litellm - 💡(How to fix) Fix [Bug]: `chatgpt/gpt-5.4` throw exception when stream is `false` [1 participants]

litellm2026-04-23 03:53:13

ON THIS PAGE

Recommended Tools

×6

Utilities matched from this issue’s tags and category — try them while you read without losing context.

GitHub issue graph ai analysis

Paste a GitHub issue URL. We fetch that issue, discover linked issues from bodies/comments/timeline, collect linked pull requests, and produce a structured English report.

The report is written in English Markdown for sharing and archival.

GitHub issue URL

Helpful · Quick feedback

GitHub stats

BerriAI/litellm#26309•Fetched 2026-04-24 05:52:39

View on GitHub

Comments

Participants

Timeline

Reactions

Author

KAIYOHUGO

Participants

KAIYOHUGO

Timeline (top)

labeled ×2

Error Message

{ "error": { "message": "litellm.APIConnectionError: APIConnectionError: ChatgptException - Unknown items in responses API response: []. Received Model Group=gpt-5.4\nAvailable Model Group Fallbacks=None", "type": null, "param": null, "code": "500" } }

Code Example

{
  "model": "gpt-5.4",
  "stream": false,
  "messages": [
    {
      "role": "system",
      "content": "Say Hello to the user"
    },
    {
      "role": "user",
      "content": "Hello"
    }
  ]
}

---

{
  "error": {
    "message": "litellm.APIConnectionError: APIConnectionError: ChatgptException - Unknown items in responses API response: []. Received Model Group=gpt-5.4\nAvailable Model Group Fallbacks=None",
    "type": null,
    "param": null,
    "code": "500"
  }
}

---

litellm-1   |     raise e
litellm-1   |   File "/app/.venv/lib/python3.13/site-packages/litellm/utils.py", line 1892, in wrapper_async
litellm-1   |     result = await original_function(*args, **kwargs)
litellm-1   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
litellm-1   |   File "/app/.venv/lib/python3.13/site-packages/litellm/main.py", line 639, in acompletion
litellm-1   |     raise exception_type(
litellm-1   |           ~~~~~~~~~~~~~~^
litellm-1   |         model=model,
litellm-1   |         ^^^^^^^^^^^^
litellm-1   |     ...<3 lines>...
litellm-1   |         extra_kwargs=kwargs,
litellm-1   |         ^^^^^^^^^^^^^^^^^^^^
litellm-1   |     )
litellm-1   |     ^
litellm-1   |   File "/app/.venv/lib/python3.13/site-packages/litellm/litellm_core_utils/exception_mapping_utils.py", line 2461, in exception_type
litellm-1   |     raise e  # it's already mapped
litellm-1   |     ^^^^^^^
litellm-1   |   File "/app/.venv/lib/python3.13/site-packages/litellm/litellm_core_utils/exception_mapping_utils.py", line 635, in exception_type
litellm-1   |     raise APIConnectionError(
litellm-1   |     ...<7 lines>...
litellm-1   |     )
litellm-1   | litellm.exceptions.APIConnectionError: litellm.APIConnectionError: APIConnectionError: ChatgptException - Unknown items in responses API response: []. Received Model Group=gpt-5.4

RAW_BUFFERClick to expand / collapse

Check for existing issues

I have searched the existing issues and checked that my issue is not a duplicate.

What happened?

The chatgpt/gpt-5.4 throw exception when stream is false. It work fine with other chatgpt/* model.

Steps to Reproduce

Try send something like this.

