diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8bb8bbfd2..361b4f8c1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -54,13 +54,14 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Added `plugins` to NodeInfoSettings ([#442](https://github.com/opensearch-project/opensearch-api-specification/pull/442)) 
 - Added test coverage ([#443](https://github.com/opensearch-project/opensearch-api-specification/pull/443))
 - Added `--opensearch-version` to `merger` that excludes schema elements per semver ([#428](https://github.com/opensearch-project/opensearch-api-specification/pull/428))
-- Added `retry` to `tester` to support asynchronous tasks ([453](https://github.com/opensearch-project/opensearch-api-specification/pull/453))
+- Added `retry` to `tester` to support asynchronous tasks ([#453](https://github.com/opensearch-project/opensearch-api-specification/pull/453))
 - Added passing OPENSEARCH_JAVA_OPTS into the docker container used for tests ([#454](https://github.com/opensearch-project/opensearch-api-specification/pull/454))
 - Added a warning on mulitple paths being tested in the same file ([#452](https://github.com/opensearch-project/opensearch-api-specification/pull/452))
 - Added validation of titles and descriptions in info and schema objects ([#463](https://github.com/opensearch-project/opensearch-api-specification/pull/463))
 - Added `/_plugins/_query/settings` ([#456](https://github.com/opensearch-project/opensearch-api-specification/pull/456))
 - Added `/_plugins/_ppl`, `explain` and `stats` ([#460](https://github.com/opensearch-project/opensearch-api-specification/pull/460))
 - Added tests against OpenSearch 3.0 ([#459](https://github.com/opensearch-project/opensearch-api-specification/pull/459))
+- Added support for request headers in tests [#461](https://github.com/opensearch-project/opensearch-api-specification/pull/461)
 
 ### Changed
 
diff --git a/TESTING_GUIDE.md b/TESTING_GUIDE.md
index 948ce228f..31323efcf 100644
--- a/TESTING_GUIDE.md
+++ b/TESTING_GUIDE.md
@@ -75,10 +75,12 @@ chapters:
   - synopsis: Create an index named `books` with mappings and settings.
     path: /{index} # The test will fail if "PUT /{index}" operation is not found in the spec.
     method: PUT
-    parameters: # All parameters are validated against their schemas in the spec
+    parameters: # All parameters are validated against their schemas in the spec.
       index: books
-    request_body: # The request body is validated against the schema of the requestBody in the spec
-      payload:
+    request: # The request.
+      headers: # Optional headers.
+        user-agent: OpenSearch API Spec/1.0
+      payload: # The request body is validated against the schema of the requestBody in the spec.
         mappings:
           properties:
             name:
@@ -88,7 +90,8 @@ chapters:
         settings:
           number_of_shards: 5
           number_of_replicas: 2
-    response: # The response body is validated against the schema of the corresponding response in the spec
+    response: # The response.
+      payload: # Matching response payload. The entire payload is validated against the schema of the corresponding response in the spec.
       status: 200 # This is the expected status code of the response. Any other status code will fail the test.
 
   - synopsis: Retrieve the mappings and settings of the `books` index.
@@ -113,7 +116,7 @@ Consider the following chapters in [ml/model_groups](tests/ml/model_groups.yaml)
     id: create_model_group # Only needed if you want to refer to this chapter in another chapter.
     path: /_plugins/_ml/model_groups/_register
     method: POST
-    request_body:
+    request:
       payload:
         name: NLP_Group
         description: Model group for NLP models.
diff --git a/json_schemas/test_story.schema.yaml b/json_schemas/test_story.schema.yaml
index d0b09e5ce..829eb5286 100644
--- a/json_schemas/test_story.schema.yaml
+++ b/json_schemas/test_story.schema.yaml
@@ -77,8 +77,8 @@ definitions:
         type: object
         additionalProperties:
           $ref: '#/definitions/Parameter'
-      request_body:
-        $ref: '#/definitions/RequestBody'
+      request:
+        $ref: '#/definitions/Request'
       output:
         $ref: '#/definitions/Output'
       version:
@@ -119,15 +119,18 @@ definitions:
         required:
           - count
 
-  RequestBody:
+  Request:
     type: object
     properties:
       content_type:
         type: string
         default: application/json
+      headers:
+        type: object
+        additionalProperties:
+          $ref: '#/definitions/Header'
       payload:
         $ref: '#/definitions/Payload'
-    required: [payload]
     additionalProperties: false
 
   ExpectedResponse:
@@ -163,6 +166,12 @@ definitions:
     required: [content_type, payload, status]
     additionalProperties: false
 
