Private Cloud Compute – Scott Loftesness

I’ve been wondering whether we’ve been looking at the AI stack from the wrong end.

Recently Kris Patel on X laid out a set of excellent questions that he’s looking to have answered as Anthropic and OpenAI move toward going public:

Do you really need frontier-scale intelligence for every task?
Can open-weight models provide an effective alternative to frontier models at a significant discount?
Is the ultimate moat the intelligence or the harness?
What other business models will the frontier labs have to adopt to make the unit economics work long term?
How are you going to prevent distillation from capturing your IP and releasing it?

I’m going to explore only the third question here — moat versus harness. The other four deserve their own consideration, particularly once we have the Anthropic and OpenAI S-1s in hand, revealing for the first time the unit economics of the two largest frontier labs and how much runway they have to support the capacity they’ve contracted.

By “harness” we mean everything surrounding the model: the interface, context, memory, tools, orchestration, evaluation, permissions, and increasingly the user’s accumulated habits and data. The model supplies intelligence. The harness turns intelligence into a product.

Listening to Gavin Baker on the recent All-In episode sharpened this line of thought into something more concrete. He referenced a thought experiment from Eric Vishria: even if OpenAI or Anthropic lost their edge at the pure model layer, they would still retain significant value because of the product harness—the interface, the surrounding tooling, the orchestration—and the user familiarity and habits that have already formed around those platforms. Baker said there is a strong element of truth to it. I think he’s right, and the reasoning behind it is worth spelling out. A model can be replicated, distilled, open-weighted, or commoditized. A mature harness has network effects, switching costs, proprietary context, distribution, workflow integration, and accumulated user behavior. That’s a much harder thing to dislodge.

We are watching intelligence become more abundant and more interchangeable at the same time that the systems built around that intelligence are becoming stickier. On the developer side, the strongest examples are already clear. Cursor turns the IDE into a multi-model agentic environment with deep codebase awareness. Claude Code runs long-horizon coding agents from the terminal, planning, editing, testing, and iterating. Grok Build, Claude Cowork and similar tools emphasize parallel agents and tighter control over local context. In each case the model is a component; the surrounding system does the real work of routing, memory, tool use, and evaluation.

The consumer version of the same idea is now taking clearer shape at Apple. The rebuilt Siri AI shown at WWDC 2026 is not trying to win the pure model race. It is built as a personal harness. A system orchestrator decides what stays on-device with Apple’s Foundation Models, what moves to Private Cloud Compute, and when heavier reasoning is required. Personal context—messages, email, photos, calendar, notes, on-screen awareness—is handled largely on-device through the Spotlight semantic index and App Toolbox. Apple is designing the system so that personal context can be used without giving Apple itself access to it. Conversation history lives in a dedicated Siri app for the user to revisit. And it all syncs across all your Apple devices.

Here is the part I think matters most, and it’s easy to miss if you only read the privacy story. Apple’s Foundation Models framework doesn’t just call Apple’s own models—it’s built to support cloud models from other providers, including Claude and Gemini, conforming to a common protocol. Which means the system orchestrator, not the user, decides which model handles which task. This request goes to the on-device model. That one goes to Private Cloud Compute. A harder one might go to Claude or Gemini. The user doesn’t need to choose, and increasingly doesn’t need to know.

That’s the inversion worth exploring further. The frontier model stops being the interface and becomes a component underneath someone else’s interface. The harness chooses the intelligence. And the company that owns the harness—the OS, the identity layer, the permissions, the apps, the sensors, the notifications, the semantic index tying all of it together—has a form of leverage that has very little to do with whose model is smartest this quarter.

