Consider Anthropic's Claude Opus 4.5 guidance for prompts and standards

[adawalli]

Summary

Anthropic has published official guidance for migrating prompts and code to Claude Opus 4.5. This guidance includes known behavioral differences that may affect how Agent OS standards, workflows, and commands should be written.

Reference: https://github.com/anthropics/claude-code/tree/main/plugins/claude-opus-4-5-migration

Key Behavioral Differences in Opus 4.5

According to Anthropic's migration skill, Opus 4.5 has these known differences:

1. Tool Overtriggering - Responds more strongly to system prompts, requiring softening of emphatic language ("MUST" becomes "should")
2. Over-Engineering - Tends to create unnecessary files or abstractions, requiring explicit scope constraints
3. Code Exploration - More conservative about reading files, needs encouragement to inspect relevant code first
4. Frontend Design - Benefits from enhanced aesthetics guidance for UI work
5. Thinking Sensitivity - When extended thinking is disabled, the term "think" requires substitution with alternatives like "consider" or "evaluate"

Questions for Consideration

1. Backwards Compatibility - Should Agent OS standards and prompts be written to work well across multiple Claude models (3.5, 4.x, 4.5)?

2. Model-Specific Configuration - Should there be switches or variants in config.yml for Claude model versions? For example:

   • `claude_model_version: opus-4.5`
   • Different prompt wording based on target model

3. Standards Updates - Should existing standards be audited for:

   • Emphatic language ("MUST", "ALWAYS", "NEVER") that may cause overtriggering
   • Missing explicit scope constraints to prevent over-engineering
   • Encouragement for code exploration

Possible Approaches

• Single universal prompt style - Write prompts that work reasonably across all models
• Model-specific profiles - Create profile variants optimized for different Claude versions
• Conditional templating - Add `{{IF claude_opus_4_5}}...{{ENDIF}}` style conditionals
• Documentation only - Document best practices and let users customize

Would appreciate thoughts on the preferred direction for Agent OS.