+  Header:
+    anyOf:
+      - type: string
+      - type: number
+      - type: boolean
+
   Payload:
     anyOf:
       - type: object
diff --git a/package.json b/package.json
index 04e7116e4..d73f0868d 100644
--- a/package.json
+++ b/package.json
@@ -7,6 +7,7 @@
   "scripts": {
     "coverage:spec": "ts-node tools/src/coverage/coverage.ts",
     "dump-cluster-spec": "ts-node tools/src/dump-cluster-spec/dump-cluster-spec.ts",
+    "generate-types": "ts-node tools/src/tester/_generate_story_types.ts",
     "lint:spec": "ts-node tools/src/linter/lint.ts",
     "lint": "eslint . --report-unused-disable-directives",
     "lint--fix": "eslint . --fix --report-unused-disable-directives",
diff --git a/tests/_core/bulk.yaml b/tests/_core/bulk.yaml
index c480b926e..abcbb438f 100644
--- a/tests/_core/bulk.yaml
+++ b/tests/_core/bulk.yaml
@@ -9,7 +9,7 @@ chapters:
   - synopsis: Create an index.
     path: /_bulk
     method: POST
-    request_body:
+    request:
       content_type: application/x-ndjson
       payload:
         - {create: {_index: movies}}
@@ -17,7 +17,7 @@ chapters:
   - synopsis: Bulk document CRUD.
     path: /_bulk
     method: POST
-    request_body:
+    request:
       content_type: application/x-ndjson
       payload:
         - {create: {_index: books, _id: book_1392214}}
diff --git a/tests/_core/mapping.yaml b/tests/_core/mapping.yaml
index 99973978f..936cf021e 100644
--- a/tests/_core/mapping.yaml
+++ b/tests/_core/mapping.yaml
@@ -6,7 +6,7 @@ prologues:
     method: PUT
     parameters:
       index: movies
-    request_body:
+    request:
       payload:
         mappings:
           properties:
diff --git a/tests/_core/reindex.yaml b/tests/_core/reindex.yaml
index 1cf82fde1..2b349d341 100644
--- a/tests/_core/reindex.yaml
+++ b/tests/_core/reindex.yaml
@@ -17,7 +17,7 @@ prologues:
     parameters:
       index: movies
       refresh: true
-    request_body:
+    request:
       payload:
         title: Beauty and the Beast
         year: 91
@@ -26,7 +26,7 @@ chapters:
   - synopsis: Reindex from movies to films.
     path: /_reindex
     method: POST
-    request_body:
+    request:
       payload:
         source:
           index: movies
@@ -39,7 +39,7 @@ chapters:
   - synopsis: Reindex a subset of documents (match).
     path: /_reindex
     method: POST
-    request_body:
+    request:
       payload:
         source:
           index: movies
@@ -55,7 +55,7 @@ chapters:
   - synopsis: Reindex a subset of documents (no match).
     path: /_reindex
     method: POST
-    request_body:
+    request:
       payload:
         source:
           index: movies
@@ -71,7 +71,7 @@ chapters:
   - synopsis: Combine two indexes.
     path: /_reindex
     method: POST
-    request_body:
+    request:
       payload:
         source:
           index:
@@ -86,7 +86,7 @@ chapters:
   - synopsis: Reindex only unique documents.
     path: /_reindex
     method: POST
-    request_body:
+    request:
       payload:
         conflicts: proceed
         source:
@@ -101,7 +101,7 @@ chapters:
   - synopsis: Transform documents during reindex.
     path: /_reindex
     method: POST
-    request_body:
+    request:
       payload:
         source:
           index: movies
@@ -120,7 +120,7 @@ chapters:
     parameters:
       max_docs: 1
       slices: 1
-    request_body:
+    request:
       payload:
         source:
           index: movies
diff --git a/tests/_core/reindex/pipeline.yaml b/tests/_core/reindex/pipeline.yaml
index f8e263ae7..fbb6e1065 100644
--- a/tests/_core/reindex/pipeline.yaml
+++ b/tests/_core/reindex/pipeline.yaml
@@ -14,7 +14,7 @@ epilogues:
 prologues:
   - path: /_ingest/pipeline/transform-and-count
     method: PUT
-    request_body:
+    request:
       payload:
         description: |
           Splits the `title`` field into a `words` list.
@@ -35,7 +35,7 @@ prologues:
     parameters:
       index: movies
       refresh: true
-    request_body:
+    request:
       payload:
         title: Beauty and the Beast
         year: 91
@@ -44,7 +44,7 @@ chapters:
   - synopsis: Transform documents using a pipeline.
     path: /_reindex
     method: POST
-    request_body:
+    request:
       payload:
         source:
           index: movies
@@ -67,7 +67,7 @@ chapters:
     method: POST
     parameters:
       index: videos
-    request_body:
+    request:
       payload:
         query:
           match_all: {}
diff --git a/tests/_core/search/_source.yaml b/tests/_core/search/_source.yaml
index 973eb3585..de34a143b 100644
--- a/tests/_core/search/_source.yaml
+++ b/tests/_core/search/_source.yaml
@@ -6,7 +6,7 @@ prologues:
     method: POST
     parameters:
       refresh: true
-    request_body:
+    request:
       payload:
         director: Bennett Miller
         title: Moneyball
@@ -22,7 +22,7 @@ chapters:
     parameters:
       index: movies
     method: POST
-    request_body:
+    request:
       payload:
         _source: true
         query:
@@ -48,7 +48,7 @@ chapters:
     parameters:
       index: movies
     method: POST
-    request_body:
+    request:
       payload:
         _source: false
         query:
@@ -70,7 +70,7 @@ chapters:
     parameters:
       index: movies
     method: POST
-    request_body:
+    request:
       payload:
         _source:
           - director
@@ -97,7 +97,7 @@ chapters:
     parameters:
       index: movies
     method: POST
-    request_body:
+    request:
       payload:
         _source:
           includes: director
@@ -123,7 +123,7 @@ chapters:
     parameters:
       index: movies
     method: POST
-    request_body:
+    request:
       payload:
         _source:
           includes: '*'
diff --git a/tests/_core/search/cancel_after_time_interval.yaml b/tests/_core/search/cancel_after_time_interval.yaml
index 012a7972e..b5bd3b510 100644
--- a/tests/_core/search/cancel_after_time_interval.yaml
+++ b/tests/_core/search/cancel_after_time_interval.yaml
@@ -6,7 +6,7 @@ prologues:
     method: POST
     parameters:
       refresh: true
-    request_body:
+    request:
       payload:
         director: Bennett Miller
         title: Moneyball
diff --git a/tests/_core/search/geo_distance.yaml b/tests/_core/search/geo_distance.yaml
index 8ce5712d0..844df33c2 100644
--- a/tests/_core/search/geo_distance.yaml
+++ b/tests/_core/search/geo_distance.yaml
@@ -4,7 +4,7 @@ description: Test search endpoint with geo_distance query.
 prologues:
   - path: /map
     method: PUT
-    request_body:
+    request:
       payload:
         mappings:
           properties:
@@ -14,7 +14,7 @@ prologues:
     method: POST
     parameters:
       refresh: true
-    request_body:
+    request:
       payload:
         field: 
           lat: 74
@@ -30,7 +30,7 @@ chapters:
     parameters:
       index: map
     method: GET
-    request_body:
+    request:
       payload:
         query:
           geo_distance:
diff --git a/tests/_core/search/match.yaml b/tests/_core/search/match.yaml
index 78afe3ddf..2766f3ac1 100644
--- a/tests/_core/search/match.yaml
+++ b/tests/_core/search/match.yaml
@@ -6,7 +6,7 @@ prologues:
     method: POST
     parameters:
       refresh: true
-    request_body:
+    request:
       payload:
         director: Bennett Miller
         title: Moneyball
@@ -22,7 +22,7 @@ chapters:
     parameters:
       index: movies
     method: POST
-    request_body:
+    request:
       payload:
         size: 1
         query:
@@ -34,7 +34,7 @@ chapters:
     parameters:
       index: movies
     method: POST
-    request_body:
+    request:
       payload:
         size: 1
         query:
diff --git a/tests/_core/search/multi_match.yaml b/tests/_core/search/multi_match.yaml
index 4ea41f74a..b5c7b3c76 100644
--- a/tests/_core/search/multi_match.yaml
+++ b/tests/_core/search/multi_match.yaml
@@ -6,7 +6,7 @@ prologues:
     method: POST
     parameters:
       refresh: true
-    request_body:
+    request:
       payload:
         director: Bennett Miller
         title: Moneyball
@@ -22,7 +22,7 @@ chapters:
     parameters:
       index: movies
     method: POST
-    request_body:
+    request:
       payload:
         size: 1
         query:
diff --git a/tests/_core/search/phase_took.yaml b/tests/_core/search/phase_took.yaml
index 846d0fe86..3e061ae0f 100644
--- a/tests/_core/search/phase_took.yaml
+++ b/tests/_core/search/phase_took.yaml
@@ -6,7 +6,7 @@ prologues:
     method: POST
     parameters:
       refresh: true
-    request_body:
+    request:
       payload:
         director: Bennett Miller
         title: Moneyball
diff --git a/tests/_core/search/seq_no_primary_term.yaml b/tests/_core/search/seq_no_primary_term.yaml
index 07b0d5834..8082de549 100644
--- a/tests/_core/search/seq_no_primary_term.yaml
+++ b/tests/_core/search/seq_no_primary_term.yaml
@@ -6,7 +6,7 @@ prologues:
     method: POST
     parameters:
       refresh: true
-    request_body:
+    request:
       payload:
         director: Bennett Miller
         title: Moneyball
diff --git a/tests/_core/search/size.yaml b/tests/_core/search/size.yaml
index 154f34638..64b2b8ca9 100644
--- a/tests/_core/search/size.yaml
+++ b/tests/_core/search/size.yaml
@@ -6,7 +6,7 @@ prologues:
     method: POST
     parameters:
       refresh: true
-    request_body:
+    request:
       payload:
         director: Bennett Miller
         title: Moneyball
@@ -22,7 +22,7 @@ chapters:
     parameters:
       index: movies
     method: POST
-    request_body:
+    request:
       payload:
         size: 0
     response:
@@ -40,7 +40,7 @@ chapters:
     parameters:
       index: movies
     method: POST
-    request_body:
+    request:
       payload:
         size: 1
         query:
diff --git a/tests/cat/indices.yaml b/tests/cat/indices.yaml
index 90c7d81b5..c8d3fcb42 100644
--- a/tests/cat/indices.yaml
+++ b/tests/cat/indices.yaml
@@ -6,7 +6,7 @@ prologues:
     method: PUT
     parameters:
