diff --git a/output/openapi/elasticsearch-openapi.json b/output/openapi/elasticsearch-openapi.json
index a2337397e8..822ec39e04 100644
--- a/output/openapi/elasticsearch-openapi.json
+++ b/output/openapi/elasticsearch-openapi.json
@@ -16619,7 +16619,7 @@
           "data stream"
         ],
         "summary": "Downsample an index",
-        "description": "Aggregate a time series (TSDS) index and store pre-computed statistical summaries (`min`, `max`, `sum`, `value_count` and `avg`) for each metric field grouped by a configured time interval.\nFor example, a TSDS index that contains metrics sampled every 10 seconds can be downsampled to an hourly index.\nAll documents within an hour interval are summarized and stored as a single document in the downsample index.\n\nNOTE: Only indices in a time series data stream are supported.\nNeither field nor document level security can be defined on the source index.\nThe source index must be read only (`index.blocks.write: true`).",
+        "description": "Downsamples a time series (TSDS) index and reduces its size by keeping the last value or by pre-aggregating metrics:\n\n- When running in `aggregate` mode, it pre-calculates and stores statistical summaries (`min`, `max`, `sum`, `value_count` and `avg`)\nfor each metric field grouped by a configured time interval and their dimensions.\n- When running in `last_value` mode, it keeps the last value for each metric in the configured interval and their dimensions.\n\nFor example, a TSDS index that contains metrics sampled every 10 seconds can be downsampled to an hourly index.\nAll documents within an hour interval are summarized and stored as a single document in the downsample index.\n\nNOTE: Only indices in a time series data stream are supported.\nNeither field nor document level security can be defined on the source index.\nThe source index must be read-only (`index.blocks.write: true`).",
         "operationId": "indices-downsample",
         "parameters": [
           {
@@ -88423,25 +88423,8 @@
               }
             ]
           },
-          "config": {
-            "description": "The downsample configuration to execute.",
-            "allOf": [
-              {
-                "$ref": "#/components/schemas/indices._types.DownsampleConfig"
-              }
-            ]
-          }
-        },
-        "required": [
-          "after",
-          "config"
-        ]
-      },
-      "indices._types.DownsampleConfig": {
-        "type": "object",
-        "properties": {
           "fixed_interval": {
-            "description": "The interval at which to aggregate the original time series index.",
+            "description": "The downsample interval.",
             "allOf": [
               {
                 "$ref": "#/components/schemas/_types.DurationLarge"
@@ -88450,6 +88433,7 @@
           }
         },
         "required": [
+          "after",
           "fixed_interval"
         ]
       },
@@ -97147,6 +97131,37 @@
           }
         ]
       },
+      "indices._types.DownsampleConfig": {
+        "type": "object",
+        "properties": {
+          "fixed_interval": {
+            "description": "The interval at which to aggregate the original time series index.",
+            "allOf": [
+              {
+                "$ref": "#/components/schemas/_types.DurationLarge"
+              }
+            ]
+          },
+          "sampling_method": {
+            "description": "The sampling method used to reduce the documents; it can be either `aggregate` or `last_value`. Defaults to `aggregate`.",
+            "allOf": [
+              {
+                "$ref": "#/components/schemas/indices._types.SamplingMethod"
+              }
+            ]
+          }
+        },
+        "required": [
+          "fixed_interval"
+        ]
+      },
+      "indices._types.SamplingMethod": {
+        "type": "string",
+        "enum": [
+          "aggregate",
+          "last_value"
+        ]
+      },
       "indices.explain_data_lifecycle.DataStreamLifecycleExplain": {
         "type": "object",
         "properties": {
diff --git a/output/openapi/elasticsearch-serverless-openapi.json b/output/openapi/elasticsearch-serverless-openapi.json
index fe34c83b3c..b772f29a13 100644
--- a/output/openapi/elasticsearch-serverless-openapi.json
+++ b/output/openapi/elasticsearch-serverless-openapi.json
@@ -60634,25 +60634,8 @@
               }
             ]
           },
-          "config": {
-            "description": "The downsample configuration to execute.",
-            "allOf": [
-              {
-                "$ref": "#/components/schemas/indices._types.DownsampleConfig"
-              }
-            ]
-          }
-        },
-        "required": [
-          "after",
-          "config"
-        ]
-      },
-      "indices._types.DownsampleConfig": {
-        "type": "object",
-        "properties": {
           "fixed_interval": {
-            "description": "The interval at which to aggregate the original time series index.",
+            "description": "The downsample interval.",
             "allOf": [
               {
                 "$ref": "#/components/schemas/_types.DurationLarge"
@@ -60661,6 +60644,7 @@
           }
         },
         "required": [
+          "after",
           "fixed_interval"
         ]
       },
diff --git a/output/schema/schema.json b/output/schema/schema.json
index 3b4fd524e7..3da2b7a6a9 100644
--- a/output/schema/schema.json
+++ b/output/schema/schema.json
@@ -7407,7 +7407,7 @@
           "stability": "experimental"
         }
       },
