Wrong input key for Cohere models in BedrockLLM

[HFR1994]

I'm using the cohere.command-r-v1:0 model to test some prompts. After noticing that Cohere doesn't support Chat #33, I changed to BedrockLLM. However I keep getting the following message:

ValueError: Error raised by bedrock service: An error occurred (ValidationException) when calling the InvokeModel operation: Malformed input request: #: required key [message] not found#: extraneous key [prompt] is not permitted, please reformat your input and try again.

I have tried several methods including:

import boto3 

session = boto3.Session(region_name=region)
boto3_bedrock = session.client(service_name="bedrock-runtime")

llm = BedrockLLM(region_name="us-east-1", model_id="cohere.command-r-v1:0" client=boto3_bedrock, verbose=verbose)
llm.invoke("Hey") # Fails

# ----------------------------------

prompt = ChatPromptTemplate.from_messages(
        [
            ("system", "You are a greeting chatbot, greet users only"),
            ("human", "{greeting}"),
        ]
    )
chain = (prompt | llm)

chain.invoke({"greeting": "Hey"}) # Fails

After validating the error message and line 134 in libs/aws/langchain_aws/llm/bedrock I think it should be rewritten as:

@classmethod
def prepare_input(
    cls,
    provider: str,
    model_kwargs: Dict[str, Any],
    prompt: Optional[str] = None,
    system: Optional[str] = None,
    messages: Optional[List[Dict]] = None,
) -> Dict[str, Any]:
    input_body = {**model_kwargs}
    if provider == "anthropic":
        if messages:
            input_body["anthropic_version"] = "bedrock-2023-05-31"
            input_body["messages"] = messages
            if system:
                input_body["system"] = system
            if "max_tokens" not in input_body:
                input_body["max_tokens"] = 1024
        if prompt:
            input_body["prompt"] = _human_assistant_format(prompt)
            if "max_tokens_to_sample" not in input_body:
                input_body["max_tokens_to_sample"] = 1024
    elif provider == "cohere"):
        input_body["message"] = prompt
    elif provider in ("ai21", "meta", "mistral"):
        input_body["prompt"] = prompt
    elif provider == "amazon":
        input_body = dict()
        input_body["inputText"] = prompt
        input_body["textGenerationConfig"] = {**model_kwargs}
    else:
        input_body["inputText"] = prompt

    return input_body

Here are my dependencies:

langchain==0.1.19 langchain-aws==0.1.3

I'm using Python 3.11

[ksaegusa]

Hello. I am facing the same problem.

I think the format of json_body is different between command-r and command, so I have to rewrite the following.

  # Command-R
  if messages:
      input_body["chat_history"] = messages['chat_history']
      input_body["message"] = messages['message']
  # Command
  else:
      input_body["prompt"] = prompt

I assume that Command R will be currently unsupported, just as Claude3 does not support BedrockBase. https://github.com/langchain-ai/langchain-aws/blob/main/libs/aws/langchain_aws/llms/bedrock.py#L744

    @root_validator()
    def validate_environment(cls, values: Dict) -> Dict:
        model_id = values["model_id"]
        if model_id.startswith("anthropic.claude-3"):
            raise ValueError(
                "Claude v3 models are not supported by this LLM."
                "Please use `from langchain_community.chat_models import BedrockChat` "
                "instead."
            )
        return super().validate_environment(values)

It would be better to use ChatBedrock for this purpose.

I am now implementing my own Rv request with the following PR. https://github.com/langchain-ai/langchain-aws/pull/42

[HFR1994]

I was trying to do my own commit; however, I'm not really sure how to locally test it. Any pointers @ksaegusa?

[ksaegusa]

@HFR1994 I followed the steps below to install my repository locally:

git clone https://github.com/ksaegusa/langchain-aws.git
cd langchain-aws
git switch add_cohere_model
pip install -e libs/aws/

After that, I wrote a simple script to verify the functionality.

I hope this answers your question

[ventz]

Thanks for this update!

Any news on when https://github.com/langchain-ai/langchain-aws/issues/43 will be merged?