diff --git a/reference/public-http-api.yaml b/reference/public-http-api.yaml
index 0b42396..5085cc6 100644
--- a/reference/public-http-api.yaml
+++ b/reference/public-http-api.yaml
@@ -948,10 +948,20 @@ paths:
       responses:
         '202':
           description: Accepted - there are in-band datasets and a load has been scheduled to start
+          content:
+            application/json:
+              schema:
+                type: string
+                minLength: 1
+                description: Pipeline load ID
         '204':
           description: No Content - there are no in-band datasets
         '400':
-          description: Bad Request - there are no datasets in pipeline
+          description: Bad Request - the body is invalid or there are no datasets in the pipeline
+          content:
+            text/plain:
+              schema:
+                type: string
         '401':
           description: Unauthorized
         '402':
@@ -978,6 +988,16 @@ paths:
                   - error
         '404':
           description: Pipeline not found.
+          content:
+            text/plain:
+              schema:
+                type: string
+        '500':
+          description: The load request failed, including when another load is already in progress.
+          content:
+            text/plain:
+              schema:
+                type: string
         '502':
           description: Problematic Request to External Server
           content:
@@ -986,14 +1006,15 @@ paths:
                 $ref: '#/components/schemas/error-message'
       description: Start a load for this pipeline.
       requestBody:
+        required: false
         content:
           application/json:
             schema:
-              type: object
-              properties:
-                returnUrl:
-                  type: string
-        description: ''
+              $ref: '#/components/schemas/pipeline-load-request'
+        description: >-
+          Omit the body, omit `datasets`, or send an empty object to start a full load with
+          debug disabled. A non-empty `datasets` array starts a partial load. An empty array,
+          malformed entry, or repeated dataset ID is rejected with a 400 response.
   '/pipelines/{pipeline-id}/rename':
     parameters:
       - schema:
@@ -2704,6 +2725,10 @@ components:
       properties:
         initialWrite:
           type: boolean
+        debug:
+          type: boolean
+          default: false
+          description: Enable immediate reader logging for this dataset's initial load.
         readRequired:
           type: boolean
           default: false
@@ -2716,6 +2741,34 @@ components:
           $ref: '#/components/schemas/initial-load-params-message-limit'
       required:
         - initialWrite
+    pipeline-load-request:
+      title: pipeline-load-request
+      type: object
+      additionalProperties: false
+      properties:
+        datasets:
+          type: array
+          minItems: 1
+          uniqueItems: true
+          description: >-
+            Datasets to include in a partial standard load. Dataset IDs must be unique.
+            Unknown IDs are ignored; if none belong to the pipeline, the request fails.
+          items:
+            $ref: '#/components/schemas/pipeline-load-dataset-options'
+    pipeline-load-dataset-options:
+      title: pipeline-load-dataset-options
+      type: object
+      additionalProperties: false
+      properties:
+        id:
+          type: string
+          minLength: 1
+        debug:
+          type: boolean
+          default: false
+          description: Enable immediate reader logging for this dataset's load.
+      required:
+        - id
     initial-load-params-message-limit:
       title: initial-load-params-message-limit
       type: object
@@ -2906,6 +2959,27 @@ components:
             minLength: 1
         loadParameters:
           $ref: '#/components/schemas/initial-load-params'
+        datasetOverrides:
+          type: object
+          description: Initial-load parameter overrides keyed by dataset ID.
+          additionalProperties:
+            $ref: '#/components/schemas/optional-initial-load-params'
+    optional-initial-load-params:
+      title: optional-initial-load-params
+      type: object
+      properties:
+        initialWrite:
+          type: boolean
+        debug:
+          type: boolean
+        readRequired:
+          type: boolean
+        reusePreviousSchema:
+          type: boolean
+        reusePreviousPrimaryKey:
+          $ref: '#/components/schemas/reuse-previous-primary-key'
+        sampleParameters:
+          $ref: '#/components/schemas/initial-load-params-message-limit'
     error-message:
       title: error-message
       type: object