# Conversational memory with LangChain

This example demonstrates how to implement conversational memory in LangChain, allowing an LLM to retain context from previous turns in a dialogue. It builds an agent with `create_agent` and attaches an `InMemorySaver` checkpointer, so every turn sent with the same thread identifier reloads the accumulated message history.

## Requirements

* [Python](https://www.python.org/) 3.10+
* An [OpenAI API key](https://platform.openai.com/api-keys) set as an environment variable (`OPENAI_API_KEY`)

## Steps for running this example in the shell

1. Install dependencies:
```bash
python -m venv .venv

# macOS/Linux:
source .venv/bin/activate

# Windows Command Prompt:
.venv\Scripts\activate.bat

# Windows PowerShell:
.venv\Scripts\Activate.ps1

pip install -r requirements.txt
```

2. Export your API key as an environment variable:
```bash
export OPENAI_API_KEY="sk-..." # Windows cmd: set OPENAI_API_KEY="sk-..." # Windows PowerShell: $env:OPENAI_API_KEY="sk-..."
```

3. Run the script:
```bash
python conversational_memory.py
```

## Output

When you run the script, it will simulate a short conversation with an LLM. The output will show each turn of the conversation, along with the AI's response and the accumulated chat history maintained by the checkpointer. You will observe how the LLM uses the past conversation to inform its answers.

Example output:

```
--- Conversation Turn 1 ---
User: Hi there! What's your name?
AI: I am an AI assistant. You can call me Assistant.
Current History: [HumanMessage(content='Hi there! What's your name?'), AIMessage(content='I am an AI assistant. You can call me Assistant.')]

--- Conversation Turn 2 ---
User: What did I just ask you?
AI: You asked me what my name is.
Current History: [HumanMessage(content='Hi there! What's your name?'), AIMessage(content='I am an AI assistant. You can call me Assistant.'), HumanMessage(content='What did I just ask you?'), AIMessage(content='You asked me what my name is.')]

--- Conversation Turn 3 ---
User: And what is your name again?
AI: My name is Assistant.
Current History: [HumanMessage(content='Hi there! What's your name?'), AIMessage(content='I am an AI assistant. You can call me Assistant.'), HumanMessage(content='What did I just ask you?'), AIMessage(content='You asked me what my name is.'), HumanMessage(content='And what is your name again?'), AIMessage(content='My name is Assistant.')]
```