region(${section.sdkConfig}.region().cloned());
-                        """,
-                    )
-                }
+            adhocCustomization<SdkConfigSection.CopySdkConfigToClientConfig> { section ->
+                rust(
+                    """
+                    ${section.serviceConfigBuilder} =
+                         ${section.serviceConfigBuilder}.region(${section.sdkConfig}.region().cloned());
+                    """,
+                )
             }
         }
     }
diff --git a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/SdkConfigDecorator.kt b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/SdkConfigDecorator.kt
index 2d1ff40a1fec50af120d218eae7494b03d8e9e19..f0e2a7e7d642bbc5d150ed1e7780b75ae32343d3 100644
--- a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/SdkConfigDecorator.kt
+++ b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/SdkConfigDecorator.kt
@@ -11,19 +11,17 @@ import software.amazon.smithy.rust.codegen.client.smithy.generators.config.Confi
 import software.amazon.smithy.rust.codegen.client.smithy.generators.config.ServiceConfig
 import software.amazon.smithy.rust.codegen.core.rustlang.RustModule
 import software.amazon.smithy.rust.codegen.core.rustlang.Writable
-import software.amazon.smithy.rust.codegen.core.rustlang.join
 import software.amazon.smithy.rust.codegen.core.rustlang.rust
 import software.amazon.smithy.rust.codegen.core.rustlang.rustTemplate
 import software.amazon.smithy.rust.codegen.core.rustlang.writable
 import software.amazon.smithy.rust.codegen.core.smithy.RuntimeConfig
 import software.amazon.smithy.rust.codegen.core.smithy.RustCrate
+import software.amazon.smithy.rust.codegen.core.smithy.customize.AdHocCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.customize.AdHocSection
-import software.amazon.smithy.rust.codegen.core.smithy.customize.Section
+import software.amazon.smithy.rust.codegen.core.smithy.customize.adhocCustomization
+import software.amazon.smithy.rust.codegen.core.smithy.customize.writeCustomizations
 
-/**
- * Section enabling linkage between `SdkConfig` and <service>::Config
- */
-object SdkConfigSection : AdHocSection<SdkConfigSection.CopySdkConfigToClientConfig>("SdkConfig") {
+sealed class SdkConfigSection(name: String) : AdHocSection(name) {
     /**
      * [sdkConfig]: A reference to the SDK config struct
      * [serviceConfigBuilder]: A reference (owned) to the `<service>::config::Builder` struct.
@@ -34,8 +32,13 @@ object SdkConfigSection : AdHocSection<SdkConfigSection.CopySdkConfigToClientCon
      * ```
      */
     data class CopySdkConfigToClientConfig(val sdkConfig: String, val serviceConfigBuilder: String) :
-        Section("CopyConfig")
+        SdkConfigSection("CopySdkConfigToClientConfig")
+}
 
+/**
+ * Section enabling linkage between `SdkConfig` and <service>::Config
+ */
+object SdkConfigCustomization {
     /**
      * Copy a field from SDK config to service config with an optional map block.
