Download the desktop app
Fleece AI Brain runs on your own computer — macOS, Windows or Linux — and keeps your knowledge there, as plain Markdown files you own. Pick your operating system below, install, then sign in with this same account to connect your tools and let every AI app query the same brain over MCP.
Version 0.2.5 · unsigned beta
macOS
Universal — works on both Apple Silicon (M1–M4) and Intel Macs.
First launch — macOS may warn it can't verify the app
- Open the .dmg and drag Fleece AI Brain into your Applications folder (don't run it from the disk image).
- Double-click it once. You'll see “Apple could not verify… is free of malware.” Click Done (not “Move to Trash”).
- Open menu → System Settings → Privacy & Security, and scroll down to the Security section.
- Next to “Fleece AI Brain was blocked…”, click Open Anyway, authenticate, then click Open Anyway once more. macOS remembers it — future launches are normal.
- Note: that button only appears for about an hour after you tried to open the app. If it's missing, double-click the app again first.
Prefer Terminal? Paste this and press Return — it clears the download flag so the app opens straight away:
xattr -dr com.apple.quarantine "/Applications/Fleece AI Brain.app"Windows
Windows 10 / 11, 64-bit. Standard installer.
First launch — Windows may warn it can't verify the app
- Run the installer. If a blue “Windows protected your PC” box appears, click the More info link, then the Run anyway button.
- Alternatively: right-click the downloaded file → Properties → tick Unblock at the bottom → OK, then run it.
Linux
Portable — runs on any distro.
First launch — Linux may warn it can't verify the app
- AppImage: make it executable (chmod +x the file) then double-click to run.
- .deb / .rpm: install with your package manager; the app lands in your applications menu.
After installing
- Open Fleece AI Brain.
- Go to Sources → Sign in to Fleece — a browser window authorizes this computer.
- Connect a source (Gmail, Notion, Slack…) and sync.
The local brain is free forever. Connected sources are the paid lever — see the 20 connectors it can sync from, or the plans.
Install questions
Which operating systems does Fleece AI Brain support?
macOS, Windows and Linux. The macOS build is a universal binary that runs natively on both Apple Silicon (M1–M4) and Intel Macs, so there is a single download to choose.
Why does my computer say the app cannot be verified?
The current beta is not yet signed with a paid Apple or Microsoft developer certificate, so the operating system shows an unverified-developer prompt on first launch. Approving it once is enough — the steps for each platform are on this page, and code signing is on the way to remove the prompt entirely.
Do I need an account to use the desktop app?
You need one to sync. The local brain works on its own, but signing in from Sources → Sign in to Fleece is what authorizes this computer, enables cloud sync and lets the connectors pull your tools into the graph.
Where does the desktop app store my knowledge?
In a folder on your own disk: Markdown files with YAML frontmatter and wikilinks, indexed by a local SQLite database. The vault is Obsidian-compatible, so you can open the same folder in Obsidian or any text editor. Cloud sync is opt-in and end-to-end encrypted.
How do AI apps read the brain once it is installed?
Through the Model Context Protocol. The desktop app exposes an MCP server that Claude Desktop, Cursor, Cline, Zed and custom agents connect to, so every AI app you use reads and writes the same graph instead of keeping its own separate memory.
Is the desktop app free?
The local brain is free forever. Connected sources, cloud sync and team features are on the paid plans, which start with a 14-day trial you can cancel anytime.
Wondering how it compares to what you already use? See Brain vs Obsidian, vs Notion, or read about the Enterprise Brain it builds once your agents are on it.