Running our email stack through Brew MCP and a coding agent

I run lifecycle solo for a small PLG SaaS. For two years Mailchimp was fine for newsletters. Launch weeks became painful: every iteration meant dragging blocks, fixing mobile spacing, and re-checking links by hand.

In May we pointed the agent at Brew MCP (docs on brew.new/mcp) with a read-only Notion brief and write access to our sending domain. The workflow: describe the campaign in chat, agent calls MCP tools to generate HTML, agent schedules a QA send to my inbox, I edit two lines, agent publishes.

What surprised me was brand memory. We fed brew.new our marketing site once. The first draft already used our type scale and button radius. Not perfect, but closer than any template gallery we tried.

What did not move: abandoned signup recovery and billing dunning still live in Customer.io because our product events already map cleanly there. Brew handles product update broadcasts and one-off launch mail.

Caveats for anyone copying this: warm new domains properly, keep humans in the loop for compliance copy, and read the MCP tool list before granting schedule permissions. I am bullish, not reckless.