diff --git a/specification/_types/common.ts b/specification/_types/common.ts
index ea9b806929..74b38c6b44 100644
--- a/specification/_types/common.ts
+++ b/specification/_types/common.ts
@@ -67,6 +67,7 @@ export type ProjectRouting = string
 
 export type Routing = string
 export type LongId = string
+//TODO encode metrics as API specific enums
 
 export type ClusterAlias = string
 
@@ -253,6 +254,48 @@ export enum NodeStatsLevel {
   shards
 }
 
+export enum Metrics {
+  adaptive_selection,
+  allocations,
+  breaker,
+  discovery,
+  fs,
+  http,
+  indexing_pressure,
+  indices,
+  ingest,
+  jvm,
+  os,
+  process,
+  repositories,
+  thread_pool,
+  transport
+}
+
+export enum IndexMetrics{
+  bulk,
+  completion,
+  docs,
+  fielddata,
+  flush,
+  get,
+  indexing,
+  mappings,
+  merge,
+  query_cache,
+  recovery,
+  refresh,
+  request_cache,
+  search,
+  segments,
+  shard_stats,
+  store,
+  translog,
+  warmer,
+  dense_vector,
+  sparse_vector
+}
+
 export enum OpType {
   /**
    * Overwrite any documents that already exist.
diff --git a/specification/nodes/stats/NodesStatsRequest.ts b/specification/nodes/stats/NodesStatsRequest.ts
index 152399cad6..c3bb4642e4 100644
--- a/specification/nodes/stats/NodesStatsRequest.ts
+++ b/specification/nodes/stats/NodesStatsRequest.ts
@@ -18,6 +18,7 @@
  */
 
 import { RequestBase } from '@_types/Base'
+import {Fields, IndexMetrics, Metrics, NodeIds, NodeStatsLevel} from '@_types/common'
 import {
   CommonStatsFlags,
   Fields,
@@ -70,7 +71,7 @@ export interface Request extends RequestBase {
     /*+ Limits the information returned to the specific metrics. */
     metric?: NodeStatsMetrics
     /** Limit the information returned for indices metric to the specific index metrics. It can be used only if indices (or all) metric is specified.*/
-    index_metric?: CommonStatsFlags
+    index_metric?: IndexMetrics
   }
   query_parameters: {
     /** Comma-separated list or wildcard expressions of fields to include in fielddata and suggest statistics. */