Does Batch API support Responses endpoint with reusable prompts?

API
, ,
1

I’m running into a consistent validation failure when trying to use the Batch API with the Responses endpoint and a saved/reusable prompt.

What I’m doing:

  • Endpoint: /v1/responses
  • Each JSONL line looks like:
{“custom_id”: “artist_1”,“method”: “POST”,“url”: “/v1/responses”,“body”: {“prompt”: {“id”: “pmpt_xxx”,“version”: “9”,“variables”: {“artist_name”: “Example”,“artist_data”: “Some data”}}}}

The body works fine in single responses.create() calls.

Problem:
When submitted via the Batch API, the job fails validation with the error that input is missing. My understanding is that input is not required when calling a saved prompt — but Batch seems to treat it as mandatory.

Question:

  1. Can the Batch API actually be used with the Responses endpoint when the request body only references a saved prompt?
  2. Or is this currently unsupported, meaning Batch requires the input parameter regardless?

Would be great to get confirmation on whether this is expected behavior or a bug.

Thanks!

Carl

2

Sure, you might have a prompt id, but what is your API call asking the AI?

That should be your "input": field, that is failing validation on you.

Input is only optional on the Responses endpoint because conversation id with the input message is an alternative.

A “prompt” is a terrible name. It should be “settings” or “template”.

4

I have a similar problem in this topic. Instead of ”input”: (which I’m actually using), Batch API blames me for not using ”model:” parameter:

BatchError(code='invalid_request', line=1, message='Model parameter is required.', param='body.model')

My batches look like this:

{"custom_id": "311360", "method": "POST", "url": "/v1/responses", "body": {"prompt": {"id": "pmpt_XXX", "version": "35"}, "input": "XXX", "reasoning": {"summary": "auto"}}}

I have the newest openai version 1.107.3.

The problem is, when using reusable prompts, it’s pointless to submit body.modelon each individual batch request because I already chose a model when I was defining my reusable prompt and, what’s more, models may differ per prompt version in my case which makes things even more complicated. So the question is: is there a way to skip the parameter body.model or assign it anything like a default value?

1 Like
5

I can confirm that I’ve successfully used the batch API with a reusable prompt ID, using /v1/responses API.
You need an “input” (user input), and you can provide a reusable system prompt using the “prompt” object containing an “id” just like in the normal real-time API.