crewAIInc/crewAI · error · ValueError

Tavily async client is not initialized. Ensure 'tavily-pytho

Error message

Tavily async client is not initialized. Ensure 'tavily-python' is installed and API key is set.

What it means

TavilyResearchTool._arun raises this ValueError when self._async_client is None prior to awaiting async_client.research(...). As with the sync path, the async client is created only during successful __init__, so the guard rejects calls on a tool that was never properly initialized.

Source

Thrown at lib/crewai-tools/src/crewai_tools/tools/tavily_research_tool/tavily_research_tool.py:181

            ),
        )

        if use_stream:
            return cast(Generator[bytes, None, None], result)

        return self._stringify_response(result)

    async def _arun(
        self,
        input: str,
        model: Literal["mini", "pro", "auto"] | None = None,
        output_schema: dict[str, Any] | None = None,
        stream: bool | None = None,
        citation_format: Literal["numbered", "mla", "apa", "chicago"] | None = None,
    ) -> str | AsyncGenerator[bytes, None]:
        """Asynchronously creates Tavily research tasks or streams results."""
        if not self._async_client:
            raise ValueError(
                "Tavily async client is not initialized. Ensure 'tavily-python' is "
                "installed and API key is set."
            )

        use_stream = self.stream if stream is None else stream
        result = await self._async_client.research(
            input=input,
            model=self.model if model is None else model,
            output_schema=self.output_schema
            if output_schema is None
            else output_schema,
            stream=use_stream,
            citation_format=(
                self.citation_format if citation_format is None else citation_format
            ),
        )

        if use_stream:

View on GitHub (pinned to 754d7323be)

Solutions

  1. Install tavily-python, confirm TAVILY_API_KEY, and instantiate a new TavilyResearchTool.
  2. Check tool._async_client truthiness before the awaited call; rebuild if missing.

Example fix

# before
out = await tool._arun(input="...")  # -> ValueError

# after
if not tool._async_client:
    tool = TavilyResearchTool()
out = await tool._arun(input="...")
Defensive patterns

Strategy: type-guard

Validate before calling

if not getattr(tool, "_async_client", None):
    raise RuntimeError("TavilyResearchTool async client missing; rebuild the tool")

Type guard

def async_research_ready(tool) -> bool:
    """True when the async Tavily research client exists."""
    return getattr(tool, "_async_client", None) is not None

Try / catch

try:
    out = await tool._arun(input="...")
except ValueError as e:
    if "async client is not initialized" in str(e):
        tool = TavilyResearchTool()
        out = await tool._arun(input="...")
    else:
        raise

Prevention

When it happens

Trigger: Awaiting tool._arun(input=...) on an instance constructed without tavily-python (or with client creation skipped).

Common situations: Async agent pipelines holding long-lived tool objects across environment fixes; deploying code that constructs tools before env vars/deps are ready.

Related errors

AI-assisted analysis of crewAIInc/crewAI@754d7323be (2026-08-15). Data as JSON: /api/errors/f18230ea984802aa. Report an issue: GitHub.