diff --git a/.generator/schemas/v1/openapi.yaml b/.generator/schemas/v1/openapi.yaml
index 3f09c0483c43..62832808c87d 100644
--- a/.generator/schemas/v1/openapi.yaml
+++ b/.generator/schemas/v1/openapi.yaml
@@ -44106,6 +44106,10 @@ paths:
 
         **Note**: All `estimated_*` usage types will be deprecated on February 1, 2027.
 
+        Each request returns usage for the month specified by `start_month`. If `end_month` is omitted
+        or differs from `start_month`, it is treated as equal to `start_month`.
+        To retrieve multiple months, make a separate request for each month.
+
         This API endpoint is paginated. To make sure you receive all records, check if the value of `next_record_id` is
         set in the response. If it is, make another request and pass `next_record_id` as a parameter.
         Pseudo code example:
@@ -44122,15 +44126,18 @@ paths:
       operationId: GetMonthlyUsageAttribution
       parameters:
         - description: |-
-            Datetime in ISO-8601 format, UTC, precise to month: `[YYYY-MM]` for usage beginning in this month.
-            Maximum of 15 months ago.
+            Datetime in ISO-8601 format, UTC, precise to month: `[YYYY-MM]` for the month to retrieve.
+            Maximum of 15 months ago. Only one month is supported per request.
           in: query
           name: start_month
           required: true
           schema:
             format: date-time
             type: string
-        - description: "Datetime in ISO-8601 format, UTC, precise to month: `[YYYY-MM]` for usage ending this month."
+        - description: |-
+            Datetime in ISO-8601 format, UTC, precise to month: `[YYYY-MM]`.
+            If omitted or different from `start_month`, it is treated as equal to `start_month`.
+            Only usage for `start_month` is returned; this parameter does not extend the requested range.
           in: query
           name: end_month
           required: false
diff --git a/lib/datadog_api_client/v1/api/usage_metering_api.rb b/lib/datadog_api_client/v1/api/usage_metering_api.rb
index 24c6c4cd0ad1..b32cb13a78a3 100644
--- a/lib/datadog_api_client/v1/api/usage_metering_api.rb
+++ b/lib/datadog_api_client/v1/api/usage_metering_api.rb
@@ -444,6 +444,10 @@ def get_monthly_usage_attribution(start_month, fields, opts = {})
     #
     # **Note**: All `estimated_*` usage types will be deprecated on February 1, 2027.
     #
+    # Each request returns usage for the month specified by `start_month`. If `end_month` is omitted
+    # or differs from `start_month`, it is treated as equal to `start_month`.
+    # To retrieve multiple months, make a separate request for each month.
+    #
     # This API endpoint is paginated. To make sure you receive all records, check if the value of `next_record_id` is
     # set in the response. If it is, make another request and pass `next_record_id` as a parameter.
     # Pseudo code example:
@@ -458,10 +462,10 @@ def get_monthly_usage_attribution(start_month, fields, opts = {})
     # END
     # ```
     #
-    # @param start_month [Time] Datetime in ISO-8601 format, UTC, precise to month: `[YYYY-MM]` for usage beginning in this month. Maximum of 15 months ago.
+    # @param start_month [Time] Datetime in ISO-8601 format, UTC, precise to month: `[YYYY-MM]` for the month to retrieve. Maximum of 15 months ago. Only one month is supported per request.
     # @param fields [MonthlyUsageAttributionSupportedMetrics] Comma-separated list of usage types to return, or `*` for all usage types. Usage types are in the format `<usage_type>_usage` and `<usage_type>_percentage`. Example: `infra_host_usage,infra_host_percentage` To obtain the complete list of usage attribution types that can be used to replace `<usage_type>` in the field names, make a request to the [Get usage attribution types API](https://docs.datadoghq.com/api/latest/usage-metering/#get-usage-attribution-types).
     # @param opts [Hash] the optional parameters
-    # @option opts [Time] :end_month Datetime in ISO-8601 format, UTC, precise to month: `[YYYY-MM]` for usage ending this month.
+    # @option opts [Time] :end_month Datetime in ISO-8601 format, UTC, precise to month: `[YYYY-MM]`. If omitted or different from `start_month`, it is treated as equal to `start_month`. Only usage for `start_month` is returned; this parameter does not extend the requested range.
     # @option opts [UsageSortDirection] :sort_direction The direction to sort by: `[desc, asc]`.
     # @option opts [MonthlyUsageAttributionSupportedMetrics] :sort_name The field to sort by. Sort fields are in the format `<usage_type>_usage`. Example: `infra_host_usage` To obtain the complete list of usage attribution types that can be used to replace `<usage_type>` in the field names, make a request to the [Get usage attribution types API](https://docs.datadoghq.com/api/latest/usage-metering/#get-usage-attribution-types).
     # @option opts [String] :tag_breakdown_keys Comma separated list of tag keys used to group usage. If no value is provided the usage will not be broken down by tags.  To see which tags are available, look for the value of `tag_config_source` in the API response.