       index: books
-    request_body:
+    request:
       payload: {}
 epilogues:
   - path: /books
diff --git a/tests/cat/pit_segments/all.yaml b/tests/cat/pit_segments/all.yaml
index 5b8a1f9ff..91b4ccdd1 100644
--- a/tests/cat/pit_segments/all.yaml
+++ b/tests/cat/pit_segments/all.yaml
@@ -11,7 +11,7 @@ prologues:
     method: POST
     parameters:
       refresh: true
-    request_body:
+    request:
       payload:
         title: Monopoly
     status: [201]
diff --git a/tests/cat/pit_segments/pit_segments.yaml b/tests/cat/pit_segments/pit_segments.yaml
index 172988830..21ea56af0 100644
--- a/tests/cat/pit_segments/pit_segments.yaml
+++ b/tests/cat/pit_segments/pit_segments.yaml
@@ -11,7 +11,7 @@ prologues:
     method: POST
     parameters:
       refresh: true
-    request_body:
+    request:
       payload:
         title: Monopoly
     status: [201]
@@ -30,7 +30,7 @@ chapters:
     method: GET
     parameters:
       format: json
-    request_body:
+    request:
       payload:
         pit_id:
           - ${create_pit.pit_id}
diff --git a/tests/cat/repositories.yaml b/tests/cat/repositories.yaml
index 80222e5ba..72cd80dce 100644
--- a/tests/cat/repositories.yaml
+++ b/tests/cat/repositories.yaml
@@ -12,7 +12,7 @@ prologues:
     method: PUT
     parameters:
       repository: my-fs-repository
-    request_body:
+    request:
       payload:
         type: fs
         settings:
diff --git a/tests/cat/snapshots.yaml b/tests/cat/snapshots.yaml
index 1163c5db5..962827112 100644
--- a/tests/cat/snapshots.yaml
+++ b/tests/cat/snapshots.yaml
@@ -8,7 +8,7 @@ epilogues:
 prologues:
   - path: /_snapshot/my-fs-repository
     method: PUT
-    request_body:
+    request:
       payload:
         type: fs
         settings:
diff --git a/tests/cat/templates.yaml b/tests/cat/templates.yaml
index b72262fe7..3f233a76b 100644
--- a/tests/cat/templates.yaml
+++ b/tests/cat/templates.yaml
@@ -8,7 +8,7 @@ epilogues:
 prologues:
   - path: /_index_template/daily_logs
     method: PUT
-    request_body:
+    request:
       payload:
         index_patterns:
           - 'logs*'
diff --git a/tests/cluster/component_template.yaml b/tests/cluster/component_template.yaml
index 05838d5db..783393591 100644
--- a/tests/cluster/component_template.yaml
+++ b/tests/cluster/component_template.yaml
@@ -11,7 +11,7 @@ chapters:
     method: POST
     parameters:
       name: template1
-    request_body:
+    request:
       payload:
         template:
           settings:
@@ -31,7 +31,7 @@ chapters:
     method: PUT
     parameters:
       name: template1
-    request_body:
+    request:
       payload:
         template:
           settings:
diff --git a/tests/indices/alias/alias.yaml b/tests/indices/alias/alias.yaml
index 5bd41501c..09962aff6 100644
--- a/tests/indices/alias/alias.yaml
+++ b/tests/indices/alias/alias.yaml
@@ -48,7 +48,7 @@ chapters:
     parameters:
       index: games
       name: jeux
-    request_body:
+    request:
       payload:
         index_routing: test1
         search_routing: test2
@@ -63,6 +63,6 @@ chapters:
     parameters:
       index: games
       name: jeux
-    request_body:
+    request:
       payload:
         is_hidden: true
diff --git a/tests/indices/aliases/aliases.yaml b/tests/indices/aliases/aliases.yaml
index a1bc2baac..22bcd95f1 100644
--- a/tests/indices/aliases/aliases.yaml
+++ b/tests/indices/aliases/aliases.yaml
@@ -18,7 +18,7 @@ chapters:
   - synopsis: Multiple alias operations.
     path: /_aliases
     method: POST
-    request_body:
+    request:
       payload:
         actions:
           - remove:
diff --git a/tests/indices/aliases/put_alias.yaml b/tests/indices/aliases/put_alias.yaml
index 7dd73fe9c..ea65d3c53 100644
--- a/tests/indices/aliases/put_alias.yaml
+++ b/tests/indices/aliases/put_alias.yaml
@@ -30,7 +30,7 @@ chapters:
     method: PUT
     parameters:
       index: test_index
-    request_body:
+    request:
       payload:
         alias: test_alias_1
     response:
@@ -43,7 +43,7 @@ chapters:
     method: PUT
     parameters:
       name: test_alias_2
-    request_body:
+    request:
       payload:
         index: test_index
     response:
@@ -54,7 +54,7 @@ chapters:
   - synopsis: Create an alias - specifying index & alias in body.
     path: /_alias
     method: PUT
-    request_body:
+    request:
       payload:
         index: test_index
         alias: test_alias_3
diff --git a/tests/indices/clone.yaml b/tests/indices/clone.yaml
index f3132ec78..dfc56119c 100644
--- a/tests/indices/clone.yaml
+++ b/tests/indices/clone.yaml
@@ -6,7 +6,7 @@ prologues:
     method: PUT
   - path: /movies/_settings
     method: PUT
-    request_body:
+    request:
       payload:
         settings:
           index.blocks.write: true
diff --git a/tests/indices/component_template.yaml b/tests/indices/component_template.yaml
index c77477f0c..d05b88f4c 100644
--- a/tests/indices/component_template.yaml
+++ b/tests/indices/component_template.yaml
@@ -20,7 +20,7 @@ chapters:
     method: POST
     parameters:
       name: component_template_1
-    request_body:
+    request:
       payload:
         template:
           mappings:
@@ -41,7 +41,7 @@ chapters:
     method: POST
     parameters:
       name: component_template_2
-    request_body:
+    request:
       payload:
         template:
           mappings:
@@ -57,7 +57,7 @@ chapters:
     method: POST
     parameters:
       name: daily_logs
-    request_body:
+    request:
       payload:
         index_patterns:
           - 'logs*'
diff --git a/tests/indices/data_stream/data_stream.yaml b/tests/indices/data_stream/data_stream.yaml
index d4b7952b2..051451286 100644
--- a/tests/indices/data_stream/data_stream.yaml
+++ b/tests/indices/data_stream/data_stream.yaml
@@ -4,7 +4,7 @@ description: Test data streams.
 prologues:
   - path: /_index_template/logs-template-nginx
     method: PUT
-    request_body:
+    request:
       payload:
         index_patterns:
           - logs-*
@@ -33,7 +33,7 @@ chapters:
     method: POST
     parameters:
       index: logs-nginx
-    request_body:
+    request:
       payload:
         message: login attempt failed
         request_time: '2013-03-01T00:00:00'
diff --git a/tests/indices/data_stream/rollover.yaml b/tests/indices/data_stream/rollover.yaml
index 2607b1c69..f8640db10 100644
--- a/tests/indices/data_stream/rollover.yaml
+++ b/tests/indices/data_stream/rollover.yaml
@@ -4,7 +4,7 @@ description: Test data streams rollover.
 prologues:
   - path: /_index_template/logs-template-nginx
     method: PUT
-    request_body:
+    request:
       payload:
         index_patterns:
           - logs-*
@@ -17,7 +17,7 @@ prologues:
     method: PUT
   - path: /logs-nginx/_doc
     method: POST
-    request_body:
+    request:
       payload:
         message: login attempt failed
         request_time: '2013-03-01T00:00:00'
diff --git a/tests/indices/data_stream/stats.yaml b/tests/indices/data_stream/stats.yaml
index c963997be..8052ff670 100644
--- a/tests/indices/data_stream/stats.yaml
+++ b/tests/indices/data_stream/stats.yaml
@@ -4,7 +4,7 @@ description: Test data streams.
 prologues:
   - path: /_index_template/logs-template-nginx
     method: PUT
-    request_body:
+    request:
       payload:
         index_patterns:
           - logs-*
@@ -17,7 +17,7 @@ prologues:
     method: PUT
   - path: /logs-nginx/_doc
     method: POST
-    request_body:
+    request:
       payload:
         message: login attempt failed
         request_time: '2013-03-01T00:00:00'
diff --git a/tests/indices/doc.yaml b/tests/indices/doc.yaml
index cf01403b8..325602d75 100644
--- a/tests/indices/doc.yaml
+++ b/tests/indices/doc.yaml
@@ -11,7 +11,7 @@ chapters:
     method: POST
     parameters:
       index: movies
-    request_body:
+    request:
       payload:
         title: Beauty and the Beast
         year: 1991
@@ -23,7 +23,7 @@ chapters:
     parameters:
       index: movies
       id: '1'
-    request_body:
+    request:
       payload:
         title: Beauty and the Beast (Id)
         year: 1991
@@ -35,7 +35,7 @@ chapters:
     parameters:
       index: movies
       id: '1'
-    request_body:
+    request:
       payload:
         title: Beauty and the Beast (Updated)
         year: 1991
diff --git a/tests/indices/index.yaml b/tests/indices/index.yaml
index 22ee0a3d7..186b7df8f 100644
--- a/tests/indices/index.yaml
+++ b/tests/indices/index.yaml
@@ -14,7 +14,7 @@ chapters:
     method: PUT
     parameters:
       index: books
-    request_body:
+    request:
       payload:
         mappings:
           properties:
diff --git a/tests/indices/index_template.yaml b/tests/indices/index_template.yaml
index c61011894..09a6ce7f4 100644
--- a/tests/indices/index_template.yaml
+++ b/tests/indices/index_template.yaml
@@ -11,7 +11,7 @@ chapters:
     method: POST
     parameters:
       name: daily_logs
-    request_body:
+    request:
       payload:
         index_patterns:
           - 'logs*'
@@ -27,7 +27,7 @@ chapters:
     method: PUT
     parameters:
       name: daily_logs
-    request_body:
+    request:
       payload:
         index_patterns:
           - 'logs*'
diff --git a/tests/indices/mapping.yml b/tests/indices/mapping.yml
index af2b29518..00a11407d 100644
--- a/tests/indices/mapping.yml
+++ b/tests/indices/mapping.yml
@@ -10,7 +10,7 @@ prologues:
     method: PUT
     parameters:
       index: movies
-    request_body:
+    request:
       payload:
         mappings:
           properties:
@@ -68,7 +68,7 @@ chapters:
       ignore_unavailable: true
       timeout: 10s
       write_index_only: true
-    request_body:
+    request:
       payload:
         dynamic: 'true'
         properties:
@@ -85,7 +85,7 @@ chapters:
     parameters:
       index: movies
       cluster_manager_timeout: 1s
-    request_body:
+    request:
       payload:
         properties:
           producer:
@@ -104,7 +104,7 @@ chapters:
       ignore_unavailable: true
       timeout: 10s
       write_index_only: true
-    request_body:
+    request:
       payload:
         dynamic: 'false'
     response:
@@ -121,7 +121,7 @@ chapters:
       ignore_unavailable: true
       timeout: 10s
       write_index_only: true
-    request_body:
+    request:
       payload:
         dynamic: strict
     response:
@@ -139,7 +139,7 @@ chapters:
       ignore_unavailable: true
       timeout: 10s
       write_index_only: true
-    request_body:
+    request:
       payload:
         dynamic: strict_allow_templates
     response:
diff --git a/tests/indices/refresh.yaml b/tests/indices/refresh.yaml
index d4aff0cef..587168962 100644
--- a/tests/indices/refresh.yaml
+++ b/tests/indices/refresh.yaml
@@ -8,7 +8,7 @@ epilogues:
 prologues:
   - path: /movies/_doc
     method: POST
-    request_body:
+    request:
       payload:
         title: Beauty and the Beast
         year: 1991
diff --git a/tests/indices/settings.yaml b/tests/indices/settings.yaml
index dc5a85f7b..a5835fdb0 100644
--- a/tests/indices/settings.yaml
+++ b/tests/indices/settings.yaml
@@ -41,7 +41,7 @@ chapters:
     method: PUT
     parameters:
       index: movies
-    request_body:
+    request:
       payload:
         settings:
           index.blocks.write: true
diff --git a/tests/indices/shrink.yaml b/tests/indices/shrink.yaml
index 58b8fee23..1803889ab 100644
--- a/tests/indices/shrink.yaml
+++ b/tests/indices/shrink.yaml
@@ -4,13 +4,13 @@ description: Test shrinking an index.
 prologues:
   - path: /movies
     method: PUT
-    request_body:
+    request:
       payload:
         settings:
           index.number_of_shards: 3
   - path: /movies/_settings
     method: PUT
-    request_body:
+    request:
       payload:
         settings:
           index.blocks.write: true
diff --git a/tests/indices/split.yaml b/tests/indices/split.yaml
index ae6204060..980feb287 100644
--- a/tests/indices/split.yaml
+++ b/tests/indices/split.yaml
@@ -4,13 +4,13 @@ description: Test splitting an index.
 prologues:
   - path: /movies
     method: PUT
-    request_body:
+    request:
       payload:
         settings:
           index.number_of_shards: 3
   - path: /movies/_settings
     method: PUT
-    request_body:
+    request:
       payload:
         settings:
           index.blocks.write: true
@@ -39,7 +39,7 @@ chapters:
       target: movies1
       wait_for_active_shards: 1
       timeout: 10s
-    request_body:
+    request:
       payload:
         settings:
           index:
@@ -58,7 +58,7 @@ chapters:
       index: movies
       target: movies2
       wait_for_completion: true
-    request_body:
+    request:
       payload:
         settings:
           index:
@@ -73,7 +73,7 @@ chapters:
       target: movies3
       wait_for_active_shards: 1
       timeout: 10s
-    request_body:
+    request:
       payload:
         settings:
           index:
@@ -94,7 +94,7 @@ chapters:
       wait_for_active_shards: 1
       cluster_manager_timeout: 10s
       timeout: 10s
-    request_body:
+    request:
       payload:
         settings:
           index:
diff --git a/tests/indices/update_by_query.yaml b/tests/indices/update_by_query.yaml
index 4043dc496..a58853f3f 100644
--- a/tests/indices/update_by_query.yaml
+++ b/tests/indices/update_by_query.yaml
@@ -10,7 +10,7 @@ prologues:
     method: POST
     parameters:
       refresh: true
-    request_body:
+    request:
       content_type: application/x-ndjson
       payload:
         - {create: {_index: books, _id: book_1392214}}
@@ -33,7 +33,7 @@ chapters:
     method: POST
     parameters:
       index: books
-    request_body:
+    request:
       payload:
         query:
           term:
@@ -56,7 +56,7 @@ chapters:
     method: POST
     parameters:
       index: books
-    request_body:
+    request:
       payload:
         query:
           term:
diff --git a/tests/ingest/pipeline.yaml b/tests/ingest/pipeline.yaml
index ee8e539ea..3319d7026 100644
--- a/tests/ingest/pipeline.yaml
+++ b/tests/ingest/pipeline.yaml
@@ -13,7 +13,7 @@ chapters:
     method: PUT
     parameters:
       id: books_pipeline
-    request_body:
+    request:
       payload:
         description: Extracts text from field and embeds it.
         processors:
diff --git a/tests/ml/model_groups.yaml b/tests/ml/model_groups.yaml
index 46f8595d7..778863820 100644
--- a/tests/ml/model_groups.yaml
+++ b/tests/ml/model_groups.yaml
@@ -6,7 +6,7 @@ version: '>= 2.11'
 prologues:
   - path: /_cluster/settings
     method: PUT
-    request_body:
+    request:
       payload:
         persistent:
           plugins:
@@ -25,7 +25,7 @@ chapters:
     id: create_model_group
     path: /_plugins/_ml/model_groups/_register
     method: POST
-    request_body:
+    request:
       payload:
         name: NLP_Group
         description: Model group for NLP models
diff --git a/tests/ml/models.yaml b/tests/ml/models.yaml
index 452f7bacf..f82d2ecda 100644
--- a/tests/ml/models.yaml
+++ b/tests/ml/models.yaml
@@ -6,7 +6,7 @@ version: '>= 2.11'
 prologues:
   - path: /_cluster/settings
     method: PUT
-    request_body:
+    request:
       payload:
         persistent:
           plugins:
@@ -17,7 +17,7 @@ chapters:
     id: create_model
     path: /_plugins/_ml/models/_register
     method: POST
-    request_body:
+    request:
       payload:
         name: huggingface/sentence-transformers/msmarco-distilbert-base-tas-b
         version: 1.0.1
diff --git a/tests/ppl/explain.yaml b/tests/ppl/explain.yaml
index 0dbc465ea..89421fb70 100644
--- a/tests/ppl/explain.yaml
+++ b/tests/ppl/explain.yaml
@@ -5,7 +5,7 @@ description: Test how a query is executed against OpenSearch.
 prologues:
   - path: /books
     method: PUT
-    request_body:
+    request:
       payload: {}
 epilogues:
   - path: /books
@@ -15,7 +15,7 @@ chapters:
   - synopsis: Get explain of SQL Query
     path: /_plugins/_ppl/_explain
     method: POST
-    request_body:
+    request:
       payload:
         query: search source=books
     response:
diff --git a/tests/ppl/query.yaml b/tests/ppl/query.yaml
index 53a9720d3..b9b3548be 100644
--- a/tests/ppl/query.yaml
+++ b/tests/ppl/query.yaml
@@ -7,7 +7,7 @@ prologues:
     method: PUT
     parameters:
       index: books
-    request_body:
+    request:
       payload: {}
 epilogues:
   - path: /books
@@ -17,7 +17,7 @@ chapters:
   - synopsis: Get PPL query
     path: /_plugins/_ppl
     method: POST
-    request_body:
+    request:
       payload:
         query: search source=books
     response:
diff --git a/tests/sql/close.yaml b/tests/sql/close.yaml
index df2910ae9..0f70d62c8 100644
--- a/tests/sql/close.yaml
+++ b/tests/sql/close.yaml
@@ -7,11 +7,11 @@ prologues:
     method: PUT
     parameters:
       index: books
-    request_body:
+    request:
       payload: {}
   - path: /_bulk
     method: POST
-    request_body:
+    request:
       content_type: application/x-ndjson
       payload:
         - {create: {_index: books, _id: book_1392214}}
@@ -24,14 +24,14 @@ prologues:
       index: books
   - path: _plugins/_query/settings
     method: PUT
-    request_body:
+    request:
       payload:
         transient:
           plugins.query.memory_limit: 100%
   - id: sql_query
     path: /_plugins/_sql
     method: POST
-    request_body:
+    request:
       payload:
         fetch_size: 1
         query: 'SELECT * FROM books'
@@ -45,7 +45,7 @@ chapters:
   - synopsis: Close cursor.
     path: /_plugins/_sql/close
     method: POST
-    request_body:
+    request:
       payload:
         cursor: ${sql_query.cursor}
     response:
diff --git a/tests/sql/explain.yaml b/tests/sql/explain.yaml
index 3679dcb29..245d65d83 100644
--- a/tests/sql/explain.yaml
+++ b/tests/sql/explain.yaml
@@ -5,11 +5,11 @@ description: Test how a query is executed against OpenSearch.
 prologues:
   - path: /books
     method: PUT
-    request_body:
+    request:
       payload: {}
   - path: _plugins/_query/settings
     method: PUT
-    request_body:
+    request:
       payload:
         transient:
           plugins.query.memory_limit: 100%
@@ -21,7 +21,7 @@ chapters:
   - synopsis: Get explain of SQL Query
     path: /_plugins/_sql/_explain
     method: POST
-    request_body:
+    request:
       payload:
         query: SELECT * FROM books
     response:
diff --git a/tests/sql/query.yaml b/tests/sql/query.yaml
index e66942606..ba1d34317 100644
--- a/tests/sql/query.yaml
+++ b/tests/sql/query.yaml
@@ -7,11 +7,11 @@ prologues:
     method: PUT
     parameters:
       index: books
-    request_body:
+    request:
       payload: {}
   - path: _plugins/_query/settings
     method: PUT
-    request_body:
+    request:
       payload:
         transient:
           plugins.query.memory_limit: 100%
@@ -25,7 +25,7 @@ chapters:
     method: POST
     parameters:
       sanitize: false
-    request_body:
+    request:
       payload:
         query: 'SELECT * FROM books'
     response:
diff --git a/tests/sql/settings.yaml b/tests/sql/settings.yaml
index 68e5f91c7..6a826806f 100644
--- a/tests/sql/settings.yaml
+++ b/tests/sql/settings.yaml
@@ -6,7 +6,7 @@ chapters:
   - synopsis: Update SQL settings.
     path: /_plugins/_query/settings
     method: PUT
-    request_body:
+    request:
       payload:
         transient: 
           plugins:
@@ -25,7 +25,7 @@ chapters:
   - synopsis: Update SQL settings with plain request body.
     path: /_plugins/_query/settings
     method: PUT
-    request_body:
+    request:
       payload:
         transient: 
           plugins.sql.enabled: true
diff --git a/tools/src/_utils/SpecificationVisitor.ts b/tools/src/_utils/SpecificationVisitor.ts
index b97a636e4..ee8fb276d 100644
--- a/tools/src/_utils/SpecificationVisitor.ts
+++ b/tools/src/_utils/SpecificationVisitor.ts
@@ -58,13 +58,13 @@ export class SpecificationVisitor {
 
