Hubble: Open-source notetaking app for you and your agents

Genuinely curious, maybe I'm missing something. What makes this more "agent-ready" than Obsidian .md files on disk or even something like .org files?

I can let my agent edit those files all the same + there's better integrations and knowledge readily available on these.

I can tell my agent to edit the Obsidian Markdown just like that, but I can also tell it to create a full-on notebook with backlinks and DataView queries. I can tell my agent to create logically complex .org notes with code blocks and references.

To me, Hubble just seems like a Markdown editor, based on the premise that agents are able to edit local files.

Usually, I have vscode/Claude Cowork up on one side and on the other is Obsidian. I made a plugin[1] that converts emails to `.md` so they can also be in Obsidian folder -- so Claude can query those emails the same way it does my notes. Works beautifully.

[1] https://github.com/chaidhat/inbox-to-md

Fair comment. Hubble and Obsidian both use Markdown on-disk, so they're equally agent-friendly.

There's a few reasons I built it instead of continuing to use Obsidian (which I've used for years):

- I wanted something closer to Apple Notes or Notion for simpler editing. Hyperlinks are popups instead of in-line strings. Formatting is WYSIWYG, without *_ characters in-line. There's a / menu to discover formatting options. etc.

- I wanted an app that could display HTML pages alongside Markdown. And more interestingly, I wanted to give those HTML pages access to Markdown files in the folder, using Markdown as a mini-database to build apps on top of. This is likely possible with Obsidian plugins (everything is) but I wanted something first-class. The hubble.md homepage tries to communicate this, but I could likely do a better job :)

- More recently, I've wanted markdown -> agent handoff to be better. We've added an embedded terminal to chat with agents alongside notes directly, and we've just added a first-party commenting system similar to commenting in a Google doc (agent accessible with in-file metadata). All of these features have been community-led. I'm very grateful for our repeat contributors.

If any of that sounds interesting, give it a try! Otherwise, feel free to give feedback on the app itself or the homepage on GitHub. All of that is open-source: https://github.com/bholmesdev/hubble.md

I feel like there's not enough content on the landing page to help me understand why I need yet another notetaking app. The burden of proof is high given how many of these there are.

Also why is it a nodejs app? With the explosion of LLM and the insane increase in productivity shouldn't it be a Rust app?

Between being criticised for too much LLLM and not enough, the developers can't win can they?

Well they can win! Since everyone is so pro LLM don't write apps in Nodejs LOL

Pre LLM nodejs was convenient option to deploy to all platforms at once.

Post LLM that's no longer a limitation! Just prompt more to create apps in native language! Anyways RAM is getting costlier by the day due to LLMs themselves

That is unless devs don't use LLMs at all. Then they should simply state in the GitHub repo that we don't use AI!

I wouldn't use AI for hobby projects tbh. It's my personal preference

> Just prompt more to create apps in native language!

If you have ever done that you know that that's as true as "write once, run everywhere". There will always be tweaks and iterations, even if it saves you a lot of time.

I was being sarcastic but okay.

Because every other day we hear how excellent LLM is that we don't need to write code anymore

Sorry, misunderstood that.

There is still a place for 'but rust’, in between too much and too little LLM usage.

What would make Rust better for this type of app compared to Node?

Pray tell me why a desktop app is running on a browser in the age of LLMs?

Electron was written to make dev times faster

But since LLMs are basically super engineers can't the app be written in native language rather than running on v8?

Maybe not rust. But then zed people did develop a cross platform library for apps didn't they?!

Tauri is a good balance. Rust "backend" plus a native web view, so less JS and a lighter binary.

Why even limit the app to Rust? Cross compilation is for humans. Just have the LLM make multiple versions of the codebase using whatever language and SDK is best integrated into each OS.

Absolutely! LLM is basically magic at this point (or so we hear)

Why limit to language and SDK? Have the LLM write machine code.

Absolutely. LLMs are Magic! Go ahead

Correct

It can be the language they prefer. Why would someone spend money to create software in some language for the sake of having an LLM generate it

The counter argument is that since LLM resembles magic why use inefficient nodejs that is basically an app running inside chrone Why not use native binaries?

Is efficiency not important in 2026?

repeating the statement doesn’t make a counter point

It does when your comment didn't address a single point of the original comment!

