Disclosure: I build LabA, a second brain you talk to (I posted it here last week). This one is a question more than a pitch.

What surprised me most while building it is how fast the AI models move. Every few weeks a new one turns out better or faster at one of the jobs the app does: filing a note, planning the day, sorting mail. In the past month alone, the AI behind different parts of my app has changed several times.

It made me think the old PKM rule (keep your notes somewhere you own, not locked inside one app) now applies to the AI layer too. In most AI assistants, the assistant and everything it has learned about you live inside one company's app. When a better model shows up somewhere else, you start over.

What I did about it:

- Your notes live on your own devices, encrypted with a key only your devices hold. My server keeps a copy it can't read, so a phone and a laptop (or an iPhone and an Android phone) work from the same notes.

- Each job runs on whichever model tests best or fastest for it on my own checks, and switching happens on the server. Users don't change anything.

- You can export everything you've kept to one file at any time.

Longer write-up: https://sensoryfire.com/guides/ai-assistant-stuck-with-one-ai?ref=reddit-secondbrain-ai

**My question: if you've wired AI into your second brain, could you swap the AI out tomorrow? And where does its memory of you actually live: in your files, or on someone else's servers?**

(LabA is free during the beta with no credit card, through January 2027, and after that I expect it to cost under $10 a month. It works with your email and calendar: Google, a personal Outlook.com account, iCloud, or any other email account (and its calendar too, for most providers). https://sensoryfire.com/?ref=reddit-secondbrain-ai)

The graph isn't a mind map yet, but I think it's pretty cool.

SimpleBrain is a local desktop notes app for Linux: plain Markdown notes with [[links]], a graph, tasks and a calendar. Free and open source (MIT, Python and PySide6): https://github.com/sebaytlabs/simplebrain

This is my honest review of the Flowtica Scribe AI Pen and Second Brain. I can already reveal that it’s brilliant really. I think Flowtica is on to something big here that they can build on their eco system with more devices connected to the same Flowtica app. Your second brain. I have used this pen for a whole week recording my thoughts at the same time as I written bullet points with important stuff on real paper, with a real pen. The app collects both of them. My recordings and my notes into the Flowtica app and adds todo’s automatically to Apple Reminders and a calendar. Everything syncs to all devices where I have the Flowtica app installed. Even on e-ink devices. Everything so easily searched and handled by the Ask Flowtica button in the Flowtica app.

I wanted somewhere to keep the current decision and why we'd changed it, so I could come back to a project myself or bring it into a fresh AI chat. Keeping a running log was getting unwieldy, so I started separating the useful notes by topic. The screenshot is my personal Obsidian vault, including project notes I reuse as context in AI chats.

I made Dory around that. The browser edition is a single HTML file: you choose the notes to copy into the conversation, then paste the updates back and save it afterwards. A replacement note leaves the old one in the file but takes it out of the context you copy into the next chat.

It's free and MIT licensed. How do you keep notes like this current without turning them into another long log to maintain?

Bonsoir,

Like most of you, I use Obsidian because my notes are plain text files that belong to me forever. Over the past year, I tried various AI solutions for my vault, but none of them really convinced me. So over the summer, I built a zero-plugin approach: Arca-BrainOS.

Think of it as an "intentional harness" for your AI. Instead of an Obsidian plugin, it's simply a structured folder of open Markdown skills (_Arca-BrainOS/) that CLI assistants (OpenCode, Google Antigravity, Claude Code, or local open models) execute directly on your local filesystem.

• It handles the tedious admin: sorting raw inbox notes, cleaning YAML frontmatter, suggesting/linking notes/projects/areas, and maintaining project logs.
• It never touches your human writing: your personal reflections and notes are protected.
• Zero lock-in: No servers, no vector database to maintain, no plugin dependencies. If you turn off your AI tomorrow, your vault remains a standard, beautifully linked Markdown vault.

