can1357/oh-my-pi · error · ValueError

ready.supportedProtocolVersions must be integers

Error message

ready.supportedProtocolVersions must be integers

What it means

When parsing a ReadyEvent, supportedProtocolVersions must be a JSON list of integers. The check explicitly rejects bools (a bool is an int in Python) and non-int members, raising ValueError if any element fails, because version negotiation depends on real integer protocol versions.

Source

Thrown at python/omp-rpc/src/omp_rpc/protocol.py:1633

def parse_extension_error(payload: JsonObject) -> ExtensionError:
    return ExtensionError(
        extension_path=_require_str(payload, "extensionPath"),
        event=_require_str(payload, "event"),
        error=_require_str(payload, "error"),
    )


def parse_notification(payload: JsonObject) -> RpcNotification:
    event_type = payload.get("type")
    if event_type == "ready":
        raw_versions = payload.get("supportedProtocolVersions")
        supported_versions: tuple[int, ...] | None = None
        if raw_versions is not None:
            if not isinstance(raw_versions, list) or any(
                not isinstance(version, int) or isinstance(version, bool)
                for version in raw_versions
            ):
                raise ValueError("ready.supportedProtocolVersions must be integers")
            supported_versions = tuple(raw_versions)
        return ReadyEvent(
            protocol_version=_optional_int(payload, "protocolVersion"),
            supported_protocol_versions=supported_versions,
            max_frame_bytes=_optional_int(payload, "maxFrameBytes"),
            max_reassembled_frame_bytes=_optional_int(
                payload, "maxReassembledFrameBytes"
            ),
        )
    if event_type == "extension_ui_request":
        return parse_extension_ui_request(payload)
    if event_type == "extension_error":
        return parse_extension_error(payload)
    if event_type == "agent_start":
        return AgentStartEvent()
    if event_type == "agent_end":
        return AgentEndEvent(
            messages=parse_agent_messages(

View on GitHub (pinned to 9690622007)

Solutions

Fix the server to emit an array of plain integers, e.g. [1, 2].
Ensure versions are serialized as JSON numbers, not quoted strings.
Verify no encoder converts ints to floats/bools during serialization.
Check client/server protocol versions are compatible.

Example fix

// before
{"ready": {"supportedProtocolVersions": ["1", "2"]}}
// after
{"ready": {"supportedProtocolVersions": [1, 2]}}

Defensive patterns

Strategy: validation

Validate before calling

versions = ready.get("supportedProtocolVersions")
if versions is not None and not (isinstance(versions, list) and all(isinstance(v, int) and not isinstance(v, bool) for v in versions)):
    raise TypeError("supportedProtocolVersions must be a list of integers")

Type guard

def is_valid_version_list(ready: dict) -> bool:
    versions = ready.get("supportedProtocolVersions")
    return versions is None or (isinstance(versions, list) and all(type(v) is int for v in versions))

Try / catch

try:
    ready = parse_ready_event(payload)
except ValueError as exc:
    raise ProtocolError(f"bad handshake: {payload!r}") from exc

Prevention

Serialize protocol versions as JSON numbers, never strings or floats.
Remember bool is a subclass of int in Python — use type(v) is int in your own checks.
Add a handshake integration test between client and server.

When it happens

Trigger: A server sends ready.supportedProtocolVersions as strings (e.g. ["1", "2"]), floats, booleans, a single int instead of a list, or a non-list container like a dict.

Common situations: Server implementations serializing versions as strings; JSON encoders emitting 1.0 instead of 1; a naive bool used as a version flag; protocol handshake changes after a server upgrade.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/4716da8c429ab59b. Report an issue: GitHub.