diff --git a/docs/changelog/129122.yaml b/docs/changelog/129122.yaml
new file mode 100644
index 000000000000..eaed27e326c0
--- /dev/null
+++ b/docs/changelog/129122.yaml
@@ -0,0 +1,5 @@
+pr: 129122
+summary: Update ecs@mappings.json with new GenAI fields
+area: Data streams
+type: feature
+issues: []
diff --git a/x-pack/plugin/core/template-resources/src/main/resources/ecs@mappings.json b/x-pack/plugin/core/template-resources/src/main/resources/ecs@mappings.json
index 997bd942881a..e1b1150fa98d 100644
--- a/x-pack/plugin/core/template-resources/src/main/resources/ecs@mappings.json
+++ b/x-pack/plugin/core/template-resources/src/main/resources/ecs@mappings.json
@@ -31,7 +31,8 @@
               "doc_values": false
             },
             "path_match": [
-              "*event.original"
+              "*event.original",
+              "*gen_ai.agent.description"
             ]
           }
         },
@@ -210,6 +211,34 @@
             "match_mapping_type": "object"
           }
         },
+        {
+          "ecs_gen_ai_integers": {
+            "mapping": {
+              "type": "integer"
+            },
+            "path_match": [
+              "*gen_ai.request.max_tokens",
+              "*gen_ai.usage.input_tokens",
+              "*gen_ai.usage.output_tokens",
+              "*gen_ai.request.choice.count",
+              "*gen_ai.request.seed"
+            ]
+          }
+        },
+        {
+          "ecs_gen_ai_doubles": {
+            "mapping": {
+              "type": "double"
+            },
+            "path_match": [
+              "*gen_ai.request.temperature",
+              "*gen_ai.request.top_k",
+              "*gen_ai.request.frequency_penalty",
+              "*gen_ai.request.presence_penalty",
+              "*gen_ai.request.top_p"
+            ]
+          }
+        },
         {
           "all_strings_to_keywords": {
             "mapping": {
diff --git a/x-pack/plugin/stack/src/javaRestTest/java/org/elasticsearch/xpack/stack/EcsDynamicTemplatesIT.java b/x-pack/plugin/stack/src/javaRestTest/java/org/elasticsearch/xpack/stack/EcsDynamicTemplatesIT.java
index eba239cd97e2..dd8dfc075a07 100644
--- a/x-pack/plugin/stack/src/javaRestTest/java/org/elasticsearch/xpack/stack/EcsDynamicTemplatesIT.java
+++ b/x-pack/plugin/stack/src/javaRestTest/java/org/elasticsearch/xpack/stack/EcsDynamicTemplatesIT.java
@@ -376,9 +376,12 @@ public class EcsDynamicTemplatesIT extends ESRestTestCase {
             case "long" -> {
                 return randomLong();
             }
-            case "int" -> {
+            case "integer" -> {
                 return randomInt();
             }
+            case "double" -> {
+                return randomDouble();
+            }
             case "float", "scaled_float" -> {
                 return randomFloat();
             }