From 65cb1199127b5a9b48cdd3f171a1821acfde06e9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Istv=C3=A1n=20Zolt=C3=A1n=20Szab=C3=B3?=
 <szabosteve@gmail.com>
Date: Wed, 9 Jul 2025 10:58:26 +0200
Subject: [PATCH 01/17] Adds custom inference service docs.

---
 specification/inference/put_custom/PutCustomRequest.ts  | 0
 specification/inference/put_custom/PutCustomResponse.ts | 0
 2 files changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 specification/inference/put_custom/PutCustomRequest.ts
 create mode 100644 specification/inference/put_custom/PutCustomResponse.ts

diff --git a/specification/inference/put_custom/PutCustomRequest.ts b/specification/inference/put_custom/PutCustomRequest.ts
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/specification/inference/put_custom/PutCustomResponse.ts b/specification/inference/put_custom/PutCustomResponse.ts
new file mode 100644
index 0000000000..e69de29bb2

From ac7739649726260fe803790d93a93813433700c3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Istv=C3=A1n=20Zolt=C3=A1n=20Szab=C3=B3?=
 <szabosteve@gmail.com>
Date: Wed, 9 Jul 2025 11:35:36 +0200
Subject: [PATCH 02/17] Adds response documentation.

---
 specification/inference/_types/Services.ts    | 34 ++++++++++++-------
 specification/inference/_types/TaskType.ts    |  7 ++++
 .../inference/put_custom/PutCustomResponse.ts | 25 ++++++++++++++
 .../PutDeepSeekRequestExample1.yaml           |  0
 .../PutDeepSeekRequestExample2.yaml           |  0
 5 files changed, 54 insertions(+), 12 deletions(-)
 rename specification/inference/put_deepseek/{request => examples}/PutDeepSeekRequestExample1.yaml (100%)
 rename specification/inference/put_deepseek/{request => examples}/PutDeepSeekRequestExample2.yaml (100%)

diff --git a/specification/inference/_types/Services.ts b/specification/inference/_types/Services.ts
index 720dd9ea43..802db7decc 100644
--- a/specification/inference/_types/Services.ts
+++ b/specification/inference/_types/Services.ts
@@ -27,6 +27,7 @@ import {
   TaskTypeAzureAIStudio,
   TaskTypeAzureOpenAI,
   TaskTypeCohere,
+  TaskTypeCustom,
   TaskTypeDeepSeek,
   TaskTypeElasticsearch,
   TaskTypeELSER,
@@ -75,18 +76,6 @@ export class InferenceEndpointInfo extends InferenceEndpoint {
    */
   task_type: TaskType
 }
-
-export class InferenceEndpointInfoJinaAi extends InferenceEndpoint {
-  /**
-   * The inference Id
-   */
-  inference_id: string
-  /**
-   * The task type
-   */
-  task_type: TaskTypeJinaAi
-}
-
 export class InferenceEndpointInfoAlibabaCloudAI extends InferenceEndpoint {
   /**
    * The inference Id
@@ -153,6 +142,16 @@ export class InferenceEndpointInfoCohere extends InferenceEndpoint {
   task_type: TaskTypeCohere
 }
 
+export class InferenceEndpointInfoCustom extends InferenceEndpoint {
+  /**
+   * The inference Id
+   */
+  inference_id: string
+  /**
+   * The task type
+   */
+  task_type: TaskTypeCustom
+}
 export class InferenceEndpointInfoDeepSeek extends InferenceEndpoint {
   /**
    * The inference Id
@@ -219,6 +218,17 @@ export class InferenceEndpointInfoHuggingFace extends InferenceEndpoint {
   task_type: TaskTypeHuggingFace
 }
 
+export class InferenceEndpointInfoJinaAi extends InferenceEndpoint {
+  /**
+   * The inference Id
+   */
+  inference_id: string
+  /**
+   * The task type
+   */
+  task_type: TaskTypeJinaAi
+}
+
 export class InferenceEndpointInfoMistral extends InferenceEndpoint {
   /**
    * The inference Id
diff --git a/specification/inference/_types/TaskType.ts b/specification/inference/_types/TaskType.ts
index 670dc3d3e5..6daed0d281 100644
--- a/specification/inference/_types/TaskType.ts
+++ b/specification/inference/_types/TaskType.ts
@@ -65,6 +65,13 @@ export enum TaskTypeCohere {
   completion
 }
 
+export enum TaskTypeCustom {
+  text_embedding,
+  sparse_embedding,
+  rerank,
+  completion
+}
+
 export enum TaskTypeDeepSeek {
   completion,
   chat_completion
diff --git a/specification/inference/put_custom/PutCustomResponse.ts b/specification/inference/put_custom/PutCustomResponse.ts
index e69de29bb2..b691dd00c3 100644
--- a/specification/inference/put_custom/PutCustomResponse.ts
+++ b/specification/inference/put_custom/PutCustomResponse.ts
@@ -0,0 +1,25 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import { InferenceEndpointInfoCustom } from '@inference/_types/Services'
+
+export class Response {
+  /** @codegen_name endpoint_info */
+  body: InferenceEndpointInfoCustom
+}
\ No newline at end of file
diff --git a/specification/inference/put_deepseek/request/PutDeepSeekRequestExample1.yaml b/specification/inference/put_deepseek/examples/PutDeepSeekRequestExample1.yaml
similarity index 100%
rename from specification/inference/put_deepseek/request/PutDeepSeekRequestExample1.yaml
rename to specification/inference/put_deepseek/examples/PutDeepSeekRequestExample1.yaml
diff --git a/specification/inference/put_deepseek/request/PutDeepSeekRequestExample2.yaml b/specification/inference/put_deepseek/examples/PutDeepSeekRequestExample2.yaml
similarity index 100%
rename from specification/inference/put_deepseek/request/PutDeepSeekRequestExample2.yaml
rename to specification/inference/put_deepseek/examples/PutDeepSeekRequestExample2.yaml

From 389ce57262ab9239037f3e9f81dbabb3c64296b7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Istv=C3=A1n=20Zolt=C3=A1n=20Szab=C3=B3?=
 <szabosteve@gmail.com>
Date: Wed, 9 Jul 2025 14:16:40 +0200
Subject: [PATCH 03/17] Adds request params docs.