That reframes the subscription question too. I don’t think the right question is whether Siri gets good enough to beat ChatGPT or Claude at reasoning. I think Siri doesn’t need to win that fight at all. It needs to win a different layer entirely—the ambient assistant layer, not the reasoning layer. They’re doing different tasks. ChatGPT or Claude might remain where you go when you think, when I need to reason about something. Siri becomes where I go when I need something done: find (or make) my reservation, text my friend, find that old photograph, update my shopping list, schedule that meeting, add this thought to my notes, figure out when we’re free next week, remind me about that thing we discussed three months ago. Apple’s advantage as an ambient assistant isn’t primarily that it has your personal data. It’s that it has OS-level authority over the world that my personal data lives in.

Of course this is still early. Execution will determine how much of the architectural promise becomes daily reality. Reliability, agentic follow-through, and the quality of the on-device models will matter as much as the privacy story or the multi-model routing. But the strategic bet itself is clear, and it aligns with the broader shift: durable value is migrating toward the systems built around the models, especially systems that sit atop private, permissioned, personal context that competitors cannot easily reach. My early personal experience with the new Siri in iOS 27 betas has impressed me so far. All of this also seems to apply to Google in the context of their Pixel family of devices.

This doesn’t mean frontier labs lose. Pricing power still exists at the high end for the hardest agentic and long-horizon work. Open-weight models will continue to pressure costs and expand access. Distillation remains a real risk. But the more the capability gap narrows, and the more a harness like Apple’s can route among interchangeable frontier models rather than depend on any single one, the stronger the case that value settles into whoever controls the context—not whoever trained the model.

The coming Anthropic and OpenAI S-1s will tell us whether the frontier labs can make their economics of intelligence work. The next generation of Siri, Gemini, ChatGPT, Claude, and whatever comes after them may tell us something even more important: who gets to own the primary relationship with the user.

The model may be the engine. But the harness is where the driver sits.

What a time to be alive!

Apple had a problem no amount of money could solve. An iPhone can’t draw the power or shed the heat of a data center, so ten different tasks can’t mean ten different models fighting for the same sliver of RAM. Apple’s answer was to freeze one small, efficient base model into the device and then swap tiny adapters in and out of it in milliseconds — a summarization adapter for your texts, a Siri adapter for on-screen actions, and a handoff to Private Cloud Compute for anything heavier. The phone behaves like it’s running many models. It’s running one model wearing many hats.

That architecture — a frozen base plus swappable adapters — is quietly becoming the default way serious AI companies build, and it’s worth understanding why, because it inverts the assumption most people still carry into this industry.

The assumption is that winning means owning a frontier model. Sierra co-founder Clay Bavor pushed back on that on a recent 20VC episode: pouring capital into your own pre-training, he argued, tends to leave you holding a highly perishable bag of floating-point numbers. Open-weight models improve fast enough that yesterday’s frontier is next quarter’s commodity. The companies playing this well aren’t racing to out-spend the labs. They’re slipstreaming behind them — taking the free, state-of-the-art engine and putting all their effort into what sits on top of it.

What sits on top is LoRA — low-rank adaptation. The old failure mode was catastrophic forgetting: fine-tune a model hard enough on your own data and it forgets how to reason generally. LoRA sidesteps this by leaving the base model untouched and training a small set of additional parameters alongside it — a thin layer of expertise bolted onto a frozen foundation. You get real domain depth without touching the thing that makes the model work at all.

The business logic that follows from this is the actual point, and it’s simpler than it looks:

You stop being hostage to any one model provider — if a better open-weight model ships next month, you port your adapter, not your whole product. You can serve hundreds of differently-customized clients off one base model on one piece of hardware, instead of running a separate giant model per customer. You can ship a fix in an afternoon, because an adapter is a few hundred megabytes, not a training run. And in regulated industries, your proprietary data can train an adapter that never leaves your own infrastructure.

None of this is really a story about model architecture. It’s a story about where the moat moved. For a while the moat was raw capability — whoever had the best model won. Apple and Sierra are betting the moat is now somewhere else entirely: in how tightly you can weave a commodity intelligence into a specific workflow, a specific dataset, a specific customer relationship. The engine is free. The adapter is the business.

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