mem0ai/mem0 · error · ValueError

Extra fields not allowed: {', '.join(extra_fields)}. Please

Error message

Extra fields not allowed: {', '.join(extra_fields)}. Please input only the following fields: {', '.join(allowed_fields)}

What it means

Raised by the Cassandra config's strict extra-fields validator. Any config key that is not a declared model field is rejected outright, with the error listing both the extras and the allowed fields. It is a typo/stale-option guard that runs before connection setup.

Source

Thrown at mem0/configs/vector_stores/cassandra.py:68

        # Either secure_connect_bundle or contact_points must be provided
        if not secure_connect_bundle and not contact_points:
            raise ValueError(
                "Either 'contact_points' or 'secure_connect_bundle' must be provided"
            )

        return values

    @model_validator(mode="before")
    @classmethod
    def validate_extra_fields(cls, values: Dict[str, Any]) -> Dict[str, Any]:
        """Validate that no extra fields are provided."""
        allowed_fields = set(cls.model_fields.keys())
        input_fields = set(values.keys())
        extra_fields = input_fields - allowed_fields

        if extra_fields:
            raise ValueError(
                f"Extra fields not allowed: {', '.join(extra_fields)}. "
                f"Please input only the following fields: {', '.join(allowed_fields)}"
            )

        return values

    model_config = ConfigDict(arbitrary_types_allowed=True)

View on GitHub (pinned to 001c235229)

Solutions

  1. Remove the extra key(s) identified in the error message
  2. Map driver-level options to the supported fields; unsupported ones must be dropped
  3. Compare your key set with the allowed list embedded in the error output
  4. Keep configs version-pinned next to the mem0 release they were written for

Example fix

# before
CassandraConfig(contact_points=["h"], protocol_version=4, keyspace="mem0")

# after
CassandraConfig(contact_points=["h"], keyspace="mem0")
Defensive patterns

Strategy: validation

Validate before calling

from mem0.configs.vector_stores.cassandra import CassandraConfig
def prune_cassandra_extra(cfg: dict) -> dict:
    extra = set(cfg) - set(CassandraConfig.model_fields)
    if extra:
        raise RuntimeError(f"Unexpected cassandra keys: {sorted(extra)}")
    return cfg

Type guard

def cassandra_keys_valid(cfg: dict) -> bool:
    return not (set(cfg) - set(CassandraConfig.model_fields))

Try / catch

from pydantic import ValidationError
try:
    CassandraConfig(**cfg)
except ValidationError as e:
    if "Extra fields not allowed" in str(e):
        # remove driver-level kwargs listed in the message
        ...

Prevention

When it happens

Trigger: Passing CassandraConfig keys like 'hosts', 'port', 'protocol_version', or any option not in its declared field set — e.g. using driver-level keywords instead of the model's names.

Common situations: Translating a raw cassandra-driver Cluster() kwargs dict into mem0 config without pruning; carrying over fields from another vector store's config; fields removed during a mem0 version bump still present in saved configs.

Related errors

AI-assisted analysis of mem0ai/mem0@001c235229 (2026-08-15). Data as JSON: /api/errors/f0f172a3486e86fa. Report an issue: GitHub.