Anthropic has reduced the system prompt for Claude Code by 80 percent due to the new Fable 5 models, which prefer smaller prompts and more context over lengthy instructions and examples. This shift in approach is a result of the models’ increased imagination and ability to understand nuances. The company’s technical staff member, Tariq Shihipar, explains that more instructions and examples can actually constrain the models, leading to less desirable outcomes. This change marks a significant evolution in how AI models are guided, moving away from hard rules and towards more subtle contextual cues. Why it matters: this development signals a major breakthrough in AI model development, as researchers learn to harness the power of these models in more intuitive and effective ways.