crewAIInc/crewAI · error · ValueError

Website URL cannot be empty

Error message

Website URL cannot be empty

What it means

Pydantic field_validator error raised while constructing SeleniumScrapingToolSchema when website_url is an empty string. The schema marks website_url as mandatory (Field(...)) and the validator rejects falsy values before any Selenium activity starts. Note it only fires for empty strings — None bypasses this branch in some Pydantic versions and is caught by later required-field enforcement.

Source

Thrown at lib/crewai-tools/src/crewai_tools/tools/selenium_scraping_tool/selenium_scraping_tool.py:30

class SeleniumScrapingToolSchema(FixedSeleniumScrapingToolSchema):
    """Input for SeleniumScrapingTool."""

    website_url: str = Field(
        ...,
        description="Mandatory website url to read the file. Must start with http:// or https://",
    )
    css_element: str = Field(
        ...,
        description="Mandatory css reference for element to scrape from the website",
    )

    @field_validator("website_url")
    @classmethod
    def validate_website_url(cls, v: str) -> str:
        if not v:
            raise ValueError("Website URL cannot be empty")

        if len(v) > 2048:  # Common maximum URL length
            raise ValueError("URL is too long (max 2048 characters)")

        if not re.match(r"^https?://", v):
            raise ValueError("URL must start with http:// or https://")

        try:
            result = urlparse(v)
            if not all([result.scheme, result.netloc]):
                raise ValueError("Invalid URL format")
        except Exception as e:
            raise ValueError(f"Invalid URL: {e!s}") from e

        if re.search(r"\s", v):
            raise ValueError("URL cannot contain whitespace")

        return v

View on GitHub (pinned to 754d7323be)

Solutions

1. Supply a non-empty website_url when creating the tool or invoking run: SeleniumScrapingTool(website_url='https://example.com', css_element='article').
2. Validate upstream input for emptiness before constructing the tool (check `if not url.strip()`).
3. If URLs come from data, filter or skip rows with empty URL values.

Example fix

# before
tool = SeleniumScrapingTool(website_url="", css_element="h1")  # ValidationError

# after
url = url.strip() or "https://fallback.example.com"
tool = SeleniumScrapingTool(website_url=url, css_element="h1")

url = (url or "").strip()
if not url:
    raise ValueError("website_url must be a non-empty string")
tool = SeleniumScrapingTool(website_url=url, css_element="article")

from pydantic import ValidationError

try:
    tool = SeleniumScrapingTool(website_url=url, css_element=css)
except ValidationError as e:
    if any(err['type'] == 'value_error' and 'empty' in err['msg'] for err in e.errors()):
        url = DEFAULT_URL
        tool = SeleniumScrapingTool(website_url=url, css_element=css)
    raise

When it happens

Trigger: Passing SeleniumScrapingToolSchema(website_url='') or SeleniumScrapingTool.run with an empty string URL; e.g. building the schema from user input or config where the URL field was left blank.

Common situations: Form or config-driven tool creation where the URL field is optional in the UI but required by the tool; reading URLs from a file/column where some rows are empty; an agent passing '' because it extracted no URL from the task.

Related errors

• URL cannot be empty
• Invalid URL format. URL must include scheme (http/https) and
• URL is too long (max 2048 characters)
• URL must start with http:// or https://
• Invalid URL format

AI-assisted analysis of crewAIInc/crewAI@754d7323be (2026-08-15). Data as JSON: /api/errors/4fa1f7ed921273d4. Report an issue: GitHub.