LiteLLM silently drops GenerateContentConfig.seed

[svfat]

🔴 Required Information

Describe the Bug:

GenerateContentConfig(seed=42) is not forwarded by LiteLlm. The seed is still present in the request config, but missing from parameters passed to LiteLLM.

Steps to Reproduce:

1. install google-adk==2.5.0
2. run code:

import asyncio
from google.adk.models.lite_llm import _get_completion_inputs
from google.adk.models.llm_request import LlmRequest
from google.genai import types

async def main():
    req = LlmRequest(
        model="openai/gpt-4o-mini",
        config=types.GenerateContentConfig(temperature=0.0, seed=42),
    )
    result = await _get_completion_inputs(req, model=req.model)
    print(result[3])

asyncio.run(main())

Expected Behaviour:

{"temperature": 0.0, "seed": 42}

Observed Behaviour:

{"temperature": 0.0}

There is no error, seed is just silently dropped.

Environment Details:

• ADK: 2.5.0
• OS: macOS
• Python: 3.13

Model Information:

• LiteLLM: Yes
• Model: openai/gpt-4o-mini, but repro does not call the model

🟡 Optional Information

Additional Context:

Looks like seed is missing from explicit parameter mapping in lite_llm.py. I also checked current main and it seems to have the same problem. I can submit a small fix and test if the approach is ok.

How often has this issue occurred?:

• Always (100%)

[surajksharma07]

@svfat seed just isn't in the param allowlist inside _get_completion_inputs, so it gets silently dropped before reaching LiteLLM.

There's already a fix up in #6516 (adds seed to that list) that we've verified locally resolves it — could you pull that branch and confirm it works for your gpt-4o-mini setup as well?

Once you've tested and confirmed it on your side, we can move forward with getting it merged!

[svfat]

@surajksharma07 Confirmed. I tested PR #6516 with openai/gpt-4o-mini, and seed=42 is now forwarded correctly in the LiteLLM generation parameters. The original reproduction now returns {"temperature": 0.0, "seed": 42}