diff --git a/docs/specs/AST-110-swizzle-output/spec.md b/docs/specs/AST-110-swizzle-output/spec.md
index ca5913fbd320a..b2397c3af9c57 100644
--- a/docs/specs/AST-110-swizzle-output/spec.md
+++ b/docs/specs/AST-110-swizzle-output/spec.md
@@ -145,6 +145,8 @@ and the repository proves it before a change that could break it merges.
   Every component swizzle can copy means Core's components as `swizzle --list`
   offers them (`spec:AST-035` FR12) and every component of each integration
   package in the repository, copied with `--package`.
+  A source check fails when a module that FR3 covers creates a module-local
+  Symbol, WeakMap or registry instead of a registered shared key.
 
 ### Platform support
 
@@ -229,8 +231,9 @@ and the repository proves it before a change that could break it merges.
 | FR5      | Swizzle into a new folder, an empty one, a marked one, and one holding a product module; read the folder and the `swizzle.copy` result                         | Default output; `--output` to a product folder; a folder of earlier copies with no marker                                                                                                                                                                                                                                                                                                                                                        | A marker lands in a folder that holds a product module, a new, empty or marked folder is left unmarked, or the result omits what a skipped folder holds                                                                                                                                                                                                                                                                                                     |
 | FR6      | The component's own interaction and accessibility checks run against the copy                                                                                  | Keyboard, pointer, screen-reader tree                                                                                                                                                                                                                                                                                                                                                                                                            | A check that passes on the package fails on the copy                                                                                                                                                                                                                                                                                                                                                                                                        |
 | FR7      | The required test lane's swizzle proof and the release-time proof; both cover Core's list and every integration package's components through `--package`       | A change to component source; a change to the swizzle copy; an unrelated change; Core, Lab, Charts, RichText, Vega                                                                                                                                                                                                                                                                                                                               | An offered component missing from the proof, a failure that does not block, a new required context, the proof adding wall-clock time to the slowest required check, or the proof pushing its job past the pull-request time budget                                                                                                                                                                                                                          |
+| FR7      | `scripts/shared-identity.test.mjs` over the source of the packages swizzle copies from, against its baseline                                                   | A module-local `Symbol()` brand in an FR3 module; the same brand under `sharedKey`; a module-scope registry an exported register function writes                                                                                                                                                                                                                                                                                                 | The module-local brand or registry passes, the `sharedKey` brand fails, or a baseline entry the source no longer has stays listed                                                                                                                                                                                                                                                                                                                           |
 
-Known verification gap: only FR3's shared-context checks (`sharedContexts.test.tsx`) exist; the other rows have no check on `main`.
+Known verification gap: only FR3's shared-context checks (`sharedContexts.test.tsx`) and FR7's source check (`scripts/shared-identity.test.mjs`) exist; the other rows have no check on `main`.
 
 ## Decision log
 
diff --git a/scripts/shared-identity.baseline.json b/scripts/shared-identity.baseline.json
new file mode 100644
index 0000000000000..bf93636558757
--- /dev/null
+++ b/scripts/shared-identity.baseline.json
@@ -0,0 +1,1013 @@
+{
+  "$comment": "Module-scope cross-module identity the FR3 check knows about (spec:AST-110 FR3, FR7). \"open\" names the fix group that removes the entry; \"allowed\" gives the approved reason. A new hit or a stale entry fails scripts/shared-identity.test.mjs.",
+  "entries": {
+    "packages/core/src/AppShell/useAppShellMainId.ts:claims": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/AppShell/useAppShellMainId.ts:listeners": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/BottomSheet/BottomSheetPanel.tsx:stopViewportResize": {
+      "status": "allowed",
+      "reason": "Each copy observes for its own subscribers; a second observer changes no result."
+    },
+    "packages/core/src/BottomSheet/BottomSheetPanel.tsx:viewportHeight": {
+      "status": "allowed",
+      "reason": "Each copy observes for its own subscribers; a second observer changes no result."
+    },
+    "packages/core/src/BottomSheet/BottomSheetPanel.tsx:viewportHeightListeners": {
+      "status": "allowed",
+      "reason": "Each copy observes for its own subscribers; a second observer changes no result."
+    },
+    "packages/core/src/BottomSheet/bottomSheetStack.ts:showFocusesContainer": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/Chat/useChatDictation.ts:_sharedAudioCtx": {
+      "status": "allowed",
+      "reason": "One audio context per copy for dictation level metering; a second context costs memory and changes no result."
