diff --git a/output/openapi/elasticsearch-openapi.json b/output/openapi/elasticsearch-openapi.json
index 3f46072a20..f9eed1b1c7 100644
--- a/output/openapi/elasticsearch-openapi.json
+++ b/output/openapi/elasticsearch-openapi.json
@@ -102368,6 +102368,11 @@
                   }
                 ]
               },
+              "media_type": {
+                "description": "The media type for encoding `value`.\nApplies only when value is a template snippet.\nMust be one of `application/json`, `text/plain`, or `application/x-www-form-urlencoded`.",
+                "default": "\"application/json\"",
+                "type": "string"
+              },
               "allow_duplicates": {
                 "description": "If `false`, the processor does not append values already present in the field.",
                 "default": true,
@@ -102375,8 +102380,7 @@
               }
             },
             "required": [
-              "field",
-              "value"
+              "field"
             ]
           }
         ]
@@ -104254,6 +104258,7 @@
               },
               "media_type": {
                 "description": "The media type for encoding `value`.\nApplies only when value is a template snippet.\nMust be one of `application/json`, `text/plain`, or `application/x-www-form-urlencoded`.",
+                "default": "\"application/json\"",
                 "type": "string"
               },
               "override": {
diff --git a/output/openapi/elasticsearch-serverless-openapi.json b/output/openapi/elasticsearch-serverless-openapi.json
index a092c73c1f..ac9a61d8a5 100644
--- a/output/openapi/elasticsearch-serverless-openapi.json
+++ b/output/openapi/elasticsearch-serverless-openapi.json
@@ -66301,6 +66301,11 @@
                   }
                 ]
               },
+              "media_type": {
+                "description": "The media type for encoding `value`.\nApplies only when value is a template snippet.\nMust be one of `application/json`, `text/plain`, or `application/x-www-form-urlencoded`.",
+                "default": "\"application/json\"",
+                "type": "string"
+              },
               "allow_duplicates": {
                 "description": "If `false`, the processor does not append values already present in the field.",
                 "default": true,
@@ -66308,8 +66313,7 @@
               }
             },
             "required": [
-              "field",
-              "value"
+              "field"
             ]
           }
         ]
@@ -68187,6 +68191,7 @@
               },
               "media_type": {
                 "description": "The media type for encoding `value`.\nApplies only when value is a template snippet.\nMust be one of `application/json`, `text/plain`, or `application/x-www-form-urlencoded`.",
+                "default": "\"application/json\"",
                 "type": "string"
               },
               "override": {
diff --git a/output/schema/schema.json b/output/schema/schema.json
index db70a45beb..3f2c7a2ff5 100644
--- a/output/schema/schema.json
+++ b/output/schema/schema.json
@@ -178739,7 +178739,7 @@
         {
           "description": "The value to be appended. Supports template snippets.",
           "name": "value",
-          "required": true,
+          "required": false,
           "type": {
             "kind": "union_of",
             "items": [
@@ -178755,6 +178755,19 @@
             ]
           }
         },
+        {
+          "description": "The media type for encoding `value`.\nApplies only when value is a template snippet.\nMust be one of `application/json`, `text/plain`, or `application/x-www-form-urlencoded`.",
+          "name": "media_type",
+          "required": false,
+          "serverDefault": "\"application/json\"",
+          "type": {
+            "kind": "instance_of",
+            "type": {
+              "name": "string",
+              "namespace": "_builtins"
+            }
+          }
+        },
         {
           "description": "If `false`, the processor does not append values already present in the field.",
           "name": "allow_duplicates",
@@ -178769,7 +178782,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L328-L343"
+      "specLocation": "ingest/_types/Processors.ts#L328-L350"
     },
     {
       "kind": "interface",
@@ -178889,7 +178902,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L345-L386"
