From 40efc2bdf339cece97860280302554be53dede9b Mon Sep 17 00:00:00 2001
From: Mason Daugherty <github@mdrxy.com>
Date: Wed, 18 Feb 2026 02:41:02 -0500
Subject: [PATCH] perf(core): defer specific `langsmith` imports to reduce
 import time

---
 libs/core/langchain_core/callbacks/manager.py | 25 +++++++++++--------
 libs/core/langchain_core/runnables/config.py  | 11 ++++++--
 2 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/libs/core/langchain_core/callbacks/manager.py b/libs/core/langchain_core/callbacks/manager.py
index 5a3433ef7e6..cd26f49f5b6 100644
--- a/libs/core/langchain_core/callbacks/manager.py
+++ b/libs/core/langchain_core/callbacks/manager.py
@@ -13,7 +13,6 @@ from contextlib import asynccontextmanager, contextmanager
 from contextvars import copy_context
 from typing import TYPE_CHECKING, Any, TypeVar, cast
 
-from langsmith.run_helpers import get_tracing_context
 from typing_extensions import Self, override
 
 from langchain_core.callbacks.base import (
@@ -29,15 +28,6 @@ from langchain_core.callbacks.base import (
 from langchain_core.callbacks.stdout import StdOutCallbackHandler
 from langchain_core.globals import get_debug
 from langchain_core.messages import BaseMessage, get_buffer_string
-from langchain_core.tracers.context import (
-    _configure_hooks,
-    _get_trace_callbacks,
-    _get_tracer_project,
-    _tracing_v2_is_enabled,
-    tracing_v2_callback_var,
-)
-from langchain_core.tracers.langchain import LangChainTracer
-from langchain_core.tracers.stdout import ConsoleCallbackHandler
 from langchain_core.utils.env import env_var_is_set
 from langchain_core.utils.uuid import uuid7
 
@@ -104,6 +94,8 @@ def trace_as_chain_group(
             manager.on_chain_end({"output": res})
         ```
     """
+    from langchain_core.tracers.context import _get_trace_callbacks  # noqa: PLC0415
+
     cb = _get_trace_callbacks(
         project_name, example_id, callback_manager=callback_manager
     )
@@ -183,6 +175,8 @@ async def atrace_as_chain_group(
             await manager.on_chain_end({"output": res})
         ```
     """
+    from langchain_core.tracers.context import _get_trace_callbacks  # noqa: PLC0415
+
     cb = _get_trace_callbacks(
         project_name, example_id, callback_manager=callback_manager
     )
@@ -2325,6 +2319,17 @@ def _configure(
     Returns:
         The configured callback manager.
     """
+    from langsmith.run_helpers import get_tracing_context  # noqa: PLC0415
+
+    from langchain_core.tracers.context import (  # noqa: PLC0415
+        _configure_hooks,
+        _get_tracer_project,
+        _tracing_v2_is_enabled,
+        tracing_v2_callback_var,
+    )
+    from langchain_core.tracers.langchain import LangChainTracer  # noqa: PLC0415
+    from langchain_core.tracers.stdout import ConsoleCallbackHandler  # noqa: PLC0415
+
     tracing_context = get_tracing_context()
     tracing_metadata = tracing_context["metadata"]
     tracing_tags = tracing_context["tags"]
diff --git a/libs/core/langchain_core/runnables/config.py b/libs/core/langchain_core/runnables/config.py
index f24f5603170..2a19dea8e21 100644
--- a/libs/core/langchain_core/runnables/config.py
+++ b/libs/core/langchain_core/runnables/config.py
@@ -20,7 +20,6 @@ from typing import (
     cast,
 )
 
-from langsmith.run_helpers import _set_tracing_context, get_tracing_context
 from typing_extensions import TypedDict
 
 from langchain_core.callbacks.manager import AsyncCallbackManager, CallbackManager
@@ -30,7 +29,6 @@ from langchain_core.runnables.utils import (
     accepts_config,
     accepts_run_manager,
 )
-from langchain_core.tracers.langchain import LangChainTracer
 
 if TYPE_CHECKING:
     from langchain_core.callbacks.base import BaseCallbackManager, Callbacks
@@ -160,6 +158,13 @@ def _set_config_context(
     Returns:
         The token to reset the config and the previous tracing context.
     """
+    from langsmith.run_helpers import (  # noqa: PLC0415
+        _set_tracing_context,
+        get_tracing_context,
+    )
+
+    from langchain_core.tracers.langchain import LangChainTracer  # noqa: PLC0415
+
     config_token = var_child_runnable_config.set(config)
     current_context = None
     if (
@@ -194,6 +199,8 @@ def set_config_context(config: RunnableConfig) -> Generator[Context, None, None]
     Yields:
         The config context.
     """
+    from langsmith.run_helpers import _set_tracing_context  # noqa: PLC0415
+
     ctx = copy_context()
     config_token, _ = ctx.run(_set_config_context, config)
     try: