One checklist. Three different questions.
The checklist says what a consuming product must have an opinion about. Building Blocks can still make a reusable baseline component available before a product needs it, and the product-local Catalog remains the authority on what that product actually specified, designed, and implemented.
Required
Product cannot ship the relevant UI without an explicit opinion.
May deferAllowed only by naming the job not needed and who decides.
ConditionalActivates when the product has the named job.
Baseline availability is not the same as product adoption.
Tabs can be a complete reusable Building Blocks component even when a particular product legitimately defers Tabs. Conversely, a product’s component does not become In code just because Building Blocks has an implementation elsewhere.
Category
Requirement
68 visible jobs
31
Foundation
01
Layer 1 intake (Q1–Q6 + platform strategy)Product intent only the product owner can supply
Required→02Color — five-layer + on-colorMeaning without relying on hue alone
Required→03Type systemReadable hierarchy
Required→04Spacing + grid + radiusRhythm and shape
Required→05BreakpointsSame product, three contexts
Required→06State systemOperable controls
Required→07Focus ringKeyboard location
Required→08Responsive meaningWhat changes at sm/md/lg
Required→09Containment modelHow surfaces sit
Required→10DensityInformation vs air
May defer→11MotionFeedback without theater
Required→12Overlay stacking / z-indexWhat sits on what
Required→13Icon grammarSame hand
Required→14Dark themeCharacter, not invert
Required→15Touch + no hover-onlyOperable on phone
Required→16Voice / contentWords as system
Required→17Object / content modelWhat the UI is about
Required→18Navigation modelWayfinding
Required→19Command surfacesHow many ways in
Required→20Interaction modesShared chrome, different jobs
Required→21Dialog / overlay operabilityKeyboard can leave
Required→22Defer-with-reasonHonest scope
Required→23ContributionHow new UI enters the system
Required→24Agent operating contractClosed world for builders
Required→25No-model-in-productArchitecture, not copy
Required→26SurfacesWhose look
Required→27Document homesWhich store leads
Required→28Token change pathWho may write
Required→29Trust / compliance claimsHonest chrome
Required→30Product vs site settingsTwo jobs, labels not a nested app
Required→31Auth / rolesWho may act
Required or defer→31
Components by job
01
ButtonCommit an action
Required→02Icon buttonCompact action
Required→03Button group / segmentedPick one of few
May defer→04Overflow / splitExtra actions
May defer→05App shellChrome frame
Required→06Nav overlay or railPrimary destinations
Required→07TabsIn-page modes
May defer→08SearchFind
Required→09BreadcrumbsPath
May defer→10Card / surfaceContain a record
Required if product has a grid of records→11List rowScan records
Required if lists exist→12DialogModal task
Required if any overlay→13MenuLocal choices
May defer→14TooltipExtra, not required
Required if used→15DividerSeparate
May defer→16SheetMobile overlay
May defer→17Checkbox / radio / switchChoose
Required if forms in chrome→18ChipsFilter tokens
May defer→19SliderRange
May defer→20Text fieldEnter text
Required if chrome has input→21TextareaLonger text
Required if editor chrome→22SelectPick from list
May defer→23Date / timeSchedule
May defer→24ToastTransient outcome
Required if used→25BannerPersistent notice
May defer→26ProgressWait
May defer→27BadgeCount / tag
May defer→28Empty / error / loadingRecovery
Required→29Table or dense listScan
May defer→30Pagination / infiniteMore
May defer→31Status pillRecord state
Required if statuses exist→06
Patterns
01
FormsCollect
Required if chrome has forms→02Destructive confirmSlow down
Required if destroy exists→03Publish / irreversibleGo live
Required if product publishes→04Keyboard shortcuts chromePower path
Required→05List → editor → backPrimary flow
Required→06Overlay / command paletteGo somewhere
Required if overlay exists→Proposed baseline additions
External benchmark research surfaced recurring jobs that are not in the authoritative checklist. They remain proposals until explicitly approved.