Ask Claude to Write a Custom ESLint Rule

The ESLint plugin ecosystem is huge but it never has the exact rule your team needs. Claude knows the AST visitor API and can write a working custom rule from a plain-English description.

Write a custom ESLint rule called no-hardcoded-urls that reports an error 
when a string literal starts with "https://" or "http://" and isn't 
assigned to a constant named with ALL_CAPS.

Claude generates the rule file, the correct visitor structure (Literal node visitor), and a full test file using RuleTester with passing and failing cases. You don't need to know anything about AST node types.

Write an ESLint rule called require-error-boundary-in-async-components that 
warns when a React component uses useQuery or useSWR but doesn't have an 
ErrorBoundary wrapper in its nearest parent component tree.

For enforcement in your codebase, Claude will also show you how to wire the rule into your eslint.config.js:

// Claude will generate this setup
import noHardcodedUrls from './eslint-rules/no-hardcoded-urls.js'

export default [
  {
    plugins: { local: { rules: { 'no-hardcoded-urls': noHardcodedUrls } } },
    rules: { 'local/no-hardcoded-urls': 'error' }
  }
]

If you can describe the bad pattern, Claude can write the rule that catches it.