r/secondbrain

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?

I spent the last 20 months over caffeinating and vibe coding to prove the humble sticky note is the perfect mental Legos....

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Hi everyone, I'm looking for advice on PKMS and want to run by my thinking with you in case you have related experiences or you have other recommendations. I'm thinking of buying SiYuan as a base level PKMS - just for text, pdf annotation, and ai capabilities.

Main Wish  List
- My main needs are PDF annotation - I read a lot of books. I also do a lot of things with other multimedia, including videos and e-books.  If anyone offered EPUB, that would be the ultimate flex for me.

- Visual graph / whiteboard / canvas

- Backlinks with visual graphs to see it

- Lifetime (No ongoing costs)

- Easy to sync. I found Obsidian a little too onerous and complicated with that

- Ideally, the ability for me to share a whiteboard or content with my family.  I really need to get my kids on some structured routines. Same with my wife. We need to better collaborate.

- Intuitive

- Ideally Notion like functionality, including the ability to track calculations across tables (this is really a minor wish)

Software I've tried / am trying

SiYuan - A little bit different call to understand some of the Chinese aspects.I love the AI integration capabilities and the fact that I can buy all in sync. I'm debating using this for most of my notes, and then when I want to do projects, I pull in notes in Noteey or another tool to do the organization on a whiteboard.

Noteey - Syncing issues / power outages have left me missing notes, and I'm wary of putting everything in it.  To be fair, synch is new, and I think part of the issue was I didn't understand how to reset the sync after a power outage. I don't really think there's a problem with the product, although I miss backlinks, It's just that I worry about my own idiocy, hitting the wrong sych button or deleting my own notes.  I think it's a fantastic system, but I really feel it's limited to one computer for me.  

Affine. I really like Affine, I've installed it on my NAS, but I don't like the fact it doesn't have PDF capabilities. I hear the AI capabilities are not as strong in the whiteboard / graph area.

Upnote - No PDF annotation and no visual graph. Otherwise, I love Upnote. I do wish there were capabilities though, because I have a ton of notes and it'd be useful to be able to summarize them. This is why I'm thinking about SiYuan.

Obsidian - I've tried it in the past, I found it requires a lot of discipline to organize and run it as a system & it has a steep learning curve.  Unfortunately that's not me.

Thoughts?

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?

English isn't my first language. I wrote this in Korean and translated it with AI, so please excuse any awkward phrasing. A short Korean summary is at the bottom.

TL;DR: When I started building my own AI tools as a non-developer, the real danger wasn't being wrong — it was not knowing I was wrong. The AI often knew my blind spots but never said anything unless I asked. So I gave my AI team a "mentor" that watches my habits instead of the output, speaks only when it matters, and "graduates" me from each lesson. Success means it eventually has nothing left to say.

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The last three posts were heavy on system design. This one is lighter: a small mechanism that I think is the most unusual part of how I use AI.

1. The problem: not knowing what I don't know

I'm not a developer. When I first started building my own skills (reusable AI workflows) with Claude Code, I wasn't good at working with AI yet. What scared me most wasn't making mistakes. It was making mistakes without noticing.

The Johari window puts it neatly:

• Open: I know it, the AI knows it
• Blind spot: I don't know it, but the AI does ← this one
• Hidden: I know it, the AI doesn't
• Unknown: neither of us knows it

Hardcoding an API key. Trusting "Done!" without running the code myself. Reading "deploy succeeded" as "my new code is live." The AI already knows these are risky. But it doesn't say anything unless you ask. It just does what it's told.

I wanted the blind-spot window to open without me having to ask.

2. The mentor note

My setup has several AI roles: planner, developer, auditor, and so on. All of them look at the work. The mentor is different. It looks at me. It doesn't write, edit, or grade any code or documents.

It shows up at the end of a response, like this:

🎓 Mentor note
- Did you actually run it and see the result yourself?

Every rule comes from that original reason:

• Only when relevant. If it shows up every time, it becomes nagging. Nagging gets ignored, and the blind spot closes again.
• 1–3 lines, phrased as questions. A question makes me check for myself; an order doesn't.
• Safety → verification → understanding. The most expensive blind spots come first.
• Graduation. Once I do the right thing on my own three times in a row, it stops mentioning it. That blind spot has moved into the open window.
• Success = silence. It was designed as training wheels from day one.

It's also cheap. It isn't a separate agent, just a few lines added to the main response, so it costs about 50–150 tokens per reply. A separate sub-agent would have cost 2,000–5,000.

3. Real mentor notes I've received

• "A 'deploy succeeded' message is not the same as your new code being live." I checked: the build I was about to ship was 11 days old. Nothing would have changed.
• "Don't just adopt my recommendations on these 6 conflicts. Decide them yourself." The AI telling me not to over-trust the AI.
• "One of your assumptions is factually wrong." It pointed straight at a gap in my own knowledge.
• "This URL is public with no login, so having zero real personal data in the database is your only safeguard."

4. The mirror had blind spots too

Here's the fun part. The mentor broke twice, and both times I noticed before the system did.

Failure 1: the mentor fell asleep. Through an entire design phase, not a single mentor note appeared. When I said "the mentor doesn't seem to be active," the AI admitted it had broken the rule and corrected itself.

Failure 2: the mentor had no memory. Graduation only works if the mentor remembers my habits. After three months I asked, "Where are mentor notes actually recorded?" It turned out the storage had never existed. The design said "shared memory across projects," but the real memory was isolated per project. For three months the mentor had been meeting me for the first time, every single session.

The mirror I built to show me my blind spots had blind spots of its own, and a human had to point them out.

5. Where it stands now

The mentor now has a real file to remember things in. But zero habits have graduated so far. I decided not to graduate anything retroactively. There's no honest way to tell, after the fact, which habits were real and which were luck.

Graduation candidate #1: "Verify it yourself, even when the AI says it's done." That used to be my biggest weakness. Recent records show it's improved a lot.

6. Want to try it?

A few lines in your AI config file (CLAUDE.md, if you use Claude Code) are enough to start:

- Watch me, not the code (verification, security, habits)
- Only when relevant, 1–3 lines, as questions
- If I do it right 3 times in a row on my own, I graduate. Don't repeat it.
- Keep the memory in a real file (check that the storage actually exists!)

That last line took me three months to learn.

Do you ever ask your AI what you might be missing?

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🇰🇷 한국어 요약 처음 AI로 스킬을 만들 때 가장 위험했던 건 '모르는 걸 모르는 것'이었습니다. 그래서 코드가 아니라 저를 보는 '멘토' 역할을 만들었습니다. 필요할 때만 1~3줄 질문으로 맹점을 짚고, 같은 습관을 3번 스스로 해내면 '졸업'시킵니다. 목표는 멘토가 할 말이 없어지는 것입니다. 정작 멘토가 잠들고 기억을 잃은 건 제가 먼저 알아챘습니다. 한국어 댓글도 좋습니다!