crewAIInc/crewAI · error · BedrockValidationError

knowledge_base_id cannot be empty

Error message

knowledge_base_id cannot be empty

What it means

A BedrockValidationError raised in BedrockKBRetrieverTool._validate_parameters when knowledge_base_id is falsy (None or ''). AWS Retrieve requires a knowledge base ID, so the tool refuses to construct without one; like the agent tool, the whole block is re-wrapped as "Parameter validation failed: ..." by the caller's except.

Source

Thrown at lib/crewai-tools/src/crewai_tools/aws/bedrock/knowledge_base/retriever_tool.py:93

    def _build_retrieval_configuration(self) -> dict[str, Any]:
        """Build the retrieval configuration based on provided parameters.

        Returns:
            Dict[str, Any]: The constructed retrieval configuration
        """
        vector_search_config = {}

        if self.number_of_results is not None:
            vector_search_config["numberOfResults"] = self.number_of_results

        return {"vectorSearchConfiguration": vector_search_config}

    def _validate_parameters(self) -> None:
        """Validate the parameters according to AWS API requirements."""
        try:
            if not self.knowledge_base_id:
                raise BedrockValidationError("knowledge_base_id cannot be empty")
            if not isinstance(self.knowledge_base_id, str):
                raise BedrockValidationError("knowledge_base_id must be a string")
            if len(self.knowledge_base_id) > 10:
                raise BedrockValidationError(
                    "knowledge_base_id must be 10 characters or less"
                )
            if not all(c.isalnum() for c in self.knowledge_base_id):
                raise BedrockValidationError(
                    "knowledge_base_id must contain only alphanumeric characters"
                )

            if self.next_token:
                if not isinstance(self.next_token, str):
                    raise BedrockValidationError("next_token must be a string")
                if len(self.next_token) < 1 or len(self.next_token) > 2048:
                    raise BedrockValidationError(
                        "next_token must be between 1 and 2048 characters"
                    )

View on GitHub (pinned to 754d7323be)

Solutions

1. Copy the Knowledge base ID from the Bedrock console (10 alphanumeric characters, e.g. 'HHTQ7DFZLV') and pass it explicitly.
2. Fail fast on config: knowledge_base_id=os.environ['BEDROCK_KB_ID'] instead of os.environ.get(...) or ''.
3. Check you are not passing the data source ID or collection ARN — those are different fields.

Example fix

# before
tool = BedrockKBRetrieverTool(knowledge_base_id=os.environ.get("BEDROCK_KB_ID", ""))

# after
tool = BedrockKBRetrieverTool(knowledge_base_id=os.environ["BEDROCK_KB_ID"])  # KeyError tells you the var is missing

import os, re

kb_id = os.environ.get("BEDROCK_KB_ID", "")
if not kb_id:
    raise SystemExit("BEDROCK_KB_ID not set — copy the Knowledge base ID from the Bedrock console")

def is_kb_id(v) -> bool:
    return isinstance(v, str) and bool(v)

try:
    tool = BedrockKBRetrieverTool(knowledge_base_id=kb_id)
except BedrockValidationError as e:
    raise ValueError(f"Bad KB config: {e}") from e

When it happens

Trigger: Creating the KB retriever tool with knowledge_base_id='' or None — typically the ID was loaded from a missing env var/config and defaulted to empty.

Common situations: Env var (e.g. BEDROCK_KB_ID) not exported in the runtime environment; wrong attribute copied from the console (knowledge base name instead of the 10-char alphanumeric ID); multi-stage pipelines where the ID is conditionally set and the branch was skipped.

Related errors

• agent_id cannot be empty
• agent_alias_id cannot be empty
• knowledge_base_id must be a string
• knowledge_base_id must be 10 characters or less
• knowledge_base_id must contain only alphanumeric characters

AI-assisted analysis of crewAIInc/crewAI@754d7323be (2026-08-15). Data as JSON: /api/errors/fb3d5df6d0020cdb. Report an issue: GitHub.