Overview
Anthropic released Claude Sonnet 5 on June 30, 2026. On agentic tasks — making plans, using tools like browsers and terminals, and running autonomously — it performs at levels that previously required larger models. At certain settings its performance is close to Opus 4.8, but at lower prices. The model ID is claude-sonnet-5.
Key improvements
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Agentic tasks
Earlier Sonnet models struggled to stay as consistent as larger models across long, autonomous, multi-tool runs. Sonnet 5 substantially outperforms Sonnet 4.6 at planning, using browsers and terminals, and running autonomously — carrying complex tasks through at lower cost.
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Coding, reasoning, and knowledge work
Benchmarks improve over Sonnet 4.6 across coding, reasoning, tool use, and knowledge work tasks. Performance is close to that of Opus 4.8, but at lower prices.
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Cost-performance options
Sonnet 5 offers a wider range of cost-performance options than Sonnet 4.6, so you can balance cost and capability against the difficulty of the task.
Notes
- Pricing — through August 31, 2026, introductory pricing is $2 input / $10 output per MTok; standard pricing afterward is $3 input / $15 output per MTok.
- Availability — it’s the default model for Free and Pro plans and is available on Max, Team, and Enterprise plans and in Claude Code, the Claude Platform, and the Claude API.
- Safety — Sonnet 5 shows an overall lower rate of undesirable behaviors than Sonnet 4.6 and substantially reduced cybersecurity capabilities compared to Opus models. It launches with cyber safeguards enabled by default.