[Bug]: DELETE /v1/responses/{id} fails via LiteLLM passthrough (Invalid model name passed in model=None)

[jrkropp]

What happened?

OpenAI's Responses API allows developers to temporarily store the model’s responses server-side. Developers can continue the conversation thread by specifying previous_response_id in future requests. This is useful in reasoning loops where you want to retain the model’s internal reasoning context across requests (since openai doesn't make reasoning tokens visable).

Once done, OpenAI lets you programmatically delete the stored responses via:
DELETE https://api.openai.com/v1/responses/{response_id} or via OpenAI SDK client.responses.delete("resp_123")

Deleting responses via LiteLLM proxy returns errors, usually:

• 400 Bad Request (adelete_responses: Invalid model name passed in model=None), or
• 500 Internal Server Error (if using LiteLLMs openai passthrough endpoint)

Loving LiteLLM so far. This is a great project!

OpenAI Documentation: https://platform.openai.com/docs/api-reference/responses/delete
LiteLLM Documentation: https://docs.litellm.ai/docs/response_api#delete-a-response-1

---

Steps to reproduce

from openai import OpenAI

PROXY_BASE = "https://LITELLM_PROXY_BASE_URL/v1"
API_KEY    = "sk-***"

client = OpenAI(base_url=PROXY_BASE, api_key=API_KEY)

resp = client.responses.create(
    model="gpt-4.1",
    input="Say hi",
    store=True,
)
print("created response_id:", resp.id)

client.responses.delete(resp.id)

Relevant log output

Traceback (most recent call last):
  File "c:\Users\username\from openai import OpenAI.py", line 17, in <module>
    client.responses.delete(resp.id)
  File "C:\Users\username\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.11_qbz5n2kfra8p0\LocalCache\local-packages\Python311\site-packages\openai\resources\responses\responses.py", line 914, in delete
    return self._delete(
           ^^^^^^^^^^^^^
  File "C:\Users\username\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.11_qbz5n2kfra8p0\LocalCache\local-packages\Python311\site-packages\openai\_base_client.py", line 1275, in delete        
    return self.request(cast_to, opts)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\username\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.11_qbz5n2kfra8p0\LocalCache\local-packages\Python311\site-packages\openai\_base_client.py", line 1034, in request       
    raise self._make_status_error_from_response(err.response) from None

openai.BadRequestError: Error code: 400 - {
  'error': {
    'message': "{'error': 'adelete_responses: Invalid model name passed in model=None. "
               "Call `/v1/models` to view available models for your key.'}",
    'type': 'None',
    'param': 'None',
    'code': '400'
  }
}

Are you a ML Ops Team?

No

What LiteLLM version are you on ?

v1.69.0

Twitter / LinkedIn details

No response

[ishaan-jaff]

cc @jugaldb this is a good issue if you're looking for one