   visit_operation (ctx: SpecificationContext, operation: OpenAPIV3.OperationObject): void {
     visit_each(ctx, operation, 'parameters', this.visit_parameter.bind(this))
-    visit(ctx, operation, 'requestBody', this.visit_request_body.bind(this))
+    visit(ctx, operation, 'requestBody', this.visit_request.bind(this))
     visit_each(ctx, operation, 'responses', this.visit_response.bind(this))
   }
 
   visit_components (ctx: SpecificationContext, components: OpenAPIV3.ComponentsObject): void {
     visit_each(ctx, components, 'parameters', this.visit_parameter.bind(this))
-    visit_each(ctx, components, 'requestBodies', this.visit_request_body.bind(this))
+    visit_each(ctx, components, 'requestBodies', this.visit_request.bind(this))
     visit_each(ctx, components, 'responses', this.visit_response.bind(this))
     visit_each(ctx, components, 'schemas', this.visit_schema.bind(this))
   }
@@ -75,10 +75,10 @@ export class SpecificationVisitor {
     visit(ctx, parameter, 'schema', this.visit_schema.bind(this))
   }
 
-  visit_request_body (ctx: SpecificationContext, request_body: MaybeRef<OpenAPIV3.RequestBodyObject>): void {
-    if (is_ref(request_body)) return
+  visit_request (ctx: SpecificationContext, request: MaybeRef<OpenAPIV3.RequestBodyObject>): void {
+    if (is_ref(request)) return
 
-    visit_each(ctx, request_body, 'content', this.visit_media_type.bind(this))
+    visit_each(ctx, request, 'content', this.visit_media_type.bind(this))
   }
 
   visit_response (ctx: SpecificationContext, response: MaybeRef<OpenAPIV3.ResponseObject>): void {
diff --git a/tools/src/linter/SchemasValidator.ts b/tools/src/linter/SchemasValidator.ts
index d22c0beaa..06672285b 100644
--- a/tools/src/linter/SchemasValidator.ts
+++ b/tools/src/linter/SchemasValidator.ts
@@ -38,7 +38,7 @@ export default class SchemasValidator {
     if (named_schemas_errors.length > 0) return named_schemas_errors
     return [
       ...this.validate_parameter_schemas(),
-      ...this.validate_request_body_schemas(),
+      ...this.validate_request_schemas(),
       ...this.validate_response_schemas()
     ]
   }
@@ -66,7 +66,7 @@ export default class SchemasValidator {
     }).filter((error) => error != null) as ValidationError[]
   }
 
-  validate_request_body_schemas (): ValidationError[] {
+  validate_request_schemas (): ValidationError[] {
     return Object.entries(this.spec.requestBodies as Record<string, any>).flatMap(([namespace, body]) => {
       const file = `namespaces/${namespace}.yaml`
       const location = `#/components/requestBodies/${namespace}`
diff --git a/tools/src/linter/components/Operation.ts b/tools/src/linter/components/Operation.ts
index bb06233ad..f55b29e27 100644
--- a/tools/src/linter/components/Operation.ts
+++ b/tools/src/linter/components/Operation.ts
@@ -40,7 +40,7 @@ export default class Operation extends ValidatorBase {
     return [
       this.validate_operation_id(),
       this.validate_description(),
-      this.validate_request_body(),
+      this.validate_request(),
       this.validate_parameters(),
       this.validate_path_parameters(),
       this.validate_order_of_parameters(),
@@ -77,7 +77,7 @@ export default class Operation extends ValidatorBase {
     if (!regex.test(id)) { return this.error(`Invalid operationId '${id}'. Must be in {x-operation-group}.{number} format.`) }
   }
 
-  validate_request_body (): ValidationError | undefined {
+  validate_request (): ValidationError | undefined {
     const body = this.spec.requestBody
     if (!body) return
     const expected = `#/components/requestBodies/${this.group}`
diff --git a/tools/src/linter/components/OperationGroup.ts b/tools/src/linter/components/OperationGroup.ts
index 5daa6adce..dc45765bc 100644
--- a/tools/src/linter/components/OperationGroup.ts
+++ b/tools/src/linter/components/OperationGroup.ts
@@ -32,7 +32,7 @@ export default class OperationGroup extends ValidatorBase {
     return [
       this.validate_description(),
       this.validate_external_docs(),
-      this.validate_request_body(),
+      this.validate_request(),
       this.validate_responses(),
       this.validate_query_parameters()
     ].filter((e) => e) as ValidationError[]
@@ -48,7 +48,7 @@ export default class OperationGroup extends ValidatorBase {
     if (uniq_external_docs.size > 1) { return this.error(`${this.operations.length} '${this.name}' operations must have identical externalDocs property.`) }
   }
 
-  validate_request_body (): ValidationError | undefined {
+  validate_request (): ValidationError | undefined {
     const uniq_request_bodies = new Set(this.operations.map((op) => op.spec.requestBody?.$ref))
     if (uniq_request_bodies.size > 1) { return this.error(`${this.operations.length} '${this.name}' operations must have identical requestBody property.`) }
   }
diff --git a/tools/src/tester/ChapterEvaluator.ts b/tools/src/tester/ChapterEvaluator.ts
index 43157d2b8..e06fca445 100644
--- a/tools/src/tester/ChapterEvaluator.ts
+++ b/tools/src/tester/ChapterEvaluator.ts
@@ -64,7 +64,7 @@ export default class ChapterEvaluator {
   async #evaluate(chapter: Chapter, operation: ParsedOperation, story_outputs: StoryOutputs, retries?: number): Promise<ChapterEvaluation> {
     const response = await this._chapter_reader.read(chapter, story_outputs)
     const params = this.#evaluate_parameters(chapter, operation)
-    const request_body = this.#evaluate_request_body(chapter, operation)
+    const request = this.#evaluate_request(chapter, operation)
     const status = this.#evaluate_status(chapter, response)
     const payload_body_evaluation = status.result === Result.PASSED ? this.#evaluate_payload_body(response, chapter.response?.payload) : { result: Result.SKIPPED }
     const payload_schema_evaluation = status.result === Result.PASSED ? this.#evaluate_payload_schema(chapter, response, operation) : { result: Result.SKIPPED }
@@ -72,7 +72,7 @@ export default class ChapterEvaluator {
 
     const evaluations = _.compact(_.concat(
       Object.values(params),
-      request_body,
+      request,
       status,
       payload_body_evaluation,
       payload_schema_evaluation,
@@ -83,7 +83,7 @@ export default class ChapterEvaluator {
       title: chapter.synopsis,
       path: `${chapter.method} ${chapter.path}`,
       overall: { result: overall_result(evaluations) },
-      request: { parameters: params, request_body },
+      request: { parameters: params, request },
       retries,
       response: {
         status,
@@ -109,12 +109,12 @@ export default class ChapterEvaluator {
     }))
   }
 
-  #evaluate_request_body(chapter: Chapter, operation: ParsedOperation): Evaluation {
-    if (!chapter.request_body) return { result: Result.PASSED }
-    const content_type = chapter.request_body.content_type ?? APPLICATION_JSON
+  #evaluate_request(chapter: Chapter, operation: ParsedOperation): Evaluation {
+    if (chapter.request?.payload === undefined) return { result: Result.PASSED }
+    const content_type = chapter.request.content_type ?? APPLICATION_JSON
     const schema = operation.requestBody?.content[content_type]?.schema
     if (schema == null) return { result: Result.FAILED, message: `Schema for "${content_type}" request body not found in the spec.` }
-    return this._schema_validator.validate(schema, chapter.request_body?.payload ?? {})
+    return this._schema_validator.validate(schema, chapter.request?.payload ?? {})
   }
 
   #evaluate_status(chapter: Chapter, response: ActualResponse): Evaluation {
diff --git a/tools/src/tester/ChapterReader.ts b/tools/src/tester/ChapterReader.ts
index 9467976d0..ae26e9920 100644
--- a/tools/src/tester/ChapterReader.ts
+++ b/tools/src/tester/ChapterReader.ts
@@ -17,6 +17,7 @@ import YAML from 'yaml'
 import CBOR from 'cbor'
 import SMILE from 'smile-js'
 import { APPLICATION_CBOR, APPLICATION_JSON, APPLICATION_SMILE, APPLICATION_YAML, TEXT_PLAIN } from "./MimeTypes";
+import _ from 'lodash'
 
 export default class ChapterReader {
   private readonly _client: OpenSearchHttpClient
@@ -31,16 +32,16 @@ export default class ChapterReader {
     const response: Record<string, any> = {}
     const resolved_params = story_outputs.resolve_params(chapter.parameters ?? {})
     const [url_path, params] = this.#parse_url(chapter.path, resolved_params)
-    const content_type = chapter.request_body?.content_type ?? APPLICATION_JSON
-    const request_data = chapter.request_body?.payload !== undefined ? this.#serialize_payload(
-      story_outputs.resolve_value(chapter.request_body.payload),
+    const [headers, content_type] = this.#serialize_headers(chapter.request?.headers, chapter.request?.content_type)
+    const request_data = chapter.request?.payload !== undefined ? this.#serialize_payload(
+      story_outputs.resolve_value(chapter.request.payload),
       content_type
     ) : undefined
-    this.logger.info(`=> ${chapter.method} ${url_path} (${to_json(params)}) [${content_type}] | ${to_json(request_data)}`)
+    this.logger.info(`=> ${chapter.method} ${url_path} (${to_json(params)}) [${content_type}] ${_.compact([to_json(headers), to_json(request_data)]).join(' | ')}`)
     await this._client.request({
       url: url_path,
       method: chapter.method,
-      headers: { 'Content-Type' : content_type },
+      headers: { 'Content-Type' : content_type, ...headers },
       params,
       data: request_data,
       paramsSerializer: (params) => { // eslint-disable-line @typescript-eslint/naming-convention
@@ -49,7 +50,8 @@ export default class ChapterReader {
     }).then(r => {
       response.status = r.status
       response.content_type = r.headers['content-type']?.split(';')[0]
-      response.payload = this.#deserialize_payload(r.data, response.content_type)
+      const payload = this.#deserialize_payload(r.data, response.content_type)
+      if (payload !== undefined) response.payload = payload
       this.logger.info(`<= ${r.status} (${r.headers['content-type']}) | ${to_json(response.payload)}`)
     }).catch(e => {
       if (e.response == null) {
@@ -59,7 +61,7 @@ export default class ChapterReader {
       response.status = e.response.status
       response.content_type = e.response.headers['content-type']?.split(';')[0]
       const payload = this.#deserialize_payload(e.response.data, response.content_type)
-      response.payload = payload?.error
+      if (payload !== undefined) response.payload = payload.error
       response.message = payload.error?.reason ?? e.response.statusText
       response.error = e
 