      *
@@ -43,18 +46,17 @@ object SdkConfigSection : AdHocSection<SdkConfigSection.CopySdkConfigToClientCon
      *
      * # Examples
      * ```kotlin
-     * SdkConfigSection.copyField("some_string_field") { rust("|s|s.to_to_string()") }
+     * SdkConfigCustomization.copyField("some_string_field") { rust("|s|s.to_to_string()") }
      * ```
      */
-    fun copyField(fieldName: String, map: Writable?) = SdkConfigSection.create { section ->
-        {
+    fun copyField(fieldName: String, map: Writable?) =
+        adhocCustomization<SdkConfigSection.CopySdkConfigToClientConfig> { section ->
             val mapBlock = map?.let { writable { rust(".map(#W)", it) } } ?: writable { }
             rustTemplate(
                 "${section.serviceConfigBuilder}.set_$fieldName(${section.sdkConfig}.$fieldName()#{map});",
                 "map" to mapBlock,
             )
         }
-    }
 }
 
 /**
@@ -64,22 +66,20 @@ class GenericSmithySdkConfigSettings : ClientCodegenDecorator {
     override val name: String = "GenericSmithySdkConfigSettings"
     override val order: Byte = 0
 
-    override fun extraSections(codegenContext: ClientCodegenContext): List<Pair<AdHocSection<*>, (Section) -> Writable>> =
+    override fun extraSections(codegenContext: ClientCodegenContext): List<AdHocCustomization> =
         listOf(
-            SdkConfigSection.create { section ->
-                writable {
-                    rust(
-                        """
-                        // resiliency
-                        ${section.serviceConfigBuilder}.set_retry_config(${section.sdkConfig}.retry_config().cloned());
-                        ${section.serviceConfigBuilder}.set_timeout_config(${section.sdkConfig}.timeout_config().cloned());
-                        ${section.serviceConfigBuilder}.set_sleep_impl(${section.sdkConfig}.sleep_impl());
-
-                        ${section.serviceConfigBuilder}.set_http_connector(${section.sdkConfig}.http_connector().cloned());
-
-                        """,
-                    )
-                }
+            adhocCustomization<SdkConfigSection.CopySdkConfigToClientConfig> { section ->
+                rust(
+                    """
+                    // resiliency
+                    ${section.serviceConfigBuilder}.set_retry_config(${section.sdkConfig}.retry_config().cloned());
+                    ${section.serviceConfigBuilder}.set_timeout_config(${section.sdkConfig}.timeout_config().cloned());
+                    ${section.serviceConfigBuilder}.set_sleep_impl(${section.sdkConfig}.sleep_impl());
+
+                    ${section.serviceConfigBuilder}.set_http_connector(${section.sdkConfig}.http_connector().cloned());
+
+                    """,
+                )
             },
         )
 }
@@ -111,8 +111,7 @@ class SdkConfigDecorator : ClientCodegenDecorator {
                 impl From<&#{SdkConfig}> for Builder {
                     fn from(input: &#{SdkConfig}) -> Self {
                         let mut builder = Builder::default();
-                        #{augmentBuilder}
-
+                        #{augmentBuilder:W}
 
                         builder
                     }
@@ -124,15 +123,15 @@ class SdkConfigDecorator : ClientCodegenDecorator {
                     }
                 }
                 """,
-                "augmentBuilder" to codegenContext.rootDecorator.extraSections(codegenContext)
-                    .filter { (t, _) -> t is SdkConfigSection }.map { (_, sectionWriter) ->
-                        sectionWriter(
-                            SdkConfigSection.CopySdkConfigToClientConfig(
-                                sdkConfig = "input",
-                                serviceConfigBuilder = "builder",
-                            ),
-                        )
-                    }.join("\n"),
+                "augmentBuilder" to writable {
+                    writeCustomizations(
+                        codegenContext.rootDecorator.extraSections(codegenContext),
+                        SdkConfigSection.CopySdkConfigToClientConfig(
+                            sdkConfig = "input",
+                            serviceConfigBuilder = "builder",
+                        ),
+                    )
+                },
                 *codegenScope,
