litellm - 💡(How to fix) Fix [Bug]: Router.get_model_group_info() raises KeyError when dict-style model_group_alias entry omits 'hidden' key [1 pull requests]

Check for existing issues

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

What happened?

get_model_group_info() crashes with KeyError: 'hidden' when a model_group_alias entry is configured as a dict without the 'hidden' key. Since TypedDict is type-hint only, Python does not inject missing keys at runtime. This crashes every single request because get_model_group_info() is called on every router completion via set_response_headers.

Expected behavior: missing 'hidden' key should be treated as hidden=False.

I have a fix ready and will submit a PR immediately after filing this issue.

Steps to Reproduce

1. Install litellm: pip install litellm

2. Run the following Python script:

from litellm import Router router = Router( model_list=[{"model_name": "gpt-4", "litellm_params": {"model": "openai/gpt-4", "api_key": "sk-fake"}}], model_group_alias={"my-alias": {"model": "gpt-4"}} ) router.get_model_group_info("my-alias")

1. Observe KeyError: 'hidden' is raised

Relevant log output

KeyError: 'hidden'
  File "litellm/router.py", line 8700, in get_model_group_info
    if item["hidden"] is True:

What part of LiteLLM is this about?

SDK (litellm Python package)

What LiteLLM version are you on ?

v1.86.0

Twitter / LinkedIn details

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