---
 specification/inference/_types/CommonTypes.ts | 130 ++++++++++++++++++
 .../inference/put_custom/PutCustomRequest.ts  |  78 +++++++++++
 2 files changed, 208 insertions(+)

diff --git a/specification/inference/_types/CommonTypes.ts b/specification/inference/_types/CommonTypes.ts
index e097e0cd6a..bd3482bcb2 100644
--- a/specification/inference/_types/CommonTypes.ts
+++ b/specification/inference/_types/CommonTypes.ts
@@ -758,6 +758,136 @@ export class CohereTaskSettings {
   truncate?: CohereTruncateType
 }
 
+export class CustomServiceSettings {
+  /**
+   * Specifies the HTTPS header parameters – such as `Authentication` or `Contet-Type` – that are required to access the custom service.
+   * For example:
+   * ```
+   * "headers":{
+   *   "Authorization": "Bearer ${api_key}",
+   *   "Content-Type": "application/json;charset=utf-8"
+   * }
+   * ```
+   */
+  headers?: object
+  /**
+   * The request configuration object.
+   */
+  request: CustomRequestParams
+  /**
+   * The response configuration object.
+   */
+  response: CustomResponseParams
+  /**
+   * Specifies secret parameters, like `api_key` or `api_token`, that are required to access the custom service.
+   * For example:
+   * ```
+   * "secret_parameters":{
+   *   "api_key":"<api_key>"
+   * }
+   * ```
+   */
+  secret_parameters: object
+  /**
+   * The URL endpoint to use for the requests.
+   */
+  url?: string
+}
+
+export class CustomRequestParams {
+  /**
+   * The body structure of the request. It requires passing in the string-escaped result of the JSON format HTTP request body.
+   * For example:
+   * ```
+   * "request":{
+   *   "content":"{\"input\":${input}}"
+   * }
+   * ```
+   * > info
+   * > The content string needs to be a single line except using the Kibana console.
+   */
+  content: string
+} 
+
+export class CustomResponseParams {
+  /**
+   * Specifies the path to the error message in the response from the custom service.
+   * For example:
+   * ```
+   * "response": {
+   *   "error_parser": {
+   *     "path": "$.error.message"
+   *   }
+   * }
+   * ```
+   */
+  error_parser: object
+  /** 
+   * Specifies the JSON parser that is used to parse the response from the custom service.
+   * Different task types require different json_parser parameters.
+   * For example:
+   * ```
+   * # text_embedding
+   * "response":{
+   *   "json_parser":{
+   *     "text_embeddings":"$.result.embeddings[*].embedding"
+   *   }
+   * }
+   * 
+   * # sparse_embedding
+   * "response":{
+   *   "json_parser":{
+   *     "token_path":"$.result[*].embeddings[*].token",
+   *     "weight_path":"$.result[*].embeddings[*].weight"
+   *   }
+   * }
+   * 
+   * # rerank
+   * "response":{
+   *   "json_parser":{
+   *     "reranked_index":"$.result.scores[*].index",    // optional
+   *     "relevance_score":"$.result.scores[*].score",
+   *     "document_text":"xxx"    // optional
+   *   }
+   * }
+   * 
+   * # completion
+   * "response":{
+   *   "json_parser":{
+   *     "completion_result":"$.result.text"
+   *   }
+   * }
+   */
+  json_parser: object
+}
+
+export enum CustomTaskType {
+  text_embedding,
+  sparse_embedding,
+  rerank,
+  completion
+}
+
+export enum CustomServiceType {
+  custom
+}
+
+export class CustomTaskSettings {
+  /**
+   * Specifies parameters that are required to run the custom service. The parameters depend on the model your custom service uses.
+   * For example:
+   * ```
+   * "task_settings":{
+   *   "parameters":{
+   *     "input_type":"query",
+   *     "return_token":true
+   *   }
+   * }
+   * ```
+   */
+  parameters?: object
+}
+
 export class EisServiceSettings {
   /**
    * The name of the model to use for the inference task.
diff --git a/specification/inference/put_custom/PutCustomRequest.ts b/specification/inference/put_custom/PutCustomRequest.ts
index e69de29bb2..f1cbe279ab 100644
--- a/specification/inference/put_custom/PutCustomRequest.ts
+++ b/specification/inference/put_custom/PutCustomRequest.ts
@@ -0,0 +1,78 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import { RequestBase } from '@_types/Base'
+import { Id } from '@_types/common'
+import {
+  CustomServiceSettings,
+  CustomServiceType,
+  CustomTaskSettings,
+  CustomTaskType
+} from '@inference/_types/CommonTypes'
+import { InferenceChunkingSettings } from '@inference/_types/Services'
+
+/**
+ * Create a custom inference endpoint.
+ *
+ * You can create an inference endpoint to perform an inference task with a custom model that supports the HTTP format.
+ * @rest_spec_name inference.put_custom
+ * @availability stack since=8.13.0 stability=stable visibility=public
+ * @availability serverless stability=stable visibility=public
+ * @cluster_privileges manage_inference
+ * @doc_id inference-api-put-custom
+ */
+export interface Request extends RequestBase {
+  urls: [
+    {
+      path: '/_inference/{task_type}/{custom_inference_id}'
+      methods: ['PUT']
+    }
+  ]
+  path_parts: {
+    /**
+     * The type of the inference task that the model will perform.
+     */
+    task_type: CustomTaskType
+    /**
+     * The unique identifier of the inference endpoint.
+     */
+    custom_inference_id: Id
+  }
+  body: {
+    /**
+     * The chunking configuration object.
+     * @ext_doc_id inference-chunking
+     */
+    chunking_settings?: InferenceChunkingSettings
+    /**
+     * The type of service supported for the specified task type. In this case, `custom`.
+     */
+    service: CustomServiceType
+    /**
+     * Settings used to install the inference model.
+     * These settings are specific to the `custom` service.
+     */
+    service_settings: CustomServiceSettings
+    /**
+     * Settings to configure the inference task.
+     * These settings are specific to the task type you specified.
+     */
+    task_settings?: CustomTaskSettings
+  }
+}
\ No newline at end of file

From 3c4eb3f703ddecf2654e6b17e12386dff5f5c0bf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Istv=C3=A1n=20Zolt=C3=A1n=20Szab=C3=B3?=
 <szabosteve@gmail.com>
Date: Wed, 9 Jul 2025 14:44:55 +0200
Subject: [PATCH 04/17] Fixes code style.

---
 specification/inference/_types/CommonTypes.ts          | 10 +++++-----
 specification/inference/put_custom/PutCustomRequest.ts |  2 +-
 .../inference/put_custom/PutCustomResponse.ts          |  2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/specification/inference/_types/CommonTypes.ts b/specification/inference/_types/CommonTypes.ts
index bd3482bcb2..17cc8c6291 100644
--- a/specification/inference/_types/CommonTypes.ts
+++ b/specification/inference/_types/CommonTypes.ts
@@ -807,7 +807,7 @@ export class CustomRequestParams {
    * > The content string needs to be a single line except using the Kibana console.
    */
   content: string
-} 
+}
 
