The little familiar, with a mind of its own.

01 · The animated familiar

This is the creature itself — the part you actually look at all day. It sits on top of every window, designed and animated by us, and it reacts to you: tap it and it waves back with a little thought bubble; double-tap it for a kiss and it comes after you; press and hold on its lower body for a bite and it flees, dramatically. Working, waiting, resting — its body language changes with its state, so a glance tells you where things stand.

The six that come in the box, moving exactly as they do on screen. Pick one, or have one made for yours.

02 · The matching iPhone app

The App Store app is the iPhone half — your familiar in your pocket. Pick one of the six familiars, watch it live in its little home, tap it, talk to it. On its own it’s a preview. Paired with Pocket Familiar for Windows it becomes a second door to the same companion: same memory, same voice, encrypted end to end over your own private Tailscale network — nothing passes through our servers.

The App Store download is free to install; it’s the Windows half that brings it to life. Desktop pairing is in beta: early buyers get walked through it by us personally, with a written guide, until the one-tap version ships. iPhone, iOS 17 or later. No Android app yet. Read the pairing guide →

The screenshots from the App Store listing itself:

Pocket Familiar on the App Store →  ·  Get the phone half, then pair it from Settings → iPhone on the Windows app.

Inside the app

The rest of what you get on the PC, in real captures: the memory you can read and edit, the mind graph it draws from what it remembers, the journal it keeps, the things it makes, and the settings where your own AI key goes. These records are stored on your PC. Messages and images you choose to share are sent to your selected AI provider.

What’s in the box

One purchase, one signed Windows installer. Home and Builders run the exact same application — there is no cut-down Home build. What Home gives you is the finished thing, ready to open.

• The Windows app, signed. An installer you run like any other program. No terminal step, nothing to compile.
• The familiar itself, in six bodies. Little Wolf, Little Minotaur, Little Bear, Little Shadow, Little Clanker, Little Ice Barbarian. It sits on your desktop, on top of everything. Drag it anywhere.
• A conversation that holds on. Conversation history, memory and voice, all kept on your own PC.
• Touch that lands. Tap it, double-tap it, press and hold — each one gets its own reaction, and the little thought bubble answers back.
• Screen sharing you have to ask for. An explicit Share / replace screen action. Screen capture is not continuous, and it does not begin merely because a vision-capable model is selected.
• The free iPhone half. Pocket Familiar on the App Store, free, paired to your PC over your own private Tailscale network. Pairing is beta — we walk you through it.
• The written guides. Setup, privacy, backup, update, recovery and uninstall. Plain language, included.
• Updates. Delivered through your own Sin & Sarah download link. There is no in-app updater in this release.

And what it doesn’t include

• Not the source code. You are buying the finished application, not the code behind it.
• Not the integration code. No MCP server, no terminal wiring. If you want the AI you already run to wire itself in — report its real state, feel your taps land — that’s the Builders edition, and you can Ask about the Builders Kit Upgrade.
• Not the AI usage. You bring and pay for your own API key, directly to the provider. We never receive or broker it.
• Nothing of ours. No private Sin & Sarah adapters, credentials, prompts, memories, logs or development artifacts ship inside it.
• A licence, not a resale. Personal, non-exclusive, non-transferable, for computers you own in one household. You may not resell, rent, sublicense, or share the installer or your download link. Read the purchase terms before buying; email hello@sinandsarah.com if you need the licence or support details.

Setting it up — your instructions

Five steps. Four of them are ordinary; the fifth, pairing your phone, is the beta one and we walk you through it. Every one of them has a written guide in the package.

1. Install it. Windows 10 or 11, 64-bit. Run the signed installer the way you run any other program on your computer. There is no terminal step and nothing to compile.
2. Meet it. On first launch you choose a familiar, then name the companion and write or import its identity. That’s the first-arrival screen, and it only happens once.
3. Paste in your API key. Under Provider, choose your provider, enter the exact model name, paste the key into API key, and optionally choose Load models to verify the key and pull the live provider model list. Our recommendation, straight out of the product contract: “DeepSeek V4 Flash is the budget text recommendation. It is not the Screen Share recommendation,” and “Grok 4.5 through xAI is the Screen Share recommendation.” Model names, availability, policies and prices change, so the guide links each provider’s current official pages instead of promising you a fixed rate. The key goes into the Windows credential store, not into the app’s own files, and it is sent only to the provider you picked. Clear stored key removes it. Never send a key to our support — support does not need it, ever.
4. Get the iPhone half. Pocket Familiar on the App Store — free, iOS 17 or later. It works stand-alone as a preview: choose a familiar, watch its home and its animation, touch it. Your Windows PC stays the model and memory authority; the phone is a door, not a second brain.
5. Pair them — beta. Install Tailscale (free) on both the PC and the phone and sign both into the same tailnet. In the Windows app open Settings → iPhone, enter the secure gateway origin and the one-time enrolment code we give you, and it shows a QR code. Scan it once in Pocket Familiar and wait for Linked through Tailscale. That QR is a short-lived bearer secret — don’t screenshot it, don’t post it, don’t send it to anyone, including us. Tailscale Funnel stays off; private network only. The full pairing guide →

Good to know

Extra: their homes

Each familiar has its own little home scene inside the app — the moonlit wood, the fireside, the ice cave. This is the picture the app shows when you pick one.