Claude Prompting Tips: Simplify for Better Fable Performance

@simonw· July 21, 2026 View original

Summary

New insights suggest that Claude, particularly Fable, performs better with simpler prompts, avoiding excessive examples or negative constraints. Claude Code's system prompt was recently reduced by 80%, indicating a shift towards more concise instructions.

Recent discussions with members of the Claude Code team, including Cat Wu and Thariq, have revealed effective strategies for optimizing prompts when working with Claude. A key takeaway is to avoid overcomplicating prompts with numerous examples or extensive lists of what the AI should not do. This simpler approach has been shown to yield better results, especially with Fable. Notably, the internal system prompt for Claude Code itself has undergone a significant 80% reduction in length. This internal optimization underscores the effectiveness of concise prompting and suggests that less can indeed be more when guiding large language models.

Why it matters

Professionals can improve the efficiency and accuracy of their AI interactions by adopting more streamlined prompting techniques, potentially reducing token usage and improving model output quality.

How to implement this in your domain

  1. 1Review existing Claude prompts for unnecessary examples or negative constraints.
  2. 2Experiment with simplifying prompts by removing redundant information.
  3. 3Test the performance of concise prompts against verbose ones for specific tasks.
  4. 4Train teams on the principle of "less is more" when crafting AI instructions.

Who benefits

Software DevelopmentAI ConsultingContent CreationCustomer Service

Key takeaways

  • Overloading Claude prompts with examples or negative lists can hinder performance.
  • Simpler, more concise prompts often lead to better results with Claude and Fable.
  • Claude Code's internal system prompt was significantly reduced, validating this approach.
  • Optimizing prompt length can improve AI efficiency and output quality.

Original post by @simonw

"I got some really useful Claude prompting tips from @_catwu and @trq212 - it's time to stop overloading our prompts with examples and lists of things not to do, Fable works better without those Claude Code's own system prompt recently shrunk by 80%! Here's my full write-up of our…"

View on X
Claude Prompting Tips: Simplify for Better Fable Performance

Originally posted by @simonw on X · view source

Want to go deeper?

Turn these trends into skills with Learnijoy's hands-on AI & tech courses.

Explore courses