The Claude API and Anthropic Patterns

Introduction to the Claude API

The Claude API allows you to integrate Claude's capabilities into your own applications. You send prompts to the API and receive structured responses. Anthropic provides official SDKs for Python, TypeScript, and Java.

Basic API Usage

import anthropic

client = anthropic.Anthropic(
    api_key="your-api-key"
)

message = client.messages.create(
    model="claude-3-5-sonnet-20241022",
    max_tokens=1024,
    messages=[
        {"role": "user", "content": "Hello, Claude!"}
    ]
)

print(message.content[0].text)

API Patterns

• Streaming - Get responses token by token for real-time display
• Tool use - Let Claude call external functions and APIs
• System prompts - Set Claude's role and behavior
• Multi-turn - Maintain conversation context across messages

Streaming Response

with client.messages.stream(
    model="claude-3-5-sonnet-20241022",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Tell me a story"}]
) as stream:
    for text in stream.text_stream:
        print(text, end="", flush=True)

Error Handling

try:
    message = client.messages.create(...)
except anthropic.RateLimitError:
    # Handle rate limiting
except anthropic.APIError as e:
    # Handle API errors

Key Points

• The Claude API uses messages with role-based content.
• Streaming provides real-time response generation.
• Tool use lets Claude call external functions.
• System prompts control Claude's behavior and role.
• Official SDKs are available for Python, TypeScript, and Java.