diff --git a/spec/namespaces/_core.yaml b/spec/namespaces/_core.yaml
index 0ef3a16a6..0089f7be4 100644
--- a/spec/namespaces/_core.yaml
+++ b/spec/namespaces/_core.yaml
@@ -1264,6 +1264,8 @@ paths:
       responses:
         '200':
           $ref: '#/components/responses/get@200'
+        '404':
+          $ref: '#/components/responses/get@200'
     head:
       operationId: exists.0
       x-operation-group: exists
@@ -1364,6 +1366,8 @@ paths:
       responses:
         '200':
           $ref: '#/components/responses/delete@200'
+        '404':
+          $ref: '#/components/responses/delete@200'
   /{index}/_explain/{id}:
     get:
       operationId: explain.0
diff --git a/spec/namespaces/indices.yaml b/spec/namespaces/indices.yaml
index dcd758619..ad4a4c8dd 100644
--- a/spec/namespaces/indices.yaml
+++ b/spec/namespaces/indices.yaml
@@ -1044,6 +1044,8 @@ paths:
       responses:
         '200':
           $ref: '#/components/responses/indices.delete@200'
+        '404':
+          $ref: '#/components/responses/indices.delete@404'
   /{index}/_alias:
     get:
       operationId: indices.get_alias.2
@@ -2400,6 +2402,11 @@ components:
         application/json:
           schema:
             $ref: '../schemas/_common.yaml#/components/schemas/IndicesResponseBase'
+    indices.delete@404:
+      content:
+        application/json:
+          schema:
+            $ref: '../schemas/indices._common.yaml#/components/schemas/IndexErrorCause'
     indices.delete_alias@200:
       content:
         application/json:
diff --git a/spec/schemas/_common.yaml b/spec/schemas/_common.yaml
index 889c8b014..e2105f8df 100644
--- a/spec/schemas/_common.yaml
+++ b/spec/schemas/_common.yaml
@@ -2238,3 +2238,7 @@ components:
       required:
         - reason
         - status
+    ResourceType:
+      type: string
+      enum:
+        - index_or_alias
diff --git a/spec/schemas/indices._common.yaml b/spec/schemas/indices._common.yaml
index 90d6776d6..6d5ec90bb 100644
--- a/spec/schemas/indices._common.yaml
+++ b/spec/schemas/indices._common.yaml
@@ -1010,3 +1010,29 @@ components:
         - mappings
         - order
         - settings
+    IndexErrorCause:
+      type: object
+      properties:
+        type:
+          description: The type of error
+          type: string
+        reason:
+          description: A human-readable explanation of the error, in english
+          type: string
+        root_cause:
+          type: array
+          items:
+            $ref: '#/components/schemas/IndexErrorCause'
+        index:
+          $ref: '_common.yaml#/components/schemas/IndexName'
+        index_uuid:
+          $ref: '_common.yaml#/components/schemas/Uuid'
+        resource.id:
+          $ref: '_common.yaml#/components/schemas/IndexName'
+        resource.type:
+          $ref: '_common.yaml#/components/schemas/ResourceType'
+      required:
+        - type
+      additionalProperties:
+        title: metadata
+        description: Additional details about the error.
diff --git a/tests/default/indices/doc.yaml b/tests/default/indices/doc.yaml
index 6eb5a8a5d..cffe8ff21 100644
--- a/tests/default/indices/doc.yaml
+++ b/tests/default/indices/doc.yaml
@@ -57,3 +57,19 @@ chapters:
       id: '1'
     response:
       status: 200
+  - synopsis: Retrieve a non existing document.
+    path: /{index}/_doc/{id}
+    method: GET
+    parameters:
+      index: movies
+      id: '1'
+    response:
+      status: 404
+  - synopsis: Delete a non existing document.
+    path: /{index}/_doc/{id}
+    method: DELETE
+    parameters:
+      index: movies
+      id: '1'
+    response:
+      status: 404
diff --git a/tests/default/indices/index.yaml b/tests/default/indices/index.yaml
index 4b34c8937..1564db477 100644
--- a/tests/default/indices/index.yaml
+++ b/tests/default/indices/index.yaml
@@ -84,4 +84,12 @@ chapters:
     version: '>= 2.0'
     parameters:
       index: books,games
-      cluster_manager_timeout: 10s     
+      cluster_manager_timeout: 10s
+
+  - synopsis: Delete non existing index `movies`.
+    path: /{index}
+    method: DELETE
+    parameters:
+      index: movies
+    response:
+      status: 404