 export class CustomResponseParams {
   /**
@@ -822,7 +822,7 @@ export class CustomResponseParams {
    * ```
    */
   error_parser: object
-  /** 
+  /**
    * Specifies the JSON parser that is used to parse the response from the custom service.
    * Different task types require different json_parser parameters.
    * For example:
@@ -833,7 +833,7 @@ export class CustomResponseParams {
    *     "text_embeddings":"$.result.embeddings[*].embedding"
    *   }
    * }
-   * 
+   *
    * # sparse_embedding
    * "response":{
    *   "json_parser":{
@@ -841,7 +841,7 @@ export class CustomResponseParams {
    *     "weight_path":"$.result[*].embeddings[*].weight"
    *   }
    * }
-   * 
+   *
    * # rerank
    * "response":{
    *   "json_parser":{
@@ -850,7 +850,7 @@ export class CustomResponseParams {
    *     "document_text":"xxx"    // optional
    *   }
    * }
-   * 
+   *
    * # completion
    * "response":{
    *   "json_parser":{
diff --git a/specification/inference/put_custom/PutCustomRequest.ts b/specification/inference/put_custom/PutCustomRequest.ts
index f1cbe279ab..fab798391a 100644
--- a/specification/inference/put_custom/PutCustomRequest.ts
+++ b/specification/inference/put_custom/PutCustomRequest.ts
@@ -75,4 +75,4 @@ export interface Request extends RequestBase {
      */
     task_settings?: CustomTaskSettings
   }
-}
\ No newline at end of file
+}
diff --git a/specification/inference/put_custom/PutCustomResponse.ts b/specification/inference/put_custom/PutCustomResponse.ts
index b691dd00c3..c09467c944 100644
--- a/specification/inference/put_custom/PutCustomResponse.ts
+++ b/specification/inference/put_custom/PutCustomResponse.ts
@@ -22,4 +22,4 @@ import { InferenceEndpointInfoCustom } from '@inference/_types/Services'
 export class Response {
   /** @codegen_name endpoint_info */
   body: InferenceEndpointInfoCustom
-}
\ No newline at end of file
+}

From bc663289e07b072be2d5c6eae19da47caeed6faf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Istv=C3=A1n=20Zolt=C3=A1n=20Szab=C3=B3?=
 <szabosteve@gmail.com>
Date: Wed, 9 Jul 2025 15:01:15 +0200
Subject: [PATCH 05/17] Fixes data type.

---
 specification/inference/_types/CommonTypes.ts | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/specification/inference/_types/CommonTypes.ts b/specification/inference/_types/CommonTypes.ts
index 17cc8c6291..c4799c1705 100644
--- a/specification/inference/_types/CommonTypes.ts
+++ b/specification/inference/_types/CommonTypes.ts
@@ -769,7 +769,7 @@ export class CustomServiceSettings {
    * }
    * ```
    */
-  headers?: object
+  headers?: UserDefinedValue
   /**
    * The request configuration object.
    */
@@ -787,7 +787,7 @@ export class CustomServiceSettings {
    * }
    * ```
    */
-  secret_parameters: object
+  secret_parameters: UserDefinedValue
   /**
    * The URL endpoint to use for the requests.
    */
@@ -821,7 +821,7 @@ export class CustomResponseParams {
    * }
    * ```
    */
-  error_parser: object
+  error_parser: UserDefinedValue
   /**
    * Specifies the JSON parser that is used to parse the response from the custom service.
    * Different task types require different json_parser parameters.
@@ -858,7 +858,7 @@ export class CustomResponseParams {
    *   }
    * }
    */
-  json_parser: object
+  json_parser: UserDefinedValue
 }
 
 export enum CustomTaskType {
@@ -885,7 +885,7 @@ export class CustomTaskSettings {
    * }
    * ```
    */
-  parameters?: object
+  parameters?: UserDefinedValue
 }
 
 export class EisServiceSettings {

From 1b3fe33579ed42cd08eadbf43ca86f8c28423c99 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Istv=C3=A1n=20Zolt=C3=A1n=20Szab=C3=B3?=
 <szabosteve@gmail.com>
Date: Wed, 9 Jul 2025 15:58:29 +0200
Subject: [PATCH 06/17] Adds json_spec.

---
 .../_json_spec/inference.put_custom.json      | 35 +++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 specification/_json_spec/inference.put_custom.json

diff --git a/specification/_json_spec/inference.put_custom.json b/specification/_json_spec/inference.put_custom.json
new file mode 100644
index 0000000000..a006e60e56
--- /dev/null
+++ b/specification/_json_spec/inference.put_custom.json
@@ -0,0 +1,35 @@
+{
+    "inference.put_cohere": {
+      "documentation": {
+        "url": "https://www.elastic.co/guide/en/elasticsearch/reference/current/infer-service-custom.html",
+        "description": "Configure a custom inference endpoint"
+      },
+      "stability": "stable",
+      "visibility": "public",
+      "headers": {
+        "accept": ["application/json"],
+        "content_type": ["application/json"]
+      },
+      "url": {
+        "paths": [
+          {
+            "path": "/_inference/{task_type}/{custom_inference_id}",
+            "methods": ["PUT"],
+            "parts": {
+              "task_type": {
+                "type": "string",
+                "description": "The task type"
+              },
+              "custom_inference_id": {
+                "type": "string",
+                "description": "The inference Id"
+              }
+            }
+          }
+        ]
+      },
+      "body": {
+        "description": "The inference endpoint's task and service settings"
+      }
+    }
+  }
\ No newline at end of file

From fab50c4400264781f4b2c0479fd44cda1b968e9e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Istv=C3=A1n=20Zolt=C3=A1n=20Szab=C3=B3?=
 <szabosteve@gmail.com>
Date: Wed, 9 Jul 2025 16:00:42 +0200
Subject: [PATCH 07/17] Fixes typo.

---
 specification/_json_spec/inference.put_custom.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/specification/_json_spec/inference.put_custom.json b/specification/_json_spec/inference.put_custom.json
index a006e60e56..d3a92937f2 100644
--- a/specification/_json_spec/inference.put_custom.json
+++ b/specification/_json_spec/inference.put_custom.json
@@ -1,5 +1,5 @@
 {
-    "inference.put_cohere": {
+    "inference.put_custom": {
       "documentation": {
         "url": "https://www.elastic.co/guide/en/elasticsearch/reference/current/infer-service-custom.html",
         "description": "Configure a custom inference endpoint"

From e185149edcc5ac457559a033659f0220fa33d3fa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Istv=C3=A1n=20Zolt=C3=A1n=20Szab=C3=B3?=
 <szabosteve@gmail.com>
Date: Wed, 9 Jul 2025 16:36:27 +0200
Subject: [PATCH 08/17] Adds doc_id to the table.csv file.