+      "specLocation": "ingest/_types/Processors.ts#L352-L393"
     },
     {
       "kind": "interface",
@@ -178943,7 +178956,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L555-L571"
+      "specLocation": "ingest/_types/Processors.ts#L562-L578"
     },
     {
       "kind": "interface",
@@ -179020,7 +179033,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L573-L596"
+      "specLocation": "ingest/_types/Processors.ts#L580-L603"
     },
     {
       "kind": "interface",
@@ -179179,7 +179192,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L598-L659"
+      "specLocation": "ingest/_types/Processors.ts#L605-L666"
     },
     {
       "kind": "interface",
@@ -179245,7 +179258,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L672-L692"
+      "specLocation": "ingest/_types/Processors.ts#L679-L699"
     },
     {
       "kind": "enum",
@@ -179279,7 +179292,7 @@
         "name": "ConvertType",
         "namespace": "ingest._types"
       },
-      "specLocation": "ingest/_types/Processors.ts#L661-L670"
+      "specLocation": "ingest/_types/Processors.ts#L668-L677"
     },
     {
       "kind": "interface",
@@ -179377,7 +179390,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L694-L727"
+      "specLocation": "ingest/_types/Processors.ts#L701-L734"
     },
     {
       "kind": "interface",
@@ -179602,7 +179615,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L729-L767"
+      "specLocation": "ingest/_types/Processors.ts#L736-L774"
     },
     {
       "kind": "interface",
@@ -179697,7 +179710,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L769-L802"
+      "specLocation": "ingest/_types/Processors.ts#L776-L809"
     },
     {
       "kind": "interface",
@@ -179763,7 +179776,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L804-L823"
+      "specLocation": "ingest/_types/Processors.ts#L811-L830"
     },
     {
       "kind": "interface",
@@ -179998,7 +180011,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L825-L843"
+      "specLocation": "ingest/_types/Processors.ts#L832-L850"
     },
     {
       "kind": "interface",
@@ -180013,7 +180026,7 @@
         "namespace": "ingest._types"
       },
       "properties": [],
-      "specLocation": "ingest/_types/Processors.ts#L845-L845"
+      "specLocation": "ingest/_types/Processors.ts#L852-L852"
     },
     {
       "kind": "interface",
@@ -180117,7 +180130,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L847-L886"
+      "specLocation": "ingest/_types/Processors.ts#L854-L893"
     },
     {
       "kind": "interface",
@@ -180145,7 +180158,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L888-L894"
+      "specLocation": "ingest/_types/Processors.ts#L895-L901"
     },
     {
       "kind": "enum",
@@ -180175,7 +180188,7 @@
         "name": "FingerprintDigest",
         "namespace": "ingest._types"
       },
-      "specLocation": "ingest/_types/Processors.ts#L896-L902"
+      "specLocation": "ingest/_types/Processors.ts#L903-L909"
     },
     {
       "kind": "interface",
@@ -180254,7 +180267,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L904-L932"
+      "specLocation": "ingest/_types/Processors.ts#L911-L939"
     },
     {
       "kind": "interface",
@@ -180307,7 +180320,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L934-L948"
+      "specLocation": "ingest/_types/Processors.ts#L941-L955"
     },
     {
       "kind": "interface",
@@ -180434,7 +180447,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L388-L429"
+      "specLocation": "ingest/_types/Processors.ts#L395-L436"
     },
     {
       "kind": "enum",
@@ -180450,7 +180463,7 @@
         "name": "GeoGridTargetFormat",
         "namespace": "ingest._types"
       },
-      "specLocation": "ingest/_types/Processors.ts#L437-L440"
+      "specLocation": "ingest/_types/Processors.ts#L444-L447"
     },
     {
       "kind": "enum",
@@ -180469,7 +180482,7 @@
         "name": "GeoGridTileType",
         "namespace": "ingest._types"
       },
-      "specLocation": "ingest/_types/Processors.ts#L431-L435"
+      "specLocation": "ingest/_types/Processors.ts#L438-L442"
     },
     {
       "kind": "interface",
@@ -180576,7 +180589,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L442-L476"
+      "specLocation": "ingest/_types/Processors.ts#L449-L483"
     },
     {
       "kind": "interface",
@@ -180681,7 +180694,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L950-L981"
+      "specLocation": "ingest/_types/Processors.ts#L957-L988"
