From 447e9cd23104d474d256e5ee5edfa36680a72f81 Mon Sep 17 00:00:00 2001
From: klaasmeinke <48212135+klaasmeinke@users.noreply.github.com>
Date: Wed, 7 Jan 2026 18:57:28 +0100
Subject: [PATCH 1/2] Refactor trace ID handling in Langchain execution

Updated the method to pass a custom trace ID in Langchain execution by using the 'trace_context' argument. Removed the previous method of using 'trace_context' in the span.
---
 .../trace-ids-and-distributed-tracing.mdx     | 28 +++++--------------
 1 file changed, 7 insertions(+), 21 deletions(-)

diff --git a/pages/docs/observability/features/trace-ids-and-distributed-tracing.mdx b/pages/docs/observability/features/trace-ids-and-distributed-tracing.mdx
index 18843595f2..271e711cb9 100644
--- a/pages/docs/observability/features/trace-ids-and-distributed-tracing.mdx
+++ b/pages/docs/observability/features/trace-ids-and-distributed-tracing.mdx
@@ -293,7 +293,7 @@ const completion = await openai.chat.completions.create({
 </Tab>
 <Tab>
 
-To pass a custom trace ID to a Langchain execution, you can wrap the execution in a span that sets a predefined trace ID. You can also retrieve the last trace ID a callback handler has created via `langfuse_handler.last_trace_id`.
+To pass a custom trace ID to a Langchain execution, you can add a trace ID to the callback handler using the `trace_context` argument. You can also retrieve the last trace ID a callback handler has created via `langfuse_handler.last_trace_id`.
 
 ```python
 from langfuse import get_client, Langfuse
@@ -305,27 +305,13 @@ langfuse = get_client()
 external_request_id = "req_12345"
 predefined_trace_id = Langfuse.create_trace_id(seed=external_request_id)
 
-langfuse_handler = CallbackHandler()
+langfuse_handler = CallbackHandler(trace_context={"trace_id": predefined_trace_id)
 
-# Use the predefined trace ID with trace_context
-with langfuse.start_as_current_observation(
-    as_type="span",
-    name="langchain-request",
-    trace_context={"trace_id": predefined_trace_id}
-) as span:
-
-    with propagate_attributes(
-    span.update_trace(
-        input={"person": "Ada Lovelace"}
-    )
-
-    # LangChain execution will be part of this trace
-    response = chain.invoke(
-        {"person": "Ada Lovelace"},
-        config={"callbacks": [langfuse_handler]}
-    )
-
-    span.update_trace(output={"response": response})
+# LangChain execution will be part of this trace
+response = chain.invoke(
+    {"person": "Ada Lovelace"},
+    config={"callbacks": [langfuse_handler]}
+)
 
 print(f"Trace ID: {predefined_trace_id}")  # Use this for scoring later
 print(f"Trace ID: {langfuse_handler.last_trace_id}") # Care needed in concurrent environments where handler is reused

From 9dd17bda97aae304786bd776a326047ec54f7094 Mon Sep 17 00:00:00 2001
From: klaasmeinke <48212135+klaasmeinke@users.noreply.github.com>
Date: Fri, 9 Jan 2026 20:04:21 +0100
Subject: [PATCH 2/2] Update
 pages/docs/observability/features/trace-ids-and-distributed-tracing.mdx

Co-authored-by: ellipsis-dev[bot] <65095814+ellipsis-dev[bot]@users.noreply.github.com>
---
 .../features/trace-ids-and-distributed-tracing.mdx              | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pages/docs/observability/features/trace-ids-and-distributed-tracing.mdx b/pages/docs/observability/features/trace-ids-and-distributed-tracing.mdx
index 271e711cb9..e84411cfa2 100644
--- a/pages/docs/observability/features/trace-ids-and-distributed-tracing.mdx
+++ b/pages/docs/observability/features/trace-ids-and-distributed-tracing.mdx
@@ -305,7 +305,7 @@ langfuse = get_client()
 external_request_id = "req_12345"
 predefined_trace_id = Langfuse.create_trace_id(seed=external_request_id)
 
-langfuse_handler = CallbackHandler(trace_context={"trace_id": predefined_trace_id)
+langfuse_handler = CallbackHandler(trace_context={"trace_id": predefined_trace_id})
 
 # LangChain execution will be part of this trace
 response = chain.invoke(