@@ -68,6 +70,19 @@ export default class ChapterReader {
     return response as ActualResponse
   }
 
+  #serialize_headers(headers?: Record<string, any>, content_type?: string): [Record<string, any> | undefined, string] {
+    headers = _.cloneDeep(headers)
+    content_type = content_type ?? APPLICATION_JSON
+    if (!headers) return [headers, content_type]
+    _.forEach(headers, (v, k) => {
+      if (k.toLowerCase() == 'content-type') {
+        content_type = v.toString()
+        if (headers) delete headers[k]
+      }
+    })
+    return [headers, content_type]
+  }
+
   #serialize_payload(payload: any, content_type: string): any {
     if (payload === undefined) return undefined
     switch (content_type) {
diff --git a/tools/src/tester/ResultLogger.ts b/tools/src/tester/ResultLogger.ts
index ddfead55c..d2ef339c2 100644
--- a/tools/src/tester/ResultLogger.ts
+++ b/tools/src/tester/ResultLogger.ts
@@ -62,7 +62,7 @@ export class ConsoleResultLogger implements ResultLogger {
   #log_chapter (chapter: ChapterEvaluation): void {
     this.#log_evaluation(chapter.overall, ansi.i(chapter.title), this._tab_width * 2)
     this.#log_parameters(chapter.request?.parameters ?? {})
-    this.#log_request_body(chapter.request?.request_body)
+    this.#log_request(chapter.request?.request)
     this.#log_status(chapter.response?.status)
     this.#log_payload_body(chapter.response?.payload_body)
     this.#log_payload_schema(chapter.response?.payload_schema)
@@ -79,7 +79,7 @@ export class ConsoleResultLogger implements ResultLogger {
     }
   }
 
-  #log_request_body (evaluation: Evaluation | undefined): void {
+  #log_request (evaluation: Evaluation | undefined): void {
     if (evaluation == null) return
     this.#log_evaluation(evaluation, 'REQUEST BODY', this._tab_width * 3)
   }
diff --git a/tools/src/tester/StoryEvaluator.ts b/tools/src/tester/StoryEvaluator.ts
index 1e2a95d52..fede2e397 100644
--- a/tools/src/tester/StoryEvaluator.ts
+++ b/tools/src/tester/StoryEvaluator.ts
@@ -170,7 +170,7 @@ export default class StoryEvaluator {
     const variables = new Set<OutputReference>()
     const title = `${chapter.method} ${chapter.path}`
     StoryEvaluator.#extract_params_variables(chapter.parameters ?? {}, variables)
-    StoryEvaluator.#extract_request_body_variables(chapter.request_body?.payload ?? {}, variables)
+    StoryEvaluator.#extract_request_variables(chapter.request?.payload ?? {}, variables)
     for (const { chapter_id, output_name } of variables) {
       if (!story_outputs.has_chapter(chapter_id)) {
         return StoryEvaluator.#failed_evaluation(title, `Chapter makes reference to non existent chapter "${chapter_id}`)
@@ -192,24 +192,24 @@ export default class StoryEvaluator {
     })
   }
 
-  static #extract_request_body_variables(request_body: any, variables: Set<OutputReference>): void {
-    const request_body_type = typeof request_body
-    switch (request_body_type) {
+  static #extract_request_variables(request: any, variables: Set<OutputReference>): void {
+    const request_type = typeof request
+    switch (request_type) {
       case 'string': {
-        const ref = OutputReference.parse(request_body as string)
+        const ref = OutputReference.parse(request as string)
         if (ref !== undefined) {
           variables.add(ref)
         }
         break
       }
       case 'object': {
-        if (Array.isArray(request_body)) {
-          for (const value of request_body) {
-            StoryEvaluator.#extract_request_body_variables(value, variables)
+        if (Array.isArray(request)) {
+          for (const value of request) {
+            StoryEvaluator.#extract_request_variables(value, variables)
           }
         } else {
-          for (const [, value] of Object.entries(request_body as Record<string, any>)) {
-            StoryEvaluator.#extract_request_body_variables(value, variables)
+          for (const [, value] of Object.entries(request as Record<string, any>)) {
+            StoryEvaluator.#extract_request_variables(value, variables)
           }
         }
         break
diff --git a/tools/src/tester/_generate_story_types.ts b/tools/src/tester/_generate_story_types.ts
index d4ab6271e..d520fc02d 100644
--- a/tools/src/tester/_generate_story_types.ts
+++ b/tools/src/tester/_generate_story_types.ts
@@ -28,7 +28,7 @@ void js2ts.compile(schema, 'Story',
 * This file was automatically generated by json-schema-to-typescript.
 * DO NOT MODIFY IT BY HAND. Instead, modify the source JSONSchema file,
 * and run json-schema-to-typescript to regenerate this file by running:
-* "npx ts-node tools/src/tester/_generate_story_types.ts" in a terminal.
+* "npm run generate-types" in a terminal.
 */
 `
   })
diff --git a/tools/src/tester/types/eval.types.ts b/tools/src/tester/types/eval.types.ts
index a89352eb0..a95104c50 100644
--- a/tools/src/tester/types/eval.types.ts
+++ b/tools/src/tester/types/eval.types.ts
@@ -39,7 +39,7 @@ export interface ChapterEvaluation {
   path?: string,
   request?: {
     parameters?: Record<string, Evaluation>
-    request_body?: Evaluation
+    request?: Evaluation
   }
   response?: {
     status: Evaluation
diff --git a/tools/src/tester/types/spec.types.ts b/tools/src/tester/types/spec.types.ts
index 06689a9eb..6a6f0f10c 100644
--- a/tools/src/tester/types/spec.types.ts
+++ b/tools/src/tester/types/spec.types.ts
@@ -11,11 +11,11 @@ import { type OpenAPIV3 } from 'openapi-types'
 
 export type ParsedOperation = OpenAPIV3.OperationObject & {
   parameters: Record<string, ParsedParameter>
-  requestBody: ParsedRequestBody
+  requestBody: ParsedRequest
   responses: Record<string, ParsedResponse>
 }
 
-export type ParsedRequestBody = OpenAPIV3.RequestBodyObject & {
+export type ParsedRequest = OpenAPIV3.RequestBodyObject & {
   content: Record<string, ParsedMediaType>
 }
 
diff --git a/tools/src/tester/types/story.types.ts b/tools/src/tester/types/story.types.ts
index 3b7fbe18b..e418ff762 100644
--- a/tools/src/tester/types/story.types.ts
+++ b/tools/src/tester/types/story.types.ts
@@ -14,7 +14,7 @@
  * This file was automatically generated by json-schema-to-typescript.
  * DO NOT MODIFY IT BY HAND. Instead, modify the source JSONSchema file,
  * and run json-schema-to-typescript to regenerate this file by running:
- * "npx ts-node tools/src/tester/_generate_story_types.ts" in a terminal.
+ * "npm run generate-types" in a terminal.
  */
 
 /**
@@ -32,6 +32,11 @@ export type SupplementalChapter = ChapterRequest & {
  * via the `definition` "Parameter".
  */
 export type Parameter = (string | number | boolean)[] | string | number | boolean;
+/**
+ * This interface was referenced by `Story`'s JSON-Schema
+ * via the `definition` "Header".
+ */
+export type Header = string | number | boolean;
 /**
  * This interface was referenced by `Story`'s JSON-Schema
  * via the `definition` "Payload".
@@ -104,18 +109,21 @@ export interface ChapterRequest {
   parameters?: {
     [k: string]: Parameter;
   };
-  request_body?: RequestBody;
+  request?: Request;
   output?: Output;
   version?: Version;
   retry?: Retry;
 }
 /**
  * This interface was referenced by `Story`'s JSON-Schema
- * via the `definition` "RequestBody".
+ * via the `definition` "Request".
  */
-export interface RequestBody {
+export interface Request {
   content_type?: string;
-  payload: Payload;
+  headers?: {
+    [k: string]: Header;
+  };
+  payload?: Payload;
 }
 /**
  * Describes output for a chapter.
diff --git a/tools/tests/linter/Operation.test.ts b/tools/tests/linter/Operation.test.ts
index c5154eb0a..4634ba4cc 100644
--- a/tools/tests/linter/Operation.test.ts
+++ b/tools/tests/linter/Operation.test.ts
@@ -78,15 +78,15 @@ test('validate_description()', () => {
 
 test('validate_requestBody()', () => {
   const no_body = operation({ 'x-operation-group': 'indices.create' })
-  expect(no_body.validate_request_body())
+  expect(no_body.validate_request())
     .toBeUndefined()
 
   const valid_body = operation({ 'x-operation-group': 'indices.create', requestBody: { $ref: '#/components/requestBodies/indices.create' } })
-  expect(valid_body.validate_request_body())
+  expect(valid_body.validate_request())
     .toBeUndefined()
 
   const invalid_body = operation({ 'x-operation-group': 'indices.create', requestBody: { $ref: '#/components/requestBodies/indices.create.1' } })
-  expect(invalid_body.validate_request_body())
+  expect(invalid_body.validate_request())
     .toEqual(invalid_body.error('The requestBody must be a reference object to \'#/components/requestBodies/indices.create\'.'))
 })
 
diff --git a/tools/tests/linter/OperationGroup.test.ts b/tools/tests/linter/OperationGroup.test.ts
index 9ad7c1f65..92351abf2 100644
--- a/tools/tests/linter/OperationGroup.test.ts
+++ b/tools/tests/linter/OperationGroup.test.ts
@@ -45,13 +45,13 @@ test('validate_requestBody()', () => {
   const valid_request_bodies = operation_group([
     { requestBody: { $ref: '#/components/requestBodies/indices.create' } },
     { requestBody: { $ref: '#/components/requestBodies/indices.create' } }])
-  expect(valid_request_bodies.validate_request_body())
+  expect(valid_request_bodies.validate_request())
     .toBeUndefined()
 