             )
         }
diff --git a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/UserAgentDecorator.kt b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/UserAgentDecorator.kt
index 54dc4f5586cb5b0770f5eaf5f89615ca00e76f65..8a2a27f66fb600f6d9512ef2a41f76a4858ceaa1 100644
--- a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/UserAgentDecorator.kt
+++ b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/UserAgentDecorator.kt
@@ -16,10 +16,10 @@ import software.amazon.smithy.rust.codegen.core.rustlang.rust
 import software.amazon.smithy.rust.codegen.core.rustlang.rustTemplate
 import software.amazon.smithy.rust.codegen.core.rustlang.writable
 import software.amazon.smithy.rust.codegen.core.smithy.RuntimeConfig
-import software.amazon.smithy.rust.codegen.core.smithy.customize.AdHocSection
+import software.amazon.smithy.rust.codegen.core.smithy.customize.AdHocCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.customize.OperationCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.customize.OperationSection
-import software.amazon.smithy.rust.codegen.core.smithy.customize.Section
+import software.amazon.smithy.rust.codegen.core.smithy.customize.adhocCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.generators.LibRsCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.generators.LibRsSection
 import software.amazon.smithy.rust.codegen.core.util.dq
@@ -56,10 +56,10 @@ class UserAgentDecorator : ClientCodegenDecorator {
         return baseCustomizations + UserAgentFeature(codegenContext.runtimeConfig)
     }
 
-    override fun extraSections(codegenContext: ClientCodegenContext): List<Pair<AdHocSection<*>, (Section) -> Writable>> {
+    override fun extraSections(codegenContext: ClientCodegenContext): List<AdHocCustomization> {
         return listOf(
-            SdkConfigSection.create { section ->
-                writable { rust("${section.serviceConfigBuilder}.set_app_name(${section.sdkConfig}.app_name().cloned());") }
+            adhocCustomization<SdkConfigSection.CopySdkConfigToClientConfig> { section ->
+                rust("${section.serviceConfigBuilder}.set_app_name(${section.sdkConfig}.app_name().cloned());")
             },
         )
     }
diff --git a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/endpoints/AwsEndpointDecorator.kt b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/endpoints/AwsEndpointDecorator.kt
index 5973d5e3c5fdabfcf3fbc30af7108af1f71d5f3f..ab9ce5bf1f7bb96a97b0c1b9e4f77372bbf77c5e 100644
--- a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/endpoints/AwsEndpointDecorator.kt
+++ b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/endpoints/AwsEndpointDecorator.kt
@@ -29,8 +29,8 @@ import software.amazon.smithy.rust.codegen.core.rustlang.writable
 import software.amazon.smithy.rust.codegen.core.smithy.CodegenContext
 import software.amazon.smithy.rust.codegen.core.smithy.RuntimeConfig
 import software.amazon.smithy.rust.codegen.core.smithy.RustCrate
-import software.amazon.smithy.rust.codegen.core.smithy.customize.AdHocSection
-import software.amazon.smithy.rust.codegen.core.smithy.customize.Section
+import software.amazon.smithy.rust.codegen.core.smithy.customize.AdHocCustomization
+import software.amazon.smithy.rust.codegen.core.smithy.customize.adhocCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.generators.LibRsCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.generators.LibRsSection
 import software.amazon.smithy.rust.codegen.core.util.extendIf
@@ -133,16 +133,14 @@ class AwsEndpointDecorator : ClientCodegenDecorator {
         }
     }
 
-    override fun extraSections(codegenContext: ClientCodegenContext): List<Pair<AdHocSection<*>, (Section) -> Writable>> {
+    override fun extraSections(codegenContext: ClientCodegenContext): List<AdHocCustomization> {
         return codegenContext.isRegionalized().thenSingletonListOf {
-            SdkConfigSection.create { section ->
-                {
-                    rust(
-                        """
-                        ${section.serviceConfigBuilder}.set_aws_endpoint_resolver(${section.sdkConfig}.endpoint_resolver().clone());
-                        """,
-                    )
-                }
+            adhocCustomization<SdkConfigSection.CopySdkConfigToClientConfig> { section ->