---
 specification/_doc_ids/table.csv                   | 1 +
 specification/_json_spec/inference.put_custom.json | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/specification/_doc_ids/table.csv b/specification/_doc_ids/table.csv
index d1a95d8747..d1606d1e33 100644
--- a/specification/_doc_ids/table.csv
+++ b/specification/_doc_ids/table.csv
@@ -356,6 +356,7 @@ inference-api-put-anthropic,https://www.elastic.co/docs/api/doc/elasticsearch/op
 inference-api-put-azureaistudio,https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-inference-put-azureaistudio,https://www.elastic.co/guide/en/elasticsearch/reference/8.18/infer-service-azure-ai-studio.html,
 inference-api-put-azureopenai,https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-inference-put-azureopenai,https://www.elastic.co/guide/en/elasticsearch/reference/8.18/infer-service-azure-openai.html,
 inference-api-put-cohere,https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-inference-put-cohere,https://www.elastic.co/guide/en/elasticsearch/reference/8.18/infer-service-cohere.html,
+inference-api-put-custom,https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-inference-put-custom,https://www.elastic.co/guide/en/elasticsearch/reference/8.19/infer-service-custom.html,
 inference-api-put-deepseek,https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-inference-put-deepseek,https://www.elastic.co/guide/en/elasticsearch/reference/8.18/infer-service-deepseek.html,
 inference-api-put-eis,https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-inference-put-eis,,
 inference-api-put-elasticsearch,https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-inference-put-elasticsearch,https://www.elastic.co/guide/en/elasticsearch/reference/8.18/infer-service-elasticsearch.html,
diff --git a/specification/_json_spec/inference.put_custom.json b/specification/_json_spec/inference.put_custom.json
index d3a92937f2..dc9df4bea4 100644
--- a/specification/_json_spec/inference.put_custom.json
+++ b/specification/_json_spec/inference.put_custom.json
@@ -1,7 +1,7 @@
 {
     "inference.put_custom": {
       "documentation": {
-        "url": "https://www.elastic.co/guide/en/elasticsearch/reference/current/infer-service-custom.html",
+        "url": "https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-inference-put-custom",
         "description": "Configure a custom inference endpoint"
       },
       "stability": "stable",

From 80510830795a4a4a962bd96dee89f3b19c44d84c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Istv=C3=A1n=20Zolt=C3=A1n=20Szab=C3=B3?=
 <szabosteve@gmail.com>
Date: Wed, 9 Jul 2025 17:48:54 +0200
Subject: [PATCH 09/17] Makes it prettier.

---
 .../_json_spec/inference.put_custom.json      | 62 +++++++++----------
 1 file changed, 31 insertions(+), 31 deletions(-)

diff --git a/specification/_json_spec/inference.put_custom.json b/specification/_json_spec/inference.put_custom.json
index dc9df4bea4..c12108683d 100644
--- a/specification/_json_spec/inference.put_custom.json
+++ b/specification/_json_spec/inference.put_custom.json
@@ -1,35 +1,35 @@
 {
-    "inference.put_custom": {
-      "documentation": {
-        "url": "https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-inference-put-custom",
-        "description": "Configure a custom inference endpoint"
-      },
-      "stability": "stable",
-      "visibility": "public",
-      "headers": {
-        "accept": ["application/json"],
-        "content_type": ["application/json"]
-      },
-      "url": {
-        "paths": [
-          {
-            "path": "/_inference/{task_type}/{custom_inference_id}",
-            "methods": ["PUT"],
-            "parts": {
-              "task_type": {
-                "type": "string",
-                "description": "The task type"
-              },
-              "custom_inference_id": {
-                "type": "string",
-                "description": "The inference Id"
-              }
+  "inference.put_custom": {
+    "documentation": {
+      "url": "https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-inference-put-custom",
+      "description": "Configure a custom inference endpoint"
+    },
+    "stability": "stable",
+    "visibility": "public",
+    "headers": {
+      "accept": ["application/json"],
+      "content_type": ["application/json"]
+    },
+    "url": {
+      "paths": [
+        {
+          "path": "/_inference/{task_type}/{custom_inference_id}",
+          "methods": ["PUT"],
+          "parts": {
+            "task_type": {
+              "type": "string",
+              "description": "The task type"
+            },
+            "custom_inference_id": {
+              "type": "string",
+              "description": "The inference Id"
             }
           }
-        ]
-      },
-      "body": {
-        "description": "The inference endpoint's task and service settings"
-      }
+        }
+      ]
+    },
+    "body": {
+      "description": "The inference endpoint's task and service settings"
     }
-  }
\ No newline at end of file
+  }
+}

From e0963ae109b6ce36ec5f064f1312d2b798a9d378 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Istv=C3=A1n=20Zolt=C3=A1n=20Szab=C3=B3?=
 <szabosteve@gmail.com>
Date: Thu, 10 Jul 2025 13:38:25 +0200
Subject: [PATCH 10/17] Adds examples.

---
 .../examples/PutCustomRequestExample1.yaml    | 24 ++++++++++++++
 .../examples/PutCustomRequestExample2.yaml    | 25 +++++++++++++++
 .../examples/PutCustomRequestExample3.yaml    | 31 +++++++++++++++++++
 .../examples/PutCustomRequestExample4.yaml    | 25 +++++++++++++++
 .../examples/PutCustomRequestExample5.yaml    | 24 ++++++++++++++
 5 files changed, 129 insertions(+)
 create mode 100644 specification/inference/put_custom/examples/PutCustomRequestExample1.yaml
 create mode 100644 specification/inference/put_custom/examples/PutCustomRequestExample2.yaml
 create mode 100644 specification/inference/put_custom/examples/PutCustomRequestExample3.yaml
 create mode 100644 specification/inference/put_custom/examples/PutCustomRequestExample4.yaml
 create mode 100644 specification/inference/put_custom/examples/PutCustomRequestExample5.yaml

