Claude 3.5 Sonnet

Overview

Claude 3.5 Sonnet is Anthropic's flagship AI model, offering the best balance of intelligence, speed, and cost. It excels at complex reasoning, coding, creative writing, and multimodal analysis with enhanced safety features.

Key Features

🧠 Advanced Reasoning

• Complex problem solving: Multi-step reasoning with high accuracy
• Mathematical computation: Strong performance on STEM tasks
• Creative writing: Nuanced, engaging content generation
• Code generation: Full-stack development capabilities

🎨 Multimodal Understanding

• Computer use: Can interact with GUIs, click buttons, type
• Image analysis: Deep visual understanding
• Document processing: PDFs, charts, diagrams

🛡️ Safety-First Design

• Constitutional AI: Built-in safety training
• Refusal patterns: Knows when to decline harmful requests
• Transparency: Honest about limitations

Installation

pip install anthropic

Quick Start

from anthropic import Anthropic

client = Anthropic(api_key="sk-ant-...")

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

print(message.content[0].text)

Computer Use (Beta)

from anthropic import Anthropic

client = Anthropic()

# Computer use requires specific tool configuration
message = client.messages.create(
    model="claude-3-5-sonnet-latest",
    max_tokens=1024,
    tools=[{
        "name": "computer_20241022",
        "description": "Control a computer",
        "input_schema": {...}
    }],
    messages=[{"role": "user", "content": "Open a browser and search for AI news"}]
)

Image Analysis

import base64

def encode_image(path):
    with open(path, "rb") as f:
        return base64.b64encode(f.read()).decode()

message = client.messages.create(
    model="claude-3-5-sonnet-latest",
    max_tokens=1024,
    messages=[{
        "role": "user",
        "content": [
            {"type": "text", "text": "What does this diagram show?"},
            {"type": "image", "source": {
                "type": "base64",
                "media_type": "image/jpeg",
                "data": encode_image("diagram.jpg")
            }}
        ]
    }]
)

Streaming

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

Pricing

Model	Input	Output
Claude 3.5 Sonnet	$3 / 1M tokens	$15 / 1M tokens
Claude 3.5 Haiku	$0.80 / 1M tokens	$4 / 1M tokens

Context Window

• 200K tokens - Process entire codebases, long documents

Best Use Cases

• Software development - Coding, debugging, refactoring
• Content creation - Articles, stories, marketing copy
• Data analysis - Extracting insights from documents
• Customer support - Natural, empathetic responses
• Education - Tutoring, explanations, feedback

Comparison

Feature	Claude 3.5 Sonnet	GPT-4o
Reasoning	⭐⭐⭐⭐⭐	⭐⭐⭐⭐
Coding	⭐⭐⭐⭐⭐	⭐⭐⭐⭐
Speed	Fast	Very Fast
Safety	Excellent	Good
Cost	Moderate	Moderate
Context	200K	128K

Resources

• Docs: https://docs.anthropic.com/claude
• Models: https://docs.anthropic.com/claude/docs/models-overview
• API: https://docs.anthropic.com/claude/reference

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Last updated: May 2026