Anthropic has cut the system prompt for Claude Code by 80 percent. According to staffer Tariq Shihipar, the new Fable 5 models need fewer instructions and examples. Guidelines can even hold the models back because they're "more imaginative" than what they're given. Instead of strict rules, Anthropic now steers through context.

Anthropic has cut the system prompt for Claude Code by 80 percent. According to staffer Tariq Shihipar, the new Fable 5 models need fewer instructions and examples. Guidelines can…

Claude Fable 5 looks genuinely better for long, agentic coding and knowledge work, but developers should use it selectively instead of treating it as the default model for…