Claude Sonnet 5
The best combination of speed and intelligence
Claude Sonnet 5 is Anthropic's Sonnet-tier model release, launched June 30, 2026, positioned as a more agentic upgrade over Claude Sonnet 4.6 for coding, tool use, agents, and professional work. It is available in Claude, Claude Code, and the Claude API under the API model ID `claude-sonnet-5`.
Pricing
Introductory pricing applies through August 31, 2026. The same page states standard pricing starting September 1, 2026 is $3/MTok input and $15/MTok output; 5-minute cache writes are $2.50/MTok and 1-hour cache writes are $4/MTok during the introductory period.
Anthropic's official Claude Platform pricing page lists Claude Sonnet 5 introductory pricing through August 31, 2026 at $2 per million base input tokens and $10 per million output tokens, with cache hits/refreshes at $0.20 per million tokens. Since today is 2026-08-10, the introductory rate is the current public first-party API pricing.
Model Intelligence
Recent stories
ClaudeDevs reports Sonnet 5 with a Fable 5 advisor reached ~92% of Fable 5's SWE-bench Pro score at ~63% of the price. Other builders route implementation to Sonnet, Codex, GPT-5.5, or GLM workers.
Claude Code 2.1.200 changed Manual permission defaults and fixed background-agent crash and recovery paths; 2.1.201 removed mid-conversation Sonnet 5 harness reminders. Update to reduce accidental advances and repeated reminders in stalled sessions.
Vals and Artificial Analysis published independent Sonnet 5 results a day after launch, placing it just behind Opus 4.8 and Fable 5 while using far more turns than Sonnet 4.6. Lower token pricing did not make agentic tasks cheaper, and some finance benchmarks still triggered refusals.
Anthropic launched Claude Sonnet 5 across Claude, the API, and Claude Code with 1M context, adaptive thinking, and $2/$10 intro pricing through Aug. 31. Independent evals place it near Opus 4.8 on coding and tool use, so teams should benchmark it against Opus before switching.