Software custom for you.

Most of the software in your life is rented. This page explains what changed, why owning has become affordable, and how the new tools actually work, in plain language.

You rent your software

Count the subscriptions: mail, files, calendar, the thing that does invoices, the thing that does what invoices cannot, and the spreadsheet with a tab called final FINAL. Each one is a lease, and each lease has a landlord who sets the price, changes the rules, and keeps your data on their server in their shape. You did not choose this so much as accept the only offer on the table, and that offer has changed. Software is taking a new form. Custom. Designer.

What owning looks like

RENTED software as a service OWNED designer software 0 4 7 / month you The meter runs every month A pattern cut to you Features chosen for everyone Source and keys in your hand Your data in their building Your data in your building A door you cannot take with you A door you walk through and keep
RENTED software as a service OWNED designer software 0 4 7 / month you The meter runs every month A pattern cut to you Features chosen for everyone Source and keys in your hand Your data in their building Your data in your building A door you cannot take with you A door you walk through and keep
The same four things, on their side of the wall and on yours.

Owning is plainer than it sounds. It means source you can read and change, keys in your own hands, data in a format you can export from a server you can name, the right to leave, and no rent per seat. Renting gives you an export button on a good day; owning gives you all five.

How we got here

1 API you make one fixed call 2 Agent a model in a loop, until done 3 MCP one socket, any host, any tool you menu service one call one answer model calendar files mail tools call result done stop chat app editor terminal hosts calendar files database mail servers MCP tools resources prompts your code decides the model picks, your code runs it written once, plugs in anywhere
1 API you make one fixed call menu one call one answer you service your code decides 2 Agent a model in a loop, until done calendar files mail model call result done stop tools the model picks, your code runs it 3 MCP one socket, any host, any tool chat app editor terminal calendar files database mail MCP hosts servers tools resources prompts written once, plugs in anywhere
Each step keeps the one before it. The menu never went away.

None of this is as new as it sounds. An API is a menu: your code reads it and places an order, and the menu decides nothing. In 2023 someone handed that menu to a language model, so that given a list of tools with plain descriptions it writes back an order of its own, naming the tool and the inputs. It runs nothing; your code does the running. Put the model in a loop and you have an agent. Agree on one format for the menu and you have MCP.

What an agent is

the model decides the tools do the work 2 · the model reads, decides 3 done? no stops when the model says done, or at a limit you set: steps, budget, time yes 7 · answer 1 · goal you 4 · asks for a tool a request, not an action 6 · result comes back you can also sit here, approving each step 5 · a tool runs files, mail, the web…
you 1 · goal 2 · the model reads, decides 3 done? stops when the model says done, or at a limit you set: steps, budget, time yes 7 · answer no 4 · asks for a tool a request, not an action the model decides the tools do the work you can also sit here, approving each step 5 · a tool runs files, mail, the web… 6 · result comes back
The model decides. Your code runs the tools and sets the limits.

An agent is a model that runs tools in a loop until the job is done or a rule tells it to stop. Think of a contractor with a phone book. You describe the job, and they decide whom to call and in what order, reading what comes back before the next call, and they stop when the work is finished or when you told them to stop after so many calls. Every call lands on your bill, and the contractor never does the work themselves, because the trades do.

There is one habit to know about. This contractor follows any written note they find on site, including one a stranger taped to the wall. So when we build one for you, it gets the fewest keys the job needs, a gate on anything that writes, sends or pays, and the boring steps to itself while you approve the ones that matter. The same loop now writes software too, planning, editing, running the tests, reading the errors and trying again, with a person checking the work.

One plug

Before After AI apps tools MCP tools · resources · prompts Chat app Editor Terminal Browser Chat app Editor Terminal Browser Calendar Files Mail Database Calendar Files Mail Database 4 × 4 = 16 wires, each written by hand 4 + 4 = 8 wires, one protocol
Before AI apps tools Chat app Calendar Editor Files Terminal Mail Browser Database 4 × 4 = 16 wires, each written by hand After AI apps tools MCP tools resources prompts Chat app Calendar Editor Files Terminal Mail Browser Database 4 + 4 = 8 wires, one protocol
Four apps and four tools: sixteen wires by hand, or eight through one plug.

Until recently every AI product needed its own connector for every service, so three assistants and four services meant twelve connectors. Now there is one open standard that no single vendor owns, and a connector written once fits every assistant that speaks it, which most of the big ones now do. The people who wrote it call it a USB-C port for AI, which is fair as far as it goes, except that a cable cannot be talked into anything. A connector is running code that holds your keys and sends text the model will read as instructions. The standard says the app must ask you before a tool runs, and it also admits it cannot enforce that. The plug is standard, then, but what you plug in is not vetted, and where it runs matters: on your machine your keys and files stay home and the model sees only what the connector hands it, while on someone else's server they live under that company's terms.

What it costs

The typing got cheap and everything else kept its price. A small team with a clear specification can now put a working first version in your hands within weeks, and what remains is deciding what to build, shaping the data, reviewing for security and keeping it running, which is most of the bill now.

Software is like a custom leather jacket. You can spend a little or a lot on the hide and the hardware, but the pattern is cut to your body either way, and the stitching is what makes it last. The pattern is boring architecture that has worked for decades, the construction is tests, review and a clean way to deploy, and the cut is what you buy this season: the screens, the integrations, the polish. A smaller build from us is fewer pieces sewn properly, so it can be let out later. Owned software still needs hosting, updates, patches and someone to answer when it breaks. The bill moved rather than vanished.

What we do

We build custom systems cut to your budget and sewn to last, we fix the thing you already have that nobody will touch, and we teach so that you understand your own tools. We love technology and hate conformity, and we would rather you own something small than rent something huge.

Talk to us

Bring us the spreadsheet.

What are you trying to build?

Tell us what you have in mind and a real person writes back.

Keep up with CKS

Essays on software and privacy, and the odd invitation to an event or a hackathon.