-      "description": "Downsample an index.\nAggregate a time series (TSDS) index and store pre-computed statistical summaries (`min`, `max`, `sum`, `value_count` and `avg`) for each metric field grouped by a configured time interval.\nFor example, a TSDS index that contains metrics sampled every 10 seconds can be downsampled to an hourly index.\nAll documents within an hour interval are summarized and stored as a single document in the downsample index.\n\nNOTE: Only indices in a time series data stream are supported.\nNeither field nor document level security can be defined on the source index.\nThe source index must be read only (`index.blocks.write: true`).",
+      "description": "Downsample an index.\nDownsamples a time series (TSDS) index and reduces its size by keeping the last value or by pre-aggregating metrics:\n\n- When running in `aggregate` mode, it pre-calculates and stores statistical summaries (`min`, `max`, `sum`, `value_count` and `avg`)\nfor each metric field grouped by a configured time interval and their dimensions.\n- When running in `last_value` mode, it keeps the last value for each metric in the configured interval and their dimensions.\n\nFor example, a TSDS index that contains metrics sampled every 10 seconds can be downsampled to an hourly index.\nAll documents within an hour interval are summarized and stored as a single document in the downsample index.\n\nNOTE: Only indices in a time series data stream are supported.\nNeither field nor document level security can be defined on the source index.\nThe source index must be read-only (`index.blocks.write: true`).",
       "docId": "indices-downsample-data-stream",
       "docTag": "data stream",
       "docUrl": "https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-indices-downsample",
@@ -149515,9 +149515,21 @@
               "namespace": "_types"
             }
           }
+        },
+        {
+          "description": "The sampling method used to reduce the documents; it can be either `aggregate` or `last_value`. Defaults to `aggregate`.",
+          "name": "sampling_method",
+          "required": false,
+          "type": {
+            "kind": "instance_of",
+            "type": {
+              "name": "SamplingMethod",
+              "namespace": "indices._types"
+            }
+          }
         }
       ],
-      "specLocation": "indices/_types/Downsample.ts#L22-L27"
+      "specLocation": "indices/_types/Downsample.ts#L22-L31"
     },
     {
       "kind": "interface",
@@ -149539,19 +149551,19 @@
           }
         },
         {
-          "description": "The downsample configuration to execute.",
-          "name": "config",
+          "description": "The downsample interval.",
+          "name": "fixed_interval",
           "required": true,
           "type": {
             "kind": "instance_of",
             "type": {
-              "name": "DownsampleConfig",
-              "namespace": "indices._types"
+              "name": "DurationLarge",
+              "namespace": "_types"
             }
           }
         }
       ],
-      "specLocation": "indices/_types/DownsamplingRound.ts#L23-L32"
+      "specLocation": "indices/_types/DownsamplingRound.ts#L22-L31"
     },
     {
       "kind": "interface",
@@ -152479,6 +152491,22 @@
       ],
       "specLocation": "indices/_types/IndexSettings.ts#L66-L68"
     },
+    {
+      "kind": "enum",
+      "members": [
+        {
+          "name": "aggregate"
+        },
+        {
+          "name": "last_value"
+        }
+      ],
+      "name": {
+        "name": "SamplingMethod",
+        "namespace": "indices._types"
+      },
+      "specLocation": "indices/_types/Downsample.ts#L33-L36"
+    },
     {
       "kind": "interface",
       "name": {
@@ -157264,7 +157292,7 @@
           }
         }
       },
-      "description": "Downsample an index.\nAggregate a time series (TSDS) index and store pre-computed statistical summaries (`min`, `max`, `sum`, `value_count` and `avg`) for each metric field grouped by a configured time interval.\nFor example, a TSDS index that contains metrics sampled every 10 seconds can be downsampled to an hourly index.\nAll documents within an hour interval are summarized and stored as a single document in the downsample index.\n\nNOTE: Only indices in a time series data stream are supported.\nNeither field nor document level security can be defined on the source index.\nThe source index must be read only (`index.blocks.write: true`).",
+      "description": "Downsample an index.\nDownsamples a time series (TSDS) index and reduces its size by keeping the last value or by pre-aggregating metrics:\n\n- When running in `aggregate` mode, it pre-calculates and stores statistical summaries (`min`, `max`, `sum`, `value_count` and `avg`)\nfor each metric field grouped by a configured time interval and their dimensions.\n- When running in `last_value` mode, it keeps the last value for each metric in the configured interval and their dimensions.\n\nFor example, a TSDS index that contains metrics sampled every 10 seconds can be downsampled to an hourly index.\nAll documents within an hour interval are summarized and stored as a single document in the downsample index.\n\nNOTE: Only indices in a time series data stream are supported.\nNeither field nor document level security can be defined on the source index.\nThe source index must be read-only (`index.blocks.write: true`).",
       "examples": {
         "DownsampleRequestExample1": {
           "alternatives": [
@@ -157334,7 +157362,7 @@
         }
       ],
       "query": [],
-      "specLocation": "indices/downsample/Request.ts#L24-L58"
+      "specLocation": "indices/downsample/Request.ts#L24-L63"
     },
     {
       "kind": "response",
diff --git a/output/typescript/types.ts b/output/typescript/types.ts
index 0ec904e4a5..51111e9d9f 100644
--- a/output/typescript/types.ts
+++ b/output/typescript/types.ts
@@ -11926,11 +11926,12 @@ export interface IndicesDataStreamVisibility {
 