+    },
+    "packages/core/src/Chat/useChatStreamScroll.ts:following": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/Chat/useSpeechRecognition.ts:_sharedAudioCtx": {
+      "status": "allowed",
+      "reason": "One audio context per copy for dictation level metering; a second context costs memory and changes no result."
+    },
+    "packages/core/src/CodeBlock/highlightRanges.ts:dynamicStyleSheet": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/CodeBlock/highlightRanges.ts:registeredHighlightTypes": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/CodeBlock/highlightStyles.ts:inserted": {
+      "status": "allowed",
+      "reason": "Deduplicates an idempotent style insertion; a copy can at most insert the same rules again."
+    },
+    "packages/core/src/CodeBlock/tokenizer.ts:langCache": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/CodeBlock/tokenizer.ts:valueCache": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/DateInput/monthGeometry.ts:GREGORIAN_MONTH_MODELS": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/DateInput/nativeDateSegments.ts:cachedEngine": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/Icon/globalIconRegistry.tsx:globalRegistry": {
+      "status": "open",
+      "group": "F8 Public registries"
+    },
+    "packages/core/src/Layer/gestureCounter.ts:claimedPress": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/gestureCounter.ts:clickedGesture": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/gestureCounter.ts:contextMenuGesture": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/gestureCounter.ts:gesture": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/gestureCounter.ts:isListening": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/gestureCounter.ts:pressPointerId": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/gestureCounter.ts:unsubscribePress": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/layerExitCopy.ts:copies": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/layerStack.ts:composingDocuments": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/layerStack.ts:entries": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/layerStack.ts:layerCountByDocument": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/layerStack.ts:nextSeq": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/layerStack.ts:seqByToken": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/layerSurfacePress.ts:surfaces": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/modalOutlet.ts:listeners": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/modalOutlet.ts:outletGroups": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/modalOutlet.ts:outlets": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/outsidePress.ts:outsideDismissals": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/popoverOperations.ts:browserHidesByDocument": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/popoverOperations.ts:browserHidesInFlight": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/popoverOperations.ts:ownOperationsByDocument": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/Layer/popoverOperations.ts:settledCallbacksByDocument": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/List/listLayoutUpdates.ts:keptStyles": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/List/listLayoutUpdates.ts:reportedRows": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/List/listReorderEngine.tsx:sessionsByOptions": {
+      "status": "open",
+      "group": "F10 List reorder"
+    },
+    "packages/core/src/Markdown/ast.ts:markdownAstLegacyCodeLanguage": {
+      "status": "open",
+      "group": "F11 Markdown protocol metadata"
+    },
+    "packages/core/src/Markdown/characterReferences.ts:namedReferences": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/Markdown/parser.ts:imageAltDepth": {
+      "status": "allowed",
+      "reason": "Per-run state of one call (a parse, a transform or a render pass) that never outlives the call; a run never crosses copies."
+    },
+    "packages/core/src/Markdown/parser.ts:incrementalCaches": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/Markdown/parser.ts:incrementalStateMode": {
+      "status": "open",
+      "group": "F11 Markdown protocol metadata"
+    },
+    "packages/core/src/Markdown/parser.ts:listMarkerShapes": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/Markdown/plugins/protocol.ts:markdownSourceLinesDefinition": {
+      "status": "allowed",
+      "reason": "Deliberately unshared: a shared key would let any module forge trust or a parse claim."
+    },
+    "packages/core/src/Markdown/plugins/protocol.ts:markdownTransformClaim": {
+      "status": "allowed",
+      "reason": "Deliberately unshared: a shared key would let any module forge trust or a parse claim."
+    },
+    "packages/core/src/Markdown/plugins/protocol.ts:markdownTransformHasRenderer": {
+      "status": "open",
+      "group": "F11 Markdown protocol metadata"
+    },
+    "packages/core/src/Markdown/plugins/protocol.ts:markdownTransformPluginName": {
+      "status": "open",
+      "group": "F11 Markdown protocol metadata"
+    },
+    "packages/core/src/Markdown/plugins/protocol.ts:markdownTransformSourceUnchanged": {
+      "status": "open",
+      "group": "F11 Markdown protocol metadata"
+    },
+    "packages/core/src/Markdown/plugins/protocol.ts:markdownTransformTrusted": {
+      "status": "allowed",
+      "reason": "Deliberately unshared: a shared key would let any module forge trust or a parse claim."
