Open Source CEO by Bill Kerr- Posts
- Building A Second Brain With Claude Cowork
The ultimate guide to one of the most elusive tools. 🧠 #
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HEAT CHECK 🌡️
Apple just sued OpenAI in federal court, claiming a coordinated scheme to nick its hardware secrets. The suit says one ex-Apple engineer walked out with a laptop full of confidential docs, and that OpenAI's hardware boss (ex-Apple himself) coached candidates to spill secrets in interviews. OpenAI denies the lot.
Which best represents your view on Apple v OpenAI? | #
Apple's camp says this is textbook trade secret theft: 400+ former Apple folks now sit in OpenAI's hardware team, and the alleged behavior went well past normal job-hopping. The other camp believes a company that missed AI is using lawyers to slow a rival's device push. Big precedent either way.
**GUEST POST **💄
I’m not sure if you feel the same way, but over the last 12-18 months, AI went through a real transition: from something that was fun, to something you saw potential in, to something useful, and finally, to something that, on the right occasion, will totally blow your mind.
One of the things white color workers and technology advocates across the globe have yearned for for years is the idea of a true ‘second brain.’ A place with all of your context that allows you to be the best version of yourself. From a personal dump file, to your health and wellness coach, to the calendar for your dog’s next vet checkup. But it’s always been a very underwhelming process because the right tool for the job hasn’t really existed, until now.
Today, I am enlisting my buddy Eliot Prince to walk us through what the ultimate second brain looks like in the age of AI. Eliot runs one of the best YouTube channels for AI upskilling online and posts his thoughts in his newsletter, too. He’s the perfect person to upskill us all today. Without further ado, here is my guy, Eliot.
Hey, ladies and gents, Eliot here! If the Guinness Book of World Records had a ‘how fast can you forget an idea’ category, I would own that title by some distance. Even a goldfish couldn’t wrestle the record away from me. I have an awful memory. Not the cute kind where I forget to pick up tomatoes for my fiancée (even when it’s the only reason I’m going to the store.) It’s the kind that’s frustrated me for a decade+ as an entrepreneur, creator, and writer. The lightning strike idea in the shower, a quote in a book that stops me dead, or a podcast line that reframed my whole mindset. Poof, Fugazi, it’s fairy dust, gone in seconds.
I’ve tried to do the diligent thing, too. Highlight the book quote, snip the podcast, and save the URLs. But here’s the cruel thing about my brain… You can only go digging for any of it if you remember it exists. I don’t just forget the idea or quote; I forget it ever existed in the first place. So in 2019, I set out on the big fix. I’d heard about something called ‘Second Brain.’ A digital mecca that catches every fleeting idea and hands it back to you exactly when you need it. That led me down a rabbit hole of 100+ hours of Notion. I bought templates, courses, and built the PERFECT architecture. It lasted two weeks.
I’d spend two hours a day keeping things tidy before I even got anything done. It felt like cooking a gourmet meal every evening, but being too tired to eat it. Everything collapsed. Over the next few years, I tried Obsidian, ClickUp, Claude connectors, and even vibe coded my own software. All sinking ships. I was just rearranging deck chairs on the Titanic.
But over the last two months, I’ve realized something: I’ve stopped yearning for a second brain. And when I thought about it, it’s because I’d quietly built the whole thing underneath Claude Cowork. All those false starts and lessons… I’d built them into how I use Cowork daily. Now I open my laptop, and it’s all there, ready to work. Every idea, every quote, running commentary of my days, transcripts from calls. And more importantly, the right information is presented to me exactly when I need it.
So if you’re here with a head full of forgotten ideas and a graveyard of note-taking apps, then I want to hand you my Claude Cowork Second Brain setup. This is your chance to wipe the slate clean and reboot your digital life. You can set the whole thing up in 1 hour. And enjoy an information dumping ground, trusting that it’ll come back to you when you truly need it. Let’s go.
