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
Standard global Claude API pricing: $2/M input and $10/M output. The official list card also lists cache-hit/refresh pricing of $0.20/M tokens; batch pricing is $1/M input and $5/M output. Regional US-only inference prices differ.
Anthropic’s announcement states the permanent price is $2 per million input tokens and $10 per million output tokens. The September 28, 2026 official list-price card independently confirms those standard global Claude API rates. Prices are USD per 1M tokens.
Model Intelligence
Recent stories
Reports place Gemini 4 Argon at 77.9% on DeepSWE, 57.6% on Terminal-Bench, 77.5% on AutomationBench-AA, and 68% on CWE-Bench. The reports also cite lower cost or token use than rivals.
Sonnet 5.5 ranks second on Artificial Analysis' Intelligence Index but uses about 193,000 output tokens per task at max effort. A comparison of AA Index results puts its cost at $7.60 per task.
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.