BerriAI/litellm · error · ValueError

Cohere API key is required. Please set 'COHERE_API_KEY' or '

Error message

Cohere API key is required. Please set 'COHERE_API_KEY' or 'CO_API_KEY' or 'litellm.cohere_key'

What it means

Error "Cohere API key is required. Please set 'COHERE_API_KEY' or 'CO_API_KEY' or 'litellm.cohere_key'" thrown in BerriAI/litellm.

Source

Thrown at litellm/llms/cohere/rerank/transformation.py:89

                top_n=top_n,
                rank_fields=rank_fields,
                return_documents=return_documents,
                max_chunks_per_doc=max_chunks_per_doc,
            )
        )

    def validate_environment(
        self,
        headers: dict,
        model: str,
        api_key: str | None = None,
        optional_params: dict | None = None,
    ) -> dict:
        if api_key is None:
            api_key = get_secret_str("COHERE_API_KEY") or get_secret_str("CO_API_KEY") or litellm.cohere_key

        if api_key is None:
            raise ValueError(
                "Cohere API key is required. Please set 'COHERE_API_KEY' or 'CO_API_KEY' or 'litellm.cohere_key'"
            )

        default_headers: Final = {
            "Authorization": f"Bearer {api_key}",
            "accept": "application/json",
            "content-type": "application/json",
        }

        # If 'Authorization' is provided in headers, it overrides the default.
        if "Authorization" in headers:
            default_headers["Authorization"] = headers["Authorization"]

        # Merge other headers, overriding any default ones except Authorization
        return {**default_headers, **headers}

    def transform_rerank_request(
        self,

View on GitHub (pinned to 6c2dcb801b)

Solutions

1. Set COHERE_API_KEY (or CO_API_KEY) or pass api_key.

When it happens

Trigger: Thrown at litellm/llms/cohere/rerank/transformation.py:89 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of BerriAI/litellm@6c2dcb801b (2026-08-15). Data as JSON: /api/errors/88cb2e264514d7b5. Report an issue: GitHub.