Newsletters aren't one thing: a guide to making Marvin send the brief you actually want

When someone says "I want a newsletter from Marvin," we've learned to ask what they mean. The word does too much work.

An investor means a portfolio brief: five tickers, overnight news, anything that affects an open thesis. A founder means competitive intel on the companies they benchmark against. A sales lead means account updates across twenty named companies. A researcher means a paper digest. A parent of a teenager means a translation guide to whatever their kid said at dinner. A traveler means what's actually happening in Lisbon next week.

Every one of these is a newsletter. None of them are the same product. You don't pick from a menu: you describe what you want in an email, and Marvin builds it. Here are six realistic setups and how to tune the result.

Six prompts that became six very different briefs

1. The investor's morning portfolio brief

To: marvin@ccmarvin.com

Hi Marvin,

Every weekday at 6:30am Pacific, send me a brief on my portfolio. Cover overnight moves on AAPL, NVDA, TSM, ASML, and the three private companies in my holdings. Include any material news, analyst rating changes, and pre-market action. Keep it under 300 words. Lead with the biggest mover.

What comes back: a scannable brief, biggest mover first, one or two lines per ticker, links out for anything worth opening. If nothing moved overnight, the brief says so. It doesn't invent action.

2. The founder's competitive intelligence digest

To: marvin@ccmarvin.com

Hi Marvin,

Send me a Tuesday and Friday digest at 8am ET on these companies: Linear, Notion, Coda, Airtable, Asana, Monday.com. I want product launches, pricing changes, major hires, layoffs, funding, and any public comments from their CEOs. No generic "best project management tools" listicles. If there's nothing new on a company, skip it. Don't pad.

What comes back: a per-company section, only for companies that actually had news. The "skip if nothing" instruction does real work here. A generalist newsletter has to fill space; yours doesn't.

3. The sales lead's account brief

Weekly Monday 7am brief on these 22 accounts: [list]. News that affects a sales conversation: leadership changes, funding, M&A, layoffs, earnings, big customer wins or losses. Group by account. Skip product launches. Omit any account with nothing meaningful this week.

What comes back: an account-by-account list of things to mention (or avoid) on next week's calls. That "skip product launches" filter is a taste decision a packaged newsletter can never make for you.

4. The researcher's paper digest

Every weekday at 5pm Pacific, digest new preprints on mechanistic interpretability, sparse autoencoders, and circuit analysis. arXiv, OpenReview, Anthropic, DeepMind, OpenAI. For each: title, authors, one-paragraph plain-English summary, link. Skip anything primarily about LLM eval benchmarks.

What comes back: three to eight items most days, with summaries you can actually read. The benchmark filter cuts maybe half the noise.

5. The parent's Gen Z translation brief

Every Sunday morning, brief me on what's trending with US teenagers: slang, TikTok moments, music, gaming, fashion. I have a 14-year-old and want to know what she's referencing. Keep it light, around 500 words. Nothing inappropriate for a parent newsletter.

What comes back: a friendly weekly read-aloud. Slang with definitions, the TikTok trend of the week, whatever song is suddenly inescapable. Genuinely useful at dinner.

6. The traveler's city brief

To: marvin@ccmarvin.com

Hi Marvin,

I'll be in Lisbon May 12-18. Each morning of that week at 7am local time, send me a brief on what's happening in the city that day: concerts, exhibitions, neighborhood events, restaurant openings, weather, and any news a visitor should know. Skip generic tourist content I could get from a guidebook.

What comes back: a "what's on today" brief, written like a local friend. After the 18th, the recurring task ends automatically.

You could keep going: an operator wants a weekly regulatory brief across three states, a lawyer wants new opinions from a specific circuit. Same shape of email every time.

How to structure the ask

There's no template to fill out, but the best prompts cover four things:

Cadence. Daily, weekdays, weekly, one-off. Give a time and timezone. "Every weekday at 6:30am Pacific" lands cleaner than "every morning."

Content. Be specific about topics, names, tickers, sources. "AI news" is bad; "AI infrastructure startup news, training and inference" is good.

Filters. What to skip matters as much as what to include. "Skip retail." "No listicles." "Don't pad if there's nothing."

Format. Word count, ordering, citations. "Under 300 words, biggest mover first, cite sources." Leave it out and Marvin picks defaults, but the defaults aren't tuned to your taste.

You write it the way you'd brief a smart intern.

The refinement loop

The first brief is never the final brief. Tuning is part of the product, and the way you tune is to reply to the newsletter itself:

Drop the Asana section, they're not a competitor for us anymore. And lead with funding news when there is any, not product launches.

Marvin updates the recurring task and confirms:

From: Marvin marvin@ccmarvin.com

Hi Nina,

Done. Asana is out, and from Friday's edition on, funding leads each company section ahead of product launches. Everything else stays the same.

Sincerely,
Marvin

You don't need the engineering details. Reply like you would to a person, and the next edition reflects the change.

Try one

Pick the brief you'd actually read tomorrow morning. Write it out the way you'd brief a smart intern: what, when, in what format, what to skip. Send it to marvin@ccmarvin.com.

If the first one isn't quite right, hit reply and say so. That's the whole product.