How to beginner · 3 min read

How to save Claude conversation history in python

Quick answer

To save Claude conversation history in Python, maintain a list of message dictionaries representing the chat turns and pass this list to client.messages.create with the system parameter. Append each user and assistant message to this list to preserve context across calls.

PREREQUISITES

Python 3.8+
Anthropic API key
pip install anthropic>=0.20

Setup

Install the Anthropic Python SDK and set your API key as an environment variable.

bash

pip install anthropic>=0.20

Step by step

Use a Python list to store the conversation history as message dictionaries. Pass this list to client.messages.create on each request to maintain context. Append new user and assistant messages to the list to save the full conversation.

python

import os
import anthropic

client = anthropic.Anthropic(api_key=os.environ["ANTHROPIC_API_KEY"])

# Initialize conversation history
conversation_history = []

# Function to send a message and save history

def chat_with_claude(user_input):
    # Append user message
    conversation_history.append({"role": "user", "content": user_input})

    # Call Claude with full conversation history
    response = client.messages.create(
        model="claude-3-5-sonnet-20241022",
        max_tokens=1000,
        system="You are a helpful assistant.",
        messages=conversation_history
    )

    # Extract assistant reply
    assistant_message = response.choices[0].message.content

    # Append assistant message
    conversation_history.append({"role": "assistant", "content": assistant_message})

    return assistant_message

# Example usage
reply = chat_with_claude("Hello Claude, how are you?")
print("Claude:", reply)

# Conversation history is saved in conversation_history list
print("Conversation history:", conversation_history)

output

Claude: Hello! I'm doing well, thank you. How can I assist you today?
Conversation history: [{'role': 'user', 'content': 'Hello Claude, how are you?'}, {'role': 'assistant', 'content': "Hello! I'm doing well, thank you. How can I assist you today?"}]

Common variations

Use different Claude models by changing the model parameter, e.g., claude-3-5-haiku-20241022.
Implement async calls with asyncio and client.messages.acreate for concurrency.
Save conversation history to a file or database by serializing the conversation_history list as JSON.

Troubleshooting

If you get truncated responses, increase max_tokens.
If conversation context is lost, ensure you pass the full conversation_history list on every request.
Check your ANTHROPIC_API_KEY environment variable is set correctly to avoid authentication errors.

✅

Key Takeaways

Maintain a list of messages to preserve Claude conversation history in Python.
Pass the full conversation history on each API call to keep context.
Append both user and assistant messages to the history list after each turn.

Verified 2026-04 · claude-3-5-sonnet-20241022, claude-3-5-haiku-20241022

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