why openai.chat's parent_span is null, trace context is lost

[15029836736]

I am using traceloop.sdk to auto instrumentation openai, but the span named "openai.chat" , this span's parent_id is null, not is task's span id, so the trace context is lost
my python code

from traceloop.sdk import Traceloop
from opentelemetry.sdk.trace.export import ConsoleSpanExporter
Traceloop.init(
    app_name="agent_demo",
    resource_attributes={"system.code": "TEST"},
    exporter=ConsoleSpanExporter(),
    disable_batch=True
)

from openai import OpenAI
client = OpenAI(api_key="xxxxxxxx")

from traceloop.sdk.decorators import workflow, task, agent, tool
@task()
class ResearchAgent:
    def openai_chat(self):
        completion = client.chat.completions.create(
            model="gpt-3.5-turbo",
            messages=[{"role": "user", "content": "Tell me a joke about opentelemetry"}],
        )
        return completion.choices[0].message.content

@workflow(name="AgentSystem")
class AgentSystem:
    def __init__(self):
        self.research_agent = ResearchAgent()
    def main(self):
        self.research_agent.openai_chat()

if __name__ == "__main__":
    s = AgentSystem()
    s.main()

I expect is 3 spans and 1 trace , relation like：workflow --> task（parent is workflow）--> openai_chat (parent is task)
but actual behavior is 3 spans and 2 traces, like:

{
    "name": "AgentSystem.workflow",
    "context": {
        "trace_id": "0x9c99221da2caa5dd06696c9076359892",
        "span_id": "0xa3131a22b53bb48a",
        "trace_state": "[]"
    },
    "kind": "SpanKind.INTERNAL",
    "parent_id": null,
    "start_time": "2026-01-22T11:22:35.463076Z",
    "end_time": "2026-01-22T11:22:35.464117Z",
    "status": {
        "status_code": "UNSET"
    },
    "attributes": {
        "traceloop.workflow.name": "AgentSystem",
        "traceloop.span.kind": "workflow",
        "traceloop.entity.name": "AgentSystem",
        "traceloop.entity.input": "{\"args\": [], \"kwargs\": {}}",
        "traceloop.entity.output": "\"AgentSystem\""
    },
    "events": [],
    "links": [],
    "resource": {
        "attributes": {
            "telemetry.sdk.language": "python",
            "telemetry.sdk.name": "opentelemetry",
            "telemetry.sdk.version": "1.39.1",
            "system.code": "TEST",
            "service.name": "agent_demo"
        },
        "schema_url": ""
    }
}

{
    "name": "ResearchAgent.task",
    "context": {
        "trace_id": "0x9c99221da2caa5dd06696c9076359892",
        "span_id": "0x73d74aab0550fc80",
        "trace_state": "[]"
    },
    "kind": "SpanKind.INTERNAL",
    "parent_id": "0xa3131a22b53bb48a",
    "start_time": "2026-01-22T11:22:35.463883Z",
    "end_time": "2026-01-22T11:22:35.463916Z",
    "status": {
        "status_code": "UNSET"
    },
    "attributes": {
        "traceloop.workflow.name": "AgentSystem",
        "traceloop.span.kind": "task",
        "traceloop.entity.name": "ResearchAgent",
        "traceloop.entity.input": "{\"args\": [], \"kwargs\": {}}",
        "traceloop.entity.output": "\"ResearchAgent\""
    },
    "events": [],
    "links": [],
    "resource": {
        "attributes": {
            "telemetry.sdk.language": "python",
            "telemetry.sdk.name": "opentelemetry",
            "telemetry.sdk.version": "1.39.1",
            "system.code": "TEST",
            "service.name": "agent_demo"
        },
        "schema_url": ""
    }
}

{
    "name": "openai.chat",
    "context": {
        "trace_id": "0xa661b6c967c35cf04126555f816836f4",
        "span_id": "0x100fceb56aa22a6c",
        "trace_state": "[]"
    },
    "kind": "SpanKind.CLIENT",
    "parent_id": null,
    "start_time": "2026-01-22T11:22:35.464245Z",
    "end_time": "2026-01-22T11:22:40.527113Z",
    "attributes": {
        "llm.request.type": "chat",
        "traceloop.workflow.name": "AgentSystem",
        "gen_ai.system": "openai",
        "gen_ai.request.model": "gpt-3.5-turbo",
        "llm.headers": "None",
        "llm.is_streaming": false,
        "gen_ai.openai.api_base": "https://api.openai.com/v1/",
        "gen_ai.prompt.0.role": "user"
    }
}

[15029836736]

the reason is that using annotations on the class causes context loss.