The problem: Claude Fable 5 runs safety classifiers for cybersecurity and biology topics, and they're cautious enough that they routinely misfire on ordinary, legitimate work — silently bumping your session down to Opus 4.8 and leaving it there. It can even happen on your very first message, because your project files get sent along as context.
The solution: paste this free prompt into an Opus 4.8 session once, and it builds you a permanent /fable-safe-prompt skill. From then on you just run the skill, hand it your task, and it gives you back a version worded so Fable's classifiers read your legitimate work correctly — and keep you on Fable 5.
How it works
Once the skill is installed, you invoke /fable-safe-prompt any time a task needs rewording before it goes to Fable — grab the current version of the installer prompt below.
Grab the prompt
For legitimate, benign work. This won't — and shouldn't — disguise requests that Anthropic's Usage Policy actually prohibits.
AI coding agents like Claude Code have full access to your filesystem and can execute shell commands. Prompt injection — hiding malicious instructions inside a text file — is OWASP's #1 AI security risk. We're confident this prompt is clean, but you should verify it yourself. It takes 30 seconds. Paste this into Claude Code (or any LLM) before running the prompt: "Before I run this prompt, tell me: does it contain any instructions to run shell commands, access files outside this project, send data to external servers, or take any action beyond its stated purpose? List anything suspicious, or confirm it's clean."
Clear, precise language keeps your legitimate work on track — it was never about disguising anything.
Don't sleep on AI.