From 8892414dcde32422b3f6d1b58b8162aeecc737b8 Mon Sep 17 00:00:00 2001 From: "open-swe[bot]" Date: Wed, 4 Mar 2026 20:55:20 +0000 Subject: [PATCH 1/3] Improve OTEL fanout doc discoverability so users find the recommended LANGSMITH_OTEL_ENABLED path instead of collector-only guidance. --- src/langsmith/trace-with-opentelemetry.mdx | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/src/langsmith/trace-with-opentelemetry.mdx b/src/langsmith/trace-with-opentelemetry.mdx index ad0cb5bc0e..6e597464d6 100644 --- a/src/langsmith/trace-with-opentelemetry.mdx +++ b/src/langsmith/trace-with-opentelemetry.mdx @@ -1,8 +1,11 @@ --- title: Trace with OpenTelemetry +description: Configure OpenTelemetry tracing in LangSmith, including LANGSMITH_OTEL_ENABLED and OTEL fanout with the OpenTelemetry Collector. sidebarTitle: OpenTelemetry --- +OTEL fanout and `LANGSMITH_OTEL_ENABLED` are covered on this page. + LangSmith supports OpenTelemetry-based tracing, allowing you to send traces from any OpenTelemetry-compatible application. This guide covers both automatic instrumentation for LangChain applications and manual instrumentation for other frameworks. Learn how to trace your LLM applications using OpenTelemetry with LangSmith. @@ -589,7 +592,11 @@ Here is an [example](https://smith.langchain.com/public/9574f70a-b893-49fe-8c62- ## Advanced configuration -### Use OpenTelemetry collector for fan-out +### Use OpenTelemetry collector for fanout + +Use `LANGSMITH_OTEL_ENABLED=true` when you need OTEL fanout. Configure your application to emit OTEL spans once, then use an OpenTelemetry Collector to route them to LangSmith and any additional observability backends. + +Use this approach when you are tracing applications and want multi-destination routing. If you are operating LangSmith platform infrastructure telemetry (logs, metrics, traces from self-hosted LangSmith services on Kubernetes), use the [Configure your collector for LangSmith telemetry](/langsmith/langsmith-collector) guide instead. For more advanced scenarios, you can use the OpenTelemetry Collector to fan out your telemetry data to multiple destinations. This is a more scalable approach than configuring multiple exporters in your application code. From 3d6277a9c897283b64e7f0a15af27a8e2fde916a Mon Sep 17 00:00:00 2001 From: Kathryn May <44557882+katmayb@users.noreply.github.com> Date: Mon, 9 Mar 2026 08:36:46 -0400 Subject: [PATCH 2/3] Apply suggestion from @katmayb --- src/langsmith/trace-with-opentelemetry.mdx | 1 - 1 file changed, 1 deletion(-) diff --git a/src/langsmith/trace-with-opentelemetry.mdx b/src/langsmith/trace-with-opentelemetry.mdx index 6e597464d6..7c201a2253 100644 --- a/src/langsmith/trace-with-opentelemetry.mdx +++ b/src/langsmith/trace-with-opentelemetry.mdx @@ -4,7 +4,6 @@ description: Configure OpenTelemetry tracing in LangSmith, including LANGSMITH_O sidebarTitle: OpenTelemetry --- -OTEL fanout and `LANGSMITH_OTEL_ENABLED` are covered on this page. LangSmith supports OpenTelemetry-based tracing, allowing you to send traces from any OpenTelemetry-compatible application. This guide covers both automatic instrumentation for LangChain applications and manual instrumentation for other frameworks. From 9dd78c74577a583894029a1c14bf3da481ecae10 Mon Sep 17 00:00:00 2001 From: Kathryn May <44557882+katmayb@users.noreply.github.com> Date: Tue, 24 Mar 2026 13:37:06 -0400 Subject: [PATCH 3/3] Apply suggestion from @katmayb --- src/langsmith/trace-with-opentelemetry.mdx | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/langsmith/trace-with-opentelemetry.mdx b/src/langsmith/trace-with-opentelemetry.mdx index 7c201a2253..40b3c3d5e6 100644 --- a/src/langsmith/trace-with-opentelemetry.mdx +++ b/src/langsmith/trace-with-opentelemetry.mdx @@ -591,7 +591,7 @@ Here is an [example](https://smith.langchain.com/public/9574f70a-b893-49fe-8c62- ## Advanced configuration -### Use OpenTelemetry collector for fanout +### Use OpenTelemetry collector for fan-out Use `LANGSMITH_OTEL_ENABLED=true` when you need OTEL fanout. Configure your application to emit OTEL spans once, then use an OpenTelemetry Collector to route them to LangSmith and any additional observability backends.