Slots

Every named slot on a derived screen, what it binds, and which Components may fill it, with the leaseclock.com example for each.

A slot is one named part of a derived screen that a Component may fill. In the design, the rest of the screen keeps deriving, and a slot never widens what the reader may do.

No served screen has a slot today. The one part that derives from column types is a list toolbar, and it appears only in static mock screens.

Slot	Binds	May hold	On leaseclock.com
`list.toolbar`	the list's Noun, its search query and its filters	CallToAction	a `status` filter over `active`, `renewed` and `terminated`
`list.empty`	the list's Noun and the reader's create grant	CallToAction	"Add your first lease", calling `Lease.create`
`record.header`	the record and its lifecycle state	StateBadge	`active`, `renewed` or `terminated` beside `Maya Ortiz`
`record.aside`	the record and its Actions	Timeline, ActionStatus	each renewal of the lease, oldest first
`record.actions`	the record and the Verbs the reader may call on it	VerbSheet, ApprovalSheet	`Lease.renew` with its fields and button
`record.tab`	the record and one Noun that points at it	DataTable, Timeline	a `Leases` tab on each `Property` record page
`form.after`	the form's Noun and its unsaved values	a Component the Startup writes	`RenewalPreview`: the date the first reminder goes out
`dashboard.section`	the Dashboard's scope	MetricTile, UsageMeter, PendingFeed	leases ending in the next 60 days

Fill a slot

In the design, the App file names the Component for each slot, per Noun. Every other part of the Lease screens keeps deriving.

apps/app/app.mdx

---
kind: saas
nouns: [Property, Lease]
slots:
  Lease:
    record.header: StateBadge
    list.empty: CallToAction
    form.after: RenewalPreview
---

A Component in record.actions calls Verbs through the reader's Permissions, so it shows no button the derived screen would leave out. Screens the definition cannot derive covers screens no slot can reach.

Fill a slotCopy Anchor Link

Fill a slot