+    },
+    "packages/core/src/Markdown/plugins/protocol.ts:preparedPluginLists": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/Markdown/plugins/protocol.ts:reportedProductionPluginFailures": {
+      "status": "allowed",
+      "reason": "Deduplicates development warnings; a copy can at most repeat a warning once."
+    },
+    "packages/core/src/Markdown/plugins/protocol.ts:reusableScratch": {
+      "status": "allowed",
+      "reason": "Per-run state of one call (a parse, a transform or a render pass) that never outlives the call; a run never crosses copies."
+    },
+    "packages/core/src/Markdown/plugins/protocol.ts:scratchInUse": {
+      "status": "allowed",
+      "reason": "Per-run state of one call (a parse, a transform or a render pass) that never outlives the call; a run never crosses copies."
+    },
+    "packages/core/src/Markdown/plugins/protocol.ts:sourceHeadingMarker": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/Markdown/plugins/semanticFence.ts:markdownFenceProposal": {
+      "status": "open",
+      "group": "F11 Markdown protocol metadata"
+    },
+    "packages/core/src/Markdown/plugins/textTransform.ts:adoptedReplacements": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/Markdown/remark.ts:REMARK_ORIGIN": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/Markdown/remark.ts:activeRun": {
+      "status": "allowed",
+      "reason": "Per-run state of one call (a parse, a transform or a render pass) that never outlives the call; a run never crosses copies."
+    },
+    "packages/core/src/Markdown/remark.ts:adapterReasons": {
+      "status": "allowed",
+      "reason": "Per-run state of one call (a parse, a transform or a render pass) that never outlives the call; a run never crosses copies."
+    },
+    "packages/core/src/NumberInput/numberParser.ts:symbolsByLocale": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/PowerSearch/formatTokenValue.ts:tokenNumeralLocales": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/Resizable/createResizable.ts:internals": {
+      "status": "open",
+      "group": "F9 Resizable"
+    },
+    "packages/core/src/Resizable/resizablePane.ts:lent": {
+      "status": "open",
+      "group": "F9 Resizable"
+    },
+    "packages/core/src/Resizable/resizablePane.ts:propsRegions": {
+      "status": "open",
+      "group": "F9 Resizable"
+    },
+    "packages/core/src/Resizable/resizablePane.ts:resizeHandles": {
+      "status": "open",
+      "group": "F9 Resizable"
+    },
+    "packages/core/src/Resizable/resizablePane.ts:watchers": {
+      "status": "open",
+      "group": "F9 Resizable"
+    },
+    "packages/core/src/Resizable/useResizable.ts:collapseControls": {
+      "status": "open",
+      "group": "F9 Resizable"
+    },
+    "packages/core/src/Resizable/useResizable.ts:effectiveMaxima": {
+      "status": "open",
+      "group": "F9 Resizable"
+    },
+    "packages/core/src/Resizable/useResizable.ts:releaseEnds": {
+      "status": "open",
+      "group": "F9 Resizable"
+    },
+    "packages/core/src/SegmentedControl/useSegmentedSelectionMotion.ts:ownSurface": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/SnapPaging/snapPagingValue.ts:attachments": {
+      "status": "allowed",
+      "reason": "The attach and the scroll calls run in the same copy; the paging value is shared."
