Error messages explain the problem and suggest a fix

Error: ENOENT: no such file or directory, open '/home/user/.mytoolrc' tells the user nothing they can act on. They Google the error code, land on Stack Overflow, waste thirty minutes. Configuration file not found: ~/.mytoolrc. Run \mytool init` to create one.` solves the problem in one line. Raw exception messages are a signal the tool was built without thinking about the user's experience on the failure path — which is, for most users, the majority of their interaction with the tool.

Wrap top-level error handling in src/cli/lib/errors.ts and translate system codes (ENOENT, ECONNREFUSED, EACCES) into human messages that name the resource and suggest a next step:

if (err.code === 'ENOENT') {
  console.error(`Config not found: ${err.path}`)
  console.error('Run `mytool init` to create one.')
  process.exit(1)
}