diff --git a/output/openapi/elasticsearch-openapi.json b/output/openapi/elasticsearch-openapi.json
index e2ec4d2723..37300a6955 100644
--- a/output/openapi/elasticsearch-openapi.json
+++ b/output/openapi/elasticsearch-openapi.json
@@ -62316,9 +62316,9 @@
       "indices._types:SourceMode": {
         "type": "string",
         "enum": [
-          "DISABLED",
-          "STORED",
-          "SYNTHETIC"
+          "disabled",
+          "stored",
+          "synthetic"
         ]
       },
       "indices._types:IndexingSlowlogSettings": {
diff --git a/output/openapi/elasticsearch-serverless-openapi.json b/output/openapi/elasticsearch-serverless-openapi.json
index 4d228e16aa..5fc9b50617 100644
--- a/output/openapi/elasticsearch-serverless-openapi.json
+++ b/output/openapi/elasticsearch-serverless-openapi.json
@@ -40814,9 +40814,9 @@
       "indices._types:SourceMode": {
         "type": "string",
         "enum": [
-          "DISABLED",
-          "STORED",
-          "SYNTHETIC"
+          "disabled",
+          "stored",
+          "synthetic"
         ]
       },
       "indices._types:IndexingSlowlogSettings": {
diff --git a/output/schema/schema-serverless.json b/output/schema/schema-serverless.json
index 5780d067d8..2d4442f58c 100644
--- a/output/schema/schema-serverless.json
+++ b/output/schema/schema-serverless.json
@@ -96916,13 +96916,13 @@
       "kind": "enum",
       "members": [
         {
-          "name": "DISABLED"
+          "name": "disabled"
         },
         {
-          "name": "STORED"
+          "name": "stored"
         },
         {
-          "name": "SYNTHETIC"
+          "name": "synthetic"
         }
       ],
       "name": {
diff --git a/output/schema/schema.json b/output/schema/schema.json
index 7e79310c18..900f8e56ca 100644
--- a/output/schema/schema.json
+++ b/output/schema/schema.json
@@ -132163,13 +132163,13 @@
       "kind": "enum",
       "members": [
         {
-          "name": "DISABLED"
+          "name": "disabled"
         },
         {
-          "name": "STORED"
+          "name": "stored"
         },
         {
-          "name": "SYNTHETIC"
+          "name": "synthetic"
         }
       ],
       "name": {
diff --git a/output/typescript/types.ts b/output/typescript/types.ts
index 4798c35c5b..a44f1f2ea7 100644
--- a/output/typescript/types.ts
+++ b/output/typescript/types.ts
@@ -11570,7 +11570,7 @@ export interface IndicesSoftDeletes {
   retention_lease?: IndicesRetentionLease
 }
 
-export type IndicesSourceMode = 'DISABLED' | 'STORED' | 'SYNTHETIC'
+export type IndicesSourceMode = 'disabled' | 'stored' | 'synthetic'
 
 export interface IndicesStorage {
   type: IndicesStorageType
diff --git a/specification/indices/_types/IndexSettings.ts b/specification/indices/_types/IndexSettings.ts
index 2680da8bbc..9b62d988a1 100644
--- a/specification/indices/_types/IndexSettings.ts
+++ b/specification/indices/_types/IndexSettings.ts
@@ -500,9 +500,9 @@ export class MappingLimitSettingsSourceFields {
 }
 
 export enum SourceMode {
-  DISABLED,
-  STORED,
-  SYNTHETIC
+  disabled,
+  stored,
+  synthetic
 }
 
 export class SlowlogSettings {