+    },
+    "packages/core/src/Spinner/spinnerRotor.ts:flushScheduled": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/Spinner/spinnerRotor.ts:pendingRotors": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/Table/glidingDivider.ts:inlineColorOf": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/Table/glidingDivider.ts:inlineTopOf": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/Table/glidingDivider.ts:markedBy": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/Table/glidingDivider.ts:sourcesOf": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/Table/plugins/groupedRows/useTableGroupedRows.tsx:GROUP_HEADER": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/Table/plugins/virtualization/useTableRowsVirtualization.ts:capabilityBrand": {
+      "status": "open",
+      "group": "F1 Table capability and plugins"
+    },
+    "packages/core/src/Table/plugins/virtualization/useTableWindow.ts:textContext": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/Table/tableColumnAdmission.ts:heightSafe": {
+      "status": "open",
+      "group": "F1 Table capability and plugins"
+    },
+    "packages/core/src/Table/tableColumnAdmission.ts:logicalRenderers": {
+      "status": "open",
+      "group": "F1 Table capability and plugins"
+    },
+    "packages/core/src/Table/tableRowContextUsage.ts:countIndependentPlugins": {
+      "status": "open",
+      "group": "F1 Table capability and plugins"
+    },
+    "packages/core/src/Table/tableRowContextUsage.ts:countReadingPlugins": {
+      "status": "open",
+      "group": "F1 Table capability and plugins"
+    },
+    "packages/core/src/Table/tableRowContextUsage.ts:indexReadingPlugins": {
+      "status": "open",
+      "group": "F1 Table capability and plugins"
+    },
+    "packages/core/src/Table/tableRowContextUsage.ts:trackedContexts": {
+      "status": "open",
+      "group": "F1 Table capability and plugins"
+    },
+    "packages/core/src/Table/tableRowContextUsage.ts:transformingPlugin": {
+      "status": "open",
+      "group": "F1 Table capability and plugins"
+    },
+    "packages/core/src/Table/tableRuntime.ts:ownedScrollWrappers": {
+      "status": "open",
+      "group": "F1 Table capability and plugins"
+    },
+    "packages/core/src/Timestamp/formatRelativeTime.ts:formatters": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/Timestamp/tooltipEntries.ts:warnedTimezoneIDs": {
+      "status": "allowed",
+      "reason": "Deduplicates development warnings; a copy can at most repeat a warning once."
+    },
+    "packages/core/src/Toast/useToast.tsx:fallbackContext": {
+      "status": "open",
+      "group": "F2 Toast host"
+    },
+    "packages/core/src/Toast/useToast.tsx:fallbackRoot": {
+      "status": "open",
+      "group": "F2 Toast host"
+    },
+    "packages/core/src/Toast/useToast.tsx:toastIdCounter": {
+      "status": "open",
+      "group": "F13 Shared id sequences"
+    },
+    "packages/core/src/TreeList/TreeList.tsx:clipGenerations": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/gestures/GestureRecognizer.ts:nextRecognizerId": {
+      "status": "open",
+      "group": "F13 Shared id sequences"
+    },
+    "packages/core/src/gestures/fingerScroll.ts:watches": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/gestures/gestureSync.ts:syncingDepth": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/gestures/haptics.ts:nextLabelId": {
+      "status": "open",
+      "group": "F13 Shared id sequences"
+    },
+    "packages/core/src/gestures/pageHold.ts:holdsByDocument": {
+      "status": "open",
+      "group": "F3 Scroll lock"
+    },
+    "packages/core/src/gestures/touchActionRule.ts:markedRoots": {
+      "status": "allowed",
+      "reason": "Deduplicates an idempotent style insertion; a copy can at most insert the same rules again."
+    },
+    "packages/core/src/gestures/touchActionRule.ts:sheets": {
+      "status": "allowed",
+      "reason": "Deduplicates an idempotent style insertion; a copy can at most insert the same rules again."
+    },
+    "packages/core/src/hooks/modalAnnounce.ts:deferredByScope": {
+      "status": "open",
+      "group": "F5 Focus and announce"
+    },
+    "packages/core/src/hooks/modalAnnounce.ts:held": {
+      "status": "open",
+      "group": "F5 Focus and announce"
+    },
+    "packages/core/src/hooks/modalAnnounce.ts:presented": {
+      "status": "open",
+      "group": "F5 Focus and announce"
+    },
+    "packages/core/src/hooks/rootScrollStyles.ts:claims": {
+      "status": "open",
+      "group": "F3 Scroll lock"
+    },
+    "packages/core/src/hooks/rootScrollStyles.ts:held": {
+      "status": "open",
+      "group": "F3 Scroll lock"
+    },
+    "packages/core/src/hooks/rootScrollStyles.ts:lockCount": {
+      "status": "open",
+      "group": "F3 Scroll lock"
+    },
+    "packages/core/src/hooks/rootScrollStyles.ts:lockListeners": {
+      "status": "open",
+      "group": "F3 Scroll lock"
+    },
+    "packages/core/src/hooks/rootScrollStyles.ts:nextClaimId": {
+      "status": "open",
+      "group": "F3 Scroll lock"
+    },
+    "packages/core/src/hooks/scrollGeometrySubscriptions.ts:listeners": {
+      "status": "allowed",
+      "reason": "Each copy observes for its own subscribers; a second observer changes no result."
