Claude 3.5 Sonnet: Why It Tops SWE-Bench and How to Use It for Code

Claude 3.5 Sonnet scored 49% on SWE-Bench Verified, outperforming GPT-4o by 11 points. Here's what makes it exceptional for coding tasks and how to use it.

Mahmudul Haque Qudrati

CEO & ML Engineer

March 10, 2026

7 min read

// tags

#claude#anthropic#coding#swe-bench#computer-use

FIG. ART-32

7 min read

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Claude 3.5 Sonnet: Why It Tops SWE-Bench and How to Use It for Code

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sections

395

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// Developer Tools

How to Build with Claude Code – Everything you can configure that the docs don't tell you

Claude Code's docs cover basics, but the real power is in hidden configs. Learn how to customize prompts, manage costs, and integrate with your workflow.

4 min read

// Developer Tools

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Calling the API With Python

Install the Anthropic Python SDK:

pip install anthropic

import anthropic

client = anthropic.Anthropic()  # reads ANTHROPIC_API_KEY from env

message = client.messages.create(
    model="claude-3-5-sonnet-20241022",
    max_tokens=1024,
    messages=[
        {
            "role": "user",
            "content": "Review this Python function for bugs and suggest improvements:

def process(data):
    result = []
    for i in data:
        result.append(i * 2)
    return result"
        }
    ]
)

print(message.content[0].text)

Extended Thinking Mode

For hard algorithmic or architectural problems, enable extended thinking to let the model reason through the problem before answering:

response = client.messages.create(
    model="claude-3-5-sonnet-20241022",
    max_tokens=16000,
    thinking={
        "type": "enabled",
        "budget_tokens": 10000
    },
    messages=[{"role": "user", "content": "Design a rate limiter for a distributed API."}]
)

for block in response.content:
    if block.type == "thinking":
        print("Reasoning:", block.thinking[:200], "...")
    elif block.type == "text":
        print("Answer:", block.text)

Tool Use (Function Calling)

Claude supports parallel tool calls, which is useful for agentic pipelines that need to fetch multiple data sources simultaneously:

tools = [
    {
        "name": "read_file",
        "description": "Read a file from the repository",
        "input_schema": {
            "type": "object",
            "properties": {
                "path": {"type": "string", "description": "File path"}
            },
            "required": ["path"]
        }
    }
]

response = client.messages.create(
    model="claude-3-5-sonnet-20241022",
    max_tokens=4096,
    tools=tools,
    messages=[{"role": "user", "content": "What does main.py do?"}]
)

Computer Use (Beta)

The computer use feature lets Claude control a browser or desktop to complete tasks autonomously. It's currently in beta and best suited for structured, well-defined automation flows. See the Anthropic docs for the full setup guide.

Summary

Claude 3.5 Sonnet is the strongest model for coding tasks as of early 2026. Its 200k context window, leading SWE-Bench score, and extended thinking mode make it particularly powerful for large refactors, code review, and agentic workflows. Explore the full model lineup at anthropic.com/claude/sonnet.

Claude 3.5 Sonnet: Why It Tops SWE-Bench and How to Use It for Code

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