+                rust(
+                    """
+                    ${section.serviceConfigBuilder}.set_aws_endpoint_resolver(${section.sdkConfig}.endpoint_resolver().clone());
+                    """,
+                )
             }
         }
     }
diff --git a/codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/client/FluentClientDecorator.kt b/codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/client/FluentClientDecorator.kt
index 1691dffe1b42935d305b0c3e396a4677c5ebf796..b6fced279fbb2b59d578ef6d57a48ce331db9b21 100644
--- a/codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/client/FluentClientDecorator.kt
+++ b/codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/client/FluentClientDecorator.kt
@@ -17,7 +17,7 @@ import software.amazon.smithy.rust.codegen.core.rustlang.writable
 import software.amazon.smithy.rust.codegen.core.smithy.CodegenContext
 import software.amazon.smithy.rust.codegen.core.smithy.RuntimeType
 import software.amazon.smithy.rust.codegen.core.smithy.RustCrate
-import software.amazon.smithy.rust.codegen.core.smithy.customize.NamedSectionGenerator
+import software.amazon.smithy.rust.codegen.core.smithy.customize.NamedCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.customize.Section
 import software.amazon.smithy.rust.codegen.core.smithy.generators.LibRsCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.generators.LibRsSection
@@ -72,7 +72,7 @@ sealed class FluentClientSection(name: String) : Section(name) {
     data class FluentClientDocs(val serviceShape: ServiceShape) : FluentClientSection("FluentClientDocs")
 }
 
-abstract class FluentClientCustomization : NamedSectionGenerator<FluentClientSection>()
+abstract class FluentClientCustomization : NamedCustomization<FluentClientSection>()
 
 class GenericFluentClient(codegenContext: CodegenContext) : FluentClientCustomization() {
     private val moduleUseName = codegenContext.moduleUseName()
diff --git a/codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/config/IdempotencyTokenProviderCustomization.kt b/codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/config/IdempotencyTokenProviderCustomization.kt
index eb7057c32c64724c460b1b03fd45547b1974616c..7cda821957ec6b28f56273685d4030d0c3c4ab58 100644
--- a/codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/config/IdempotencyTokenProviderCustomization.kt
+++ b/codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/config/IdempotencyTokenProviderCustomization.kt
@@ -10,12 +10,12 @@ import software.amazon.smithy.rust.codegen.core.rustlang.rust
 import software.amazon.smithy.rust.codegen.core.rustlang.rustTemplate
 import software.amazon.smithy.rust.codegen.core.rustlang.writable
 import software.amazon.smithy.rust.codegen.core.smithy.RuntimeType
-import software.amazon.smithy.rust.codegen.core.smithy.customize.NamedSectionGenerator
+import software.amazon.smithy.rust.codegen.core.smithy.customize.NamedCustomization
 
 /**
  * Add a `make_token` field to Service config. See below for the resulting generated code.
  */
-class IdempotencyTokenProviderCustomization : NamedSectionGenerator<ServiceConfig>() {
+class IdempotencyTokenProviderCustomization : NamedCustomization<ServiceConfig>() {
     override fun section(section: ServiceConfig): Writable {
         return when (section) {
             is ServiceConfig.ConfigStruct -> writable {
diff --git a/codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/config/ServiceConfigGenerator.kt b/codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/config/ServiceConfigGenerator.kt
index 5966c401c33466c343a46e965bd2bb002dacfd49..00bc592ff485b965b848f188aadc53158fa0cf15 100644
--- a/codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/config/ServiceConfigGenerator.kt
+++ b/codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/config/ServiceConfigGenerator.kt
@@ -23,7 +23,7 @@ import software.amazon.smithy.rust.codegen.core.rustlang.rustBlock
 import software.amazon.smithy.rust.codegen.core.rustlang.rustTemplate
 import software.amazon.smithy.rust.codegen.core.rustlang.writable
 import software.amazon.smithy.rust.codegen.core.smithy.CodegenContext
-import software.amazon.smithy.rust.codegen.core.smithy.customize.NamedSectionGenerator
