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

-32022

-32022

Error message

Unsupported protocol version

What it means

Error "Unsupported protocol version" thrown in rohitg00/ai-engineering-from-scratch.

Source

Thrown at phases/13-tools-and-protocols/10-mcp-resources-and-prompts/code/main.py:90

def response_meta() -> dict[str, Any]:
    return {"io.modelcontextprotocol/serverInfo": SERVER_INFO.copy()}


def complete(**payload: Any) -> dict[str, Any]:
    return {"resultType": "complete", **payload, "_meta": response_meta()}


def validate_request_meta(params: dict[str, Any]) -> None:
    meta = params.get("_meta")
    if not isinstance(meta, dict):
        raise RpcError(-32602, "Missing request metadata")
    requested = meta.get("io.modelcontextprotocol/protocolVersion")
    if not isinstance(requested, str):
        raise RpcError(-32602, "Missing or invalid protocol version")
    if requested != PROTOCOL_VERSION:
        raise RpcError(
            -32022,
            "Unsupported protocol version",
            {"supported": [PROTOCOL_VERSION], "requested": requested},
        )
    if not isinstance(meta.get("io.modelcontextprotocol/clientCapabilities"), dict):
        raise RpcError(-32602, "Missing client capabilities")


def server_discover(_: dict[str, Any]) -> dict[str, Any]:
    return complete(
        supportedVersions=[PROTOCOL_VERSION],
        capabilities={
            "resources": {"listChanged": True, "subscribe": True},
            "prompts": {"listChanged": True},
        },
        instructions="Read notes by URI and let users select review prompts.",
        ttlMs=3_600_000,
        cacheScope="public",

View on GitHub (pinned to 39ea8a1c6d)

When it happens

Trigger: Thrown at phases/13-tools-and-protocols/10-mcp-resources-and-prompts/code/main.py:90 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/5cb8358b2c386b87. Report an issue: GitHub.