rohitg00/ai-engineering-from-scratch · error · ValueError

-32602

-32602

Error message

arguments must be an object

What it means

Error "arguments must be an object" thrown in rohitg00/ai-engineering-from-scratch.

Source

Thrown at certifications/claude/lessons/11-mcp-server-design-and-integration/code/main.py:45

class ProtocolError(Exception):
    def __init__(self, code: int, message: str, data: Any | None = None) -> None:
        super().__init__(message)
        self.code = code
        self.message = message
        self.data = data


@dataclass(frozen=True)
class Capability:
    name: str
    description: str
    input_schema: dict[str, Any]
    handler: Callable[[dict[str, Any]], Any]

    def validate_arguments(self, arguments: Any) -> dict[str, Any]:
        if not isinstance(arguments, dict):
            raise ValueError("arguments must be an object")
        properties = self.input_schema.get("properties", {})
        required = self.input_schema.get("required", [])
        missing = [name for name in required if name not in arguments]
        if missing:
            raise ValueError(f"missing {', '.join(missing)}")
        unexpected = set(arguments) - set(properties)
        if unexpected and self.input_schema.get("additionalProperties") is False:
            raise ValueError(f"unexpected fields: {', '.join(sorted(unexpected))}")

        checks: dict[str, Callable[[Any], bool]] = {
            "integer": lambda value: isinstance(value, int) and not isinstance(value, bool),
            "string": lambda value: isinstance(value, str),
        }
        for name, value in arguments.items():
            if name not in properties:
                continue
            expected = properties[name].get("type")
            if expected not in checks:

View on GitHub (pinned to 39ea8a1c6d)

When it happens

Trigger: Thrown at certifications/claude/lessons/11-mcp-server-design-and-integration/code/main.py:45 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of rohitg00/ai-engineering-from-scratch@39ea8a1c6d (2026-08-26). Data as JSON: /api/errors/39a33a25a8975955. Report an issue: GitHub.