First thing, download and install the Claude desktop app. You can't do this in Claude Chat in the browser; there isn't enough power under the hood. Open the app, click into Projects, and create a New Project. Start from scratch. Call it ‘Second Brain’. Leave the custom instructions blank; we’ll build that later. This is the only project you'll ever need to build, because your whole world is going to live inside it. And here's the bit I love. You're not going to build the structure by hand (we’re AI architects after all). Claude is going to build it for you.
Normal filing systems are cruddy. You end up with giant department folders, then folders inside folders inside folders. It’s folderception. You spend more time hunting for info than doing the work. So today we flip it. We use an organizational system called PARA, from a book by Tiago Forte. Here’s the TLDR: PARA uses four folders.
Projects: Live work that's time-bound and has a finish line. A product launch, a fundraise, a client deliverable, a talk you're writing for next month.Areas: The ongoing parts of your work and life that never really ‘finish’. Think hiring, finances, house management, marketing. They don't have a deadline; they just keep rolling, and you're responsible for them month after month.Resources: Knowledge you know you'll want one day that doesn't belong to any current project or area. For me, that's a folder of business growth advice I'm slowly collecting. For you, it might be business frameworks, leadership resources, fundraising notes, anything.Archive: Anything that's gone quiet. Finished projects, dormant areas. Out of the way but not deleted.
That's it. Four buckets. Everything you own has one obvious home.
Imagine you have the perfect organizational system that told you exactly where to put every piece of information in your digital life and exactly where to find it when you need it.
Now imagine you give that power to Claude Cowork too!?
Next, hand Claude the job of setting up your PARA folder structure. Drop this prompt into your Second Brain project:
Prompt:
You're setting up my second brain in this project. Create a PARA folder structure for me. Make four top-level folders: Projects (live, time-bound work with a deadline), Areas (ongoing responsibilities with no end date), Resources (reference material I'll want later but that doesn't fit a current project or area), and Archive (anything finished or dormant). Leave them empty for now. When you're done, show me the structure so I can check it.
Give it a few seconds, and your Second Brain folder structure on your computer will look like this. Remember, Cowork runs using files and folders on your computer!
The single biggest reason my old systems died was capture. An idea hits while you're mid-task, and to save it properly, you have to stop, decide which folder, which note, which database, which Drive. By the time you've filed it, you've lost the thread of what you were doing. So you stop filing, the system rots, and you end up with a million different browser tabs open in your brain. The fix is an Inbox. One folder that sits right next to Projects, Areas, Resources, and Archive, and acts as your dumping ground. Capture first, organize later. You don't decide anything when you capture. You just dump. Sorting happens later, either by you or, as you'll see in a minute, by Claude.
Prompt:
Add one more folder at the same level as Projects, Areas, Resources and Archive. Call it Inbox. This is my capture folder. Anything I drop in here is unsorted and temporary, and gets filed into the right PARA folder later. Don't put anything in it yet.
Hey, it’s Doc again here. I just wanted to quickly make a note of Eliot’s channel in a bit of a broader way. I stumbled upon Eliot, and we started chatting because his channel was the main channel I would share during our fortnight AI Watch Party at Athyna, my startup.
Eliot is too humble to try to shoehorn his own videos into this step-by-step style piece, so I thought I’d better go ahead and do it for him. Here is but a small sliver of his best stuff. Onwards!
You've got the architecture. Now you tell Cowork how to behave inside it. This is where CLAUDE.md files come in, and they're the part most people have never heard of.
A CLAUDE.md is a plain-text instructions file you put inside a folder, and Claude reads it every time it runs in that folder. Think of it as a system prompt that lives with the folder. Every folder in your second brain can have its own, so each part of your world behaves exactly how you want it to. You can ask Cowork to write these from scratch, or use the framework I've set out in the prompt below, which gives you a sensible setup straight away.
