Claude Sonnet Glossary

The mid-tier of Anthropic's *Claude* family — balanced capability and cost. The default model for most agentic-tool-use workflows.

Claude Sonnet is the middle tier of Anthropic’s Claude model family, between the high-capability Opus tier and the smaller Haiku tier. Claude 3.5 Sonnet, released in June 2024, helped establish Sonnet as a practical model for coding and production tool use.

Sonnet is often used where an operator needs stronger performance than a small model provides but cannot justify the cost or latency of the highest tier. Tool use, routine drafting, summarisation, and moderate code changes are common examples. The appropriate choice still depends on the model generation and the cost of checking its work.

According to Boris Cherny’s Coding Solved talk, Sonnet 3.5 supported Claude Code during its early product development, before later Opus models changed the tool’s capability profile.

See also

• Claude — the model family
• Claude Opus, Claude Haiku — peer tiers
• Claude Code
• Opus Addict

Return to Dictionary All Entries (A–Z) For Students Other Writing Capstone 2.0