With the explosion in token usage, why not write it in z80 assembly and run it in a z80 emulator written in webasm?

Why not?

At least it is self describing, unlike some other projects that are like "An alternative to faomz with deliric integration"

Good feedback, I'd like to add more sections to the homepage to describe the components / motivations more clearly. The scope has increased to more agent collaboration features this past month too. Here's the reasons I shared elsewhere here:

- I wanted something closer to Apple Notes or Notion for simpler editing. Hyperlinks are popups instead of in-line strings. Formatting is WYSIWYG, without *_ characters in-line. There's a / menu to discover formatting options. etc.

- I wanted an app that could display HTML pages alongside Markdown. And more interestingly, I wanted to give those HTML pages access to Markdown files in the folder, using Markdown as a mini-database to build apps on top of. This is likely possible with Obsidian plugins (everything is) but I wanted something first-class. The hubble.md homepage tries to communicate this, but I could likely do a better job :)

- More recently, I've wanted markdown -> agent handoff to be better. We've added an embedded terminal to chat with agents alongside notes directly, and we've just added a first-party commenting system similar to commenting in a Google doc (agent accessible with in-file metadata). All of these features have been community-led. I'm very grateful for our repeat contributors.

Will check this out too.

Now, I'm having fun with tldraw.[1] With their new tldraw offline, I can continue to work in Claude Code (and others) and I can either output or interact/input from tldraw. This is more of a free-form, infinite canvas. I treat it like Excalidraw + Draw.io + Freeform Notetaker.

For text, most agents/LLM/assistants are pretty happy and smart using the same Markdown files to anywhere I have allowed them to interact.

1. https://www.tldraw.com/

TIL agents can interact with tldraw documents. Thanks for sharing

I'm trying to understand why this can't just be a folder on your disk. Agents know how to use "ls" and "cat" so I guess I'm missing something.

You’re not, thing that makes it agent friendly is copy path button

Isn’t that less friendly to agents than just looking at the file path on the filesystem?

Yes, in this case mcp or cli or even skill is better, you can ask agent

It's just a folder on your filesystem, no fancy cloud setup. Similar to Obsidian.

I’ve been waiting for an app like this to be developed! .md files can be opened from Finder! The tree file view is just like I’m used to with Obsidian! Frontmatter support! There’s even an editor toolbar. Almost everything on my wishlist for a Markdown editor, except for Mermaid rendering.

Since this project uses such good agentic engineering practices, I was able to use Claude Code to add support for Mermaid diagram rendering and produce my very own local build on Mac, all in about 30 minutes.

Thank you! Hubble+cmux gets me close to the agentic IDE I’m working towards.

You seems pretty enthusiastic about this very new and not very well known software...

It's 680 commits old.

Which in this brave new agentic world could be what, 2 days? :)

Ben Holmes is active at X, you can check him out @BHolmesDev, he works for Warp.dev, they do multi-harness IDE named Oz.

Seems odd that you wouldn't comment on the existing issue, or open a PR?

https://github.com/bholmesdev/hubble.md/issues/176

If you don't mind me asking, what are "good agentic engineering practices"? To my knowledge, we are still exploring many techniques of using agents within a codebase, and have not widely agreed on "best practice".

Do you mean "good code" and "good documentation"?

Thanks, glad you like it! Feel free to start an issue and a prototype PR for mermaid diagramming support. It's been on my todos to add: github.com/bholmesdev/hubble.md/issues

There are also a lot of mcp agents for Joplin: https://discourse.joplinapp.org/t/ai-agents-and-joplin/46168 Dare I say, another, more popular, note taking app for you and your agents.

I really like it as I run a webdav service and can read/write and sync notes between multiple Mac desktops and Android. Encrypted while I am at it.

Markdown native.

But does joblin support anything more than markdown? I'm thinking of using it as a like a store for agent plans, so I can easily edit stuff. Can an agent add rendered HTML, meramaid etc in joblin?

All my agents need are plain .md files in my project directories.

it's interesting -- i think most (non-technical) people don't really have a muscle memory go-to markdown editor. i certainly didn't. i hated obsidian at first! funny how learning to like markdown makes obsidian like 1000x better haha

The value proposition of Markdown is that you don't need a special editor, you can open it with any text editor that comes with your OS and it's human readable already.