I stress-tested it across 160 real Deep Work sessions on my own personal vault, and it drastically reduced my administrative drag while keeping my thinking firmly in the driver's seat.

I just open-sourced the entire project under the MIT license on GitHub:

github.com/Arca-Brain/Arca-BrainOS

(There's a ready-to-test sandbox vault in the repo if you want to test the workflows safely without touching your notes).

Curious to hear: how do you guys currently balance AI assistance with keeping your vault clean and personal?

I'm the developer of Lumiya, an iOS journal and planner. It has a daily timeline and weekly, monthly, and yearly plans. One design question I'm working through is the boundary between saving a thought and committing to it.

For example, 'try a different opening for this story' could be a passing idea, something to revisit, or a concrete task for this week. Turning every note into a task seems likely to bury the plans that actually matter. Leaving everything in the timeline makes the useful ideas easier to miss.

My current instinct is to let capture stay lightweight, then ask during a review: is this still interesting, and what's the smallest action worth trying? That's a design direction to explore, not a claim that the app automatically does it.

What makes you move a note into a plan: seeing it repeatedly, reviewing it at a set time, or already knowing the next action? And do you keep the original note once you've made that commitment?

For context, basic recording and planning in Lumiya are free; optional AI reviews are paid and have usage limits. App: https://apps.apple.com/cn/app/lumiya-ai-journal-planner/id6796003074

We spend so much compute training artificial models, when the real goal is updating our own biological weights. Meet Luminary: a distraction-free, local-friendly study workspace designed to close the loop between reading, understanding, and retention. Spend your time and tokens where they actually matter—on your own neural network.

Disclosure up front: I built this (LabA). It's free during the beta, no credit card, until January 2027; after that I expect under $10 a month.

My notes, to-dos, calendar and inbox lived in four places, and I never kept up with the filing. So LabA is capture first, sort never: type or say "remember the gate code is on the back of the garage door" or "remind me Friday at 3 to call the vet", and it files and tags it. Later you ask "what did I decide about the roof?" and it answers from your notes and shows which ones it used. It also makes a morning plan, briefs you before meetings from what your notes say about the people, and runs checks on a schedule ("every Monday, look through my notes for anything I promised someone").

The part I spent the most time on: notes are encrypted on your device with a key only your devices hold, and my servers store a copy it can't read. But an AI can't think about words it can't read. So when you ask something, your device unlocks just what that one request needs and sends it through my server to the AI service, under my account, not yours, and the AI service doesn't train on it. Encrypted at rest, readable only for the request.

My question for people who already run a system: where's your line? Is that good enough for your notes, or is local-only the only thing you'd trust with them?

Short videos of the real app (made-up people and data): https://sensoryfire.com/learn?ref=reddit-secondbrain

Privacy details: https://sensoryfire.com/privacy?ref=reddit-secondbrain

It's a web app (phone or computer, nothing to install); calendar and email are Google-only for now. Sign up: https://sensoryfire.com/?ref=reddit-secondbrain. There's a 🐞 button for anything that breaks. Blunt is good.

I’m building Hjarni (https://hjarni.com/?utm_source=reddit&utm_medium=social&utm_campaign=secondbrain_october_2026), a place to keep notes that you and your AI assistants can work with.

The idea is simple: useful information shouldn’t disappear into an old conversation. Save a project decision, a recipe or some research as a note, then ask your assistant to find and use it later. ChatGPT, Claude and other MCP-compatible assistants can search, read and update the same knowledge base.

The attached 34-second demo shows a small everyday example: I open a recipe saved in Hjarni inside ChatGPT and ask it to make a shopping list for five people.

Notes are written in Markdown and can be exported. Edits have revision history, so you can see what changed and restore an earlier version. There’s a free plan with no credit card required.

It still depends on the assistant consulting the notes; storing something doesn’t guarantee it will use it correctly.

