engines field declares node >=18.0.0 but code requires Node.js 20+ (Symbol.dispose)

Summary

Claude Code's package.json declares engines: { node: ">=18.0.0" }, but the bundled code uses Explicit Resource Management (using declarations / Symbol.dispose) which requires Node.js 20+. This causes a cryptic runtime error on Node.js 18.x with no prior warning during installation.

Steps to reproduce

1. Install Node.js v18.16.0 (or any 18.x)
2. npm install -g @anthropic-ai/claude-code@latest
3. Run claude

Expected behavior

Either:

• npm install warns that the Node.js version is incompatible (if engines is updated to >=20.0.0)
• Or the code works on Node.js 18.x

Actual behavior

Crashes immediately with:

TypeError: Object not disposable
    at hY (file:///.../cli.js:8:1213)
    at Object.existsSync (file:///.../cli.js:9:208)

Root cause

The bundled cli.js contains a polyfill for Symbol.dispose:

var XEq = Symbol.dispose || Symbol.for("Symbol.dispose")

On Node.js 18.x, Symbol.dispose is undefined, so it falls back to Symbol.for("Symbol.dispose"). However, Node.js built-in objects (e.g. file handles from fs/promises) don't implement this polyfill symbol — they only support the native Symbol.dispose, introduced in Node.js 20+.

Suggested fix

Update engines in package.json to "node": ">=20.0.0".

Environment

• OS: Ubuntu Linux (kernel 6.8.0-85-generic)
• Node.js: v18.16.0 (failing), v24.13.1 (working)
• Claude Code: latest (@anthropic-ai/claude-code@latest)