+import software.amazon.smithy.rust.codegen.core.smithy.customize.NamedCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.customize.Section
 import software.amazon.smithy.rust.codegen.core.smithy.makeOptional
 import software.amazon.smithy.rust.codegen.core.util.hasTrait
@@ -39,7 +39,7 @@ import software.amazon.smithy.rust.codegen.core.util.hasTrait
  *
  * Usage:
  * ```kotlin
- * class AddRegion : NamedSectionGenerator<ServiceConfig>() {
+ * class AddRegion : NamedCustomization<ServiceConfig>() {
  *  override fun section(section: ServiceConfig): Writable {
  *    return when (section) {
  *      is ServiceConfig.ConfigStruct -> writeable {
@@ -156,7 +156,7 @@ fun ServiceShape.needsIdempotencyToken(model: Model): Boolean {
         .any { it.hasTrait<IdempotencyTokenTrait>() }
 }
 
-typealias ConfigCustomization = NamedSectionGenerator<ServiceConfig>
+typealias ConfigCustomization = NamedCustomization<ServiceConfig>
 
 /**
  * Generate a `Config` struct, implementation & builder for a given service, approximately:
diff --git a/codegen-client/src/test/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/config/ServiceConfigGeneratorTest.kt b/codegen-client/src/test/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/config/ServiceConfigGeneratorTest.kt
index 0241133f231c34ff79c91be064545853d92b652f..366ff370dc076c88d4841d925107613275d3cf95 100644
--- a/codegen-client/src/test/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/config/ServiceConfigGeneratorTest.kt
+++ b/codegen-client/src/test/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/config/ServiceConfigGeneratorTest.kt
@@ -13,7 +13,7 @@ import software.amazon.smithy.rust.codegen.core.rustlang.RustModule
 import software.amazon.smithy.rust.codegen.core.rustlang.Writable
 import software.amazon.smithy.rust.codegen.core.rustlang.rust
 import software.amazon.smithy.rust.codegen.core.rustlang.writable
-import software.amazon.smithy.rust.codegen.core.smithy.customize.NamedSectionGenerator
+import software.amazon.smithy.rust.codegen.core.smithy.customize.NamedCustomization
 import software.amazon.smithy.rust.codegen.core.testutil.TestWorkspace
 import software.amazon.smithy.rust.codegen.core.testutil.asSmithyModel
 import software.amazon.smithy.rust.codegen.core.testutil.compileAndTest
@@ -78,7 +78,7 @@ internal class ServiceConfigGeneratorTest {
 
     @Test
     fun `generate customizations as specified`() {
-        class ServiceCustomizer : NamedSectionGenerator<ServiceConfig>() {
+        class ServiceCustomizer : NamedCustomization<ServiceConfig>() {
             override fun section(section: ServiceConfig): Writable {
                 return when (section) {
                     ServiceConfig.ConfigStructAdditionalDocs -> emptySection
diff --git a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/customize/CoreCodegenDecorator.kt b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/customize/CoreCodegenDecorator.kt
index 6a33d82c96054dea40fc787dc368360dd786d92f..c886c4ed97cb023469a7df23c8ed988f6ab135ed 100644
--- a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/customize/CoreCodegenDecorator.kt
+++ b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/customize/CoreCodegenDecorator.kt
@@ -8,7 +8,6 @@ package software.amazon.smithy.rust.codegen.core.smithy.customize
 import software.amazon.smithy.build.PluginContext
 import software.amazon.smithy.model.Model
 import software.amazon.smithy.model.shapes.ServiceShape
-import software.amazon.smithy.rust.codegen.core.rustlang.Writable
 import software.amazon.smithy.rust.codegen.core.smithy.RustCrate
 import software.amazon.smithy.rust.codegen.core.smithy.generators.LibRsCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.generators.ManifestCustomizations
@@ -66,7 +65,7 @@ interface CoreCodegenDecorator<CodegenContext> {
     /**
      * Extra sections allow one decorator to influence another. This is intended to be used by querying the `rootDecorator`
      */
-    fun extraSections(codegenContext: CodegenContext): List<Pair<AdHocSection<*>, (Section) -> Writable>> = listOf()
+    fun extraSections(codegenContext: CodegenContext): List<AdHocCustomization> = listOf()
 }
 
 /**
@@ -99,7 +98,7 @@ abstract class CombinedCoreCodegenDecorator<CodegenContext, Decorator : CoreCode
             decorator.transformModel(otherModel.expectShape(service.id, ServiceShape::class.java), otherModel)
