chroma-core/chroma · error · ValueError

Keyword argument {key} is not a primitive type

Error message

Keyword argument {key} is not a primitive type

What it means

AmazonBedrockEmbeddingFunction persists itself via get_config(), which stores arbitrary **kwargs, so the constructor enforces that every kwarg value is a JSON-friendly primitive (str, int, float, bool, list, dict, tuple). Any non-conforming value — a boto3 Session, botocore Config, client object, or custom class instance — fails this isinstance check and raises ValueError. The dedicated session= parameter is intentionally excluded from this check because it is serialized separately into session_args.

Source

Thrown at chromadb/utils/embedding_functions/amazon_bedrock_embedding_function.py:39

        Args:
            session (boto3.Session): The boto3 session to use. You need to have boto3
                installed, `pip install boto3`. Access & secret key are not supported.
            model_name (str, optional): Identifier of the model, defaults to "amazon.titan-embed-text-v1"
            **kwargs: Additional arguments to pass to the boto3 client.

        Example:
            >>> import boto3
            >>> session = boto3.Session(profile_name="profile", region_name="us-east-1")
            >>> bedrock = AmazonBedrockEmbeddingFunction(session=session)
            >>> texts = ["Hello, world!", "How are you?"]
            >>> embeddings = bedrock(texts)
        """

        self.model_name = model_name
        # check kwargs are primitives only
        for key, value in kwargs.items():
            if not isinstance(value, (str, int, float, bool, list, dict, tuple)):
                raise ValueError(f"Keyword argument {key} is not a primitive type")
        self.kwargs = kwargs

        # Store the session for serialization
        self._session_args = {}
        if hasattr(session, "region_name") and session.region_name:
            self._session_args["region_name"] = session.region_name
        if hasattr(session, "profile_name") and session.profile_name:
            self._session_args["profile_name"] = session.profile_name

        self._client = session.client(
            service_name="bedrock-runtime",
            **kwargs,
        )

    def __call__(self, input: Documents) -> Embeddings:
        """
        Generate embeddings for the given documents.

View on GitHub (pinned to aecdd12c8a)

Solutions

1. Pass the boto3 Session through the session= parameter — it is handled and serialized separately (region_name/profile_name).
2. Convert typed objects to plain primitives before passing: botocore Config → {"retries": {"max_attempts": 5, "mode": "standard"}}, paths as strings, options as dicts/lists.
3. Drop the non-serializable kwarg entirely if Bedrock does not need it.

Example fix

# before: ValueError "Keyword argument config is not a primitive type"
import botocore.config
ef = AmazonBedrockEmbeddingFunction(
    session=boto3.Session(),
    config=botocore.config.Config(retries={"max_attempts": 5}),
)

# after
import botocore.config
session = boto3.Session(region_name="us-east-1")
session.client("bedrock-runtime", config=botocore.config.Config(retries={"max_attempts": 5}))
ef = AmazonBedrockEmbeddingFunction(session=session)  # or pass primitives-only kwargs

PRIMITIVES = (str, int, float, bool, list, dict, tuple)

def check_kwargs_primitive(kwargs: dict) -> None:
    bad = [k for k, v in kwargs.items() if not isinstance(v, PRIMITIVES) or isinstance(v, type)]
    if bad:
        raise TypeError(f"Non-primitive kwargs will be rejected: {bad}")

check_kwargs_primitive(bedrock_kwargs)
ef = AmazonBedrockEmbeddingFunction(session=session, **bedrock_kwargs)

def is_primitive_kwarg(value: object) -> bool:
    if isinstance(value, type):  # a class, not an instance
        return False
    if isinstance(value, (str, int, float, bool)):
        return True
    if isinstance(value, (list, tuple)):
        return all(is_primitive_kwarg(v) for v in value)
    if isinstance(value, dict):
        return all(isinstance(k, str) and is_primitive_kwarg(v) for k, v in value.items())
    return False

try:
    ef = AmazonBedrockEmbeddingFunction(session=session, **kwargs)
except ValueError as e:
    if "not a primitive type" in str(e):
        kwargs = {k: v for k, v in kwargs.items() if is_primitive_kwarg(v)}  # or convert objects to dicts
        ef = AmazonBedrockEmbeddingFunction(session=session, **kwargs)
    else:
        raise

When it happens

Trigger: AmazonBedrockEmbeddingFunction(session=s, some_param=<object>) — e.g. passing a botocore.config.Config instance, a boto3 Session, or any class instance through **kwargs instead of primitives like retries={"max_attempts": 5} or strings/numbers.

Common situations: Copying boto3 client setup code into the embedding function call; trying to hand the Session through kwargs instead of the session= argument; passing typed config objects that feel natural in boto3-land but are not serializable.

Related errors

• The model name cannot be changed after the embedding functio
• The boto3 python package is not installed. Please install it
• Keyword argument {key} is not a primitive type
• Failed to register embedding function: {e}
• Failed to register sparse embedding function: {e}

AI-assisted analysis of chroma-core/chroma@aecdd12c8a (2026-08-16). Data as JSON: /api/errors/76206d0285198465. Report an issue: GitHub.