diff --git a/compiler-rs/clients_schema/src/transform/expand_generics.rs b/compiler-rs/clients_schema/src/transform/expand_generics.rs
index d6346cd319..50c1db12b1 100644
--- a/compiler-rs/clients_schema/src/transform/expand_generics.rs
+++ b/compiler-rs/clients_schema/src/transform/expand_generics.rs
@@ -211,8 +211,10 @@ pub fn expand(model: IndexedModel, config: ExpandConfig) -> anyhow::Result<Index
 
         expand_behaviors(&mut resp.behaviors, &mappings, model, ctx)?;
         expand_body(&mut resp.body, &mappings, model, ctx)?;
-
-        // TODO: exceptions
+        
+        for exception in &mut resp.exceptions {
+            expand_body(&mut exception.body, &mappings, model, ctx)?;
+        }
 
         Ok(resp.into())
     }
diff --git a/compiler/src/steps/validate-model.ts b/compiler/src/steps/validate-model.ts
index 70f3e123cb..706d2f983c 100644
--- a/compiler/src/steps/validate-model.ts
+++ b/compiler/src/steps/validate-model.ts
@@ -502,6 +502,23 @@ export default async function validateModel (apiModel: model.Model, restSpec: Ma
         // eslint-disable-next-line @typescript-eslint/restrict-template-expressions
         throw new Error(`Unknown kind: ${typeDef.body.kind}`)
     }
+
+    if (typeDef.exceptions != null) {
+      for (const ex of typeDef.exceptions) {
+        switch (ex.body.kind) {
+          case 'properties':
+            validateProperties(ex.body.properties, openGenerics, new Set<string>())
+            break
+          case 'value':
+            validateValueOf(ex.body.value, openGenerics)
+            break
+          case 'no_body':
+            // Nothing to validate
+            break
+        }
+      }
+    }
+
     context.pop()
   }
 
diff --git a/compiler/src/transform/expand-generics.ts b/compiler/src/transform/expand-generics.ts
index 348cc9b365..f128eb264c 100644
--- a/compiler/src/transform/expand-generics.ts
+++ b/compiler/src/transform/expand-generics.ts
@@ -27,7 +27,7 @@ import {
   Request,
   Response,
   Body,
-  InstanceOf, Inherits, Property
+  InstanceOf, Inherits, Property, ResponseException
 } from '../model/metamodel'
 import { readFile, writeFile } from 'fs/promises'
 import stringify from 'safe-stable-stringify'
@@ -293,6 +293,17 @@ export function expandGenerics (inputModel: Model, config?: ExpansionConfig): Mo
     return addIfNotSeen(resp.name, () => {
       const result = { ...resp }
       result.body = expandBody(resp.body, genericParamMapping(resp.generics, params))
+      if (resp.exceptions != null) {
+        result.exceptions = []
+        for (const exception of resp.exceptions) {
+          const except: ResponseException = {
+            description: exception.description,
+            statusCodes: exception.statusCodes,
+            body: expandBody(exception.body, genericParamMapping(resp.generics, params))
+          }
+          result.exceptions.push(except)
+        }
+      }
       result.generics = undefined
       return result
     })
diff --git a/specification/indices/get_alias/IndicesGetAliasResponse.ts b/specification/indices/get_alias/IndicesGetAliasResponse.ts
index ddc1676942..0c3831e196 100644
--- a/specification/indices/get_alias/IndicesGetAliasResponse.ts
+++ b/specification/indices/get_alias/IndicesGetAliasResponse.ts
@@ -19,8 +19,10 @@
 
 import { ErrorResponseBase } from '@_types/Base'
 import { IndexName } from '@_types/common'
-import { AliasDefinition } from '@indices/_types/AliasDefinition'
-import { AdditionalProperties } from '@spec_utils/behaviors'
+import {
+  IndexAliases,
+  NotFoundAliases
+} from '@indices/get_alias/_types/response'
 import { Dictionary } from '@spec_utils/Dictionary'
 
 export class Response {
@@ -33,12 +35,3 @@ export class Response {
     }
   ]
 }
-
-export class IndexAliases {
-  aliases: Dictionary<string, AliasDefinition>
-}
-
-class NotFoundAliases implements AdditionalProperties<string, IndexAliases> {
-  error: string
-  status: number
-}
diff --git a/specification/indices/get_alias/_types/response.ts b/specification/indices/get_alias/_types/response.ts
new file mode 100644
index 0000000000..20bd1d4989
--- /dev/null
+++ b/specification/indices/get_alias/_types/response.ts
@@ -0,0 +1,33 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import { AliasDefinition } from '@indices/_types/AliasDefinition'
+import { AdditionalProperties } from '@spec_utils/behaviors'
+import { Dictionary } from '@spec_utils/Dictionary'
+
+export class IndexAliases {
+  aliases: Dictionary<string, AliasDefinition>
+}
+
+export class NotFoundAliases
+  implements AdditionalProperties<string, IndexAliases>
+{
+  error: string
+  status: number
+}