codeClaude Opus 5.5 & Sonnet 5: The Definitive Guide to Autonomous Software Engineering (Late September 2026)
Independent technical audit of Anthropic's Claude Sonnet 5 and the newly released Claude Opus 5.5 (Sept 22, 2026). Benchmarking SWE-bench Verified pass rates (79.4%), dynamic thinking budgets (0 to 64k tokens), prompt cache economics, and Claude Code CLI workflows.








