microsoft/autogen · error · ValueError

Unknown destination type: {type(destination)}

Error message

Unknown destination type: {type(destination)}

What it means

The tracing config turns a messaging destination into a span attribute string; _get_destination_str accepts only AgentId, TopicId, plain str, or None. Any other object raises ValueError naming its type. This is an internal instrumentation helper, so the error almost always means a custom messaging path passed a non-standard destination object into tracing.

Source

Thrown at python/packages/autogen-core/src/autogen_core/_telemetry/_tracing_config.py:189

        if operation in ["create", "send", "publish"]:
            return SpanKind.PRODUCER
        elif operation in ["receive", "intercept", "process", "ack"]:
            return SpanKind.CONSUMER
        else:
            return SpanKind.CLIENT

    # TODO: Use stringified convention
    def _get_destination_str(self, destination: MessagingDestination) -> str:
        if isinstance(destination, AgentId):
            return f"{destination.type}.({destination.key})-A"
        elif isinstance(destination, TopicId):
            return f"{destination.type}.({destination.source})-T"
        elif isinstance(destination, str):
            return destination
        elif destination is None:
            return ""
        else:
            raise ValueError(f"Unknown destination type: {type(destination)}")

    def _get_operation_type(self, operation: MessagingOperation) -> str:
        if operation in ["send", "publish"]:
            return "publish"
        if operation in ["create"]:
            return "create"
        elif operation in ["receive", "intercept", "ack"]:
            return "receive"
        elif operation in ["process"]:
            return "process"
        else:
            return "Unknown"

View on GitHub (pinned to 027ecf0a37)

Solutions

1. Always pass AgentId, TopicId, str, or None as the destination to messaging operations.
2. If you have a custom destination object, stringify it (`str(dest)`) or map it to AgentId/TopicId before it reaches tracing.
3. Disable/replace the instrumentation config for the custom path if it cannot produce standard destinations.

Example fix

# before
tracer_config._get_destination_str(("worker", "default"))  # ValueError

# after
tracer_config._get_destination_str(AgentId("worker", "default"))  # "worker.(default)-A"

def is_supported_destination(d: object) -> bool:
    return d is None or isinstance(d, (AgentId, TopicId, str))

from typing import Union, Optional
from autogen_core import AgentId, TopicId

MessagingDestinationLike = Optional[Union[AgentId, TopicId, str]]

def coerce_destination(d: MessagingDestinationLike) -> str:
    return d if isinstance(d, str) else ("" if d is None else str(d))

When it happens

Trigger: Calling message-instrumentation code with a destination that is e.g. a tuple, int, or a custom wrapper type instead of AgentId/TopicId/str; a custom runtime subclass that forwards its own destination abstraction into the tracing config.

Common situations: Extending autogen-core with custom routing abstractions; test fakes that use string tuples for destinations; version upgrades where a destination field changed from str to a structured type in user adapters.

Related errors

• Unknown metadata type: {type(metadata)}
• Invalid topic type: {self.type}. Must match the pattern: ^[\
• Invalid topic id: {topic_id}
• The string must contain exactly one function
• buffer_size must be greater than 0.

AI-assisted analysis of microsoft/autogen@027ecf0a37 (2026-08-15). Data as JSON: /api/errors/2cbd2a2ec1051395. Report an issue: GitHub.