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

invalid JSON-RPC response envelope

Error message

invalid JSON-RPC response envelope

What it means

Error "invalid JSON-RPC response envelope" thrown in rohitg00/ai-engineering-from-scratch.

Source

Thrown at phases/13-tools-and-protocols/31-mcp-conformance-versioning-and-operations/code/main.py:389

@dataclass(frozen=True)
class CaseResult:
    name: str
    passed: bool
    detail: str
    evidence_digest: str


def validate_response(
    request: dict[str, Any],
    status: int,
    response: dict[str, Any],
    era: str,
    capabilities: set[str],
) -> None:
    if not isinstance(response, dict) or response.get("jsonrpc") != "2.0":
        raise ProtocolViolation("invalid JSON-RPC response envelope")
    request_id = request.get("id")
    response_id = response.get("id")
    if type(response_id) is not type(request_id) or response_id != request_id:
        raise ProtocolViolation("response id does not exactly match request id")
    has_result = "result" in response
    has_error = "error" in response
    if has_result == has_error:
        raise ProtocolViolation("response must contain exactly one of result or error")
    if has_result:
        if status != 200:
            raise ProtocolViolation("successful JSON-RPC result requires HTTP 200")
        validate_result(response["result"], era, capabilities)
        validate_method_result(request["method"], response["result"])
        return

    error = response["error"]
    if not isinstance(error, dict):
        raise ProtocolViolation("JSON-RPC error must be an object")

View on GitHub (pinned to 39ea8a1c6d)

When it happens

Trigger: Thrown at phases/13-tools-and-protocols/31-mcp-conformance-versioning-and-operations/code/main.py:389 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

AI-assisted analysis of rohitg00/ai-engineering-from-scratch@39ea8a1c6d (2026-08-26). Data as JSON: /api/errors/3795ad581f3449d7. Report an issue: GitHub.