Fixes a problem where formatted tools would break

It seems like the first time we are calling _format_tools everything works fine, but on a second run, the _snake_case_to_camel_case converts the input parameters to camelCase and breaks the tools.

libs/aws/langchain_aws/chat_models/bedrock_converse.py

@@ -268,7 +268,7 @@ class Joke(BaseModel):
     max_tokens: Optional[int] = None
     """Max tokens to generate."""
 
-    stop_sequences: Optional[List[str]] = Field(default=None, alias="stop")
+    stop_sequences: Optional[List[str]] = Field(None, alias="stop")
     """Stop generation if any of these substrings occurs."""
 
     temperature: Optional[float] = None
@@ -308,12 +308,17 @@ class Joke(BaseModel):
     have an ARN associated with them.
     """
 
-    endpoint_url: Optional[str] = Field(default=None, alias="base_url")
+    endpoint_url: Optional[str] = Field(None, alias="base_url")
     """Needed if you don't want to default to us-east-1 endpoint"""
 
     config: Any = None
     """An optional botocore.config.Config instance to pass to the client."""
 
+    formatted_tools: List[
+        Dict[Literal["toolSpec"], Dict[str, Union[Dict[str, Any], str]]]
+    ] = Field(default_factory=list, exclude=True)
+    """"Formatted tools to be stored and used in the toolConfig parameter."""
+
     class Config:
         """Configuration for this pydantic object."""
 
@@ -413,7 +418,8 @@ def bind_tools(
     ) -> Runnable[LanguageModelInput, BaseMessage]:
         if tool_choice:
             kwargs["tool_choice"] = _format_tool_choice(tool_choice)
-        return self.bind(tools=_format_tools(tools), **kwargs)
+        self.formatted_tools = _format_tools(tools)
+        return self.bind(tools=self.formatted_tools, **kwargs)
 
     def with_structured_output(
         self,
@@ -467,7 +473,7 @@ def _converse_params(
             }
         if not toolConfig and tools:
             toolChoice = _format_tool_choice(toolChoice) if toolChoice else None
-            toolConfig = {"tools": _format_tools(tools), "toolChoice": toolChoice}
+            toolConfig = {"tools": self.formatted_tools, "toolChoice": toolChoice}
         return _drop_none(
             {
                 "modelId": modelId or self.model_id,