 export interface IndicesDownsampleConfig {
   fixed_interval: DurationLarge
+  sampling_method?: IndicesSamplingMethod
 }
 
 export interface IndicesDownsamplingRound {
   after: Duration
-  config: IndicesDownsampleConfig
+  fixed_interval: DurationLarge
 }
 
 export interface IndicesFailureStore {
@@ -12226,6 +12227,8 @@ export interface IndicesRetentionLease {
   period: Duration
 }
 
+export type IndicesSamplingMethod = 'aggregate' | 'last_value'
+
 export interface IndicesSearchIdle {
   after?: Duration
 }
diff --git a/specification/indices/_types/Downsample.ts b/specification/indices/_types/Downsample.ts
index f34526fc48..46fa228a0c 100644
--- a/specification/indices/_types/Downsample.ts
+++ b/specification/indices/_types/Downsample.ts
@@ -24,4 +24,13 @@ export class DownsampleConfig {
    * The interval at which to aggregate the original time series index.
    */
   fixed_interval: DurationLarge
+  /**
+   * The sampling method used to reduce the documents; it can be either `aggregate` or `last_value`. Defaults to `aggregate`.
+   */
+  sampling_method?: SamplingMethod
+}
+
+enum SamplingMethod {
+  aggregate,
+  last_value
 }
diff --git a/specification/indices/_types/DownsamplingRound.ts b/specification/indices/_types/DownsamplingRound.ts
index 71cb430c4d..7f0890ae88 100644
--- a/specification/indices/_types/DownsamplingRound.ts
+++ b/specification/indices/_types/DownsamplingRound.ts
@@ -17,8 +17,7 @@
  * under the License.
  */
 
-import { Duration } from '@_types/Time'
-import { DownsampleConfig } from '@indices/_types/Downsample'
+import { Duration, DurationLarge } from '@_types/Time'
 
 export class DownsamplingRound {
   /**
@@ -26,7 +25,7 @@ export class DownsamplingRound {
    */
   after: Duration
   /**
-   * The downsample configuration to execute.
+   * The downsample interval.
    */
-  config: DownsampleConfig
+  fixed_interval: DurationLarge
 }
diff --git a/specification/indices/downsample/Request.ts b/specification/indices/downsample/Request.ts
index 64e32d4d41..5fed5390a2 100644
--- a/specification/indices/downsample/Request.ts
+++ b/specification/indices/downsample/Request.ts
@@ -23,13 +23,18 @@ import { DownsampleConfig } from '@indices/_types/Downsample'
 
 /**
  * Downsample an index.
- * Aggregate a time series (TSDS) index and store pre-computed statistical summaries (`min`, `max`, `sum`, `value_count` and `avg`) for each metric field grouped by a configured time interval.
+ * Downsamples a time series (TSDS) index and reduces its size by keeping the last value or by pre-aggregating metrics:
+ *
+ * - When running in `aggregate` mode, it pre-calculates and stores statistical summaries (`min`, `max`, `sum`, `value_count` and `avg`)
+ * for each metric field grouped by a configured time interval and their dimensions.
+ * - When running in `last_value` mode, it keeps the last value for each metric in the configured interval and their dimensions.
+ *
  * For example, a TSDS index that contains metrics sampled every 10 seconds can be downsampled to an hourly index.
  * All documents within an hour interval are summarized and stored as a single document in the downsample index.
  *
  * NOTE: Only indices in a time series data stream are supported.
  * Neither field nor document level security can be defined on the source index.
- * The source index must be read only (`index.blocks.write: true`).
+ * The source index must be read-only (`index.blocks.write: true`).
  * @doc_id indices-downsample-data-stream
  * @rest_spec_name indices.downsample
  * @availability stack since=8.5.0 stability=experimental