+    },
+    "packages/core/src/hooks/scrollOwnerRegistry.ts:owners": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/hooks/useAnnounce.ts:clearTimers": {
+      "status": "open",
+      "group": "F5 Focus and announce"
+    },
+    "packages/core/src/hooks/useAnnounce.ts:lastJoined": {
+      "status": "open",
+      "group": "F5 Focus and announce"
+    },
+    "packages/core/src/hooks/useAnnounce.ts:modalRoute": {
+      "status": "open",
+      "group": "F5 Focus and announce"
+    },
+    "packages/core/src/hooks/useAnnounce.ts:pendingByRegion": {
+      "status": "open",
+      "group": "F5 Focus and announce"
+    },
+    "packages/core/src/hooks/useAnnounce.ts:pendingFrames": {
+      "status": "open",
+      "group": "F5 Focus and announce"
+    },
+    "packages/core/src/hooks/useAnnounce.ts:pendingMessages": {
+      "status": "open",
+      "group": "F5 Focus and announce"
+    },
+    "packages/core/src/hooks/useAnnounce.ts:regions": {
+      "status": "open",
+      "group": "F5 Focus and announce"
+    },
+    "packages/core/src/hooks/useEntryAnimation.ts:initialPaintComplete": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/hooks/useFocusTrap.ts:activeEscapeTrapCount": {
+      "status": "open",
+      "group": "F5 Focus and announce"
+    },
+    "packages/core/src/hooks/useFocusTrap.ts:activeRegionContainers": {
+      "status": "open",
+      "group": "F5 Focus and announce"
+    },
+    "packages/core/src/hooks/useMediaQuery.ts:watches": {
+      "status": "allowed",
+      "reason": "Each copy observes for its own subscribers; a second observer changes no result."
+    },
+    "packages/core/src/hooks/useMenuPress.ts:isModelActivation": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/hooks/useOverflow.ts:pendingMeasures": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/hooks/useScrollLock.ts:activeLock": {
+      "status": "open",
+      "group": "F3 Scroll lock"
+    },
+    "packages/core/src/hooks/useScrollLock.ts:lockCount": {
+      "status": "open",
+      "group": "F3 Scroll lock"
+    },
+    "packages/core/src/i18n/resolve.ts:formatterCache": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/keyboard/keyboardHeight.ts:focusTakeovers": {
+      "status": "open",
+      "group": "F6 Keyboard"
+    },
+    "packages/core/src/keyboard/keyboardHeight.ts:stores": {
+      "status": "open",
+      "group": "F6 Keyboard"
+    },
+    "packages/core/src/keyboard/keyboardHeight.ts:touchStartWatches": {
+      "status": "open",
+      "group": "F6 Keyboard"
+    },
+    "packages/core/src/keyboard/keyboardLayoutGuide.ts:guides": {
+      "status": "open",
+      "group": "F6 Keyboard"
+    },
+    "packages/core/src/keyboard/keyboardTarget.ts:currentRides": {
+      "status": "open",
+      "group": "F6 Keyboard"
+    },
+    "packages/core/src/keyboard/keyboardTarget.ts:riddenAnimators": {
+      "status": "open",
+      "group": "F6 Keyboard"
+    },
+    "packages/core/src/keyboard/keyboardTarget.ts:targets": {
+      "status": "open",
+      "group": "F6 Keyboard"
+    },
+    "packages/core/src/keyboard/useMobileKeyboard.ts:revealsAtReport": {
+      "status": "open",
+      "group": "F6 Keyboard"
+    },
+    "packages/core/src/motion/animatedLayout.ts:batches": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animatedLayout.ts:changeStarts": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animatedLayout.ts:edgeMotions": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animatedLayout.ts:endedReports": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animatedLayout.ts:exits": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animatedLayout.ts:glideReports": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animatedLayout.ts:glides": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animatedLayout.ts:heldSlides": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animatedLayout.ts:ours": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animatedLayout.ts:presentedGlides": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animatedLayout.ts:releaseGlides": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animatedLayout.ts:replaced": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animatedLayout.ts:resizeReveals": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animatedLayout.ts:slideTargets": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animatedLayout.ts:stoppedShown": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animator.ts:frameDepth": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animator.ts:frameRead": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animator.ts:openCall": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animator.ts:openTask": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animator.ts:shared": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animator.ts:sheetReads": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animator.ts:taskBakes": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animator.ts:waitingCalls": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/animator.ts:waitingRead": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/resolveMotion.ts:springsAtTempo": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/motion/roles.ts:pathOfGroup": {
+      "status": "allowed",
+      "reason": "Each copy registers and reads its own motion role tables; lookups never cross copies."
