Claude Sonnet 5
Anthropic's Claude Sonnet 5 language model with 1M context and adaptive thinking.
Claude Sonnet 5 is presented in the supplied evidence context as a language-model release from Anthropic, launched across Claude, the API, and Claude Code with a 1M-token context window, adaptive thinking, and introductory $2/$10 per-million-token pricing.
Pricing
Official table also lists 5-minute cache writes at $2.50/MTok, 1-hour cache writes at $4/MTok, and cache hits/refreshes at $0.20/MTok. MTok means million tokens.
Anthropic's official pricing page lists Claude Sonnet 5 at $2 per million input tokens and $10 per million output tokens. The page states this pricing is now standard, after introductory pricing through August 31, 2026.
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.