Rules are organized into a common layer plus language-specific directories:

rules/
├── common/          # Language-agnostic principles (always install)
│   ├── coding-style.md
│   ├── git-workflow.md
│   ├── testing.md
│   ├── performance.md
│   ├── patterns.md
│   ├── hooks.md
│   ├── agents.md
│   └── security.md
├── typescript/      # TypeScript/JavaScript specific
├── angular/         # Angular specific
├── vue/             # Vue 3 specific
├── nuxt/            # Nuxt 4 specific
├── python/          # Python specific
├── golang/          # Go specific
├── web/             # Web and frontend specific
├── react-native/    # React Native / Expo specific
├── swift/           # Swift specific
├── php/             # PHP specific
├── ruby/            # Ruby / Rails specific
└── arkts/           # HarmonyOS / ArkTS specific

• common/ contains universal principles — no language-specific code examples.
• Language directories extend the common rules with framework-specific patterns, tools, and code examples. Each file references its common counterpart.

# Install common + one or more language-specific rule sets
./install.sh typescript
./install.sh angular
./install.sh vue
./install.sh nuxt
./install.sh python
./install.sh golang
./install.sh web
./install.sh react-native
./install.sh swift
./install.sh php
./install.sh ruby
./install.sh arkts

# Install multiple languages at once
./install.sh typescript python

Important: Copy entire directories — do NOT flatten with /*. Common and language-specific directories contain files with the same names. Flattening them into one directory causes language-specific files to overwrite common rules, and breaks the relative ../common/ references used by language-specific files.

Use the ECC-owned namespace below for user-level Claude installs. Flat package-level destinations can collide with non-ECC rule packs and do not match the main README guidance.

# Create the ECC rule namespace once.
mkdir -p ~/.claude/rules/ecc

# Install common rules (required for all projects)
cp -r rules/common ~/.claude/rules/ecc/

# Install language-specific rules based on your project's tech stack
cp -r rules/typescript ~/.claude/rules/ecc/
cp -r rules/angular ~/.claude/rules/ecc/
cp -r rules/vue ~/.claude/rules/ecc/
cp -r rules/nuxt ~/.claude/rules/ecc/
cp -r rules/python ~/.claude/rules/ecc/
cp -r rules/golang ~/.claude/rules/ecc/
cp -r rules/web ~/.claude/rules/ecc/
cp -r rules/react-native ~/.claude/rules/ecc/
cp -r rules/swift ~/.claude/rules/ecc/
cp -r rules/php ~/.claude/rules/ecc/
cp -r rules/ruby ~/.claude/rules/ecc/
cp -r rules/arkts ~/.claude/rules/ecc/

# Attention ! ! ! Configure according to your actual project requirements; the configuration here is for reference only.

For project-local rules, use the same namespace under the project root:

mkdir -p .claude/rules/ecc
cp -r rules/common .claude/rules/ecc/
cp -r rules/typescript .claude/rules/ecc/

• Rules define standards, conventions, and checklists that apply broadly (e.g., "80% test coverage", "no hardcoded secrets").
• Skills (skills/ directory) provide deep, actionable reference material for specific tasks (e.g., python-patterns, golang-testing).

Language-specific rule files reference relevant skills where appropriate. Rules tell you what to do; skills tell you how to do it.

To add support for a new language (e.g., rust/):

1. Create a rules/rust/ directory
2. Add files that extend the common rules:
   • coding-style.md — formatting tools, idioms, error handling patterns
   • testing.md — test framework, coverage tools, test organization
   • patterns.md — language-specific design patterns
   • hooks.md — PostToolUse hooks for formatters, linters, type checkers
   • security.md — secret management, security scanning tools
3. Each file should start with:

   > This file extends [common/xxx.md](../common/xxx.md) with <Language> specific content.
   

4. Reference existing skills if available, or create new ones under skills/.

For non-language domains like web/, follow the same layered pattern when there is enough reusable domain-specific guidance to justify a standalone ruleset.

When language-specific rules and common rules conflict, language-specific rules take precedence (specific overrides general). This follows the standard layered configuration pattern (similar to CSS specificity or .gitignore precedence).

• rules/common/ defines universal defaults applicable to all projects.
• rules/golang/, rules/python/, rules/swift/, rules/php/, rules/typescript/, rules/react-native/, etc. override those defaults where language idioms differ.

common/coding-style.md recommends immutability as a default principle. A language-specific golang/coding-style.md can override this:

Idiomatic Go uses pointer receivers for struct mutation — see common/coding-style.md for the general principle, but Go-idiomatic mutation is preferred here.

Rules in rules/common/ that may be overridden by language-specific files are marked with:

Language note: This rule may be overridden by language-specific rules for languages where this pattern is not idiomatic.