     },
     {
       "kind": "interface",
@@ -180759,7 +180772,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L983-L1007"
+      "specLocation": "ingest/_types/Processors.ts#L990-L1014"
     },
     {
       "kind": "interface",
@@ -180813,7 +180826,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1009-L1025"
+      "specLocation": "ingest/_types/Processors.ts#L1016-L1032"
     },
     {
       "kind": "interface",
@@ -180847,7 +180860,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1066-L1078",
+      "specLocation": "ingest/_types/Processors.ts#L1073-L1085",
       "variants": {
         "kind": "container"
       }
@@ -180924,7 +180937,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1093-L1119"
+      "specLocation": "ingest/_types/Processors.ts#L1100-L1126"
     },
     {
       "kind": "interface",
@@ -180960,7 +180973,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1080-L1091"
+      "specLocation": "ingest/_types/Processors.ts#L1087-L1098"
     },
     {
       "kind": "interface",
@@ -181071,7 +181084,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1027-L1059"
+      "specLocation": "ingest/_types/Processors.ts#L1034-L1066"
     },
     {
       "kind": "interface",
@@ -181152,7 +181165,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1061-L1064"
+      "specLocation": "ingest/_types/Processors.ts#L1068-L1071"
     },
     {
       "kind": "interface",
@@ -181259,7 +181272,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L478-L512"
+      "specLocation": "ingest/_types/Processors.ts#L485-L519"
     },
     {
       "kind": "interface",
@@ -181321,7 +181334,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1121-L1136"
+      "specLocation": "ingest/_types/Processors.ts#L1128-L1143"
     },
     {
       "kind": "interface",
@@ -181400,7 +181413,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1138-L1167"
+      "specLocation": "ingest/_types/Processors.ts#L1145-L1174"
     },
     {
       "kind": "enum",
@@ -181418,7 +181431,7 @@
         "name": "JsonProcessorConflictStrategy",
         "namespace": "ingest._types"
       },
-      "specLocation": "ingest/_types/Processors.ts#L1169-L1174"
+      "specLocation": "ingest/_types/Processors.ts#L1176-L1181"
     },
     {
       "kind": "interface",
@@ -181575,7 +181588,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1176-L1228"
+      "specLocation": "ingest/_types/Processors.ts#L1183-L1235"
     },
     {
       "kind": "interface",
@@ -181650,7 +181663,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1230-L1246"
+      "specLocation": "ingest/_types/Processors.ts#L1237-L1253"
     },
     {
       "kind": "interface",
@@ -181766,7 +181779,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1248-L1282"
+      "specLocation": "ingest/_types/Processors.ts#L1255-L1289"
     },
     {
       "kind": "interface",
@@ -181945,7 +181958,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1284-L1295"
+      "specLocation": "ingest/_types/Processors.ts#L1291-L1302"
     },
     {
       "kind": "interface",
@@ -182928,7 +182941,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1297-L1338"
+      "specLocation": "ingest/_types/Processors.ts#L1304-L1345"
     },
     {
       "kind": "interface",
@@ -182981,7 +182994,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1340-L1356"
+      "specLocation": "ingest/_types/Processors.ts#L1347-L1363"
     },
     {
       "kind": "interface",
@@ -183034,7 +183047,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1358-L1372"
+      "specLocation": "ingest/_types/Processors.ts#L1365-L1379"
     },
     {
       "kind": "interface",
@@ -183087,7 +183100,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1374-L1390"
+      "specLocation": "ingest/_types/Processors.ts#L1381-L1397"
     },
     {
       "kind": "interface",
@@ -183169,7 +183182,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1392-L1420"
+      "specLocation": "ingest/_types/Processors.ts#L1399-L1427"
     },
     {
       "kind": "interface",
@@ -183241,7 +183254,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1422-L1442"
+      "specLocation": "ingest/_types/Processors.ts#L1429-L1449"
     },
     {
       "kind": "interface",
@@ -183297,6 +183310,7 @@
           "description": "The media type for encoding `value`.\nApplies only when value is a template snippet.\nMust be one of `application/json`, `text/plain`, or `application/x-www-form-urlencoded`.",
