diff --git a/output/openapi/elasticsearch-serverless-openapi.json b/output/openapi/elasticsearch-serverless-openapi.json
index 3c8bbf9e34..9e8b35759d 100644
--- a/output/openapi/elasticsearch-serverless-openapi.json
+++ b/output/openapi/elasticsearch-serverless-openapi.json
@@ -22837,23 +22837,39 @@
         "summary": "Get tags",
         "description": "Get the tags that are defined for the project.\n\n## Required authorization\n\n* Cluster privileges: `monitor`\n",
         "operationId": "project-tags",
+        "parameters": [
+          {
+            "$ref": "#/components/parameters/project.tags-project_routing"
+          }
+        ],
         "responses": {
           "200": {
-            "description": "",
-            "content": {
-              "application/json": {
-                "schema": {
-                  "$ref": "#/components/schemas/project.tags.ProjectTags"
-                },
-                "examples": {
-                  "ProjectTagsResponseExample1": {
-                    "summary": "Project tags",
-                    "description": "A successful response from `GET /_project/tags`",
-                    "value": "{\n  \"origin\": {\n    \"c56c4f8849c64cc6ae59c261f40bd195\": {\n      \"_id\": \"c56c4f8849c64cc6ae59c261f40bd195\"\n      \"_type\": \"elasticsearch\",\n      \"_alias\": \"project-1\",\n      \"_csp\": \"aws\",\n      \"_region\": \"us-east-1\"\n      \"mytag1\": \"foo\",\n      \"mytag2\": \"bar\"\n    }\n  },\n  \"linked_projects\": {\n    \"a3b88ea3f195a336ae59c261f40bd195\": {\n      \"_id\": \"a3b88ea3f195a336ae59c261f40bd195\"\n      \"_type\": \"security\",\n      \"_alias\": \"project-2\",\n      \"_csp\": \"aws\",\n      \"_region\": \"us-east-1\"\n      \"mytag1\": \"foo\",\n      \"mytag2\": \"bar\"\n    },\n    \"f40bd195389s3761023ca7aa8a3r0932\": {\n      \"_id\": \"f40bd195389s3761023ca7aa8a3r0932\"\n      \"_type\": \"observability\",\n      \"_alias\": \"project-3\",\n      \"_csp\": \"aws\",\n      \"_region\": \"us-east-1\"\n      \"mytag1\": \"foo\",\n      \"mytag2\": \"bar\"\n    }\n  }\n}"
-                  }
-                }
-              }
-            }
+            "$ref": "#/components/responses/project.tags-200"
+          }
+        },
+        "x-state": "Technical preview",
+        "x-metaTags": [
+          {
+            "content": "Elasticsearch",
+            "name": "product_name"
+          }
+        ]
+      },
+      "post": {
+        "tags": [
+          "project"
+        ],
+        "summary": "Get tags",
+        "description": "Get the tags that are defined for the project.\n\n## Required authorization\n\n* Cluster privileges: `monitor`\n",
+        "operationId": "project-tags-1",
+        "parameters": [
+          {
+            "$ref": "#/components/parameters/project.tags-project_routing"
+          }
+        ],
+        "responses": {
+          "200": {
+            "$ref": "#/components/responses/project.tags-200"
           }
         },
         "x-state": "Technical preview",
@@ -83211,6 +83227,23 @@
           }
         }
       },
+      "project.tags-200": {
+        "description": "",
+        "content": {
+          "application/json": {
+            "schema": {
+              "$ref": "#/components/schemas/project.tags.ProjectTags"
+            },
+            "examples": {
+              "ProjectTagsResponseExample1": {
+                "summary": "Project tags",
+                "description": "A successful response from `GET /_project/tags`",
+                "value": "{\n  \"origin\": {\n    \"c56c4f8849c64cc6ae59c261f40bd195\": {\n      \"_id\": \"c56c4f8849c64cc6ae59c261f40bd195\"\n      \"_type\": \"elasticsearch\",\n      \"_alias\": \"project-1\",\n      \"_csp\": \"aws\",\n      \"_region\": \"us-east-1\"\n      \"mytag1\": \"foo\",\n      \"mytag2\": \"bar\"\n    }\n  },\n  \"linked_projects\": {\n    \"a3b88ea3f195a336ae59c261f40bd195\": {\n      \"_id\": \"a3b88ea3f195a336ae59c261f40bd195\"\n      \"_type\": \"security\",\n      \"_alias\": \"project-2\",\n      \"_csp\": \"aws\",\n      \"_region\": \"us-east-1\"\n      \"mytag1\": \"foo\",\n      \"mytag2\": \"bar\"\n    },\n    \"f40bd195389s3761023ca7aa8a3r0932\": {\n      \"_id\": \"f40bd195389s3761023ca7aa8a3r0932\"\n      \"_type\": \"observability\",\n      \"_alias\": \"project-3\",\n      \"_csp\": \"aws\",\n      \"_region\": \"us-east-1\"\n      \"mytag1\": \"foo\",\n      \"mytag2\": \"bar\"\n    }\n  }\n}"
