DOC: description issue?

[woodliu]

URL

https://github.com/langchain-ai/langchain/blob/master/docs/docs/concepts/chat_history.mdx

Checklist

• I added a very descriptive title to this issue.
• I included a link to the documentation page I am referring to (if applicable).

Issue with current documentation:

There is a description about the chat historyas:
The last message should be either a "user" message or a "tool" message containing the result of a tool call.
Isn't it should be
The last message should be either a "assistant" message or a "tool" message containing the result of a tool call.
according to the picture: https://python.langchain.com/docs/concepts/chat_history/#conversation-patterns

Idea or request for content:

No response

[YassinNouh21]

@woodliu I think it should be like this

- The conversation should follow one of these structures:
    - The first message is either a "user" message or a "system" message, followed by a "user" and then an "assistant" message.
    - When sending messages to a chat model for inference, the last message should be either a "user" message or a "tool" message containing the result of a tool call.
    - In a complete conversation, the final message would typically be an "assistant" message (the model's response).