Wrong response format type when retrieving prompt template from prompt registry

[hokaej]

Describe the Problem/Bug

I created a Prompt Template with a response format of type ResponseFormatJsonObject (under the prompt.registry library). However, when I get the same prompt template from the prompt registry, the response format under the spec returns as type ResponseFormatText.

I have verified that the prompt template created in the prompt registry does contain the json object response format through the direct api call.

    "response_format": {
      "type": "json_object"
    },

Additionally, tested with the java sdk orchestration's chatCompletion.

Steps to Reproduce

1. Run the code snippet
2. Check the spec in the PromptTemplateGetResponse from the call promptClient.getPromptTemplateByUuid(<prompt_id>).
3. getReq.getSpec().getResponseFormat() returns

class ResponseFormatText {
    type: unknown_default_open_api
}

Expected Behavior

I expected the PromptTemplateGetResponse spec responseFormat to return of type ResponseFormatJsonObject.class.

Screenshots

No response

Used Versions

• Java and Maven version via mvn --version: 23.0.2

• SAP Cloud SDK for AI version: tested with 1.9.0 and 1.13.0

• Spring Boot or CAP version: ...

  Dependency tree via mvn dependency:tree

Dependency tree here

Code Examples

    String scenerio = "categorization";
    // 1. Create Prompt Template
    PromptClient promptClient = new PromptClient();
    var spec = PromptTemplateSpec.create()
            .template(
                    SingleChatTemplate.create().role("system").content("Translate from {{?source_language}} to {{?target_language}}."),
                    SingleChatTemplate.create().role("user").content("{{?sentence}}."))
              .responseFormat(ResponseFormatJsonObject.create().type(ResponseFormatJsonObject.TypeEnum.JSON_OBJECT));

    var postReq = PromptTemplatePostRequest.create()
            .name("translate-template")
            .version("1.0.0")
            .scenario("categorization")
            .spec(spec);
    PromptTemplatePostResponse created = promptClient.createUpdatePromptTemplate(postReq);

    String templateId = created.getId().toString();

    var getReq = promptClient.getPromptTemplateByUuid(created.getId());

Stack Trace

No response

Log File

Log file

...

Affected Development Phase

Development

Impact

Blocked

Timeline

release of our api in mid Jan 2026

[rpanackal]

Hi @hokaej ,

Thanks for spotting the bug and creating an issue!

We have already added a fix to the problem and will be available on the next release (soon).

We will update you here as soon as we release.

---

In the meantime, here is a potential workaround - there is a different way to consume the prompt template in Prompt Registry service via Orchestration Service.

Instead of directly retrieving the template (which is currently buggy)

var getReq = promptClient.getPromptTemplateByUuid(created.getId());

You can let the orchestration service fetch the prompt template,

val template = TemplateConfig.reference().byId(created.getId());   // provide the template id

var config = new OrchestrationModuleConfig().withLlmConfig(GPT_4O_MINI);
val configWithTemplate = config.withTemplateConfig(template);

val inputParams = Map.of("source_language", "Italian", "target_language", "German", "sentence", "something");
val prompt = new OrchestrationPrompt(inputParams);

orchestrationClient.chatCompletion(prompt, configWithTemplate)