Prompt:
Write CLAUDE.md behaviour files for my second brain. The root CLAUDE.md should explain PARA (every file lives in one of Projects, Areas, Resources or Archive, with Inbox as the staging area for anything unsorted), tell you to start each session by asking me as a multiple-choice question whether it's Inbox capture, a Project, or an Area (for a Project or Area, ask which, scope in, and stay there unless I say otherwise; for Inbox capture, save everything I send to the Inbox as dated notes and do nothing else), make captures always hit the Inbox first rather than a deep folder mid-task, and put anything you create in an Outputs folder inside the current Project or Area, creating it if needed. Then add a short CLAUDE.md in Projects, Areas and Resources saying what belongs there and how to name files, and if one's empty, help me decide its starting knowledge base. During long sessions or after critical outputs you should write/update a memory.md file to keep a project or area upto date.
When Claude finishes, you'll have CLAUDE.md files sitting through your folder structure.
The root file teaches Claude the whole filing system and tells it to ask, every time you log in, what you're working on and where to scope in. Plus any other house rules. The folder-level files give each area its own rules, so your Finances folder can behave differently from your Marketing one if you want.
Two ways to do this, and the right one depends on what you've already got organized. If you've already got knowledge sitting in other places, old notes, a swipe file, or docs from past projects, seed it. For example, my projects are filled with client and internal projects that are live. Each has its own folder holding the key knowledge and outputs. Either add these folders and files yourself. Or ask Cowork to help!
If you're starting cold, build as you go. Every call transcript, every idea, every useful article goes into the Inbox, and over a few weeks, the thing fills itself.
Last build step, and it's the one that makes the whole thing run itself. We're going to give Claude a repeatable routine for sorting your Inbox and filing everything into the right place.
Prompt:
Using the /skill-creator, build me an inbox-processing skill I can run any time I say "process my inbox". Go through every file in the Inbox folder one at a time. For each item, read it, work out which Projects, Areas or Resources folder it belongs in based on what it's about, then suggest where it should go and a clean filename. Once I approve, move it there. If something has no obvious home, leave it in the Inbox and tell me why. Never delete anything. Give me a short summary at the end of what moved where.
Now your loop is closed. Capture into the Inbox whenever, however messily you like, and let Claude file it later. You can run it on demand by typing ‘process my inbox’, or set it to run on a scheduled task.
💡** **Note: 65,000+ professionals and founders every week read and watch Eliot every week. Get access to 200+ prompts at his AI Recipe Vault.
Once it's built, the daily rhythm is boringly simple. You open Cowork, say ‘Let's work,’ and Claude asks one thing: are you here to capture, or to work on a Project or Area? Pick capture and just dump a quote, a link, a half-formed idea between meetings. It all lands in your Inbox without breaking your stride. Pick a Project or Area and Claude scopes into that folder, pulling you in with all the context already loaded. No hunting.
When the Inbox has built up over a day or week, you say "process my inbox" and let Claude file everything away, or leave the scheduled run to do it for you. Once you've lived in it for a few weeks, you start extending it. You can wire in your call transcripts so every meeting lands in the inbox automatically. Point it at your email to pull out anything worth keeping. You can connect it to your CRM, so the client context is always at hand. The architecture stays the same, you're just feeding it more and more of your world.
Did you like this new 'tutorial' style post? | #
We Raised $2.5M To Build Athyna AI- May, 2024If You Ain’t AI First, You’re Last- November, 2025Treating Candidates Well, Post-Training & AI Recruitment- June, 2026
And that's it! You can follow Eliot on LinkedIn, and also don’t forget to check out his website while you’re at it.
BRAIN FOOD 🧠
TOOLS WE RECOMMEND 🛠️
Every week, we highlight tools we like and those we actually use inside our business and give them an honest review. Today, we are highlighting Granola*—an AI-powered notepad that takes, summarizes, and organizes meeting notes without using intrusive recording bots.
See the full set of tools we use inside Athyna & Open Source CEO here.
**HOW I CAN HELP **🥳
Hiring global talent:If you’re hiringtech, business or ops talent and want to do it 80% less, check out my startup,Athyna. 🌏See my tech stack: Find our suite oftools & resourcesfor both this newsletter and Athynahere. 🧰Reach an audience of tech leaders:Advertisewith us if you want to get in front offounders, investors and leadersin tech. 👀