diff --git a/prompt-registry/src/main/java/com/sap/ai/sdk/prompt/registry/model/PromptTemplateSpec.java b/prompt-registry/src/main/java/com/sap/ai/sdk/prompt/registry/model/PromptTemplateSpec.java
index 4f3d861b2..bc7e94b84 100644
--- a/prompt-registry/src/main/java/com/sap/ai/sdk/prompt/registry/model/PromptTemplateSpec.java
+++ b/prompt-registry/src/main/java/com/sap/ai/sdk/prompt/registry/model/PromptTemplateSpec.java
@@ -41,6 +41,9 @@ public class PromptTemplateSpec
   @JsonProperty("additionalFields")
   private Object additionalFields;
 
+  @JsonProperty("additional_fields")
+  private Object additionalFields;
+
   @JsonProperty("response_format")
   private PromptTemplateSpecResponseFormat responseFormat;
 
@@ -130,6 +133,40 @@ public void setDefaults(@Nullable final Object defaults) {
     this.defaults = defaults;
   }
 
+  /**
+   * Set the additionalFields of this {@link PromptTemplateSpec} instance and return the same
+   * instance.
+   *
+   * @param additionalFields DEPRECATED. Please use additional_fields instead.
+   * @return The same instance of this {@link PromptTemplateSpec} class
+   */
+  @Nonnull
+  public PromptTemplateSpec additionalFields(@Nullable final Object additionalFields) {
+    this.additionalFields = additionalFields;
+    return this;
+  }
+
+  /**
+   * DEPRECATED. Please use additional_fields instead.
+   *
+   * @return additionalFields The additionalFields of this {@link PromptTemplateSpec} instance.
+   * @deprecated
+   */
+  @Deprecated
+  @Nonnull
+  public Object getAdditionalFields() {
+    return additionalFields;
+  }
+
+  /**
+   * Set the additionalFields of this {@link PromptTemplateSpec} instance.
+   *
+   * @param additionalFields DEPRECATED. Please use additional_fields instead.
+   */
+  public void setAdditionalFields(@Nullable final Object additionalFields) {
+    this.additionalFields = additionalFields;
+  }
+
   /**
    * Set the additionalFields of this {@link PromptTemplateSpec} instance and return the same
    * instance.
@@ -285,6 +322,7 @@ public Map<String, Object> toMap() {
     if (template != null) declaredFields.put("template", template);
     if (defaults != null) declaredFields.put("defaults", defaults);
     if (additionalFields != null) declaredFields.put("additionalFields", additionalFields);
+    if (additionalFields != null) declaredFields.put("additionalFields", additionalFields);
     if (responseFormat != null) declaredFields.put("responseFormat", responseFormat);
     if (tools != null) declaredFields.put("tools", tools);
     return declaredFields;
@@ -315,6 +353,7 @@ public boolean equals(@Nullable final java.lang.Object o) {
         && Objects.equals(this.template, promptTemplateSpec.template)
         && Objects.equals(this.defaults, promptTemplateSpec.defaults)
         && Objects.equals(this.additionalFields, promptTemplateSpec.additionalFields)
+        && Objects.equals(this.additionalFields, promptTemplateSpec.additionalFields)
         && Objects.equals(this.responseFormat, promptTemplateSpec.responseFormat)
         && Objects.equals(this.tools, promptTemplateSpec.tools);
   }
@@ -322,7 +361,13 @@ public boolean equals(@Nullable final java.lang.Object o) {
   @Override
   public int hashCode() {
     return Objects.hash(
-        template, defaults, additionalFields, responseFormat, tools, cloudSdkCustomFields);
+        template,
+        defaults,
+        additionalFields,
+        additionalFields,
+        responseFormat,
+        tools,
+        cloudSdkCustomFields);
   }
 
   @Override
@@ -333,6 +378,7 @@ public String toString() {
     sb.append("    template: ").append(toIndentedString(template)).append("\n");
     sb.append("    defaults: ").append(toIndentedString(defaults)).append("\n");
     sb.append("    additionalFields: ").append(toIndentedString(additionalFields)).append("\n");
+    sb.append("    additionalFields: ").append(toIndentedString(additionalFields)).append("\n");
     sb.append("    responseFormat: ").append(toIndentedString(responseFormat)).append("\n");
     sb.append("    tools: ").append(toIndentedString(tools)).append("\n");
     cloudSdkCustomFields.forEach(
diff --git a/prompt-registry/src/main/resources/spec/prompt-registry.yaml b/prompt-registry/src/main/resources/spec/prompt-registry.yaml
index e1046648a..2632a9d2d 100644
--- a/prompt-registry/src/main/resources/spec/prompt-registry.yaml
+++ b/prompt-registry/src/main/resources/spec/prompt-registry.yaml
@@ -29,12 +29,12 @@ paths:
                     example: "Service Unavailable"
   /internal/promptTemplates/provisioning:
     parameters:
-      - in: header
-        name: AI-Main-Tenant
-        required: true
-        schema:
-          type: string
-        description: The main tenant name
+    - in: header
+      name: AI-Main-Tenant
+      required: true
+      schema:
+        type: string
+      description: The main tenant name
     post:
       operationId: registry.controller.prompt_controller.onboard_tenant
       responses:
@@ -369,7 +369,7 @@ components:
       properties:
         type:
           type: string
-          enum: [ "text" ]
+          enum: ["text"]
         text:
           type: string
     ImageContent:
@@ -380,7 +380,7 @@ components:
       properties:
         type:
           type: string
-          enum: [ "image_url" ]
+          enum: ["image_url"]
         image_url:
           type: object
           required:
@@ -405,6 +405,11 @@ components:
           type: object
         additionalFields:
           type: object
+          description: >
+            DEPRECATED. Please use additional_fields instead.
+          deprecated: true
+        additional_fields:
+          type: object
         response_format:
           description: >
             Response format that the model output should adhere to.
@@ -422,7 +427,7 @@ components:
             This is the same as the OpenAI definition.
           items:
             $ref: "#/components/schemas/ChatCompletionTool"
-
+    
     # below ReponseFormats are copied from openapi spec: https://github.com/openai/openai-openapi/blob/e0cb2d721753e13e69e918465795d6e9f87ab15a/openapi.yaml#L12286
     ResponseFormatText:
       type: object
@@ -549,7 +554,7 @@ components:
         documentation about the format. 
         Omitting `parameters` defines a function with an empty parameter list.
       additionalProperties: true
-
+    
     PromptTemplatePostRequest:
       type: object
       required:
@@ -695,4 +700,4 @@ components:
       content:
         application/json:
           schema:
-            $ref: "#/components/schemas/ErrorResponse"
\ No newline at end of file
+            $ref: "#/components/schemas/ErrorResponse"