I Helped a Client Teach Claude to Send Their Email. Here's the Setup.

Parts 11 and 12 laid the ground: a domain, real email, and a brand the emails can wear. This is what we built on it. A client's recurring customer email, the one the owner used to write by hand every week, now drafts and sends itself on schedule, from their own address, in their own brand. Claude does the writing. The owner still makes the calls.

Three pieces, three jobs

• The skill knows how. A skill is a short set of instructions Claude loads when a task needs it. This one holds the template, the tone, the facts it needs, and the rules: never invent a date, never send without a recipient, flag anything that looks off instead of guessing.
• The routine knows when. A routine is a scheduled task. On its schedule it wakes up, gathers the facts, and runs the skill once per recipient.
• Resend does the sending. Resend is the service that delivers from the client's own verified domain, using a template built from their design system. Because the domain was authenticated in Part 11, the mail lands in inboxes, not spam.

Separate how, when and from where. When something breaks, you'll know which of the three to look at.

I run the same pattern myself

This isn't a setup I sold before living in it. Every email my client portal sends goes through Resend from the Clarent domain: invites, document requests, "your deliverable is ready." They're batched, so a client gets one email that lists everything waiting rather than one per click. And since Part 9, Claude stages deliverables into the portal and I publish them after a look. Same shape: Claude writes, a human approves, the service sends.

The guardrails we started with

• Draft first, send later. For the first few weeks the routine made drafts for the owner to approve. It only sent on its own once the drafts stopped needing edits.
• Test sends to ourselves. Every template change goes to an internal address before any customer sees it.
• One email per person per run. Each send carries a unique key, so a routine that runs twice by mistake can't send twice.
• Unsubscribes and bounces respected. Anyone who opts out or bounces is suppressed automatically, and the routine checks before it sends.
• A summary to the owner after each run. Who got what, and anything the skill flagged instead of sending.

Why not an email-marketing tool?

The client could have bought one. Those are built for campaigns: one message to a list. This was the opposite. Each email was a little different and depended on facts about that one customer. That's the kind of writing Claude is good at, and a skill keeps it consistent. Resend just delivers what the skill wrote.

What I'd tell a small business owner

• Start with the email you already write by hand. You know what good looks like.
• Write the rules down before you automate. The skill is mostly your judgment, in writing.
• Approve drafts until you're bored of approving them. Then let it send.
• Send from your own domain. It's the difference between a business email and a spam email.

Questions I get about this

What if Claude writes something wrong? That's why it drafted for weeks before it sent. The skill has explicit rules for when not to send, and it reports those cases instead of guessing. A wrong email that never left is a flag. A wrong email that left is a problem.

Do I need a developer? Someone has to verify the domain with the sending service and connect it. After that, the skill and the routine are plain-language instructions the owner can read and change.

What does it cost to run? At this volume, the sending service is free, and the routine runs on the Claude plan the business already pays for.

If there's an email you write by hand every week, ask me whether this would fit it. Usually it does, and the first version takes an afternoon. And if you've automated something like this and it went sideways, tell me how. I'd rather learn from your mistake than make it.