   const invalid_request_bodies = operation_group([
     { requestBody: { $ref: '#/components/requestBodies/indices.create' } },
     {}])
-  expect(invalid_request_bodies.validate_request_body())
+  expect(invalid_request_bodies.validate_request())
     .toEqual(invalid_request_bodies.error('2 \'indices.create\' operations must have identical requestBody property.'))
 })
 
diff --git a/tools/tests/linter/factories/operation.ts b/tools/tests/linter/factories/operation.ts
index b4f90363e..2a87677be 100644
--- a/tools/tests/linter/factories/operation.ts
+++ b/tools/tests/linter/factories/operation.ts
@@ -40,7 +40,7 @@ export function mocked_operation (returned_values: MockedReturnedValues): Operat
   op.validate_namespace = jest.fn()
   op.validate_operation_id = jest.fn()
   op.validate_description = jest.fn()
-  op.validate_request_body = jest.fn()
+  op.validate_request = jest.fn()
   op.validate_responses = jest.fn()
   op.validate_parameters = jest.fn()
   op.validate_path_parameters = jest.fn()
@@ -49,7 +49,7 @@ export function mocked_operation (returned_values: MockedReturnedValues): Operat
   if (returned_values.validate_namespace != null) (op.validate_namespace as jest.Mock).mockReturnValue(returned_values.validate_namespace)
   if (returned_values.validate_operationId != null) (op.validate_operation_id as jest.Mock).mockReturnValue(returned_values.validate_operationId)
   if (returned_values.validate_description != null) (op.validate_description as jest.Mock).mockReturnValue(returned_values.validate_description)
-  if (returned_values.validate_requestBody != null) (op.validate_request_body as jest.Mock).mockReturnValue(returned_values.validate_requestBody)
+  if (returned_values.validate_requestBody != null) (op.validate_request as jest.Mock).mockReturnValue(returned_values.validate_requestBody)
   if (returned_values.validate_responses != null) (op.validate_responses as jest.Mock).mockReturnValue(returned_values.validate_responses)
   if (returned_values.validate_parameters != null) (op.validate_parameters as jest.Mock).mockReturnValue(returned_values.validate_parameters)
   if (returned_values.validate_path_parameters != null) (op.validate_path_parameters as jest.Mock).mockReturnValue(returned_values.validate_path_parameters)
diff --git a/tools/tests/linter/factories/operation_group.ts b/tools/tests/linter/factories/operation_group.ts
index 1e5fa04c6..ab68e3ea5 100644
--- a/tools/tests/linter/factories/operation_group.ts
+++ b/tools/tests/linter/factories/operation_group.ts
@@ -38,13 +38,13 @@ export function mocked_operation_group (returned_values: MockedReturnedValues, o
 
   op_group.validate_description = jest.fn()
   op_group.validate_external_docs = jest.fn()
-  op_group.validate_request_body = jest.fn()
+  op_group.validate_request = jest.fn()
   op_group.validate_responses = jest.fn()
   op_group.validate_query_parameters = jest.fn()
 
   if (returned_values.validate_description != null) (op_group.validate_description as jest.Mock).mockReturnValue(returned_values.validate_description)
   if (returned_values.validate_externalDocs != null) (op_group.validate_external_docs as jest.Mock).mockReturnValue(returned_values.validate_externalDocs)
-  if (returned_values.validate_requestBody != null) (op_group.validate_request_body as jest.Mock).mockReturnValue(returned_values.validate_requestBody)
+  if (returned_values.validate_requestBody != null) (op_group.validate_request as jest.Mock).mockReturnValue(returned_values.validate_requestBody)
   if (returned_values.validate_responses != null) (op_group.validate_responses as jest.Mock).mockReturnValue(returned_values.validate_responses)
   if (returned_values.validate_query_parameters != null) (op_group.validate_query_parameters as jest.Mock).mockReturnValue(returned_values.validate_query_parameters)
 
diff --git a/tools/tests/tester/ChapterReader.test.ts b/tools/tests/tester/ChapterReader.test.ts
index 34eb6e893..7e1776bb2 100644
--- a/tools/tests/tester/ChapterReader.test.ts
+++ b/tools/tests/tester/ChapterReader.test.ts
@@ -44,11 +44,11 @@ describe('ChapterReader', () => {
         path: 'path',
         method: 'GET',
         parameters: undefined,
-        request_body: undefined,
+        request: undefined,
         output: undefined
       }, new StoryOutputs())
 
-      expect(result).toEqual({ status: 200, content_type: 'application/json', payload: undefined })
+      expect(result).toStrictEqual({ status: 200, content_type: 'application/json' })
       expect(mocked_axios.request.mock.calls).toEqual([
         [{
           url: 'path',
@@ -67,19 +67,19 @@ describe('ChapterReader', () => {
         path: '{index}/path',
         method: 'GET',
         parameters: { index: 'books' },
-        request_body: undefined,
+        request: undefined,
         output: undefined
       }, new StoryOutputs())
 
-      expect(result).toEqual({ status: 200, content_type: 'application/json', payload: undefined })
+      expect(result).toEqual({ status: 200, content_type: 'application/json' })
       expect(mocked_axios.request.mock.calls).toEqual([
         [{
           url: 'books/path',
           method: 'GET',
+          data: undefined,
           headers: { 'Content-Type': 'application/json' },
           params: {},
-          paramsSerializer: expect.any(Function),
-          data: undefined
+          paramsSerializer: expect.any(Function)
         }]
       ])
     })
@@ -90,11 +90,11 @@ describe('ChapterReader', () => {
         path: '/path',
         method: 'GET',
         parameters: { indexes: ['book1', 'book2'] },
-        request_body: undefined,
+        request: undefined,
         output: undefined
       }, new StoryOutputs())
 
-      expect(result).toEqual({ status: 200, content_type: 'application/json', payload: undefined })
+      expect(result).toEqual({ status: 200, content_type: 'application/json' })
       expect(mocked_axios.request.mock.calls).toEqual([
         [{
           url: '/path',
@@ -116,11 +116,11 @@ describe('ChapterReader', () => {
         path: 'path',
         method: 'POST',
         parameters: { 'x': 1 },
-        request_body: { payload: { "body": "present" } },
+        request: { payload: { "body": "present" } },
         output: undefined
       }, new StoryOutputs())
 
-      expect(result).toEqual({ status: 200, content_type: 'application/json', payload: undefined })
+      expect(result).toEqual({ status: 200, content_type: 'application/json' })
       expect(mocked_axios.request.mock.calls).toEqual([
         [{
           url: 'path',
@@ -139,14 +139,14 @@ describe('ChapterReader', () => {
         path: 'path',
         method: 'POST',
         parameters: { 'x': 1 },
-        request_body: {
+        request: {
           content_type: 'application/x-ndjson',
           payload: [{ "body": "present" }]
         },
         output: undefined
       }, new StoryOutputs())
 
-      expect(result).toEqual({ status: 200, content_type: 'application/json', payload: undefined })
+      expect(result).toEqual({ status: 200, content_type: 'application/json' })
       expect(mocked_axios.request.mock.calls).toEqual([
         [{
           url: 'path',
@@ -158,6 +158,67 @@ describe('ChapterReader', () => {
         }]
       ])
     })
+
+    it('sends headers', async () => {
+      const result = await reader.read({
+        id: 'id',
+        path: 'path',
+        method: 'GET',
+        request: {
+          headers: {
+            'string': 'bar',
+            'number': 1,
+            'boolean': true
+          },
+        },
+        output: undefined
+      }, new StoryOutputs())
+
+      expect(result).toStrictEqual({ status: 200, content_type: 'application/json' })
+      expect(mocked_axios.request.mock.calls).toStrictEqual([
+        [{
+          url: 'path',
+          method: 'GET',
+          data: undefined,
+          headers: {
+            'Content-Type': 'application/json',
+            'string': 'bar',
+            'number': 1,
+            'boolean': true
+          },
+          params: {},
+          paramsSerializer: expect.any(Function)
+        }]
+      ])
+    })
+
+    it('overwrites case-insensitive content-type', async () => {
+      const result = await reader.read({
+        id: 'id',
+        path: 'path',
+        method: 'GET',
+        request: {
+          headers: {
+            'content-type': 'application/overwritten'
+          },
+        },
+        output: undefined
+      }, new StoryOutputs())
+
+      expect(result).toStrictEqual({ status: 200, content_type: 'application/json' })
+      expect(mocked_axios.request.mock.calls).toStrictEqual([
+        [{
+          url: 'path',
+          method: 'GET',
+          data: undefined,
+          headers: {
+            'Content-Type': 'application/overwritten',
+          },
+          params: {},
+          paramsSerializer: expect.any(Function)
+        }]
+      ])
+    })
   })
 
