Lieben posts his Claude Code list build for 500-prospect sends
Standing rules in one file, GTM substance in another, accounts tiered T1 to T3, phones enriched only for the top tier.
Michel Lieben published the Claude Code setup he uses to build lists and write copy, and the whole thing points at one number. Send to 500 prospects instead of 100,000. He follows that with a claim that micro-lists return 20-30% replies against 2-3% for blasts, based on what he says is 1M+ emails analysed in Instantly.
The file structure
Two files do the work. Standing rules go in CLAUDE.md, meaning who you sell to, what tone to write in and what never to say. Lieben says keep it under 200 lines because past that the model starts dropping rules. The GTM substance goes in brain.md, which holds the ICP, the best angles and the three best closed deals. At the bottom of that file he ranks sources, closed-won CRM data first, so the model stops picking a winner silently.
Data tools get connected one at a time with a single claude mcp add line, and he tells you to single-quote the key so it does not end up in the file you are about to commit. This follows the earlier list of APIs he runs inside Claude Code.
Tiering decides what you spend
The model tiers accounts. T1 fits and has a live signal, T2 fits with nothing live yet, T3 goes on a watchlist. Emails get enriched for everyone, phones for T1 only, because Lieben says a phone lookup costs about 10x an email.
Copy follows the same split. One prompt per T1 account written off its signal, one template with a variable swapped for T2, the volume sequence for T3. Lieben says to read every T1 email yourself before anything goes out, and calls that the only part still yours. Replies go back into brain.md so run two beats run one.
On speed, he says a campaign can be dictated in three sentences, and that Louis on his team did exactly that and had a verified list and the copy sitting in Instantly 27 minutes later.
For people sending, the 20-30% figure is Lieben's own read of his platform's data rather than an independent test, and the structure only pays if you can actually write per account. A 500-prospect list with T3 template copy on all of it is just a small blast.
Micro-lists get 20-30% replies, blasts get 2-3%, across 1M+ emails we analyzed in Instantly
enrich emails for everyone and phones for T1 only, a phone lookup costs about 10x an email
Know what is landing before you burn another domain
One email a day. Under three minutes. What the operators found out yesterday.