fix(gemini): accept top_logprobs on Google AI Studio models

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

litellm/llms/gemini/chat/transformation.py

@@ -95,6 +95,7 @@ class GoogleAIStudioGeminiConfig(VertexGeminiConfig):
             "n",
             "stop",
             "logprobs",
+            "top_logprobs",
             "frequency_penalty",
             "presence_penalty",
             "seed",

tests/integration/translation/chat_completions/params/test_chat_completions_params_gemini_logprobs.py

@@ -0,0 +1,30 @@
+from dataclasses import replace
+from typing import Final
+
+import pytest
+from integration._support.client import Gateway
+from integration._support.provider import SharedProvider
+from integration.translation.case import TranslationTestCase
+from integration.translation.chat_completions.bases.gemini import GEMINI_3_5_FLASH_TEST_CASE
+from integration.translation.params import with_field
+from integration.translation.runner import assert_translation
+
+GEMINI_3_5_FLASH_TOP_LOGPROBS_TEST_CASE: Final = replace(
+    GEMINI_3_5_FLASH_TEST_CASE,
+    scenario="logprobs_top_logprobs",
+    litellm_request={**GEMINI_3_5_FLASH_TEST_CASE.litellm_request, "logprobs": True, "top_logprobs": 3},
+    expected_provider_request=with_field(
+        with_field(GEMINI_3_5_FLASH_TEST_CASE.expected_provider_request, ("generationConfig", "responseLogprobs"), True),
+        ("generationConfig", "logprobs"),
+        3,
+    ),
+)
+
+CASES: Final = (GEMINI_3_5_FLASH_TOP_LOGPROBS_TEST_CASE,)
+
+
+@pytest.mark.parametrize("case", CASES, ids=lambda case: case.id)
+def test_chat_completions_params_gemini_logprobs(
+    case: TranslationTestCase, gateway: Gateway, provider: SharedProvider
+) -> None:
+    assert_translation(case, gateway, provider)

tests/integration/translation/params.py

@@ -0,0 +1,13 @@
+from collections.abc import Mapping, Sequence
+from typing import Final
+
+from pydantic import JsonValue
+
+
+def with_field(mapping: Mapping[str, JsonValue], path: Sequence[str], value: JsonValue) -> Mapping[str, JsonValue]:
+    """Return a copy of `mapping` with the nested key `path` set to `value`, creating intermediate objects."""
+    head: Final = path[0]
+    if len(path) == 1:
+        return {**mapping, head: value}
+    inner: Final = mapping.get(head)
+    return {**mapping, head: with_field(inner if isinstance(inner, dict) else {}, path[1:], value)}

tests/integration/translation/responses/params/test_responses_params_gemini_logprobs.py

@@ -0,0 +1,26 @@
+from dataclasses import replace
+from typing import Final
+
+import pytest
+from integration._support.client import Gateway
+from integration._support.provider import SharedProvider
+from integration.translation.case import TranslationTestCase
+from integration.translation.params import with_field
+from integration.translation.responses.bases.gemini import GEMINI_3_5_FLASH_TEST_CASE
+from integration.translation.runner import assert_translation
+
+GEMINI_3_5_FLASH_TOP_LOGPROBS_TEST_CASE: Final = replace(
+    GEMINI_3_5_FLASH_TEST_CASE,
+    scenario="top_logprobs",
+    litellm_request={**GEMINI_3_5_FLASH_TEST_CASE.litellm_request, "top_logprobs": 3},
+    expected_provider_request=with_field(
+        GEMINI_3_5_FLASH_TEST_CASE.expected_provider_request, ("generationConfig", "logprobs"), 3
+    ),
+)
+
+CASES: Final = (GEMINI_3_5_FLASH_TOP_LOGPROBS_TEST_CASE,)
+
+
+@pytest.mark.parametrize("case", CASES, ids=lambda case: case.id)
+def test_responses_params_gemini_logprobs(case: TranslationTestCase, gateway: Gateway, provider: SharedProvider) -> None:
+    assert_translation(case, gateway, provider)

tests/unit/llms/gemini/chat/test_transformation.py

@@ -0,0 +1,17 @@
+from litellm.llms.gemini.chat.transformation import GoogleAIStudioGeminiConfig
+
+
+def test_top_logprobs_maps_to_generation_config_logprobs():
+    config = GoogleAIStudioGeminiConfig()
+
+    assert "top_logprobs" in config.get_supported_openai_params("gemini-3.5-flash")
+
+    optional_params = config.map_openai_params(
+        non_default_params={"logprobs": True, "top_logprobs": 3},
+        optional_params={},
+        model="gemini-3.5-flash",
+        drop_params=False,
+    )
+
+    assert optional_params["responseLogprobs"] is True
+    assert optional_params["logprobs"] == 3