   describe('deserialize_payload', () => {
diff --git a/tools/tests/tester/fixtures/evals/error/chapter_error.yaml b/tools/tests/tester/fixtures/evals/error/chapter_error.yaml
index 775bffb2e..450d9c5a3 100644
--- a/tools/tests/tester/fixtures/evals/error/chapter_error.yaml
+++ b/tools/tests/tester/fixtures/evals/error/chapter_error.yaml
@@ -26,7 +26,7 @@ chapters:
     path: DELETE /{index}
     request:
       parameters: {}
-      request_body:
+      request:
         result: PASSED
     response:
       status:
diff --git a/tools/tests/tester/fixtures/evals/error/output_error.yaml b/tools/tests/tester/fixtures/evals/error/output_error.yaml
index ed4e57ac3..27ac940d3 100644
--- a/tools/tests/tester/fixtures/evals/error/output_error.yaml
+++ b/tools/tests/tester/fixtures/evals/error/output_error.yaml
@@ -16,7 +16,7 @@ chapters:
       parameters:
         format:
           result: PASSED
-      request_body:
+      request:
         result: PASSED
     response:
       payload_body:
diff --git a/tools/tests/tester/fixtures/evals/failed/invalid_data.yaml b/tools/tests/tester/fixtures/evals/failed/invalid_data.yaml
index 91aeca18b..3f59fe0e8 100644
--- a/tools/tests/tester/fixtures/evals/failed/invalid_data.yaml
+++ b/tools/tests/tester/fixtures/evals/failed/invalid_data.yaml
@@ -14,7 +14,7 @@ chapters:
         index:
           result: FAILED
           message: data must be string
-      request_body:
+      request:
         result: PASSED
     response:
       status:
@@ -33,7 +33,7 @@ chapters:
       parameters:
         index:
           result: PASSED
-      request_body:
+      request:
         result: FAILED
         message: 'data contains unsupported properties: aliases'
     response:
@@ -55,7 +55,7 @@ chapters:
           result: PASSED
         index:
           result: PASSED
-      request_body:
+      request:
         result: PASSED
     response:
       status:
@@ -75,7 +75,7 @@ chapters:
       parameters:
         index:
           result: PASSED
-      request_body:
+      request:
         result: PASSED
     response:
       status:
@@ -96,7 +96,7 @@ chapters:
       parameters:
         index:
           result: PASSED
-      request_body:
+      request:
         result: PASSED
     response:
       status:
diff --git a/tools/tests/tester/fixtures/evals/failed/not_found.yaml b/tools/tests/tester/fixtures/evals/failed/not_found.yaml
index ec760c0b1..ecbd88992 100644
--- a/tools/tests/tester/fixtures/evals/failed/not_found.yaml
+++ b/tools/tests/tester/fixtures/evals/failed/not_found.yaml
@@ -25,7 +25,7 @@ chapters:
         timeout:
           result: FAILED
           message: Schema for "timeout" parameter not found.
-      request_body:
+      request:
         result: PASSED
     response:
       status:
@@ -44,7 +44,7 @@ chapters:
       parameters:
         index:
           result: PASSED
-      request_body:
+      request:
         result: FAILED
         message: Schema for "application/json" request body not found in the spec.
     response:
@@ -64,7 +64,7 @@ chapters:
       parameters:
         index:
           result: PASSED
-      request_body:
+      request:
         result: PASSED
     response:
       status:
diff --git a/tools/tests/tester/fixtures/evals/passed.yaml b/tools/tests/tester/fixtures/evals/passed.yaml
index f0118f111..bb74087e8 100644
--- a/tools/tests/tester/fixtures/evals/passed.yaml
+++ b/tools/tests/tester/fixtures/evals/passed.yaml
@@ -13,7 +13,7 @@ chapters:
       parameters:
         index:
           result: PASSED
-      request_body:
+      request:
         result: PASSED
     response:
       status:
@@ -30,7 +30,24 @@ chapters:
     path: GET /_cat
     request:
       parameters: {}
-      request_body:
+      request:
+        result: PASSED
+    response:
+      status:
+        result: PASSED
+      payload_body:
+        result: PASSED
+      payload_schema:
+        result: PASSED
+      output_values:
+        result: SKIPPED
+  - title: This GET /_cat chapter with a header should pass.
+    overall:
+      result: PASSED
+    path: GET /_cat
+    request:
+      parameters: {}
+      request:
         result: PASSED
     response:
       status:
@@ -49,7 +66,7 @@ chapters:
       parameters:
         format:
           result: PASSED
-      request_body:
+      request:
         result: PASSED
     response:
       status:
@@ -68,7 +85,7 @@ chapters:
       parameters:
         format:
           result: PASSED
-      request_body:
+      request:
         result: PASSED
     response:
       status:
@@ -87,7 +104,7 @@ chapters:
       parameters:
         format:
           result: PASSED
-      request_body:
+      request:
         result: PASSED
     response:
       status:
@@ -106,7 +123,7 @@ chapters:
       parameters:
         format:
           result: PASSED
-      request_body:
+      request:
         result: PASSED
     response:
       status:
@@ -125,7 +142,7 @@ chapters:
       parameters:
         format:
           result: PASSED
-      request_body:
+      request:
         result: PASSED
     response:
       status:
@@ -144,7 +161,7 @@ chapters:
       parameters:
         format:
           result: PASSED
-      request_body:
+      request:
         result: PASSED
     response:
       status:
diff --git a/tools/tests/tester/fixtures/fail_non_existent_variable.yaml b/tools/tests/tester/fixtures/fail_non_existent_variable.yaml
index cb4e80d61..3dc1a8c9d 100644
--- a/tools/tests/tester/fixtures/fail_non_existent_variable.yaml
+++ b/tools/tests/tester/fixtures/fail_non_existent_variable.yaml
@@ -7,7 +7,7 @@ chapters:
     id: create_model_group
     path: /_plugins/_ml/model_groups/_register
     method: POST
-    request_body:
+    request:
       payload:
         name: NLP_Group
         description: Model group for NLP models
diff --git a/tools/tests/tester/fixtures/stories/failed/invalid_data.yaml b/tools/tests/tester/fixtures/stories/failed/invalid_data.yaml
index ba84d4200..45b00ee0b 100644
--- a/tools/tests/tester/fixtures/stories/failed/invalid_data.yaml
+++ b/tools/tests/tester/fixtures/stories/failed/invalid_data.yaml
@@ -19,7 +19,7 @@ chapters:
     method: PUT
     parameters:
       index: books
-    request_body:
+    request:
       payload:
         aliases: {}
   - synopsis: This chapter should fail because the response content type does not match.
diff --git a/tools/tests/tester/fixtures/stories/failed/not_found.yaml b/tools/tests/tester/fixtures/stories/failed/not_found.yaml
index 0c0778268..0b61b03a9 100644
--- a/tools/tests/tester/fixtures/stories/failed/not_found.yaml
+++ b/tools/tests/tester/fixtures/stories/failed/not_found.yaml
@@ -20,7 +20,7 @@ chapters:
     method: HEAD
     parameters:
       index: books
-    request_body:
+    request:
       payload: {}
   - synopsis: This chapter should fail because the response is not defined in the spec.
     path: /{index}
diff --git a/tools/tests/tester/fixtures/stories/passed.yaml b/tools/tests/tester/fixtures/stories/passed.yaml
index b1d458f25..b4b08b963 100644
--- a/tools/tests/tester/fixtures/stories/passed.yaml
+++ b/tools/tests/tester/fixtures/stories/passed.yaml
@@ -21,6 +21,17 @@ chapters:
     response:
       status: 200
       content_type: text/plain
+  - synopsis: This GET /_cat chapter with a header should pass.
+    path: /_cat
+    method: GET
+    warnings:
+      multiple-paths-detected: false
+    request:
+      headers:
+        User-Agent: OpenSearch API Spec/1.0
+    response:
+      status: 200
+      content_type: text/plain
   - synopsis: This GET /_cat/health chapter returns application/json and should pass.
     path: /_cat/health
     parameters:
diff --git a/tools/tests/tester/helpers.ts b/tools/tests/tester/helpers.ts
index 57cbcff16..5ee331a14 100644
--- a/tools/tests/tester/helpers.ts
+++ b/tools/tests/tester/helpers.ts
@@ -97,7 +97,7 @@ export function flatten_errors (evaluation: StoryEvaluation): StoryEvaluation {
 
       if (c.request !== undefined) {
         result.request = {
-          request_body: flatten(c.request.request_body)
+          request: flatten(c.request.request)
         }
 
         if (c.request.parameters !== undefined) {
diff --git a/tools/tests/tester/test.test.ts b/tools/tests/tester/test.test.ts
index a7db537d7..ee76c19b9 100644
--- a/tools/tests/tester/test.test.ts
+++ b/tools/tests/tester/test.test.ts
@@ -10,7 +10,7 @@
 import { spawnSync } from 'child_process'
 import * as ansi from 'tester/Ansi'
 import * as path from 'path'
-import { type Chapter, type ChapterRequest, type Output, type RequestBody, type ActualResponse, Story } from 'tester/types/story.types'
+import { type Chapter, type ChapterRequest, type Output, type Request, type ActualResponse, Story } from 'tester/types/story.types'
 import { type EvaluationWithOutput, Result, ChapterEvaluation, StoryEvaluation } from 'tester/types/eval.types'
 import { ChapterOutput } from 'tester/ChapterOutput'
 import StoryEvaluator from 'tester/StoryEvaluator'
@@ -102,11 +102,11 @@ function dummy_chapter_request(id?: string, output?: Output): ChapterRequest {
   }
 }
 
-function dummy_chapter_request_with_input(parameters?: Record<string, any>, request_body?: RequestBody, id?: string, output?: Output): ChapterRequest {
+function dummy_chapter_request_with_input(parameters?: Record<string, any>, request?: Request, id?: string, output?: Output): ChapterRequest {
   return {
     ...dummy_chapter_request(id, output),
     parameters,
-    request_body
+    request
   }
 }