claude-opus-5-5Prompting and harness guidance specific to Claude Opus 5.5 (claude-opus-5-5). Use when writing or tuning a system prompt, agent loop, or Messages API request for Opus 5.5, or when migrating prompts from Claude Opus 5. Also use when choosing an effort level, when a request with thinking disabled retu
engineerUse when asked to engineer, improve, and validate prompts using a dual-persona Prompt Builder / Prompt Tester methodology. Analyzes sources, applies imperative-language best practices, and runs mandatory validation cycles before finalizing any prompt.