           "name": "media_type",
           "required": false,
+          "serverDefault": "\"application/json\"",
           "type": {
             "kind": "instance_of",
             "type": {
@@ -183327,7 +183341,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1444-L1478"
+      "specLocation": "ingest/_types/Processors.ts#L1451-L1486"
     },
     {
       "kind": "interface",
@@ -183370,7 +183384,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1480-L1489"
+      "specLocation": "ingest/_types/Processors.ts#L1488-L1497"
     },
     {
       "kind": "enum",
@@ -183386,7 +183400,7 @@
         "name": "ShapeType",
         "namespace": "ingest._types"
       },
-      "specLocation": "ingest/_types/Processors.ts#L1491-L1494"
+      "specLocation": "ingest/_types/Processors.ts#L1499-L1502"
     },
     {
       "kind": "interface",
@@ -183485,7 +183499,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1496-L1512"
+      "specLocation": "ingest/_types/Processors.ts#L1504-L1520"
     },
     {
       "kind": "interface",
@@ -183564,7 +183578,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1514-L1539"
+      "specLocation": "ingest/_types/Processors.ts#L1522-L1547"
     },
     {
       "kind": "interface",
@@ -183579,7 +183593,7 @@
         "namespace": "ingest._types"
       },
       "properties": [],
-      "specLocation": "ingest/_types/Processors.ts#L1541-L1541"
+      "specLocation": "ingest/_types/Processors.ts#L1549-L1549"
     },
     {
       "kind": "interface",
@@ -183633,7 +183647,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1543-L1559"
+      "specLocation": "ingest/_types/Processors.ts#L1551-L1567"
     },
     {
       "kind": "interface",
@@ -183687,7 +183701,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1561-L1577"
+      "specLocation": "ingest/_types/Processors.ts#L1569-L1585"
     },
     {
       "kind": "interface",
@@ -183767,7 +183781,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1597-L1623"
+      "specLocation": "ingest/_types/Processors.ts#L1605-L1631"
     },
     {
       "kind": "interface",
@@ -183821,7 +183835,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L1579-L1595"
+      "specLocation": "ingest/_types/Processors.ts#L1587-L1603"
     },
     {
       "kind": "interface",
@@ -183929,7 +183943,7 @@
           }
         }
       ],
-      "specLocation": "ingest/_types/Processors.ts#L514-L545"
+      "specLocation": "ingest/_types/Processors.ts#L521-L552"
     },
     {
       "kind": "enum",
@@ -183954,7 +183968,7 @@
         "name": "UserAgentProperty",
         "namespace": "ingest._types"
       },
-      "specLocation": "ingest/_types/Processors.ts#L547-L553"
+      "specLocation": "ingest/_types/Processors.ts#L554-L560"
     },
     {
       "kind": "interface",
diff --git a/output/typescript/types.ts b/output/typescript/types.ts
index 9818e3e8d0..15d367610b 100644
--- a/output/typescript/types.ts
+++ b/output/typescript/types.ts
@@ -14882,7 +14882,8 @@ export type InferenceUpdateResponse = InferenceInferenceEndpointInfo
 
 export interface IngestAppendProcessor extends IngestProcessorBase {
   field: Field
-  value: any | any[]
+  value?: any | any[]
+  media_type?: string
   allow_duplicates?: boolean
 }
 
diff --git a/specification/ingest/_types/Processors.ts b/specification/ingest/_types/Processors.ts
index 60ab53a4d7..065d101cbc 100644
--- a/specification/ingest/_types/Processors.ts
+++ b/specification/ingest/_types/Processors.ts
@@ -334,7 +334,14 @@ export class AppendProcessor extends ProcessorBase {
   /**
    * The value to be appended. Supports template snippets.
    */
-  value: UserDefinedValue | UserDefinedValue[]
+  value?: UserDefinedValue | UserDefinedValue[]
+  /**
+   * The media type for encoding `value`.
+   * Applies only when value is a template snippet.
+   * Must be one of `application/json`, `text/plain`, or `application/x-www-form-urlencoded`.
+   * @server_default "application/json"
+   */
+  media_type?: string
   /**
    * If `false`, the processor does not append values already present in the field.
    * @server_default true
@@ -1461,6 +1468,7 @@ export class SetProcessor extends ProcessorBase {
    * The media type for encoding `value`.
    * Applies only when value is a template snippet.
    * Must be one of `application/json`, `text/plain`, or `application/x-www-form-urlencoded`.
+   * @server_default "application/json"
    */
   media_type?: string
   /**