App vs assistant vs keyboard

The AI that reaches every app is the one inside the keyboard.

ChatGPT, Claude and Gemini are apps — you switch to them. But the keyboard shows up in every app you type in. That difference in surface area is why “agentic keyboard” is an interesting idea. Explore where each AI layer sits on the 3D stack below.

Drag to rotate · highlighted layer shows what AI there can touch

Layer

Four places AI can live

1 · Standalone app. The chatbot in its own window. Powerful, but siloed — to use it you copy text out of one app and paste the answer back. Reach: one app (itself).

2 · In-app feature. AI built into a specific product (an email client’s “write for me”). Deeply integrated with that app’s data, but it can’t help you anywhere else.

3 · OS assistant. A system-level helper (Siri, Google Assistant, Copilot) that can be summoned over any app and, increasingly, act across a few of them. Broad, but gated by what the OS lets it see.

4 · The keyboard. A custom keyboard is a system extension that appears in every text field in every app. Put AI there and it can read what you’re typing, rewrite it, translate it, or take an action — inside your messaging app, your bank app, your notes, all without switching context. Maximum surface area, minimum friction.

Why surface area matters — and why it’s risky

Interfaces win by reducing steps. The web browser beat native installers because it reached every site; the app store beat the browser on mobile because icons beat URLs. “Put the AI where the user already is” is the same move — and typing is the single most universal action on a phone. An assistant that lives in the keyboard removes the app-switch tax on every interaction at once.

The same property that makes a keyboard powerful makes it sensitive: a custom keyboard can, in principle, see everything you type — passwords, card numbers, private messages. On iOS this requires the explicit “Allow Full Access” toggle, and it’s the single most important permission to scrutinise. Prefer keyboards that process on-device and are clear about what leaves your phone.

The takeaway from the tweet is a real product thesis: the next AI battleground may not be “a better chatbot app” but the layer with the most reach. Whoever owns the keyboard, the assistant, or the OS owns the default — and defaults win. Click through the layers above to feel how reach climbs as you move down the stack toward the keyboard.