+              }
+            }
+          }
+        }
+      },
       "put_script-200": {
         "description": "",
         "content": {
@@ -88146,6 +88179,17 @@
         },
         "style": "form"
       },
+      "project.tags-project_routing": {
+        "in": "query",
+        "name": "project_routing",
+        "description": "A Lucene query using project metadata tags used to filter which projects are returned in the response, such as _alias:_origin or _alias:*pr*.",
+        "deprecated": false,
+        "schema": {
+          "type": "string"
+        },
+        "x-state": "Technical preview",
+        "style": "form"
+      },
       "put_script-id": {
         "in": "path",
         "name": "id",
diff --git a/output/schema/schema.json b/output/schema/schema.json
index 5d4331d5dd..1cefbbda25 100644
--- a/output/schema/schema.json
+++ b/output/schema/schema.json
@@ -16928,7 +16928,8 @@
       "urls": [
         {
           "methods": [
-            "GET"
+            "GET",
+            "POST"
           ],
           "path": "/_project/tags"
         }
@@ -233943,8 +233944,27 @@
         "namespace": "project.tags"
       },
       "path": [],
-      "query": [],
-      "specLocation": "project/tags/TagsRequest.ts#L22-L39"
+      "query": [
+        {
+          "availability": {
+            "serverless": {
+              "stability": "experimental",
+              "visibility": "public"
+            }
+          },
+          "description": "A Lucene query using project metadata tags used to filter which projects are returned in the response, such as _alias:_origin or _alias:*pr*.",
+          "name": "project_routing",
+          "required": false,
+          "type": {
+            "kind": "instance_of",
+            "type": {
+              "name": "string",
+              "namespace": "_builtins"
+            }
+          }
+        }
+      ],
+      "specLocation": "project/tags/TagsRequest.ts#L22-L46"
     },
     {
       "kind": "response",
diff --git a/output/typescript/types.ts b/output/typescript/types.ts
index b6fc1f0aca..741821f3f6 100644
--- a/output/typescript/types.ts
+++ b/output/typescript/types.ts
@@ -19828,6 +19828,7 @@ export interface ProjectTagsProjectTags {
 }
 
 export interface ProjectTagsRequest extends RequestBase {
+  project_routing?: string
 }
 
 export type ProjectTagsResponse = ProjectTagsProjectTags
diff --git a/specification/_json_spec/project.tags.json b/specification/_json_spec/project.tags.json
index 898154e50b..577324eabe 100644
--- a/specification/_json_spec/project.tags.json
+++ b/specification/_json_spec/project.tags.json
@@ -13,9 +13,15 @@
       "paths": [
         {
           "path": "/_project/tags",
-          "methods": ["GET"]
+          "methods": ["GET", "POST"]
         }
       ]
+    },
+    "params": {
+      "project_routing": {
+        "type": "string",
+        "description": "A Lucene query using project metadata tags used to filter which projects are returned in the response, such as _alias:_origin or _alias:*pr*."
+      }
     }
   }
 }
diff --git a/specification/project/tags/TagsRequest.ts b/specification/project/tags/TagsRequest.ts
index 25f3b57778..0a9f833e3f 100644
--- a/specification/project/tags/TagsRequest.ts
+++ b/specification/project/tags/TagsRequest.ts
@@ -33,7 +33,14 @@ export interface Request extends RequestBase {
   urls: [
     {
       path: '/_project/tags'
-      methods: ['GET']
+      methods: ['GET', 'POST']
     }
   ]
+  query_parameters: {
+    /**
+     * A Lucene query using project metadata tags used to filter which projects are returned in the response, such as _alias:_origin or _alias:*pr*.
+     * @availability serverless stability=experimental visibility=public
+     */
+    project_routing?: string
+  }
 }