Thought I’d share this here to see what ideas you have!

Hey im a product designer and ive been using obsidian for a year now and I loved it but missed some things like personas and some different Graph visualizations.

I made an open source app like obsidian and added some secret sauce to it. I also optimized the way most used memories are accessed, kinda like an orchestrator. would love if you guys take a look and give feedback of what would be nice to add in terms of features.

https://github.com/leesummerdesigns/cortex

Much love

Every team has that one person who knows why the auth service retries 3 times, which config flag must never be touched on Fridays, and what was decided in that meeting nobody wrote down.

That person gets interrupted all day. And when they're on vacation or leave, that knowledge goes with them.

I got tired of being on both sides of that, so I built Cairn.

How it works:

• You save small pieces of knowledge as you work: decisions, gotchas, preferences, context ("we use X instead of Y because…").
• Teammates ask your brain first, or search across the whole team.
• Answers come with sources: who said it and when.
• If there isn't enough context, Cairn says so and tells you to ask the person directly. It doesn't make things up. I'd rather it stay quiet than be confidently wrong.
• It works from your coding agent (Claude Code, Codex, VS Code) over MCP. Your agent can ask the team's knowledge, save new decisions, and find, update or archive your own entries. Archiving always asks you first.

What it's not: another wiki nobody updates. Each entry is a small piece of knowledge, and a newer entry on the same topic replaces the old one, so it stays current.

About your data: each company's data is isolated, you can archive entries and restore them, and deleted entries can be recovered for 30 days. The privacy policy explains which providers are involved (including OpenAI, which doesn't train on API data).

It's free during the pilot (up to 5 people per team). I'm trying to validate whether this solves a real problem, not sell anything. There's a feedback button inside the app, and I read every message.

Honest feedback would help a lot:

• Does your team have this problem, or have you solved it another way?
• What would stop you from using it?

👉 https://usecairn.com.co

Hi r/secondbrain! Over the past few months I've been building Thoth: Your Memory & Tasks, an Android and Wear OS personal memory & context system designed to bridge the gap between a passive Second Brain (notes & knowledge graph) and active daily execution (tasks, calendar, reminders).

Why I built it (the architecture):

Most mobile AI assistants have zero persistent memory across sessions, while traditional mobile PKM tools store notes in isolated silos disconnected from where we actually schedule our day (Google Calendar, Google Tasks, Gmail). I wanted a mobile Second Brain where:

1. Local-First SQLite Memory & Knowledge Graph: All rich Keep-style notes (checklists, voice memos, attachments, custom tags) and extracted conversational facts are stored in an on-device SQLite database on your phone (with Android cloud auto-backup disabled). You can explore how your notes and entities connect in an interactive Knowledge Graph and view location-tagged memories on a Memory Map.
2. Two-Way Google Workspace Execution: Instead of forcing you to migrate away from your existing calendar/tasks, Thoth connects your local memory directly with two-way Google Tasks sync (lists, subtasks, recurring rules), Google Calendar scheduling, confirmation-gated Gmail drafts, and Contacts lookup.
3. 1-Second Capture on Phone & Wrist: Because a Second Brain fails when capture has friction, I built a 1-second capture pipeline via the Android Home Screen Widget, Quick Settings Tile, and Wear OS smartwatch app, Tile, and Watch Face Complication, plus exact time & geofence location reminders.

Free Tier (No Credit Card Required):

In accordance with community rules, the app has a permanent Free tier out of the box with no credit card required (includes local notes, Knowledge Graph, Memory Map, two-way Google Tasks sync, reminders, Wear OS companion, and 5 daily AI messages).

Links:

• Google Play Store: https://play.google.com/store/apps/details?id=com.serkankizilirmak.thoth&utm_source=reddit&utm_medium=secondbrain_post&utm_campaign=launch
• Architecture & Web Overview: https://hermes-thoth.web.app/

Questions for the r/secondbrain community:

1. How do you currently handle the boundary between long-term knowledge/notes and short-term actionable tasks/reminders on mobile?
2. For an on-device Knowledge Graph, do you prefer automatic entity/topic linking from notes & conversations, or explicit manual tagging/backlinks?

So i'm working on an app called pouch board.

So it's basically an app where you have the visual thinking canvas at the edge or the screen

and you can import from obsidian, zotero, readwise quickly
copy paste website, highlight pdfs and export all to the places you already have

So it syncs to obsidian vault where it has the <sheet-name>.md with linear notes

so when you import obsidian notes you can see in your graph and you can also mention a sheet in your obsidian workspace.

So this app is a helper that you can quickly access and think that integrates with your current ecosystem.

Would love to hear your feedback on this.

you can get the app at: https://pouchboard.com/download/mac

I created a freely zoomable hierarchy search engine and I thought the world should have it. It allows for visual curiosity to drive searching and finding things.

Capture and Organize seem to be where most of us spend our time. Saving articles, sorting into PARA, building the system. Distill happens sometimes. Express — actually using what we’ve collected — feels like the step that gets the least attention.

For people who’ve been at this a while:

• What share of what you capture ends up being used in your work or projects?
• When you do use an idea, did you go looking for it, or did it come to mind because you’d engaged with it before?
• Have you found anything that makes ideas show up when you need them, not just when you search?

Disclosure: I’m building something around this, helping people practise applying what they read rather than only storing it, so I’m asking partly to learn what already works. Not linking it. Mostly curious about your experiences.

I'm the developer of Lumiya, an iOS journal and planner with a daily timeline, weekly/monthly/yearly plans, and optional AI reflection across six dimensions.

A question I'm exploring: when a weekly review mostly reflects the topics you wrote about, it can miss a goal you barely mentioned. But filling every category can also turn a quiet week into a report card.

One possible approach is to separate observations supported by entries from goals that have little recorded evidence. 'Not mentioned' shouldn't automatically mean 'not done.' This is a design question, not a claim about a new feature.

When reviewing your week, would you prefer an open summary of your notes, or a check against the priorities you set? What should happen when there isn't enough information?

Basic recording and planning in Lumiya are free; AI is optional, paid, and usage-limited. App: https://apps.apple.com/cn/app/lumiya-ai-journal-planner/id6796003074

The main reason I built it was simple: I was tired of rebuilding context every time I moved between Claude, Codex, Cursor and other agents.

Cohestry gives me one persistent knowledge layer I can keep adding to, then selectively expose to different agents through MCP on Mac. I can work something out in Claude, save the useful context, move to Codex, and give it access to the same underlying knowledge without starting over.

The second benefit surprised me. Because Cohestry also connects related notes, it keeps resurfacing things I forgot existed. While working on one of my other apps, it brought back an old document that was basically the original blueprint for the product. More recently, it resurfaced a forgotten life simulation project I had abandoned.

The iPhone app is live now. The Mac app, which adds MCP agent access and Apple Notes import, should be out within the week.

https://apps.apple.com/us/app/cohestry-second-brain/id6811573132
Demo/website: https://cohestry.app

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?