Ask Claude Code to "add a user dashboard" to a Nuxt 3 app and the default output is a 2018 Vue tutorial: an Options API component, a Vuex store wired with mutations, mounted() doing a $fetch , v-if and v-for on the same element, and a prop being mutated three layers deep. None of it is broken — all of it is wrong for a Vue 3 + Nuxt 3 app shipped in 2026. The fix is not a longer prompt. It is a CLAUDE.md at the repo root — the file Claude reads on every turn — encoding the patterns that make generated code look like your codebase instead of a Stack Overflow answer from 2019. Get the full CLAUDE.md Rules Pack for 20+ frameworks — oliviacraftlat.gumroad.com/l/skdgt . The rules below are a free preview. Here are 13 rules that survive review. Each one started as a recurring failure in real Vue/Nuxt PRs. 1. Composition API + <script setup> only — no Options API, no mixins Half of Vue's training data is Vue 2.…