ScrapeGraphAI/Scrapegraph-ai · error · ValueError

Invalid operator usage.

Error message

Invalid operator usage.

What it means

Raised when the input-key boolean expression starts or ends with '&' or '|', or contains doubled ('&&', '||') or mixed ('&|', '|&') operator sequences. These shapes make the expression unparseable, so the node refuses to compute its input keys.

Source

Thrown at scrapegraphai/nodes/base_node.py:178

            + "|".join(re.escape(key) for key in state.keys())
            + r")\b"
        )
        if re.search(pattern, expression):
            raise ValueError(
                "Adjacent state keys found without an operator between them."
            )

        expression = expression.replace(" ", "")

        if (
            expression[0] in "&|"
            or expression[-1] in "&|"
            or "&&" in expression
            or "||" in expression
            or "&|" in expression
            or "|&" in expression
        ):
            raise ValueError("Invalid operator usage.")

        open_parentheses = close_parentheses = 0
        for i, char in enumerate(expression):
            if char == "(":
                open_parentheses += 1
            elif char == ")":
                close_parentheses += 1
            # Check for invalid operator sequences
            if char in "&|" and i + 1 < len(expression) and expression[i + 1] in "&|":
                raise ValueError(
                    "Invalid operator placement: operators cannot be adjacent."
                )

        if open_parentheses != close_parentheses:
            raise ValueError("Missing or unbalanced parentheses in expression.")

        def evaluate_simple_expression(exp: str) -> List[str]:
            """Evaluate an expression without parentheses."""

View on GitHub (pinned to 532dfffbf6)

Solutions

1. Use single '&' and '|' operators only: "key1 & key2 | key3"
2. Strip trailing/leading operators from programmatically built expressions before passing them
3. Never use '&&' or '||' in the input expression

Example fix

// before
input="parsed_docs && user_prompt"
// after
input="parsed_docs & user_prompt"

def valid_ops(expr: str) -> bool:
    e = expr.replace(' ', '')
    return not (e.startswith(('&','|')) or e.endswith(('&','|')) or '&&' in e or '||' in e or '&|' in e or '|&' in e)

try:
    node.get_input_keys(state)
except ValueError as e:
    raise ValueError(f'Bad input expression, check operators: {e}') from e

When it happens

Trigger: input="& key1", input="key1 |", input="key1 && key2", or input="key1 |& key2". Any leading/trailing operator or doubled operator token triggers this immediately after whitespace is stripped.

Common situations: Typos when hand-writing input expressions; dynamically building the expression string and accidentally appending a trailing '|'; assuming '&&'/'||' (Python/JS style) work instead of ScrapeGraphAI's single '&' and '|'.

Related errors

• Adjacent state keys found without an operator between them.
• Invalid operator placement: operators cannot be adjacent.
• Missing or unbalanced parentheses in expression.
• No state keys matched the expression.
• You need to provide key_name inside the node config

AI-assisted analysis of ScrapeGraphAI/Scrapegraph-ai@532dfffbf6 (2026-08-28). Data as JSON: /api/errors/e7985d7f0c28f5e0. Report an issue: GitHub.