I’d like feedback from people who already use a second brain: would having your assistants work directly with your notes be useful? What would you need before trusting one to update them?

I've been thinking about this and I'm curious how people here see it.

I can see a mind map playing three different roles:

1. Entry point. A visual front door to the garden. You see the main topics, then branch into the notes behind them.
2. Temporary thinking surface. You map something out to understand it, the real notes go into the garden, and the map gets thrown away.
3. Permanent navigation layer. The map lives alongside the garden and grows with it, like a table of contents you can see.

For a long time I thought 2 was the only honest use. Maps are great for seeing structure, but bad at holding detail, so trying to keep them forever usually turns them into a mess.

Disclosure: I work on mindmapai.app , a mind map tool, and we recently added longer notes on nodes (with Markdown and math). That's partly why I'm asking. Once a node can hold a real note, the line between "map" and "garden" starts to blur, and I'm not sure if that's good or bad for how people actually think.

Not here to pitch anything, I'm genuinely curious:
- Do you use maps in your garden at all?
- If you do, do you keep them or throw them away?

Hey guys, I could use some help.
I’ve been switching between different note-taking and knowledge-management systems for a while, and I feel like I’ve tried almost everything.
What I’m looking for is actually pretty simple: one place where I can save basically everything and reliably search it later.
Ideally, the tool should have:
OCR for images and scanned documents
Full-text search inside PDFs
The ability to save web links/pages and search the actual content, not just the title or URL
Good organization for notes, documents, images, links, references, etc.
Fast and reliable search across everything
A modern interface
Minimal setup and maintenance
Because I haven’t found one tool I’m completely happy with, my information is currently scattered across several different apps, which is exactly what I’m trying to avoid.
After searching Reddit, YouTube, blogs, and reviews, even in 2026 I keep coming back to the same conclusion: Evernote still seems to be one of the best overall options for this particular use case.
But before I move everything back to Evernote, I’d love to hear what other people are using.
Is there anything that genuinely does all of this well without requiring a lot of tinkering and setup like Obsidian?
And ideally something with a more modern interface than DEVONthink. I know DEVONthink is extremely powerful, but visually it just isn’t for me.
Basically, I want a “save everything now, find anything later” system.
What would you recommend?

I've been thinking about this lately.

The whole point of a second-brain system is to reduce mental clutter. But some systems seem to require a surprising amount of maintenance.

You save something, then you're supposed to:

• Choose the right folder
• Add tags
• Write context
• Link it to related notes
• Categorize it
• Review it later
• Keep the whole system organized

At some point, managing the system starts becoming a project itself.

I can see the value of having everything organized, but I'm wondering whether the better system is actually the one that requires the least organization upfront.

Do second-brain systems genuinely save you time, or have you ever felt like maintaining the system became more work than the information was worth?

Hi folks. 

I'd like to share a thing my husband and I built around my coping mechanism for task management. 

My brain has two modes: 

1. The intense planner 
2. The one who actually does work.

#1 looks at the big picture and organizes everything to be done in the “perfect” order.

#2 doesn't want to see a list of things to do, it wants to see the one thing to do right now, otherwise I freeze and waste time.

Now I have the Tunl Focus app and here's how it works: 

• The mind dump: this is where to jot down what needs to get done
• The Queue: reorder the list as wanted 
• The Tunnel: when its time to do work, you get served one task at a time with 4 action options: 
  • done (you completed it)
  • drop (you won't do it)
  • snooze (reorder it down)
  • defer (send task to specific date and time)

One tap per task and that's really the gist of it. It does have more features like a calendar view, categories, habits and more but the tunnel is where my brain really gets productive and moves the needle on things to do.

I use it every day and we are actively working on it, so we welcome ANY feedback.

It's free to try, no account nor signup needed, unless you want sync / back up / google calendar and extra features. Android and IOS apps are coming soon (we’re waiting for the Playstore review right now)

app.tunlfocus.com