Your AI tool going mobile is an architecture confession

Claude Cowork arrived on iOS and Android today, which is a good feature and a better diagnostic.

Every tool that announces mobile support is telling you something it did not mean to. It is telling you where it kept your stuff.

Because a phone is a hostile environment for badly built software. No filesystem to rummage in. No background process quietly holding state. Nothing local to lean on. If a tool survives that trip, it was built as two things. If it falls over, it was one thing pretending.

The split that decides it

Any AI setup worth running has two halves, and the whole game is keeping them apart.

The first half is the brain. Your methods, your skills, the sequence you want a job done in, the standards you will not drop. This is knowledge. It does not belong to any one machine, and it should not live on one.

The second half is your context. Your revenue, your customers, your pricing arguments with yourself at 2am, the document where you finally worked out what the business is. This is yours in a way the methods are not.

Most people merge them. It is genuinely easier. You dump everything into one place, it works beautifully at your desk, and you feel organised.

Then you try to work from a train and discover your entire operation was a folder. Or, worse, it does work from the train, because at some point you uploaded your P&L to a company whose name you would struggle to spell.

Keep them apart and both problems disappear. The brain lives remotely and follows you around. The context lives in a folder you own and goes nowhere.

What actually works on a phone

Here is the honest version, quoted rather than glossed, because the launch posts will not tell you this bit.

Remote connectors work. Anthropic’s documentation is specific about the exception:

Local connectors and plugins that include local MCP servers work through the desktop app only.

Remote ones are fine. So if your methods are served remotely, they are on your phone already.

Your local files are conditional:

A cloud session can read and write files in folders you’ve connected on your computer only while the desktop app is open on that computer.

Read that twice, because it is the whole practical picture. Leave your desktop running and your phone reaches everything you own. Shut the laptop and you have the methods without the memory. A very well-briefed consultant who has not read today’s brief.

Some people will call that a limitation. It is mostly a diagnosis, and a fairly flattering one. It means your business context sits somewhere that requires your machine to be awake. That is not a bug in the design. That is the design.

What phones are actually for

Now the opinionated part.

Nobody has ever done their best thinking on a phone. Not once. Not you, not me, not the man in the LinkedIn post who runs his entire company from an airport lounge and wants you to know about it.

“Working from my phone” is, for most founders, anxiety-scrolling Slack in a Pret and calling it a workday. It has the shape of work. It produces the feeling of work. It generates no work.

What a phone is genuinely, unreasonably good at is catching a thought before it dies. The idea in the taxi. The thing you understand in the shower and have completely lost by the time you find a towel. The realisation, mid-conversation, that the pricing page has been wrong for four months.

Those thoughts have a half-life measured in minutes. If catching one requires opening a laptop, you will not catch it, and you will tell yourself it was probably not that good. It usually was.

So the useful division is not desk versus mobile. It is capture versus build.

Capture on the phone. Build at the desk. Stop trying to change a tyre with a teaspoon.

Building it yourself

If you want the worked example, this is how ours is put together.

The brain is a remote MCP server. Skills and knowledge, served over HTTPS, identical for everyone using it, containing nothing about any particular business. Because it is remote rather than local, it appears as a connector and turns up on the phone with no extra work.

The context is a folder. Plain text, on the machine, owned by the person whose business it describes. It never travels to us, which is not a privacy feature bolted on afterwards but the reason the phone thing works at all.

You do not need our version to do this. The pattern is free. Put your methods somewhere portable, keep your facts somewhere you control, and refuse to let anyone talk you into merging them for convenience.

The convenience is real. So is the bill.