fix(llama.cpp) - add ToolChoice and validation of model config values (#838)

Author: awsarron

src/strands/models/llamacpp.py

@@ -33,7 +33,8 @@
 from ..types.content import ContentBlock, Messages
 from ..types.exceptions import ContextWindowOverflowException, ModelThrottledException
 from ..types.streaming import StreamEvent
-from ..types.tools import ToolSpec
+from ..types.tools import ToolChoice, ToolSpec
+from ._validation import validate_config_keys, warn_on_tool_choice_not_supported
 from .model import Model
 
 logger = logging.getLogger(__name__)
@@ -149,12 +150,15 @@ def __init__(
                 (connect, read) timeouts.
             **model_config: Configuration options for the llama.cpp model.
         """
+        validate_config_keys(model_config, self.LlamaCppConfig)
+
         # Set default model_id if not provided
         if "model_id" not in model_config:
             model_config["model_id"] = "default"
 
         self.base_url = base_url.rstrip("/")
         self.config = dict(model_config)
+        logger.debug("config=<%s> | initializing", self.config)
 
         # Configure HTTP client
         if isinstance(timeout, tuple):
@@ -173,19 +177,14 @@ def __init__(
             timeout=timeout_obj,
         )
 
-        logger.debug(
-            "base_url=<%s>, model_id=<%s> | initializing llama.cpp provider",
-            base_url,
-            model_config.get("model_id"),
-        )
-
     @override
     def update_config(self, **model_config: Unpack[LlamaCppConfig]) -> None:  # type: ignore[override]
         """Update the llama.cpp model configuration with provided arguments.
 
         Args:
             **model_config: Configuration overrides.
         """
+        validate_config_keys(model_config, self.LlamaCppConfig)
         self.config.update(model_config)
 
     @override
@@ -514,6 +513,7 @@ async def stream(
         messages: Messages,
         tool_specs: Optional[list[ToolSpec]] = None,
         system_prompt: Optional[str] = None,
+        tool_choice: ToolChoice | None = None,
         **kwargs: Any,
     ) -> AsyncGenerator[StreamEvent, None]:
         """Stream conversation with the llama.cpp model.
@@ -522,6 +522,8 @@ async def stream(
             messages: List of message objects to be processed by the model.
             tool_specs: List of tool specifications to make available to the model.
             system_prompt: System prompt to provide context to the model.
+            tool_choice: Selection strategy for tool invocation. **Note: This parameter is accepted for
+                interface consistency but is currently ignored for this model provider.**
             **kwargs: Additional keyword arguments for future extensibility.
 
         Yields:
@@ -531,19 +533,21 @@ async def stream(
             ContextWindowOverflowException: When the context window is exceeded.
             ModelThrottledException: When the llama.cpp server is overloaded.
         """
+        warn_on_tool_choice_not_supported(tool_choice)
+
         # Track request start time for latency calculation
         start_time = time.perf_counter()
 
         try:
-            logger.debug("formatting request for llama.cpp server")
+            logger.debug("formatting request")
             request = self._format_request(messages, tool_specs, system_prompt)
             logger.debug("request=<%s>", request)
 
-            logger.debug("sending request to llama.cpp server")
+            logger.debug("invoking model")
             response = await self.client.post("/v1/chat/completions", json=request)
             response.raise_for_status()
 
-            logger.debug("processing streaming response")
+            logger.debug("got response from model")
             yield self._format_chunk({"chunk_type": "message_start"})
             yield self._format_chunk({"chunk_type": "content_start", "data_type": "text"})
 
@@ -648,12 +652,10 @@ async def stream(
                 yield self._format_chunk({"chunk_type": "content_stop"})
 
             # Send stop reason
-            logger.debug("finish_reason=%s, tool_calls=%s", finish_reason, bool(tool_calls))
             if finish_reason == "tool_calls" or tool_calls:
                 stop_reason = "tool_calls"  # Changed from "tool_use" to match format_chunk expectations
             else:
                 stop_reason = finish_reason or "end_turn"
-            logger.debug("stop_reason=%s", stop_reason)
             yield self._format_chunk({"chunk_type": "message_stop", "data": stop_reason})
 
             # Send usage metadata if available
@@ -676,7 +678,7 @@ async def stream(
                     }
                 )
 
-            logger.debug("finished streaming response")
+            logger.debug("finished streaming response from model")
 
         except httpx.HTTPStatusError as e:
             if e.response.status_code == 400: