For PCs with an NPU
Put your NPU to work.
Your PC has a neural processing unit, and most days it sits idle. Castellan gives it a staff of local AI agents that name your downloads, make your scans searchable and shrink your videos, without asking and without sending anything away.
No NPU? It runs on your graphics card or processor instead, a little slower.
Nobody to ask, nothing to upload
The AI runs on your PC. Your documents, screenshots, photos and code are read there and stay there.
Work done in the background
The NPU does its work while you do yours: quietly, coolly and with little drain on the battery.
Your cloud AI goes further
Reeve reads the long build logs and test runs on your own hardware, so your AI coding assistant gets the few lines that matter: fewer tokens and usage limits that last longer.
What it does
The jobs your NPU gets
Each agent takes one chore. They work on their own, within what you allow: anything that changes your files or your PC waits for your tick.
Warrener
A name and a home for what piles up in Downloads and on the Desktop.
Clerk
Makes your screenshots and scans searchable.
Miller
Big videos and photos, made small.
Porter
What's new on your PC, who signed it, and whether it matches.
Herald
The news you follow, summed up.
Reeve
The local helper for your AI coding assistant, and rounds on your repositories.
Which NPUs
Snapdragon X, Intel Core Ultra and AMD Ryzen AI.
The setup finds your NPU, and installs the model server that runs on it with your consent: the download is several gigabytes, and it asks first. Everything is checked against pinned checksums before it's used, and the NPU is only turned on once it has answered a test question. No NPU, or one we don't cover yet? Your graphics card or processor does the work.
Snapdragon X
- Snapdragon X Elite / X Plus (Hexagon v73)
- Snapdragon X2 Elite / X2 Plus (Hexagon v81)
Intel Core Ultra
- Core Ultra Series 1, Meteor Lake (NPU 3720)
- Core Ultra 200H/U, Arrow Lake (NPU 3720)
- Core Ultra 200V, Lunar Lake (NPU 4)
- Core Ultra Series 3, Panther Lake (NPU 5)
AMD Ryzen AI
- Ryzen AI 300 and later: Strix Point, Krackan, Strix Halo, Gorgon Point (XDNA 2)
Not supported: Ryzen 7040/8040, Phoenix and Hawk Point (XDNA). There, the graphics card or processor does the work.
Prices
From $4 a month. Keep what you paid for.
Seven days of everything, with no card. Stop paying and nothing stops working: every version you paid for is yours to keep.