{
  "model": "gpt-5.4",
  "stream": false,
  "messages": [
    {
      "role": "system",
      "content": "Say Hello to the user"
    },
    {
      "role": "user",
      "content": "Hello"
    }
  ]
}

Then you will always get this:

{
  "error": {
    "message": "litellm.APIConnectionError: APIConnectionError: ChatgptException - Unknown items in responses API response: []. Received Model Group=gpt-5.4\nAvailable Model Group Fallbacks=None",
    "type": null,
    "param": null,
    "code": "500"
  }
}

Relevant log output

litellm-1   |     raise e
litellm-1   |   File "/app/.venv/lib/python3.13/site-packages/litellm/utils.py", line 1892, in wrapper_async
litellm-1   |     result = await original_function(*args, **kwargs)
litellm-1   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
litellm-1   |   File "/app/.venv/lib/python3.13/site-packages/litellm/main.py", line 639, in acompletion
litellm-1   |     raise exception_type(
litellm-1   |           ~~~~~~~~~~~~~~^
litellm-1   |         model=model,
litellm-1   |         ^^^^^^^^^^^^
litellm-1   |     ...<3 lines>...
litellm-1   |         extra_kwargs=kwargs,
litellm-1   |         ^^^^^^^^^^^^^^^^^^^^
litellm-1   |     )
litellm-1   |     ^
litellm-1   |   File "/app/.venv/lib/python3.13/site-packages/litellm/litellm_core_utils/exception_mapping_utils.py", line 2461, in exception_type
litellm-1   |     raise e  # it's already mapped
litellm-1   |     ^^^^^^^
litellm-1   |   File "/app/.venv/lib/python3.13/site-packages/litellm/litellm_core_utils/exception_mapping_utils.py", line 635, in exception_type
litellm-1   |     raise APIConnectionError(
litellm-1   |     ...<7 lines>...
litellm-1   |     )
litellm-1   | litellm.exceptions.APIConnectionError: litellm.APIConnectionError: APIConnectionError: ChatgptException - Unknown items in responses API response: []. Received Model Group=gpt-5.4

What part of LiteLLM is this about?

Proxy

What LiteLLM version are you on ?

v1.83.8

Twitter / LinkedIn details

No response

extent analysis

TL;DR

The issue can be fixed by setting the stream parameter to true when using the gpt-5.4 model.

Guidance

Verify that the issue is specific to the gpt-5.4 model by testing other models with stream set to false.
Check the LiteLLM documentation to see if there are any known issues or limitations with the gpt-5.4 model and the stream parameter.
Try setting the stream parameter to true when using the gpt-5.4 model to see if it resolves the issue.
If the issue persists, check the LiteLLM version and consider upgrading to a newer version if available.

Notes

The issue seems to be specific to the gpt-5.4 model and the stream parameter set to false. The error message suggests that there is an unknown item in the API response, which may be related to the model or the parameter.

Recommendation

Apply workaround: set stream to true when using the gpt-5.4 model, as this may resolve the issue.

Vote matrix · Quick signals

Works

Did the solution work? Tap to confirm.

Easy Fix

Was it a quick fix?

Time Saver

Did it save you time?

Blocking

Was it severely blocking?

Common Issue

Are others likely hitting this too?

Flaky / Intermittent

Is it intermittent?

Verified / Reproducible

Can you reproduce it reliably?

#api #memory optimization #batch processing #GPU compatibility #latency issue

Still need to ship something?

×6

Another batch ranked right after the header list — different links, same matching logic.

Data

Security

Network

Code

UI/UX

Text

System

Multimedia

Protocol

API

Engineering

litellm - 💡(How to fix) Fix [Bug]: `chatgpt/gpt-5.4` throw exception when stream is `false` [1 participants]

Recommended Tools

GitHub issue graph ai analysis

Error Message

Code Example

Check for existing issues

What happened?

Steps to Reproduce

Relevant log output

What part of LiteLLM is this about?

What LiteLLM version are you on ?

Twitter / LinkedIn details

extent analysis

TL;DR

Guidance

Notes

Recommendation

Still need to ship something?

TRENDING

litellm - 💡(How to fix) Fix [Bug]: `chatgpt/gpt-5.4` throw exception when stream is `false` [1 participants]

Recommended Tools

GitHub issue graph ai analysis

Error Message

Code Example

Check for existing issues

What happened?

Steps to Reproduce

Relevant log output

What part of LiteLLM is this about?

What LiteLLM version are you on ?

Twitter / LinkedIn details

extent analysis

TL;DR

Guidance

Notes

Recommendation

Still need to ship something?

RELATED_DISCOVERY

TRENDING