Claude Sonnet
Anthropic's mid-tier Claude model family — the default workhorse balancing speed, cost, and reasoning quality.
Definition
Claude Sonnet sits between Haiku (fast and cheap) and Opus (slow and capable) in Anthropic's model lineup. For most agentic tasks Sonnet is the default: long context, strong tool use, and good code synthesis at a fraction of Opus's per-token cost. Versions like Sonnet 4 and 4.5 update on Anthropic's release cadence.
When to use
See also
- Claude Opus — Anthropic's most capable Claude tier — highest reasoning quality at the highest cost and latency.
- Claude Haiku — Anthropic's smallest, fastest, cheapest Claude tier — used for bulk classification, routing, and trivial agent steps.
- LLM — Large Language Model — a transformer-based model trained on internet-scale text to generate and reason.