Claude Sonnet 5 for Web3, released in late June 2026, became Anthropic's default model for free and paid Claude accounts and is available through Amazon Bedrock and the Claude platform on AWS. It is designed for long-context research, tool-calling agents, content review, community triage, and operational automation, paying for itself when it reads a governance archive, writes a neutral proposal brief, checks a docs update against Solidity interfaces, and routes tasks to support or publishing tools. Anthropic lists a 1 million token context window, with a 2 million token option exposed through a special header. AWS positions Sonnet 5 for agents that call tools, run multi-step tasks, and automate browser or desktop workflows. Anthropic reported 92.4 percent on SWE-bench Verified, a benchmark built around real software engineering issues. The model reached 88.3 percent on OSWorld-Verified, a desktop automation benchmark, beating the reported 72.4 percent human expert baseline. Useful outputs include protocol documentation, DAO governance briefs, tokenomics explainers, release notes for smart contract upgrades, and risk disclosure drafts, though Sonnet 5 should not be the final authority on legal, financial, or security claims.