diff --git a/specification/inference/put_custom/examples/PutCustomRequestExample1.yaml b/specification/inference/put_custom/examples/PutCustomRequestExample1.yaml
new file mode 100644
index 0000000000..c042c109dd
--- /dev/null
+++ b/specification/inference/put_custom/examples/PutCustomRequestExample1.yaml
@@ -0,0 +1,24 @@
+summary: Custom text embedding task (OpenAI)
+description: Run `PUT _inference/text_embedding/custom-embeddings` to create an inference endpoint that performs a text embedding task.
+method_request: 'PUT _inference/text_embedding/custom-embeddings'
+# type: "request"
+value: |-
+  {
+      "service": "custom",
+      "service_settings": {
+          "secret_parameters": {
+              "api_key": "<api key>"
+          },
+          "url": "https://api.openai.com/v1/embeddings",
+          "headers": {
+              "Authorization": "Bearer ${api_key}",
+              "Content-Type": "application/json;charset=utf-8"
+          },
+          "request": "{\"input\": ${input}, \"model\": \"text-embedding-3-small\"}",
+          "response": {
+              "json_parser": {
+                  "text_embeddings": "$.data[*].embedding[*]"
+              }
+          }
+      }
+  }
\ No newline at end of file
diff --git a/specification/inference/put_custom/examples/PutCustomRequestExample2.yaml b/specification/inference/put_custom/examples/PutCustomRequestExample2.yaml
new file mode 100644
index 0000000000..1fb61b58c1
--- /dev/null
+++ b/specification/inference/put_custom/examples/PutCustomRequestExample2.yaml
@@ -0,0 +1,25 @@
+summary: Custom rerank task (Cohere APIv2)
+description: Run `PUT _inference/rerank/custom-rerank` to create an inference endpoint that performs a rerank task.
+method_request: 'PUT _inference/rerank/custom-rerank'
+# type: "request"
+value: |-
+  {
+    "service": "custom",
+    "service_settings": {
+        "secret_parameters": {
+            "api_key": "<api key>"
+        },
+        "url": "https://api.cohere.com/v2/rerank",
+        "headers": {
+            "Authorization": "bearer ${api_key}",
+            "Content-Type": "application/json"
+        },
+        "request": "{\"documents\": ${input}, \"query\": ${query}, \"model\": \"rerank-v3.5\"}",
+        "response": {
+            "json_parser": {
+                "reranked_index":"$.results[*].index",
+                "relevance_score":"$.results[*].relevance_score"
+            }
+        }
+    }
+  }
diff --git a/specification/inference/put_custom/examples/PutCustomRequestExample3.yaml b/specification/inference/put_custom/examples/PutCustomRequestExample3.yaml
new file mode 100644
index 0000000000..e5d4f35ed8
--- /dev/null
+++ b/specification/inference/put_custom/examples/PutCustomRequestExample3.yaml
@@ -0,0 +1,31 @@
+summary: Custom text embedding task (Cohere APIv2)
+description: Run `PUT _inference/text_embedding/custom-text-embedding` to create an inference endpoint that performs a text embedding task.
+method_request: 'PUT _inference/text_embedding/custom-text-embedding'
+# type: "request"
+value: |-
+  {
+    "service": "custom",
+    "service_settings": {
+        "secret_parameters": {
+            "api_key": "<api key>"
+        },
+        "url": "https://api.cohere.com/v2/embed",
+        "headers": {
+            "Authorization": "bearer ${api_key}",
+            "Content-Type": "application/json"
+        },
+        "request": "{\"texts\": ${input}, \"model\": \"embed-v4.0\", \"input_type\": ${input_type}}",
+        "response": {
+            "json_parser": {
+                "text_embeddings":"$.embeddings.float[*]"
+            }
+        },
+        "input_type": {
+            "translation": {
+                "ingest": "search_document",
+                "search": "search_query"
+            },
+            "default": "search_document"
+        }
+    }
+  }
\ No newline at end of file
diff --git a/specification/inference/put_custom/examples/PutCustomRequestExample4.yaml b/specification/inference/put_custom/examples/PutCustomRequestExample4.yaml
new file mode 100644
index 0000000000..2a754d342d
--- /dev/null
+++ b/specification/inference/put_custom/examples/PutCustomRequestExample4.yaml
@@ -0,0 +1,25 @@
+summary: Custom rerank task (Jina AI)
+description: Run `PUT _inference/rerank/custom-rerank-jina` to create an inference endpoint that performs a rerank task.
+method_request: 'PUT _inference/rerank/custom-rerank-jina'
+# type: "request"
+value: |-
+  {
+    "service": "custom",
+    "service_settings": {
+      "secret_parameters": {
+        "api_key": "<api key>"
+      },    
+      "url": "https://api.jina.ai/v1/rerank",
+      "headers": {
+        "Content-Type": "application/json",
+        "Authorization": "Bearer ${api_key}"
+      },
+      "request": "{\"model\": \"jina-reranker-v2-base-multilingual\",\"query\": ${query},\"documents\":${input}}",
+      "response": {
+        "json_parser": {
+          "relevance_score": "$.results[*].relevance_score",
+          "reranked_index": "$.results[*].index"
+        }
+      }
+    }
+  }
\ No newline at end of file
diff --git a/specification/inference/put_custom/examples/PutCustomRequestExample5.yaml b/specification/inference/put_custom/examples/PutCustomRequestExample5.yaml
new file mode 100644
index 0000000000..427c92927d
--- /dev/null
+++ b/specification/inference/put_custom/examples/PutCustomRequestExample5.yaml
@@ -0,0 +1,24 @@
+summary: Custom text embedding task (Hugging Face)
+description: Run `PUT _inference/text_embedding/custom-text-embedding-hf` to create an inference endpoint that performs a text embedding task by using the Qwen/Qwen3-Embedding-8B model.
+method_request: 'PUT _inference/text_embedding/custom-text-embedding-hf'
+# type: "request"
+value: |-
+  {
+    "service": "custom",
+    "service_settings": {
+        "secret_parameters": {
+            "api_key": "<api key>"
+        },
+        "url": "<dedicated inference endpoint on HF>/v1/embeddings",
+        "headers": {
+            "Authorization": "Bearer ${api_key}",
+            "Content-Type": "application/json"
+        },
+        "request": "{\"input\": ${input}}",
+        "response": {
+            "json_parser": {
+                "text_embeddings":"$.data[*].embedding[*]"
+            }
+        }
+    }
+  }
\ No newline at end of file

From d568234476db26ac2b720864c86d4dd9aa5923eb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Istv=C3=A1n=20Zolt=C3=A1n=20Szab=C3=B3?=
 <szabosteve@gmail.com>
Date: Thu, 10 Jul 2025 13:40:44 +0200
Subject: [PATCH 11/17] Format fix.

---
 .../inference/put_custom/examples/PutCustomRequestExample1.yaml | 2 +-
 .../inference/put_custom/examples/PutCustomRequestExample3.yaml | 2 +-
 .../inference/put_custom/examples/PutCustomRequestExample4.yaml | 2 +-
 .../inference/put_custom/examples/PutCustomRequestExample5.yaml | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/specification/inference/put_custom/examples/PutCustomRequestExample1.yaml b/specification/inference/put_custom/examples/PutCustomRequestExample1.yaml
index c042c109dd..dabe71ed86 100644
--- a/specification/inference/put_custom/examples/PutCustomRequestExample1.yaml
+++ b/specification/inference/put_custom/examples/PutCustomRequestExample1.yaml
@@ -21,4 +21,4 @@ value: |-
               }
           }
       }
-  }
\ No newline at end of file
+  }
diff --git a/specification/inference/put_custom/examples/PutCustomRequestExample3.yaml b/specification/inference/put_custom/examples/PutCustomRequestExample3.yaml
index e5d4f35ed8..70e5609051 100644
--- a/specification/inference/put_custom/examples/PutCustomRequestExample3.yaml
+++ b/specification/inference/put_custom/examples/PutCustomRequestExample3.yaml
@@ -28,4 +28,4 @@ value: |-
             "default": "search_document"
         }
     }
-  }
\ No newline at end of file
+  }
diff --git a/specification/inference/put_custom/examples/PutCustomRequestExample4.yaml b/specification/inference/put_custom/examples/PutCustomRequestExample4.yaml
index 2a754d342d..4ecaaf020b 100644
--- a/specification/inference/put_custom/examples/PutCustomRequestExample4.yaml
+++ b/specification/inference/put_custom/examples/PutCustomRequestExample4.yaml
@@ -22,4 +22,4 @@ value: |-
         }
       }
     }
-  }
\ No newline at end of file
+  }
diff --git a/specification/inference/put_custom/examples/PutCustomRequestExample5.yaml b/specification/inference/put_custom/examples/PutCustomRequestExample5.yaml
index 427c92927d..c9f86dad8d 100644
--- a/specification/inference/put_custom/examples/PutCustomRequestExample5.yaml
+++ b/specification/inference/put_custom/examples/PutCustomRequestExample5.yaml
@@ -21,4 +21,4 @@ value: |-
             }
         }
     }
-  }
\ No newline at end of file
+  }

From b4c99e61322432f1ccd17c0976f22998165ca983 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Istv=C3=A1n=20Zolt=C3=A1n=20Szab=C3=B3?=
 <szabosteve@gmail.com>
Date: Mon, 21 Jul 2025 12:00:33 +0200
Subject: [PATCH 12/17] Addresses feedback.

