Merge accca32aba into 77765fd302

litellm/llms/vertex_ai/gemini/transformation.py

@@ -1215,12 +1215,12 @@ def _transform_request_body(
                     generation_config["mediaResolution"] = media_resolution_value["level"]
 
         data: Final = RequestBody(contents=content)
-        # Vertex rejects system_instruction/tools/toolConfig alongside cachedContent.
+        # Vertex rejects systemInstruction/tools/toolConfig alongside cachedContent.
         # Treat dropping these fields as a request mutation guarded by modify_params.
         can_send_cache_incompatible_fields: Final = cached_content is None or litellm.modify_params is False
         if can_send_cache_incompatible_fields:
             if system_instructions is not None:
-                data["system_instruction"] = system_instructions
+                data["systemInstruction"] = system_instructions
             if tools is not None:
                 data["tools"] = tools
             if tool_choice is not None:

litellm/types/llms/vertex_ai.py

@@ -338,7 +338,7 @@ class CachedContent(TypedDict, total=False):
 
 class RequestBody(TypedDict, total=False):
     contents: Required[list[ContentType]]
-    system_instruction: SystemInstructions
+    systemInstruction: SystemInstructions
     tools: Tools
     toolConfig: ToolConfig
     safetySettings: list[SafetSettingsConfig]

tests/local_testing/test_amazing_vertex_completion.py

@@ -2906,7 +2906,7 @@ def test_gemini_function_call_parameter_in_messages():
                         ],
                     },
                 ],
-                "system_instruction": {
+                "systemInstruction": {
                     "parts": [{"text": "Use search for most queries."}]
                 },
                 "tools": [

tests/test_litellm/llms/vertex_ai/gemini/test_vertex_ai_gemini_transformation.py

@@ -123,7 +123,7 @@ def test_cached_content_respects_modify_params_for_cache_incompatible_fields():
             cached_content=cache_name,
         )
         assert result.get("cachedContent") == cache_name
-        assert "system_instruction" in result
+        assert "systemInstruction" in result
         assert "tools" in result
         assert "toolConfig" in result
         assert "contents" in result
@@ -139,7 +139,7 @@ def test_cached_content_respects_modify_params_for_cache_incompatible_fields():
             cached_content=cache_name,
         )
         assert result_modify_true.get("cachedContent") == cache_name
-        assert "system_instruction" not in result_modify_true
+        assert "systemInstruction" not in result_modify_true
         assert "tools" not in result_modify_true
         assert "toolConfig" not in result_modify_true
         assert "contents" in result_modify_true
@@ -153,13 +153,32 @@ def test_cached_content_respects_modify_params_for_cache_incompatible_fields():
             litellm_params={},
             cached_content=None,
         )
-        assert "system_instruction" in result_no_cache
+        assert "systemInstruction" in result_no_cache
         assert "tools" in result_no_cache
         assert "toolConfig" in result_no_cache
     finally:
         litellm.modify_params = original_modify_params
 
 
+@pytest.mark.parametrize("custom_llm_provider", ["gemini", "vertex_ai"])
+def test_system_instruction_uses_canonical_rest_key(custom_llm_provider):
+    """Regression for #37028: strict generateContent endpoints reject the snake_case alias."""
+    result = _transform_request_body(
+        messages=[
+            {"role": "system", "content": "You are a concise assistant."},
+            {"role": "user", "content": "Reply with exactly: ok"},
+        ],
+        model="gemini-2.5-pro",
+        optional_params={},
+        custom_llm_provider=custom_llm_provider,
+        litellm_params={},
+        cached_content=None,
+    )
+
+    assert "system_instruction" not in result
+    assert result["systemInstruction"]["parts"][0]["text"] == "You are a concise assistant."
+
+
 # Tests for issue #14556: Labels field provider-aware filtering
 def test_google_genai_excludes_labels():
     """Test that Google GenAI/AI Studio endpoints exclude labels when custom_llm_provider='gemini'"""

tests/test_litellm/llms/vertex_ai/test_vertex.py

@@ -1579,5 +1579,5 @@ def test_system_prompt_only_adds_blank_user_message():
     #########################################################
     # system message was passed in
     #########################################################
-    assert len(data["system_instruction"]) == 1
-    assert data["system_instruction"]["parts"][0]["text"] == SYSTEM_INSTRUCTION
+    assert len(data["systemInstruction"]) == 1
+    assert data["systemInstruction"]["parts"][0]["text"] == SYSTEM_INSTRUCTION