Claude API · Setup and first request

Send your first message (Python)

Create a client and send one message. The response content is a list of blocks, so check each block's type.

import anthropic

client = anthropic.Anthropic()

response = client.messages.create(
    model="claude-opus-5-5",
    max_tokens=16000,
    messages=[{"role": "user", "content": "What is the capital of France?"}],
)
for block in response.content:
    if block.type == "text":
        print(block.text)

Official Claude API documentation

More setup and first request commands

Install the Python SDK
Install the TypeScript SDK
Set your API key
Send your first message (TypeScript)
Send your first message (curl)
Pick a model

All setup and first request commands · Claude API cheatsheet