PROCESS

Here is How to Build

Design

System

What crosses

Value marked the crossings. This discipline designs them. Every point where work passes from one box to another is a link: an order from selling to providing, a charge request from providing to collecting payments, a case from support back to providing. A link is not a step inside either box. It is the agreement between them about how work crosses. Inside a process, the joints between its parts are the seams the Sub volume designs. Between boxes on the map, the crossings are links, and this is where they are designed.

A link has three parts. What passes: one thing, named and complete, so the receiving side never has to go back and ask. When it passes: the trigger, so the receiving side knows when to expect it. And what received means: the done-state of the handover, the moment both sides agree the work has changed hands. A link missing any of the three still works most of the time. It fails on the days that matter: when volume rises, when a case is unusual, when someone new sits at either end.

Most links on a map have never been designed. They grew: a spreadsheet emailed on Fridays, a field one team learned to fill in for the other, a habit of calling someone. They work because the people at each end know each other. Designing a link writes down what those people already know and closes what they quietly work around, so the link holds when the people change.

The highest possible standard is to treat every crossing between boxes as a link, to agree for each one what passes, when it passes and what received means, and to write down the links that grew by habit so they hold when the people at either end change.

Key Takeaway: Every point where work passes from one box to another is a link: not a step inside either box, but the agreement between them about how work crosses. The seams inside a process belong to Sub; the links between boxes belong here. A link has three parts: what passes, when it passes and what received means (the done-state of the handover). Most links grew rather than being designed, and they work only while the same people sit at each end. Designing a link writes down what they know and closes what they work around.

A link is not a step in either box. It is the agreement about how work crosses between them.

MarvinPro · PROCESS · Here is How to Build · Design · System · Discipline 6: Links · Section: What crosses

MarvinPro | October 2026

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Handed on, never shared

The Map set a principle for crossings: work is handed on, never shared. At any moment the work sits on one side of the link, and the link is the exact point where it moves. Before that point, the work is the sending side's; after it, the work is the receiving side's. Work that sits on both sides at once sits on neither, because each side assumes the other has it.

That is why a link is agreed by both sides. A link written by the sending side alone describes what it sends, not what the other side needs. A link written by the receiving side alone describes what it wants, not what the other side can give. Agreed together, the link records both: what passes, in a form the sending side can produce and the receiving side can use. Core treated the charge as a connection, reached from inside the core. At the height of the map, the same connection is a link with two sides, and both sides design it.

Agreement also fixes what is not handed on. Information can be shared freely: both sides may see the customer's record, the history and the status. What is never shared is the work itself: the next action that someone has to take. Shared information keeps both sides informed. Shared work leaves both sides waiting.

The highest possible standard is to hand work on across every link and never share it, so that at any moment it sits on exactly one side, to agree each link with both sides together, and to share information freely while keeping the next action on one side only.

Key Takeaway: Work is handed on, never shared. At any moment it sits on one side of the link, and the link is the exact point where it moves; work on both sides at once sits on neither. A link is agreed by both sides, because one side alone describes only half of it. Core's connection to payments, seen from the height of the map, is a link with two sides. Information can be shared freely; the work itself (the next action) never is.

Work is handed on, never shared. Shared information keeps both sides informed; shared work leaves both sides waiting.

MarvinPro · PROCESS · Here is How to Build · Design · System · Discipline 6: Links · Section: Handed on, never shared

MarvinPro | October 2026

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The way back

Work goes forward across a link. Information has to come back: a rejection when what arrived was incomplete, a failure when the receiving side could not do its part, a change when one side alters something the other depends on. A link with no way back is the one Value warned about: a change one team made that the next never heard about. The way back is designed with the same three parts as the way forward: what comes back, when it comes back and what received means.

A link is agreed by both sides, so a change on either side reopens it, however small. Before the change goes live, the agreed cases are run across the link, the ordinary ones and the failures, and each is checked to land where it should. The smallest changes are the most dangerous, because no one thinks of them as changes to the link. A large change is planned and tested. A minor update is installed on an ordinary Tuesday, and the link it breaks stays broken in silence.

Every link is also a place where value can be lost, so the best number of links is the smallest number the work needs. The map and the value test have already removed the crossings that served no one. The links that remain are designed on purpose, each with its way forward, its way back and its cases ready to run.

The highest possible standard is to design a way back for every link, with the same three parts as the way forward, to treat any change on either side as reopening the link however small it is, to run the agreed cases across it before the change goes live, and to keep the number of links to the fewest the work needs.

Key Takeaway: Work goes forward across a link, and rejections, failures and changes have to come back, designed with the same three parts as the way forward. A link with no way back fails in silence. A change on either side reopens the link, however small, and the agreed cases are run across it before the change goes live. The smallest changes are the most dangerous, because no one thinks of them as changes to the link. Every link is a place where value can be lost, so the fewest links the work needs is the right number.

A link with no way back fails in silence. A change on either side reopens it, however small.

MarvinPro · PROCESS · Here is How to Build · Design · System · Discipline 6: Links · Section: The way back

MarvinPro | October 2026

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A real example

When a subscription is activated, provide subscriptions sends a charge request to collect payments, and it sends another at every renewal. At launch, a failed payment came back across the link, and the software was held back on time.

Collect payments then installed a routine update to its payments software: a minor release with small fixes, nothing anyone thought of as a change. One of those fixes renamed the status the software used to report a failed payment. Provide subscriptions was still listening for the old name. Nothing broke on either side, so no error appeared anywhere. Failures simply stopped arriving.

For the next few weeks, failed payments went nowhere. Provide subscriptions kept the software running for customers who were not paying, and support customers heard nothing. Then a manual clean-up cut those customers off all at once. The calls started, and support could not tell them why.

The redesign started by writing the link down, agreed by both boxes. What passes: the charge request, with customer, amount and period. When: at activation and at each renewal. What received means: acknowledged and scheduled by collect payments. The way back was written the same way. A failed payment returns to provide subscriptions, which holds back the software after a set grace period, and support customers is told at the same moment. Then came the rule: any change on either side that touches the link reopens it, and before the change goes live, three agreed cases are run across the link: a payment that succeeds, one that fails and one that arrives late.

The next routine update renamed a field again. It was caught when the three cases ran, two days before release. Customers whose payments failed now heard about it from the company first, and when they called, support already knew why.

A minor update renamed one status and broke a link in silence; written down, agreed and tested on every change, the link now catches the next one before release.

MarvinPro · PROCESS · Here is How to Build · Design · System · Discipline 6: Links · A real example

MarvinPro | October 2026

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Links

Every crossing between boxes is a link: the agreement between two boxes about how work crosses, distinct from the seams inside a process. A link has three parts: what passes, when it passes and what received means. Links that grew rather than being designed work while the same people sit at each end, and fail when those people change.

Work is handed on, never shared. At any moment it sits on one side of the link, and the link is the point where it moves, so both sides agree the link together. Information can be shared freely; the work itself (the next action) never is.

Every link needs a way back for rejections, failures and changes, designed like the way forward. A change on either side reopens the link, however small, and the agreed cases are run across it before the change goes live. The smallest changes are the most dangerous, because no one thinks of them as changes to the link. Designed this way, the fewest links the work needs carry it across the map in both directions, and stay proven.

Design every link between boxes: what passes, when, and what received means, with a way back, and prove it again whenever either side changes.

MarvinPro · PROCESS · Here is How to Build · Design · System · Discipline 6: Links · Chapter Outcome

MarvinPro | October 2026

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