         }
 
-    final override fun extraSections(codegenContext: CodegenContext): List<Pair<AdHocSection<*>, (Section) -> Writable>> =
+    final override fun extraSections(codegenContext: CodegenContext): List<AdHocCustomization> =
         addCustomizations { decorator -> decorator.extraSections(codegenContext) }
 
     /**
diff --git a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/customize/NamedSectionGenerator.kt b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/customize/Customization.kt
similarity index 61%
rename from codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/customize/NamedSectionGenerator.kt
rename to codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/customize/Customization.kt
index ccc9702e09a2a034a6007d98b2fc90707c820849..d563349867db4b3ff0993d083059e6689a46b0eb 100644
--- a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/customize/NamedSectionGenerator.kt
+++ b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/customize/Customization.kt
@@ -23,31 +23,39 @@ import software.amazon.smithy.rust.codegen.core.rustlang.writable
  */
 abstract class Section(val name: String)
 
+/** Customization type returned by [adhocCustomization] */
+typealias AdHocCustomization = NamedCustomization<AdHocSection>
+
+/** Adhoc section for code generation. Similar to [Section], but for use with [adhocCustomization]. */
+abstract class AdHocSection(name: String) : Section(name)
+
 /**
- * Detatched section abstraction to allow adhoc sections to be created. By using the `.writer` method, a instantiation
- * of this section can be easily created.
+ * Allows for one-off customizations such that a `when` statement switching on
+ * the section type is not necessary.
  */
-abstract class AdHocSection<T : Section>(val name: String) {
-    /**
-     * Helper to enable easily combining detached sections with the [CoreCodegenDecorator.extraSections] method.
-     */
-    fun create(w: (T) -> Writable): Pair<AdHocSection<*>, (Section) -> Writable> = this to { s: Section ->
-        w((s as T))
+inline fun <reified T : AdHocSection> adhocCustomization(
+    crossinline customization: RustWriter.(T) -> Unit,
+): AdHocCustomization =
+    object : AdHocCustomization() {
+        override fun section(section: AdHocSection): Writable = writable {
+            if (section is T) {
+                customization(section)
+            }
+        }
     }
-}
 
 /**
- * A named section generator allows customization via a predefined set of named sections.
+ * A named section generator that allows customization via a predefined set of named sections.
  *
  * Implementors MUST override section and use a `when` clause to handle each section individually
  */
-abstract class NamedSectionGenerator<T : Section> {
+abstract class NamedCustomization<T : Section> {
     abstract fun section(section: T): Writable
     protected val emptySection = writable { }
 }
 
 /** Convenience for rendering a list of customizations for a given section */
-fun <T : Section> RustWriter.writeCustomizations(customizations: List<NamedSectionGenerator<T>>, section: T) {
+fun <T : Section> RustWriter.writeCustomizations(customizations: List<NamedCustomization<T>>, section: T) {
     for (customization in customizations) {
         customization.section(section)(this)
     }
diff --git a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/customize/OperationCustomization.kt b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/customize/OperationCustomization.kt
index a7dd176a9e227a208f39b46cdb3756026700073c..d11f98a5c7a1325744a7da57e1159e6d548d1860 100644
--- a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/customize/OperationCustomization.kt
+++ b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/customize/OperationCustomization.kt
@@ -55,7 +55,7 @@ sealed class OperationSection(name: String) : Section(name) {
     ) : OperationSection("MutateOutput")
 }
 
-abstract class OperationCustomization : NamedSectionGenerator<OperationSection>() {
+abstract class OperationCustomization : NamedCustomization<OperationSection>() {
     open fun retryType(): RuntimeType? = null
 
     /**
diff --git a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/generators/Instantiator.kt b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/generators/Instantiator.kt