---
 specification/inference/_types/CommonTypes.ts    | 16 +---------------
 .../inference/put_custom/PutCustomRequest.ts     |  3 ++-
 2 files changed, 3 insertions(+), 16 deletions(-)

diff --git a/specification/inference/_types/CommonTypes.ts b/specification/inference/_types/CommonTypes.ts
index c4799c1705..867cfbb243 100644
--- a/specification/inference/_types/CommonTypes.ts
+++ b/specification/inference/_types/CommonTypes.ts
@@ -799,9 +799,7 @@ export class CustomRequestParams {
    * The body structure of the request. It requires passing in the string-escaped result of the JSON format HTTP request body.
    * For example:
    * ```
-   * "request":{
-   *   "content":"{\"input\":${input}}"
-   * }
+   * "request": "{\"input\":${input}}"
    * ```
    * > info
    * > The content string needs to be a single line except using the Kibana console.
@@ -810,18 +808,6 @@ export class CustomRequestParams {
 }
 
 export class CustomResponseParams {
-  /**
-   * Specifies the path to the error message in the response from the custom service.
-   * For example:
-   * ```
-   * "response": {
-   *   "error_parser": {
-   *     "path": "$.error.message"
-   *   }
-   * }
-   * ```
-   */
-  error_parser: UserDefinedValue
   /**
    * Specifies the JSON parser that is used to parse the response from the custom service.
    * Different task types require different json_parser parameters.
diff --git a/specification/inference/put_custom/PutCustomRequest.ts b/specification/inference/put_custom/PutCustomRequest.ts
index fab798391a..8c19e2a72c 100644
--- a/specification/inference/put_custom/PutCustomRequest.ts
+++ b/specification/inference/put_custom/PutCustomRequest.ts
@@ -30,7 +30,8 @@ import { InferenceChunkingSettings } from '@inference/_types/Services'
 /**
  * Create a custom inference endpoint.
  *
- * You can create an inference endpoint to perform an inference task with a custom model that supports the HTTP format.
+ * The custom service gives more control over how to interact with external inference services that aren't explicitly supported through dedicated integrations.
+ * The custom service gives you the ability to define the headers, url, query parameters, request body, and secrets.
  * @rest_spec_name inference.put_custom
  * @availability stack since=8.13.0 stability=stable visibility=public
  * @availability serverless stability=stable visibility=public

From 9dfe0ef20b38dc11304facb8e1c77d4f11a144f1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Istv=C3=A1n=20Zolt=C3=A1n=20Szab=C3=B3?=
 <szabosteve@gmail.com>
Date: Mon, 21 Jul 2025 12:28:19 +0200
Subject: [PATCH 13/17] Adds more parameters and explanations.

---
 specification/inference/_types/CommonTypes.ts | 11 ++++++
 .../inference/put_custom/PutCustomRequest.ts  | 38 +++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/specification/inference/_types/CommonTypes.ts b/specification/inference/_types/CommonTypes.ts
index 867cfbb243..1cee460070 100644
--- a/specification/inference/_types/CommonTypes.ts
+++ b/specification/inference/_types/CommonTypes.ts
@@ -770,6 +770,17 @@ export class CustomServiceSettings {
    * ```
    */
   headers?: UserDefinedValue
+  /**
+   * Specifies the query parameters as a list of tuples. The arrays inside the `query_parameters` must have two items, a key and a value.
+   * For example:
+   * ```
+   * "query_parameters":[
+   *   ["param_key", "some_value"],
+   *   ["param_key", "another_value"]
+   * ]
+   * ```
+   */
+  query_parameters?: UserDefinedValue
   /**
    * The request configuration object.
    */
diff --git a/specification/inference/put_custom/PutCustomRequest.ts b/specification/inference/put_custom/PutCustomRequest.ts
index 8c19e2a72c..50dd302802 100644
--- a/specification/inference/put_custom/PutCustomRequest.ts
+++ b/specification/inference/put_custom/PutCustomRequest.ts
@@ -32,6 +32,44 @@ import { InferenceChunkingSettings } from '@inference/_types/Services'
  *
  * The custom service gives more control over how to interact with external inference services that aren't explicitly supported through dedicated integrations.
  * The custom service gives you the ability to define the headers, url, query parameters, request body, and secrets.
+ * The custom service supports the template replacement functionality, which enables you to define a template that can be replaced with the contents of a value that defines that key.
+ * Templates are portions of a string that start with `${` and end with `}`.
+ * The parameters `secret_parameters` and `task_settings` are checked for keys for template replacement. Template replacement is supported in the `request`, `headers`, `url`, and `query_parameters`.
+ * If the definition (key) is not found for a template, an error message is returned.
+ * In case of an endpoint definition like the following:
+ * ```
+ * PUT _inference/text_embedding/test-text-embedding
+ * {
+ *   "service": "custom",
+ *   "service_settings": {
+ *      "secret_parameters": {
+ *           "api_key": "<some api key>"
+ *      },
+ *      "url": "...endpoints.huggingface.cloud/v1/embeddings",
+ *      "headers": {
+ *          "Authorization": "Bearer ${api_key}",
+ *          "Content-Type": "application/json"
+ *      },
+ *      "request": "{\"input\": ${input}}",
+ *      "response": {
+ *          "json_parser": {
+ *              "text_embeddings":"$.data[*].embedding[*]"
+ *          }
+ *      }
+ *   }
+ * }
+ * ```
+ * To replace `${api_key}` the `secret_parameters` and `task_settings` are checked for a key named `api_key`.
+ * 
+ * > info
+ * > Templates should not be surrounded by quotes.
+ * 
+ * Pre-defined templates:
+ * * `${input}` refers to the array of input strings that comes from the `input` field of the subsequent inference requests.
+ * * `${input_type}` refers to the input type translation values.
+ * * `${query}` refers to the query field used specifically for reranking tasks.
+ * * `${top_n}` refers to the `top_n` field available when performing rerank requests.
+ * * `${return_documents}` refers to the `return_documents` field available when performing rerank requests.
  * @rest_spec_name inference.put_custom
  * @availability stack since=8.13.0 stability=stable visibility=public
  * @availability serverless stability=stable visibility=public

From 3961f12c7226074b00f3ee3a058e318bbedbe959 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Istv=C3=A1n=20Zolt=C3=A1n=20Szab=C3=B3?=
 <szabosteve@gmail.com>
Date: Mon, 21 Jul 2025 14:14:29 +0200
Subject: [PATCH 14/17] Completes json_parser.

