From 7f989d3c3b466566be531f01b6096c9509425803 Mon Sep 17 00:00:00 2001
From: Mason Daugherty <github@mdrxy.com>
Date: Fri, 8 Aug 2025 13:02:59 -0400
Subject: [PATCH] feat(docs): clarify `ToolMessage` `content`field usage

---
 libs/core/langchain_core/v1/messages.py | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/libs/core/langchain_core/v1/messages.py b/libs/core/langchain_core/v1/messages.py
index 1f86188550a..e8fcca0f506 100644
--- a/libs/core/langchain_core/v1/messages.py
+++ b/libs/core/langchain_core/v1/messages.py
@@ -797,7 +797,13 @@ class ToolMessage(ToolOutputMixin):
     """
 
     content: list[types.ContentBlock]
-    """Message content as a list of content blocks."""
+    """Message content as a list of content blocks.
+
+    The tool's output should be included in the content, mapped to the appropriate
+    content block type (e.g., text, image, etc.). For instance, if the tool call returns
+    a string, it should be wrapped in a ``TextContentBlock``.
+
+    """
 
     type: Literal["tool"] = "tool"
     """The type of the message. Must be a string that is unique to the message type.