LangSmith Traces

If your application already uses LangSmith tracing, Inference platform can bridge LangSmith OpenTelemetry spans to the Inference platform tracer provider. This keeps LangSmith traceable functions and framework integrations visible with the rest of your application traces.

If a LangSmith-traced function is the boundary of an agent run, add an outer agentSpan() / agent_span() with a stable agent.id. LangSmith spans remain visible under that AGENT span.

Install

TypeScript Traceable Function

TypeScript

import { setup } from "@inference/tracing";
import { Client } from "langsmith";
import { traceable } from "langsmith/traceable";

process.env.LANGSMITH_TRACING = "true";
process.env.LANGSMITH_TRACING_MODE = "otel";

const tracing = await setup({ serviceName: "langsmith-worker" });
const client = new Client({ tracingMode: "otel" });

const answerQuestion = traceable(
  async (input: { question: string }) => ({
    answer: input.question.toUpperCase(),
  }),
  {
    name: "answerQuestion",
    run_type: "tool",
    client,
    tracer: tracing.provider.getTracer("langsmith-app"),
  },
);

console.log(await answerQuestion({ question: "hi" }));
await client.flush();
await tracing.shutdown();

Python Traceable Function

Python

import os

from inference_tracing import setup
from langsmith import Client, traceable

os.environ["LANGSMITH_TRACING"] = "true"
os.environ["LANGSMITH_TRACING_MODE"] = "otel"

tracing = setup(service_name="langsmith-worker")
client = Client()

@traceable(name="answer_question", run_type="tool", client=client, enabled=True)
def answer_question(question: str) -> str:
    return question.upper()

print(answer_question("hi"))
client.flush()
tracing.shutdown()

Hybrid Mode

If LANGSMITH_TRACING=true is set and LANGSMITH_TRACING_MODE is not set, Inference Tracing defaults LangSmith to hybrid mode. That keeps existing LangSmith tracing active while also routing OpenTelemetry spans through the Inference platform.

export LANGSMITH_TRACING=true
# Inference Tracing sets LANGSMITH_TRACING_MODE=hybrid when unset.

Stable Agent Identity

Use this pattern around LangSmith-traced work when you want the Agents dashboard to group executions by your product agent ID.