Chat history management in LangChain - Mini Project: Build & Apply

Chat History Management

📖 Scenario: You are building a simple chatbot application that remembers the conversation history. This helps the chatbot respond better by knowing what was said before.

🎯 Goal: Create a chat history manager that stores messages, limits history size, and retrieves the recent conversation.

📋 What You'll Learn

Create a list called chat_history to store messages

Add a variable max_history to limit stored messages

Write a function add_message to add new messages and keep history within limit

Write a function get_recent_history to return the last few messages

💡 Why This Matters

🌍 Real World

Chatbots need to remember past messages to respond naturally and keep conversations coherent.

💼 Career

Managing chat history is a key skill for developers building conversational AI and customer support bots.

1

Create the chat history list

Create a list called chat_history and initialize it as empty to store chat messages.

LangChain

# Create an empty list called chat_history
# Your code here

Need a hint?

Use square brackets [] to create an empty list named chat_history.

2

Set the maximum history size

Create a variable called max_history and set it to 5 to limit how many messages are stored.

LangChain

chat_history = []
# Set max_history to 5
# Your code here

Need a hint?

Use a simple assignment to create max_history with value 5.

3

Add messages and keep history size

Write a function called add_message that takes a message string, appends it to chat_history, and removes the oldest message if the list is longer than max_history.

LangChain

chat_history = []
max_history = 5

# Define add_message function
# Your code here

Need a hint?

Use append to add messages and pop(0) to remove the oldest message when needed.

4

Retrieve recent chat history

Write a function called get_recent_history that returns a copy of the current chat_history list.

LangChain

chat_history = []
max_history = 5

def add_message(message):
    chat_history.append(message)
    if len(chat_history) > max_history:
        chat_history.pop(0)

# Define get_recent_history function
# Your code here

Need a hint?

Return a copy of chat_history to avoid accidental changes outside the function.