Anthropic Claude Opus 5.5 Prompting Guide Highlights
September 27, 2026
Anthropic's official guide for Opus 5.5 details agentic orchestration through time budgets and new thinking-block API plumbing. It also notes that safety guardrails for biology and cybersecurity are active and that unattended agents may terminate early during progress updates.
HOW THIS AFFECTS YOU
●
builderYou should implement time-budgeting logic and handle new thinking-block API structures to prevent UI freezes.