index 01c7a8d740cf610e9f21094a6b3c39c3c506bc34..a2683ab7139c410e51c4534c6b7e19e03ab3ba67 100644
--- a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/generators/Instantiator.kt
+++ b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/generators/Instantiator.kt
@@ -46,7 +46,7 @@ import software.amazon.smithy.rust.codegen.core.rustlang.writable
 import software.amazon.smithy.rust.codegen.core.smithy.RuntimeConfig
 import software.amazon.smithy.rust.codegen.core.smithy.RuntimeType
 import software.amazon.smithy.rust.codegen.core.smithy.RustSymbolProvider
-import software.amazon.smithy.rust.codegen.core.smithy.customize.NamedSectionGenerator
+import software.amazon.smithy.rust.codegen.core.smithy.customize.NamedCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.customize.Section
 import software.amazon.smithy.rust.codegen.core.smithy.isOptional
 import software.amazon.smithy.rust.codegen.core.smithy.rustType
@@ -66,7 +66,7 @@ sealed class InstantiatorSection(name: String) : Section(name) {
 /**
  * Customization for the instantiator.
  */
-typealias InstantiatorCustomization = NamedSectionGenerator<InstantiatorSection>
+typealias InstantiatorCustomization = NamedCustomization<InstantiatorSection>
 
 /**
  * Instantiator generates code to instantiate a given shape given a `Node` representing the value.
diff --git a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/generators/LibRsGenerator.kt b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/generators/LibRsGenerator.kt
index c15d545e6b6cbcaa8f4dc13ecd47ad02d0f6688b..359386e34da2fc23c1c9a5eed3ae99e9ad2a8df9 100644
--- a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/generators/LibRsGenerator.kt
+++ b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/generators/LibRsGenerator.kt
@@ -13,7 +13,7 @@ import software.amazon.smithy.rust.codegen.core.rustlang.escape
 import software.amazon.smithy.rust.codegen.core.rustlang.isEmpty
 import software.amazon.smithy.rust.codegen.core.rustlang.rust
 import software.amazon.smithy.rust.codegen.core.smithy.CoreRustSettings
-import software.amazon.smithy.rust.codegen.core.smithy.customize.NamedSectionGenerator
+import software.amazon.smithy.rust.codegen.core.smithy.customize.NamedCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.customize.Section
 import software.amazon.smithy.rust.codegen.core.util.getTrait
 
@@ -27,7 +27,7 @@ sealed class LibRsSection(name: String) : Section(name) {
     }
 }
 
-typealias LibRsCustomization = NamedSectionGenerator<LibRsSection>
+typealias LibRsCustomization = NamedCustomization<LibRsSection>
 
 class LibRsGenerator(
     private val settings: CoreRustSettings,
diff --git a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/generators/http/HttpBindingGenerator.kt b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/generators/http/HttpBindingGenerator.kt
index 597ff267e26b1cae641ce2070f8cedbec5dc1330..b2ca5e066fed9cec516d0681d34f547fdb411105 100644
--- a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/generators/http/HttpBindingGenerator.kt
+++ b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/generators/http/HttpBindingGenerator.kt
@@ -41,7 +41,7 @@ import software.amazon.smithy.rust.codegen.core.rustlang.withBlock
 import software.amazon.smithy.rust.codegen.core.smithy.CodegenContext
 import software.amazon.smithy.rust.codegen.core.smithy.CodegenTarget
 import software.amazon.smithy.rust.codegen.core.smithy.RuntimeType
-import software.amazon.smithy.rust.codegen.core.smithy.customize.NamedSectionGenerator
+import software.amazon.smithy.rust.codegen.core.smithy.customize.NamedCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.customize.Section
 import software.amazon.smithy.rust.codegen.core.smithy.generators.OperationBuildError
 import software.amazon.smithy.rust.codegen.core.smithy.generators.operationBuildError
@@ -90,7 +90,7 @@ sealed class HttpBindingSection(name: String) : Section(name) {
         HttpBindingSection("AfterDeserializingIntoAHashMapOfHttpPrefixHeaders")
 }
 
-typealias HttpBindingCustomization = NamedSectionGenerator<HttpBindingSection>
+typealias HttpBindingCustomization = NamedCustomization<HttpBindingSection>
 
 /**
  * This class generates Rust functions that (de)serialize data from/to an HTTP message.
