# Inheritance

URL: /systems/trust-and-governance/inheritance · Id: `page:systems/trust-and-governance/inheritance`

> How each Control resolves along the tree from platform to Studio to Startup, and how the platform proves every Startup runs the same tested Versions.

A [Startup](/business/nouns/startup) inherits every [Control](/business/nouns/control) above it in the tree, from the platform through its [Studio](/business/nouns/studio). It can tighten an inherited Control and can never loosen one.

## One tree, nearest first
The platform, each Studio and each Startup is a namespace. Controls resolve the way [Settings](/business/nouns/setting) do: a namespace reads the nearest value set above it.

Every Control value is a locked floor. A descendant may raise it and never lower it.

So one check proves the whole tree: no Setting sits below its ancestor's floor. [Inherited floors](/systems/trust-and-governance/controls/inherited-floors) runs that check over every namespace, every day.

## Three answers
Resolution gives each Control one of three answers in each namespace.

| Resolution | Who operates it | Example |
| --- | --- | --- |
| `inherited` | The platform or the Studio, with no act by the Startup | [Append-only records](/systems/trust-and-governance/controls/append-only-records): no writer can delete an [Event](/business/nouns/event) |
| `shared` | The platform, on values the Startup sets | [Retention restriction](/systems/trust-and-governance/controls/retention-restriction): the platform enforces the retention the Startup sets per [Purpose](/business/nouns/purpose) |
| `owned` | The Startup alone | [Policy approval](/systems/trust-and-governance/controls/policy-approval): an officer of the Startup's [Company](/business/nouns/company) signs |

Most Controls resolve to `inherited` for most Startups. The `shared` and `owned` remainder is the Startup's [floor](/systems/trust-and-governance/floor).

## Wakes
A Control can wake as a Startup grows. Adding a field that holds patient data wakes [Health data agreements](/systems/trust-and-governance/controls/health-data-agreements). Seating the first [Human](/business/nouns/human) [Worker](/business/nouns/worker) wakes the human side of the people Controls, such as background checks.

Connecting an [Integration](/business/nouns/integration) to an upstream with no current report wakes [Upstream review](/systems/trust-and-governance/controls/upstream-review). Each wake is checked on the [Change](/business/nouns/change) that causes it.

[Control wake review](/systems/trust-and-governance/controls/control-wake-review) opens a [Task](/business/nouns/task) before that Change merges. A Startup never runs, even for an hour, outside a Control it has woken.

## Same Control, same Version
Inheritance is a claim, and sameness proves it. An auditor who tests one Control needs to know that a thousand Startups ran the Control it tested, not copies that drifted.

[Control sameness](/systems/trust-and-governance/controls/control-sameness) reads the content hash of every [Version](/business/nouns/version) that implements a Control, and the resolved Settings in each namespace. It answers in one of two ways: identical within tested bounds, or a list of strata, each naming the Change that created it.

The auditor then tests each stratum once instead of each Startup. That is what lets one engagement cover a Studio of any size.

## Buying from a sibling
A Startup that buys an outcome from a sibling under an [Agreement](/business/nouns/agreement) inherits the sibling's Controls for that work. The sibling becomes an inclusive subservice organization in the buyer's report, and the sibling's customer controls join the buyer's floor.

Take a support desk for online course creators that buys bookkeeping from a sibling. It inherits the sibling's Controls over the ledger. Its own floor gains one item: approving what it sends the sibling to book.

## Next
- [The floor](/systems/trust-and-governance/floor): what resolution leaves each Startup.
- [How proof works](/systems/trust-and-governance/proof): how every inherited Control is tested.