From 987031f86c306daeb85651aeefaec78aaae95f31 Mon Sep 17 00:00:00 2001
From: Mason Daugherty <github@mdrxy.com>
Date: Fri, 15 Aug 2025 16:27:08 -0400
Subject: [PATCH] fix: `_LC_ID_PREFIX` back

---
 libs/core/langchain_core/messages/__init__.py | 2 ++
 libs/core/langchain_core/messages/ai.py       | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/libs/core/langchain_core/messages/__init__.py b/libs/core/langchain_core/messages/__init__.py
index a0482bee862..3787da41e8f 100644
--- a/libs/core/langchain_core/messages/__init__.py
+++ b/libs/core/langchain_core/messages/__init__.py
@@ -21,6 +21,7 @@ from langchain_core._import_utils import import_attr
 
 if TYPE_CHECKING:
     from langchain_core.messages.ai import (
+        _LC_ID_PREFIX,
         AIMessage,
         AIMessageChunk,
     )
@@ -90,6 +91,7 @@ if TYPE_CHECKING:
 __all__ = (
     "LC_AUTO_PREFIX",
     "LC_ID_PREFIX",
+    "_LC_ID_PREFIX",
     "AIMessage",
     "AIMessageChunk",
     "Annotation",
diff --git a/libs/core/langchain_core/messages/ai.py b/libs/core/langchain_core/messages/ai.py
index 76bc8d980a1..e2e045c7107 100644
--- a/libs/core/langchain_core/messages/ai.py
+++ b/libs/core/langchain_core/messages/ai.py
@@ -26,6 +26,8 @@ from langchain_core.utils.usage import _dict_int_op
 
 logger = logging.getLogger(__name__)
 
+_LC_ID_PREFIX = types.LC_ID_PREFIX
+
 
 class InputTokenDetails(TypedDict, total=False):
     """Breakdown of input token counts.