diff --git a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/protocols/parse/JsonParserGenerator.kt b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/protocols/parse/JsonParserGenerator.kt
index 2f1e30a38f618ece431a6da6b7dac05179748bfd..34a47e597616fec2201a5f54b06bff84d527a468 100644
--- a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/protocols/parse/JsonParserGenerator.kt
+++ b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/protocols/parse/JsonParserGenerator.kt
@@ -40,7 +40,7 @@ import software.amazon.smithy.rust.codegen.core.smithy.CodegenContext
 import software.amazon.smithy.rust.codegen.core.smithy.CodegenTarget
 import software.amazon.smithy.rust.codegen.core.smithy.RuntimeType
 import software.amazon.smithy.rust.codegen.core.smithy.canUseDefault
-import software.amazon.smithy.rust.codegen.core.smithy.customize.NamedSectionGenerator
+import software.amazon.smithy.rust.codegen.core.smithy.customize.NamedCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.customize.Section
 import software.amazon.smithy.rust.codegen.core.smithy.generators.TypeConversionGenerator
 import software.amazon.smithy.rust.codegen.core.smithy.generators.UnionGenerator
@@ -70,7 +70,7 @@ sealed class JsonParserSection(name: String) : Section(name) {
 /**
  * Customization for the JSON parser.
  */
-typealias JsonParserCustomization = NamedSectionGenerator<JsonParserSection>
+typealias JsonParserCustomization = NamedCustomization<JsonParserSection>
 
 data class ReturnSymbolToParse(val symbol: Symbol, val isUnconstrained: Boolean)
 
diff --git a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/protocols/serialize/JsonSerializerGenerator.kt b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/protocols/serialize/JsonSerializerGenerator.kt
index 69deb870d70c44f34bebe94f5d86acdafe0d1c77..89dd945d30ba38345458dd6d9ec3d2915b9f9c1a 100644
--- a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/protocols/serialize/JsonSerializerGenerator.kt
+++ b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/protocols/serialize/JsonSerializerGenerator.kt
@@ -36,7 +36,7 @@ import software.amazon.smithy.rust.codegen.core.rustlang.withBlock
 import software.amazon.smithy.rust.codegen.core.smithy.CodegenContext
 import software.amazon.smithy.rust.codegen.core.smithy.RuntimeType
 import software.amazon.smithy.rust.codegen.core.smithy.RustSymbolProvider
-import software.amazon.smithy.rust.codegen.core.smithy.customize.NamedSectionGenerator
+import software.amazon.smithy.rust.codegen.core.smithy.customize.NamedCustomization
 import software.amazon.smithy.rust.codegen.core.smithy.customize.Section
 import software.amazon.smithy.rust.codegen.core.smithy.generators.TypeConversionGenerator
 import software.amazon.smithy.rust.codegen.core.smithy.generators.UnionGenerator
@@ -81,7 +81,7 @@ sealed class JsonSerializerSection(name: String) : Section(name) {
 /**
  * Customization for the JSON serializer.
  */
-typealias JsonSerializerCustomization = NamedSectionGenerator<JsonSerializerSection>
+typealias JsonSerializerCustomization = NamedCustomization<JsonSerializerSection>
 
 class JsonSerializerGenerator(
     codegenContext: CodegenContext,