TemporaryFailureTool Class — langchain Architecture

Source Code

libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_tool_retry.py lines 34–62

class TemporaryFailureTool:
    """Tool that fails a certain number of times before succeeding."""

    def __init__(self, fail_count: int):
        """Initialize with the number of times to fail.

        Args:
            fail_count: Number of times to fail before succeeding.
        """
        self.fail_count = fail_count
        self.attempt = 0

    def __call__(self, value: str) -> str:
        """Execute the tool.

        Args:
            value: Input string.

        Returns:
            Success message if attempt >= fail_count.

        Raises:
            ValueError: If attempt < fail_count.
        """
        self.attempt += 1
        if self.attempt <= self.fail_count:
            msg = f"Temporary failure {self.attempt}"
            raise ValueError(msg)
        return f"Success after {self.attempt} attempts: {value}"