+    },
+    "packages/core/src/motion/roles.ts:roleIdOfPath": {
+      "status": "allowed",
+      "reason": "Each copy registers and reads its own motion role tables; lookups never cross copies."
+    },
+    "packages/core/src/motion/roles.ts:roleOfLeaf": {
+      "status": "allowed",
+      "reason": "Each copy registers and reads its own motion role tables; lookups never cross copies."
+    },
+    "packages/core/src/motion/roles.ts:rolesById": {
+      "status": "allowed",
+      "reason": "Each copy registers and reads its own motion role tables; lookups never cross copies."
+    },
+    "packages/core/src/motion/roles.ts:tablesById": {
+      "status": "allowed",
+      "reason": "Each copy registers and reads its own motion role tables; lookups never cross copies."
+    },
+    "packages/core/src/motion/transientCopy.ts:carriedMotion": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/transientCopy.ts:inheritedValues": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/motion/transientCopy.ts:scrollOffsets": {
+      "status": "open",
+      "group": "F7 Motion frame"
+    },
+    "packages/core/src/privateAttributes/travelling.stylex.ts:marks": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/reorderable/createReorderable.ts:reorderableBrand": {
+      "status": "open",
+      "group": "F10 List reorder"
+    },
+    "packages/core/src/theme/Theme.tsx:injectedThemes": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/theme/declarationBoundary.ts:DECLARATION_ANALYSIS_CACHE": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/theme/dynamicType.ts:sharedSyncs": {
+      "status": "allowed",
+      "reason": "Each copy writes the same reader text-size variables to the document root; the duplicate sync is idempotent."
+    },
+    "packages/core/src/theme/generateThemeRules.ts:REACHABLE_MATCH_SET_CACHE": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/theme/generateThemeRules.ts:STATUS_ROLE_GENERATION_CACHE": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/theme/generateThemeRules.ts:activeStatusRoleGeneration": {
+      "status": "allowed",
+      "reason": "Per-run state of one call (a parse, a transform or a render pass) that never outlives the call; a run never crosses copies."
+    },
+    "packages/core/src/theme/statusRoleDerivation.ts:coreCache": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/theme/themeRegistry.ts:themeRegistry": {
+      "status": "open",
+      "group": "F8 Public registries"
+    },
+    "packages/core/src/theme/useTheme.ts:rootModeAttrListeners": {
+      "status": "allowed",
+      "reason": "Each copy observes for its own subscribers; a second observer changes no result."
+    },
+    "packages/core/src/theme/useTheme.ts:rootModeAttrObserver": {
+      "status": "allowed",
+      "reason": "Each copy observes for its own subscribers; a second observer changes no result."
+    },
+    "packages/core/src/theme/useTheme.ts:rootNameAttrListeners": {
+      "status": "allowed",
+      "reason": "Each copy observes for its own subscribers; a second observer changes no result."
+    },
+    "packages/core/src/theme/useTheme.ts:rootNameAttrObserver": {
+      "status": "allowed",
+      "reason": "Each copy observes for its own subscribers; a second observer changes no result."
+    },
+    "packages/core/src/utils/boxHold.ts:waits": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/calendarDateParser.ts:displayOptionCache": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/utils/calendarDateParser.ts:eraChangeCache": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/utils/calendarDateParser.ts:lexicons": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/utils/calendarSystem.ts:supportedCalendars": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/utils/devWarning.ts:warnedKeys": {
+      "status": "allowed",
+      "reason": "Deduplicates development warnings; a copy can at most repeat a warning once."
