PR #25364: fix(lemonade): use configured api_key instead of hardcoded value

• Repository: BerriAI/litellm
• Author: Bahtya
• State: open | merged: False
• Link: https://github.com/BerriAI/litellm/pull/25364

Description (problem / solution / changelog)

Problem

Fixes #25363

The Lemonade provider ignores the api_key parameter and always uses the hardcoded string "lemonade". When Lemonade Server is configured with a custom API key via LEMONADE_API_KEY, all requests fail authentication.

Root Cause

In litellm/llms/lemonade/chat/transformation.py, _get_openai_compatible_provider_info() receives api_key as a parameter but ignores it entirely:

# Before — hardcoded key
key = "lemonade"

This is inconsistent with how api_base is handled (which properly falls back through the parameter → env var → default).

Solution

Apply the same fallback pattern used for api_base:

# After — respect configured key with fallback
key = (
    api_key
    or get_secret_str("LEMONADE_API_KEY")
    or "lemonade"
)

This preserves backward compatibility (default "lemonade" still works when no key is configured) while enabling authentication when LEMONADE_API_KEY is set.

Testing

• Without LEMONADE_API_KEY: behavior unchanged (key = "lemonade")
• With LEMONADE_API_KEY env var: uses the configured key
• With api_key in litellm_params: uses the explicitly provided key

Changed files

• litellm/llms/lemonade/chat/transformation.py (modified, +5/-1)