LM-Kit OneThe Private AI Application Server
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Cobalt is an open-source app platform for Kobo e-readers: a launcher, a signed App Store, a Rust SDK, and a capability-isolated runtime. One USB install; every app after that arrives over Wi-Fi.
What's great
Bought a used Kobo specifically to try this after seeing the HN thread. The Claude Code / terminal controller app is the killer feature for me - I do long agent sessions and my eyes were done with staring at a laptop screen for the "watch it think" parts. Sideloading over Wi-Fi after the one-time USB setup is exactly the right tradeoff, most e-ink hacking projects make you plug in a cable every single time which kills the habit fast.
What needs improvement
Device support list is still short - my older Kobo model isn't on it yet, so I had to buy a newer used one specifically to try this. Also the app store is pretty thin right now, which makes sense for a launch, but it needs more third-party apps beyond what the team built themselves to really justify calling it an app store.
vs Alternatives
Looked at just running a normal Android tablet in grayscale mode instead, but that's a battery-life and eye-strain compromise, not a real e-ink experience. Nothing else gets you an actual app store on real e-ink hardware without a jailbreak-and-pray process.
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Cobalt
Hi!
I wanted to break free from watching my laptop screen for long Claude sessions partially due to degrading eyesight and have a sidekick for approvals streamed to the Kobo. I ended up building that, a SDK and full app store for Kobo.
Introducing Cobalt - an Android like platform for Kobo to develop apps and enable reading more things than books.
We read a lot more things than books daily: forums, long form articles, research papers, Coding agents logs etc.
If you really need these, usually the way is to search, download, convert elsewhere like a laptop and then sideload on the eInk display. Cobalt makes it much easier.
Some of the apps we have added to Cobalt app store:
1. A RSS discovery & reader
2. An audiobook generator using deep research and ElevenLabs API all running on it.
3. An arXiv browser and reader for people doing research
4. Gutenberg browser and reader
5. Offline games for your flight
6. A Claude Code / Codex controller
7. A terminal
We now support Libra Color, Libra 2, Clara BW, Elipsa 2E, Clara HD, Clara Color and a lot more apps are in the pipeline. You can build your own favorite app too.
We were recently #1 on hackernews with 650+ votes, https://news.ycombinator.com/ite...
Hope you are as amazed by your $100 device as I was!
Cobalt
Managing Claude code and Codex from a $100 device with a month long battery life on the go has been a real help with Cobalt. A lot more use cases come up once you map your problems to an app using the Cobalt SDK.