feat(py): add system instructions support for openai-compat plugin (#2524)

Author: timere-nemo

py/plugins/compat-oai/src/genkit/plugins/compat_oai/models/model.py

@@ -46,6 +46,8 @@ class OpenAIModel:
     Handles OpenAI API interactions for the Genkit plugin.
     """
 
+    _role_map = {Role.SYSTEM: 'developer', Role.MODEL: 'assistant'}
+
     def __init__(self, model: str, client: OpenAI, registry: GenkitRegistry):
         """
         Initializes the OpenAIModel instance with the specified model and OpenAI client parameters.
@@ -74,7 +76,7 @@ def _get_messages(self, messages: list[Message]) -> list[dict]:
             raise ValueError('No messages provided in the request.')
         return [
             {
-                'role': m.role.value,
+                'role': self._role_map.get(m.role, m.role.value),
                 'content': ''.join(
                     filter(None, (part.root.text for part in m.content))
                 ),
@@ -140,7 +142,7 @@ def _get_evaluated_tool_message_param(
         :return: A dictionary formatted as a response message from a tool.
         """
         return {
-            'role': Role.TOOL.value,
+            'role': self._role_map.get(Role.TOOL, Role.TOOL.value),
             'tool_call_id': tool_call.id,
             'content': self._evaluate_tool(
                 tool_call.function.name, tool_call.function.arguments
@@ -157,7 +159,7 @@ def _get_assistant_message_param(
         :return: A dictionary representing the tool calls formatted for OpenAI.
         """
         return {
-            'role': 'assistant',
+            'role': self._role_map.get(Role.MODEL, 'assistant'),
             'tool_calls': [
                 {
                     'id': tool_call.id,

py/plugins/compat-oai/tests/conftest.py

@@ -31,7 +31,11 @@ def sample_request():
     """Fixture to create a sample GenerateRequest object."""
     return GenerateRequest(
         messages=[
-            Message(role=Role.USER, content=[TextPart(text='Hello, world!')])
+            Message(
+                role=Role.SYSTEM,
+                content=[TextPart(text='You are an assistant')],
+            ),
+            Message(role=Role.USER, content=[TextPart(text='Hello, world!')]),
         ],
         config=OpenAIConfig(
             model=GPT_4,

py/plugins/compat-oai/tests/test_model.py

@@ -35,9 +35,12 @@ def test_get_messages(sample_request):
     model = OpenAIModel(model=GPT_4, client=MagicMock(), registry=MagicMock())
     messages = model._get_messages(sample_request.messages)
 
-    assert len(messages) == 1
-    assert messages[0]['role'] == Role.USER
-    assert messages[0]['content'] == 'Hello, world!'
+    assert len(messages) == 2
+    assert messages[0]['role'] == 'developer'
+    assert messages[0]['content'] == 'You are an assistant'
+
+    assert messages[1]['role'] == Role.USER
+    assert messages[1]['content'] == 'Hello, world!'
 
 
 def test_get_messages_empty():

py/samples/openai/src/main.py

@@ -82,6 +82,7 @@ def get_weather_tool(coordinates: WeatherRequest) -> str:
 async def get_weather_flow(location: str):
     response = await ai.generate(
         model=openai_model('gpt-4'),
+        system='You are an assistant that provides current weather information.',
         config={'model': 'gpt-4-0613', 'temperature': 1},
         prompt=f"What's the weather like in {location} today?",
         tools=['get_weather_tool'],