That's all Hubble is! You can treat it like a text editor for your existing .md files

The current sepia color scheme you see on all vibecoded websites is so, so tiring.

And before you ask, the next "trend" will be as much tiring.

Looks interesting. The dual interface from the start (React UI for humans and just editing .md for the agents with skills) is an interesting idea and probably how a lot of new software projects will work going forward

I feel like tables are generally underrated while the AI ecosystem is focused on .md files but I guess markdown has tables so they’re included to some extent

I think that is a really nice implementation. A few questions:

Can you easily share lists or pages or is it all local? (Is there a cloud element to it)

What are the most useful examples you’ve personally found when it comes to using the HYML component?

I built https://smalldocs.org for my agent’s Markdown needs. I extended it so it can render complex formats: Mermaid diagrams, charts, in-document slides and even in-document spreadsheets. It gives your agent a good selection of formats to express itself as it helps you understand whatever topic you’re looking into.

Here is a sample document: https://smalldocs.org/blogs/what-is-a-smalldoc

I publish anonymous analytics here: https://smalldocs.org/analytics

Please stop spamming your project.

https://news.ycombinator.com/item?id=48838274

I also have one I developed according to my use: https://github.com/egeozcan/mahpastes

It has a rest api and a cli tool, and also the possibility to make headless deployments, and it can sync clips without a sync server. It can serve folders/tags and optionally expose a read or read/write api for JSON files on the same level. It supports lua plugins, and I have a fal.ai plugin to generate/edit images already in the repo (some other examples there).

It has a lot of features so maybe it's better if I just link to the docs: https://egeozcan.github.io/mahpastes/

What are your thoughts on Hubble?

I think it looks high quality. Perhaps it needs a way for those mini-html apps to store data? Also some additional docs and clear marketing that differentiates it from Obsidian would be cool as well.

Thanks for sharing this handfuloflight! This is Ben, creator of Hubble. I've been replying to comments throughout this post (appreciate the thorough feedback). If you have any questions for me, fire away.

How is this different from Obsidian? Why would someone switch? The page is a bit lacking on detail.

I'll be more blunt than other commenters: this is useless. Obsidian and plenty of other note taking apps already do the same and more.

Add to that the fact that it's likely entirely vibe-coded, there's really 0 value proposition here.

Cool, I needed a lightweight markdown editor. I like Obsidian but it's not really a notebook. What's missing is a ToC view for your .md as a sidebar which Obsidian has.

I have always found markdown cumbersome. Will try this later. Seems like the main thing is having agent input right there, which is handy.

as a lightweight markdown reader on macOS, I much prefer the native mdv* app than running a nodejs app.

* https://github.com/tqbf/mdv

so, Obsidian?

There's even a community plugin MCP that makes this easier. Afaik the hot reload is the only thing that "beats" this but I haven't had issues with Agents interacting with obsidian through the MCP - I'm not sure how much more useful it is to talk with an agent through a note taking app vs through its CLI.

Obsidian does hot reloading too. Usually, I have vscode/Claude Cowork up on one side and on the other is Obsidian. I made a plugin[1] that converts emails to `.md` so they can also be in Obsidian folder -- so Claude can query those emails the same way it does my notes. Works beautifully.

[1] https://github.com/chaidhat/inbox-to-md

Obsidian exists. It is more feature rich and mature.

You could at least read the tagline or something, before leaving low-effort comments. Im a big fan of Obsidian, use it every day, but if Im looking for something "backed by Markdown and HTML" then obviously its not even an alternative...

What is your Obsidian backed by?

Oh look, a new note taking app. Must be Wednesday.

but how is it different from my notion?

local files on disk. we should make notion Just Work with real markdown files on disk like this too.

midwit meme, but both ends are just "a pile of .md files in a synced directory somewhere"

Uhh yeah I don't let agents edit files that I'm writing - that's how you get psychosis. I enforce this via snapshots before and after tool calls

Sorry, but wtf is this and why is it on the front-page??

"Agent ready"? Eg, it uses markdown like... everything else? There is literally no information here.

internet reinvents vi lock files from first principles

ANOTHER.md

can we have a moratorium on notetaking apps?

The shared markdown files between human and agent notes is a nice touch — no proprietary format lock-in, and agents can just read the files directly. Does it handle conflicts when both the user and an agent edit the same note at the same time?

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