---
 specification/inference/_types/CommonTypes.ts | 108 +++++++++++++++++-
 1 file changed, 104 insertions(+), 4 deletions(-)

diff --git a/specification/inference/_types/CommonTypes.ts b/specification/inference/_types/CommonTypes.ts
index 1cee460070..4b07424f53 100644
--- a/specification/inference/_types/CommonTypes.ts
+++ b/specification/inference/_types/CommonTypes.ts
@@ -825,21 +825,97 @@ export class CustomResponseParams {
    * For example:
    * ```
    * # text_embedding
+   * # For a response like this:
+   * 
+   * {
+   *  "object": "list",
+   *  "data": [
+   *      {
+   *        "object": "embedding",
+   *        "index": 0,
+   *        "embedding": [
+   *            0.014539449,
+   *            -0.015288644
+   *        ]
+   *      }
+   *  ],
+   *  "model": "text-embedding-ada-002-v2",
+   *  "usage": {
+   *      "prompt_tokens": 8,
+   *      "total_tokens": 8
+   *  }
+   * }
+   * 
+   * # the json_parser definition should look like this:
+   * 
    * "response":{
    *   "json_parser":{
-   *     "text_embeddings":"$.result.embeddings[*].embedding"
+   *     "text_embeddings":"$.data[*].embedding[*]"
    *   }
    * }
    *
    * # sparse_embedding
+   * # For a response like this:
+   * 
+   * {
+   *   "request_id": "75C50B5B-E79E-4930-****-F48DBB392231",
+   *   "latency": 22,
+   *   "usage": {
+   *      "token_count": 11
+   *   },
+   *   "result": {
+   *      "sparse_embeddings": [
+   *         {
+   *           "index": 0,
+   *           "embedding": [
+   *             {
+   *               "token_id": 6,
+   *               "weight": 0.101
+   *             },
+   *             {
+   *               "token_id": 163040,
+   *               "weight": 0.28417
+   *             }
+   *           ]
+   *         }
+   *      ]
+   *   }
+   * }
+   * 
+   * # the json_parser definition should look like this:
+   * 
    * "response":{
    *   "json_parser":{
-   *     "token_path":"$.result[*].embeddings[*].token",
-   *     "weight_path":"$.result[*].embeddings[*].weight"
+   *     "token_path":"$.result.sparse_embeddings[*].embedding[*].token_id",
+   *     "weight_path":"$.result.sparse_embeddings[*].embedding[*].weight"
    *   }
    * }
    *
    * # rerank
+   * # For a response like this:
+   * 
+   * {
+   *   "results": [
+   *     {
+   *       "index": 3,
+   *       "relevance_score": 0.999071,
+   *       "document": "abc"
+   *     },
+   *     {
+   *       "index": 4,
+   *       "relevance_score": 0.7867867,
+   *       "document": "123"
+   *     },
+   *     {
+   *       "index": 0,
+   *       "relevance_score": 0.32713068,
+   *       "document": "super"
+   *     }
+   *   ],
+   * }
+   * 
+   * # the json_parser definition should look like this: 
+   * 
    * "response":{
    *   "json_parser":{
    *     "reranked_index":"$.result.scores[*].index",    // optional
@@ -849,9 +925,33 @@ export class CustomResponseParams {
    * }
    *
    * # completion
+   * # For a response like this:
+   * 
+   * {
+   *  "id": "chatcmpl-B9MBs8CjcvOU2jLn4n570S5qMJKcT",
+   *  "object": "chat.completion",
+   *  "created": 1741569952,
+   *  "model": "gpt-4.1-2025-04-14",
+   *  "choices": [
+   *    {
+   *     "index": 0,
+   *     "message": {
+   *       "role": "assistant",
+   *       "content": "Hello! How can I assist you today?",
+   *       "refusal": null,
+   *       "annotations": []
+   *     },
+   *     "logprobs": null,
+   *     "finish_reason": "stop"
+   *   }
+   *  ]
+   * }
+   * 
+   * # the json_parser definition should look like this:
+   * 
    * "response":{
    *   "json_parser":{
-   *     "completion_result":"$.result.text"
+   *     "completion_result":"$.choices[*].message.content"
    *   }
    * }
    */

From a0baab6b32005ea6c8ead777485791314a00db24 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Istv=C3=A1n=20Zolt=C3=A1n=20Szab=C3=B3?=
 <szabosteve@gmail.com>
Date: Mon, 21 Jul 2025 14:51:33 +0200
Subject: [PATCH 15/17] Addresses feedback.

---
 specification/inference/_types/CommonTypes.ts | 21 +++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/specification/inference/_types/CommonTypes.ts b/specification/inference/_types/CommonTypes.ts
index 4b07424f53..e9525fa59f 100644
--- a/specification/inference/_types/CommonTypes.ts
+++ b/specification/inference/_types/CommonTypes.ts
@@ -770,6 +770,27 @@ export class CustomServiceSettings {
    * ```
    */
   headers?: UserDefinedValue
+  /**
+   * Specifies the input type translation values that are used to replace the `${input_type}` template in the request body.
+   * For example:
+   * ```
+   * "input_type": { 
+   *   "translation": { 
+   *     "ingest": "do_ingest", 
+   *     "search": "do_search" 
+   *   }, 
+   *   "default": "a_default" 
+   * },
+   * ```
+   * If the subsequent inference requests come from a search context, the `search` key will be used and the template will be replaced with `do_search`.
+   * If it comes from the ingest context `do_ingest` is used. If it's a different context that is not specified, the default value will be used. If no default is specified an empty string is used.
+   * `transition` can be:
+   * * `classification` 
+   * * `clustering` 
+   * * `ingest` 
+   * * `search`
+   */
+  input_type?: UserDefinedValue
   /**
    * Specifies the query parameters as a list of tuples. The arrays inside the `query_parameters` must have two items, a key and a value.
    * For example:

From d63c4d7329f8b3e5af5fe20e82b1bfee11918f86 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Istv=C3=A1n=20Zolt=C3=A1n=20Szab=C3=B3?=
 <szabosteve@gmail.com>
Date: Mon, 21 Jul 2025 14:52:37 +0200
Subject: [PATCH 16/17] Format fix.