+    },
+    "packages/core/src/utils/focusReturn.ts:focusDetachedAtRemovalStart": {
+      "status": "open",
+      "group": "F5 Focus and announce"
+    },
+    "packages/core/src/utils/focusReturn.ts:temporaryFocus": {
+      "status": "open",
+      "group": "F5 Focus and announce"
+    },
+    "packages/core/src/utils/hitArea.ts:frame": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/hitArea.ts:interactive": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/hitArea.ts:interactiveDocument": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/hitArea.ts:isCoarse": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/hitArea.ts:observedSizes": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/hitArea.ts:pending": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/hitArea.ts:pointer": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/hitArea.ts:pressDocument": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/hitArea.ts:resize": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/hitArea.ts:scopeTimers": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/hitArea.ts:stopInteractiveWatch": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/hitArea.ts:view": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/hitArea.ts:visibility": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/hitArea.ts:watched": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/layoutViewport.ts:thicknesses": {
+      "status": "open",
+      "group": "F6 Keyboard"
+    },
+    "packages/core/src/utils/plainDate.ts:dateTimeFormats": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/utils/plainDate.ts:dayNumberFormats": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/utils/pressClaim.ts:watchers": {
+      "status": "open",
+      "group": "F4 Layers and popovers"
+    },
+    "packages/core/src/utils/pressFeedback.ts:boxHold": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/pressFeedback.ts:button": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/pressFeedback.ts:contact": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/pressFeedback.ts:finger": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/pressFeedback.ts:holders": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/pressFeedback.ts:keyHeld": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/pressFeedback.ts:lastScrollAt": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/pressFeedback.ts:lastScroller": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/pressFeedback.ts:lastTouchAt": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/pressFeedback.ts:lastTouchTarget": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/pressFeedback.ts:stopTouchCancel": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/pressFeedback.ts:stopWatchingPointer": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/pressFeedback.ts:unsubscribers": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/rowMotion.ts:motions": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/selectionLock.ts:locks": {
+      "status": "open",
+      "group": "F3 Scroll lock"
+    },
+    "packages/core/src/utils/sharedMutationObserver.ts:observers": {
+      "status": "allowed",
+      "reason": "Each copy observes for its own subscribers; a second observer changes no result."
+    },
+    "packages/core/src/utils/sharedResizeObserver.ts:callbacks": {
+      "status": "allowed",
+      "reason": "Each copy observes for its own subscribers; a second observer changes no result."
+    },
+    "packages/core/src/utils/sharedResizeObserver.ts:observer": {
+      "status": "allowed",
+      "reason": "Each copy observes for its own subscribers; a second observer changes no result."
+    },
+    "packages/core/src/utils/timeFormat.ts:symbolsByLocale": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/core/src/utils/touchHitArea.ts:heldWatches": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/core/src/utils/windowExtent.ts:stopObserving": {
+      "status": "allowed",
+      "reason": "Each copy observes for its own subscribers; a second observer changes no result."
+    },
+    "packages/core/src/utils/windowExtent.ts:windowWidth": {
+      "status": "allowed",
+      "reason": "Each copy observes for its own subscribers; a second observer changes no result."
+    },
+    "packages/core/src/utils/windowExtent.ts:windowWidthListeners": {
+      "status": "allowed",
+      "reason": "Each copy observes for its own subscribers; a second observer changes no result."
+    },
+    "packages/lab/src/CodeEditor/CodeEditor.tsx:editorInstanceCounter": {
+      "status": "open",
+      "group": "F13 Shared id sequences"
+    },
+    "packages/lab/src/EmojiPicker/EmojiPicker.tsx:bundledCategories": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/lab/src/EmojiPicker/EmojiPicker.tsx:bundledLabelKeys": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/lab/src/LineClamp/LineClamp.tsx:deferredSyncs": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/lab/src/LineClamp/LineClamp.tsx:isReleaseFlushing": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/lab/src/Schedule/Schedule.tsx:eventLoaderCache": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/lab/src/Schedule/useCurrentTime.ts:currentTime": {
+      "status": "allowed",
+      "reason": "Each copy observes for its own subscribers; a second observer changes no result."
+    },
+    "packages/lab/src/Schedule/useCurrentTime.ts:interval": {
+      "status": "allowed",
+      "reason": "Each copy observes for its own subscribers; a second observer changes no result."
+    },
+    "packages/lab/src/Schedule/useCurrentTime.ts:listeners": {
+      "status": "allowed",
+      "reason": "Each copy observes for its own subscribers; a second observer changes no result."
+    },
+    "packages/richtext/src/CodeSyntaxPlugin.tsx:hasInjectedRules": {
+      "status": "allowed",
+      "reason": "Deduplicates an idempotent style insertion; a copy can at most insert the same rules again."
+    },
+    "packages/richtext/src/markdownExtensionNode.ts:decorators": {
+      "status": "open",
+      "group": "F12 RichText extensions"
+    },
+    "packages/richtext/src/markdownExtensions.ts:extensionPlugin": {
+      "status": "open",
+      "group": "F12 RichText extensions"
+    },
+    "packages/richtext/src/markdownExtensions.ts:withExport": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/richtext/src/markdownSource.ts:canonicalCache": {
+      "status": "allowed",
+      "reason": "A memo cache; a second cache per copy changes no result."
