Overview
- Anthropic has made Claude Sonnet 5 available to developers on Claude Code and Claude Platform under the API name "claude-sonnet-5".
- Sonnet 5 can plan multi-step tasks, call tools such as a web browser and a terminal, and run autonomously to carry out agent workflows.
- The company published promotional pricing that charges $2 per 1M input tokens and $10 per 1M output tokens through Aug. 31, 2026, with rates rising to $3 and $15 per 1M tokens afterward.
- Anthropic reports measurable gains over Sonnet 4.6 on agent benchmarks including BrowseComp and OSWorld‑Verified, and says Sonnet 5 approaches Opus 4.8 on some tasks.
- The firm also says Sonnet 5 shows lower overall bad‑behavior rates and better resistance to malicious prompts, prompt injection, hallucinations, and sycophancy, though those results come from company tests rather than independent validation.