Add custom assistant context aggregator for Grok due to content requirement in function calling

examples/foundational/14j-function-calling-nim.py

@@ -65,7 +65,7 @@ async def main():
         )
 
         llm = NimLLMService(
-            api_key=os.getenv("NVIDIA_API_KEY"), model="meta/llama-3.1-405b-instruct"
+            api_key=os.getenv("NVIDIA_API_KEY"), model="meta/llama-3.3-70b-instruct"
         )
         # Register a function_name of None to get all functions
         # sent to the same callback with an additional function_name parameter.
@@ -76,18 +76,18 @@ async def main():
                 type="function",
                 function={
                     "name": "get_current_weather",
-                    "description": "Get the current weather",
+                    "description": "Returns the current weather at a location, if one is specified, and defaults to the user's location.",
                     "parameters": {
                         "type": "object",
                         "properties": {
                             "location": {
                                 "type": "string",
-                                "description": "The city and state, e.g. San Francisco, CA",
+                                "description": "The location to find the weather of, or if not provided, it's the default location.",
                             },
                             "format": {
                                 "type": "string",
                                 "enum": ["celsius", "fahrenheit"],
-                                "description": "The temperature unit to use. Infer this from the users location.",
+                                "description": "Whether to use SI or USCS units (celsius or fahrenheit).",
                             },
                         },
                         "required": ["location", "format"],

src/pipecat/services/grok.py

@@ -5,11 +5,102 @@
 #
 
 
+import json
+from dataclasses import dataclass
+
 from loguru import logger
 
 from pipecat.metrics.metrics import LLMTokenUsage
-from pipecat.processors.aggregators.openai_llm_context import OpenAILLMContext
-from pipecat.services.openai import OpenAILLMService
+from pipecat.processors.aggregators.openai_llm_context import (
+    OpenAILLMContext,
+    OpenAILLMContextFrame,
+)
+from pipecat.services.openai import (
+    OpenAIAssistantContextAggregator,
+    OpenAILLMService,
+    OpenAIUserContextAggregator,
+)
+
+
+class GrokAssistantContextAggregator(OpenAIAssistantContextAggregator):
+    """Custom assistant context aggregator for Grok that handles empty content requirement."""
+
+    async def _push_aggregation(self):
+        if not (
+            self._aggregation or self._function_call_result or self._pending_image_frame_message
+        ):
+            return
+
+        run_llm = False
+
+        aggregation = self._aggregation
+        self._reset()
+
+        try:
+            if self._function_call_result:
+                frame = self._function_call_result
+                self._function_call_result = None
+                if frame.result:
+                    # Grok requires an empty content field for function calls
+                    self._context.add_message(
+                        {
+                            "role": "assistant",
+                            "content": "",  # Required by Grok
+                            "tool_calls": [
+                                {
+                                    "id": frame.tool_call_id,
+                                    "function": {
+                                        "name": frame.function_name,
+                                        "arguments": json.dumps(frame.arguments),
+                                    },
+                                    "type": "function",
+                                }
+                            ],
+                        }
+                    )
+                    self._context.add_message(
+                        {
+                            "role": "tool",
+                            "content": json.dumps(frame.result),
+                            "tool_call_id": frame.tool_call_id,
+                        }
+                    )
+                    # Only run the LLM if there are no more function calls in progress.
+                    run_llm = not bool(self._function_calls_in_progress)
+            else:
+                self._context.add_message({"role": "assistant", "content": aggregation})
+
+            if self._pending_image_frame_message:
+                frame = self._pending_image_frame_message
+                self._pending_image_frame_message = None
+                self._context.add_image_frame_message(
+                    format=frame.user_image_raw_frame.format,
+                    size=frame.user_image_raw_frame.size,
+                    image=frame.user_image_raw_frame.image,
+                    text=frame.text,
+                )
+                run_llm = True
+
+            if run_llm:
+                await self._user_context_aggregator.push_context_frame()
+
+            frame = OpenAILLMContextFrame(self._context)
+            await self.push_frame(frame)
+
+        except Exception as e:
+            logger.error(f"Error processing frame: {e}")
+
+
+@dataclass
+class GrokContextAggregatorPair:
+    _user: "OpenAIUserContextAggregator"
+    _assistant: "GrokAssistantContextAggregator"
+
+    def user(self) -> "OpenAIUserContextAggregator":
+        return self._user
+
+    def assistant(self) -> "GrokAssistantContextAggregator":
+        return self._assistant
 
 
 class GrokLLMService(OpenAILLMService):
@@ -101,3 +192,13 @@ class GrokLLMService(OpenAILLMService):
         # Update completion tokens count if it has increased
         if tokens.completion_tokens > self._completion_tokens:
             self._completion_tokens = tokens.completion_tokens
+
+    @staticmethod
+    def create_context_aggregator(
+        context: OpenAILLMContext, *, assistant_expect_stripped_words: bool = True
+    ) -> GrokContextAggregatorPair:
+        user = OpenAIUserContextAggregator(context)
+        assistant = GrokAssistantContextAggregator(
+            user, expect_stripped_words=assistant_expect_stripped_words
+        )
+        return GrokContextAggregatorPair(_user=user, _assistant=assistant)

src/pipecat/services/openai.py

@@ -559,7 +559,6 @@ class OpenAIAssistantContextAggregator(LLMAssistantContextAggregator):
                     self._context.add_message(
                         {
                             "role": "assistant",
-                            "content": "",  # content field required for Grok function calling
                             "tool_calls": [
                                 {
                                     "id": frame.tool_call_id,