Claude Sonnet 4.6

Overview

Claude Sonnet 4.6 (early 2026) is Anthropic's latest Sonnet-tier model, performing at near-Opus level while maintaining Sonnet speed and pricing. The best general-purpose AI model for most production applications.

Key Strengths

• Near-Opus intelligence: Matches Opus on most benchmarks at fraction of the cost
• Speed: 3-5x faster than Opus
• Extended thinking: Deep reasoning mode for complex problems
• Code: Exceptional code generation, refactoring, and review
• Instruction following: Precise adherence to complex, multi-part instructions
• Safety: Balanced helpfulness with appropriate caution

Prompting Tips

XML Structure (Claude's Superpower)

Claude uniquely excels with XML-tagged prompts:

<task>Review this pull request for security issues</task>
<context>
  <language>TypeScript</language>
  <framework>Next.js 16</framework>
  <focus>Authentication and data validation</focus>
</context>
<code>
[paste code here]
</code>
<output_format>
For each issue:
- File and line number
- Severity: critical/high/medium/low
- Description
- Suggested fix with code
</output_format>

System Prompt Best Practices

You are a [specific role]. You specialize in [domains].

Rules:
- [Rule 1]
- [Rule 2]
- If unsure, say so rather than guessing

Communication style:
- [How to format responses]
- [What to prioritize]

Extended Thinking

For complex reasoning, Sonnet 4.6 can think deeply:

Before answering, think through this problem carefully. Consider multiple approaches and potential edge cases.

Best Use Cases

Use Case	Quality
Code generation & review	Excellent
Technical writing	Excellent
Data analysis	Excellent
Content creation	Very Good
Complex reasoning	Very Good
Creative writing	Good

vs Claude 4 Opus

• 3-5x faster response times
• ~5x cheaper per token
• Nearly identical quality for most tasks
• Opus still better for: very long documents, subtle creative writing, complex multi-step research

Pricing

• Input: $3/1M tokens
• Output: $15/1M tokens
• Extended thinking tokens at reduced rate