Pattern matching helper.
"Just validate the email" is one of the oldest traps in software. The one-line regex you copied off Stack Overflow happily accepts throwaway addresses, so your signup list fills with accounts that vanish in ten minutes. Writing a pattern that is strict about format and also blocks the junk domains is fiddly, and getting it wrong quietly costs you a clean list. This blueprint hands you a pattern built for that job, plus the explanation, so you understand what you are deploying.
It generates a strict regular expression that matches valid email addresses and excludes temporary or disposable providers, the ten-minute-mail domains people use to dodge signups. Then it does the part most snippets skip: it explains each piece of the pattern in plain English, the local part, the at sign, the domain rules, and the exclusion list, so you can read it, trust it, and change it later instead of pasting in a black box.
You watch it happen in the task workspace: the agent writes the pattern, tests it against sample addresses including known disposable domains, and confirms it accepts the good ones and rejects the rest before handing it over. The code lands on a branch in your repository with a pull request ready.
The pattern is a starting point you steer with plain follow-up messages:
Each follow-up wakes the same repository and the agent continues on its own code.
Why not just check for an at sign? Because that lets disposable and malformed addresses straight through; the stricter pattern is what keeps your list real.
Can the block list get out of date? It can, so treat it as a living list and ask the agent to add new throwaway domains as you spot them.
Will it work in my language? Regex is portable, so the pattern drops into JavaScript, Python, or most anywhere; ask the agent to adapt the syntax if needed.