sgl-project/sglang · error · ValueError

Unknown recipient: {message.recipient}

Error message

Unknown recipient: {message.recipient}

What it means

Inside the commentary-channel branch, a message's recipient is not any of the recognized targets (analysis, functions.*, browser.*), so parse_output_message cannot decide what output item to build and raises.

Source

Thrown at python/sglang/srt/entrypoints/harmony_utils.py:329

                output_items.append(response_item)
        elif message.recipient.startswith("python") or message.recipient.startswith(
            "browser"
        ):
            for content in message.content:
                reasoning_item = ResponseReasoningItem(
                    id=f"rs_{random_uuid()}",
                    type="reasoning",
                    summary=[],
                    content=[
                        ResponseReasoningTextContent(
                            text=content.text, type="reasoning_text"
                        )
                    ],
                    status=None,
                )
                output_items.append(reasoning_item)
        else:
            raise ValueError(f"Unknown recipient: {message.recipient}")
    elif message.channel == "final":
        contents = []
        for content in message.content:
            output_text = ResponseOutputText(
                text=content.text,
                annotations=[],  # TODO
                type="output_text",
                logprobs=None,  # TODO
            )
            contents.append(output_text)
        text_item = ResponseOutputMessage(
            id=f"msg_{random_uuid()}",
            content=contents,
            role=message.author.role,
            status="completed",
            type="message",
        )
        output_items.append(text_item)

View on GitHub (pinned to 0132848349)

Solutions

1. Ensure tool recipients are namespaced as functions.<name> or browser.<action>
2. Adjust prompts/tool definitions so the model emits only recognized recipients
3. Extend parse_output_message with a branch for the new recipient namespace

Example fix

# before
msg = msg.with_recipient("python")
# after
msg = msg.with_recipient("functions.run_python")

KNOWN_PREFIXES = ("functions.", "browser.")
KNOWN_RECIPIENTS = {"analysis"}
assert message.recipient is None or message.recipient in KNOWN_RECIPIENTS or message.recipient.startswith(KNOWN_PREFIXES)

def is_known_recipient(recipient) -> bool:
    if recipient is None:
        return True
    return recipient == "analysis" or recipient.startswith(("functions.", "browser."))

try:
    items = parse_output_message(message)
except ValueError as e:
    if "Unknown recipient" in str(e):
        return []  # skip unrecognized routing
    raise

When it happens

Trigger: A commentary message with an unrecognized recipient string, e.g. 'python' or a hallucinated tool name not prefixed with functions. or browser., reaching parse_output_message.

Common situations: Model hallucinating recipient names; custom system prompts introducing new recipient conventions; new tool namespaces added without parser support.

Related errors

• Unknown channel: {message.channel}
• No call message found for {call_id}
• Unknown input type: {response_msg['type']}
• Unknown output type: {type(output)}
• Invalid number of contents in browser message

AI-assisted analysis of sgl-project/sglang@0132848349 (2026-08-28). Data as JSON: /api/errors/749f267e0aafb840. Report an issue: GitHub.