---
 specification/inference/_types/CommonTypes.ts | 44 +++++++++----------
 .../inference/put_custom/PutCustomRequest.ts  |  4 +-
 2 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/specification/inference/_types/CommonTypes.ts b/specification/inference/_types/CommonTypes.ts
index e9525fa59f..215553bd0e 100644
--- a/specification/inference/_types/CommonTypes.ts
+++ b/specification/inference/_types/CommonTypes.ts
@@ -774,20 +774,20 @@ export class CustomServiceSettings {
    * Specifies the input type translation values that are used to replace the `${input_type}` template in the request body.
    * For example:
    * ```
-   * "input_type": { 
-   *   "translation": { 
-   *     "ingest": "do_ingest", 
-   *     "search": "do_search" 
-   *   }, 
-   *   "default": "a_default" 
+   * "input_type": {
+   *   "translation": {
+   *     "ingest": "do_ingest",
+   *     "search": "do_search"
+   *   },
+   *   "default": "a_default"
    * },
    * ```
    * If the subsequent inference requests come from a search context, the `search` key will be used and the template will be replaced with `do_search`.
    * If it comes from the ingest context `do_ingest` is used. If it's a different context that is not specified, the default value will be used. If no default is specified an empty string is used.
    * `transition` can be:
-   * * `classification` 
-   * * `clustering` 
-   * * `ingest` 
+   * * `classification`
+   * * `clustering`
+   * * `ingest`
    * * `search`
    */
   input_type?: UserDefinedValue
@@ -847,7 +847,7 @@ export class CustomResponseParams {
    * ```
    * # text_embedding
    * # For a response like this:
-   * 
+   *
    * {
    *  "object": "list",
    *  "data": [
@@ -866,9 +866,9 @@ export class CustomResponseParams {
    *      "total_tokens": 8
    *  }
    * }
-   * 
+   *
    * # the json_parser definition should look like this:
-   * 
+   *
    * "response":{
    *   "json_parser":{
    *     "text_embeddings":"$.data[*].embedding[*]"
@@ -877,7 +877,7 @@ export class CustomResponseParams {
    *
    * # sparse_embedding
    * # For a response like this:
-   * 
+   *
    * {
    *   "request_id": "75C50B5B-E79E-4930-****-F48DBB392231",
    *   "latency": 22,
@@ -902,9 +902,9 @@ export class CustomResponseParams {
    *      ]
    *   }
    * }
-   * 
+   *
    * # the json_parser definition should look like this:
-   * 
+   *
    * "response":{
    *   "json_parser":{
    *     "token_path":"$.result.sparse_embeddings[*].embedding[*].token_id",
@@ -914,7 +914,7 @@ export class CustomResponseParams {
    *
    * # rerank
    * # For a response like this:
-   * 
+   *
    * {
    *   "results": [
    *     {
@@ -934,9 +934,9 @@ export class CustomResponseParams {
    *     }
    *   ],
    * }
-   * 
-   * # the json_parser definition should look like this: 
-   * 
+   *
+   * # the json_parser definition should look like this:
+   *
    * "response":{
    *   "json_parser":{
    *     "reranked_index":"$.result.scores[*].index",    // optional
@@ -947,7 +947,7 @@ export class CustomResponseParams {
    *
    * # completion
    * # For a response like this:
-   * 
+   *
    * {
    *  "id": "chatcmpl-B9MBs8CjcvOU2jLn4n570S5qMJKcT",
    *  "object": "chat.completion",
@@ -967,9 +967,9 @@ export class CustomResponseParams {
    *   }
    *  ]
    * }
-   * 
+   *
    * # the json_parser definition should look like this:
-   * 
+   *
    * "response":{
    *   "json_parser":{
    *     "completion_result":"$.choices[*].message.content"
diff --git a/specification/inference/put_custom/PutCustomRequest.ts b/specification/inference/put_custom/PutCustomRequest.ts
index 50dd302802..80f7038fe1 100644
--- a/specification/inference/put_custom/PutCustomRequest.ts
+++ b/specification/inference/put_custom/PutCustomRequest.ts
@@ -60,10 +60,10 @@ import { InferenceChunkingSettings } from '@inference/_types/Services'
  * }
  * ```
  * To replace `${api_key}` the `secret_parameters` and `task_settings` are checked for a key named `api_key`.
- * 
+ *
  * > info
  * > Templates should not be surrounded by quotes.
- * 
+ *
  * Pre-defined templates:
  * * `${input}` refers to the array of input strings that comes from the `input` field of the subsequent inference requests.
  * * `${input_type}` refers to the input type translation values.

From 52c19aa3437ddf26b82b1512da38fe073aa088de Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Istv=C3=A1n=20Zolt=C3=A1n=20Szab=C3=B3?=
 <szabosteve@gmail.com>
Date: Mon, 21 Jul 2025 17:15:22 +0200
Subject: [PATCH 17/17] Addresses more feedback.

---
 specification/inference/_types/CommonTypes.ts          | 8 +++++---
 specification/inference/put_custom/PutCustomRequest.ts | 2 +-
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/specification/inference/_types/CommonTypes.ts b/specification/inference/_types/CommonTypes.ts
index f533423f4b..4941cb9210 100644
--- a/specification/inference/_types/CommonTypes.ts
+++ b/specification/inference/_types/CommonTypes.ts
@@ -782,7 +782,7 @@ export class CustomServiceSettings {
    * ```
    * If the subsequent inference requests come from a search context, the `search` key will be used and the template will be replaced with `do_search`.
    * If it comes from the ingest context `do_ingest` is used. If it's a different context that is not specified, the default value will be used. If no default is specified an empty string is used.
-   * `transition` can be:
+   * `translation` can be:
    * * `classification`
    * * `clustering`
    * * `ingest`
@@ -795,9 +795,11 @@ export class CustomServiceSettings {
    * ```
    * "query_parameters":[
    *   ["param_key", "some_value"],
-   *   ["param_key", "another_value"]
+   *   ["param_key", "another_value"],
+   *   ["other_key", "other_value"]
    * ]
    * ```
+   * If the base url is `https://www.elastic.co` it results in: `https://www.elastic.co?param_key=some_value&param_key=another_value&other_key=other_value`.
    */
   query_parameters?: UserDefinedValue
   /**
@@ -832,7 +834,7 @@ export class CustomRequestParams {
    * "request": "{\"input\":${input}}"
    * ```
    * > info
-   * > The content string needs to be a single line except using the Kibana console.
+   * > The content string needs to be a single line except when using the Kibana console.
    */
   content: string
 }
diff --git a/specification/inference/put_custom/PutCustomRequest.ts b/specification/inference/put_custom/PutCustomRequest.ts
index 80f7038fe1..04d1e056a8 100644
--- a/specification/inference/put_custom/PutCustomRequest.ts
+++ b/specification/inference/put_custom/PutCustomRequest.ts
@@ -32,7 +32,7 @@ import { InferenceChunkingSettings } from '@inference/_types/Services'
  *
  * The custom service gives more control over how to interact with external inference services that aren't explicitly supported through dedicated integrations.
  * The custom service gives you the ability to define the headers, url, query parameters, request body, and secrets.
- * The custom service supports the template replacement functionality, which enables you to define a template that can be replaced with the contents of a value that defines that key.
+ * The custom service supports the template replacement functionality, which enables you to define a template that can be replaced with the value associated with that key.
  * Templates are portions of a string that start with `${` and end with `}`.
  * The parameters `secret_parameters` and `task_settings` are checked for keys for template replacement. Template replacement is supported in the `request`, `headers`, `url`, and `query_parameters`.
  * If the definition (key) is not found for a template, an error message is returned.