3Accessing Claude with the API

Chat exercise

2 min read350 words

Time: 10–15 minutes

Implement the multi-turn chat pattern from scratch and prove it works with a follow-up question that depends on earlier context.

Step 1Set Up Your Environment

Open a notebook or Python file. Import the Anthropic SDK, call load_dotenv(), and initialise the client. Create an empty messages list that you will grow across turns.

from dotenv import load_dotenv
load_dotenv()

from anthropic import Anthropic

client = Anthropic()
model = "claude-sonnet-4-0"

messages = []
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You can now build applications that maintain meaningful conversations with Claude across multiple turns.