+    },
+    "packages/richtext/src/markdownSource.ts:importCount": {
+      "status": "open",
+      "group": "triage"
+    },
+    "packages/vega/src/viewInputs.ts:OPAQUE": {
+      "status": "open",
+      "group": "triage"
+    }
+  }
+}
diff --git a/scripts/shared-identity.mjs b/scripts/shared-identity.mjs
new file mode 100644
index 0000000000000..304eaa97a6f54
--- /dev/null
+++ b/scripts/shared-identity.mjs
@@ -0,0 +1,332 @@
+// Copyright (c) Meta Platforms, Inc. and affiliates.
+
+/**
+ * @file shared-identity.mjs
+ * @input The source of the packages swizzle copies components from
+ * @output The places where a module keeps cross-module identity in module
+ *   scope instead of a registered shared key (spec:AST-110 FR3): a
+ *   module-local symbol that keys an exported type or that an exported
+ *   function reaches, and module-scope state (a `let`, or a collection or an
+ *   object or array literal that changes) that an exported function reaches, directly or through the
+ *   module's own functions, or that is keyed by a document or window
+ * @position Read by shared-identity.test.mjs; no Vitest import
+ */
+
+import fs from 'node:fs';
+import {createRequire} from 'node:module';
+import path from 'node:path';
+import {fileURLToPath} from 'node:url';
+
+export const REPO = path.resolve(
+  path.dirname(fileURLToPath(import.meta.url)),
+  '..',
+);
+const ts = createRequire(path.join(REPO, 'package.json'))('typescript');
+
+/** The packages swizzle copies components from. */
+export const SOURCE_ROOTS = ['core', 'lab', 'charts', 'richtext', 'vega'].map(
+  name => `packages/${name}/src`,
+);
+const SOURCE_FILE = /\.tsx?$/;
+const NOT_SHIPPED =
+  /\.(?:test|spec|stories|story|d|bench)\.tsx?$|(?:^|\/)__(?:tests|fixtures|mocks)__\//;
+const COLLECTION = /^(?:Map|Set|WeakMap|WeakSet)$/;
+const DOCUMENT_KEY = /^(?:Document|Window)$/;
+const MUTATING_METHOD =
+  /^(?:push|pop|shift|unshift|splice|sort|reverse|fill|copyWithin|set|add|delete|clear)$/;
+
+/** Every shipped source file, repository-relative. */
+export function sourceFiles() {
+  return SOURCE_ROOTS.flatMap(root =>
+    fs
+      .readdirSync(path.join(REPO, root), {recursive: true})
+      .map(String)
+      .map(file => path.join(root, file))
+      .filter(file => SOURCE_FILE.test(file) && !NOT_SHIPPED.test(file)),
+  ).sort();
+}
+
+/**
+ * The cross-module identity one module keeps in module scope.
+ * @param {string} file repository-relative
+ * @returns {Array<{file: string, name: string, kind: 'symbol'|'registry', why: string}>}
+ */
+export function findInFile(file) {
+  return findInSource(file, fs.readFileSync(path.join(REPO, file), 'utf8'));
+}
+
+/**
+ * The cross-module identity one module's source keeps in module scope.
+ * @param {string} file the name to report
+ * @param {string} code the module's source
+ * @returns {Array<{file: string, name: string, kind: 'symbol'|'registry', why: string}>}
+ */
+export function findInSource(file, code) {
+  const source = ts.createSourceFile(file, code, ts.ScriptTarget.Latest, true);
+  /** @type {Map<string, 'symbol'|'registry'|'document-registry'>} */
+  const candidates = new Map();
+  /** Top-level functions, classes and types, by name. */
+  /** @type {Map<string, {node: import('typescript').Node, isType: boolean}>} */
+  const scopes = new Map();
+  /** Names the module exports, from modifiers, `export {…}` lists and defaults. */
+  const exported = new Set();
+  const hasExport = node =>
+    (ts.getCombinedModifierFlags(node) & ts.ModifierFlags.Export) !== 0;
+  /** Whether the module writes into the value `name` holds. */
+  const isMutated = name => {
+    const rootOf = expression => {
+      let node = expression;
+      while (
+        ts.isPropertyAccessExpression(node) ||
+        ts.isElementAccessExpression(node) ||
+        ts.isNonNullExpression(node) ||
+        ts.isParenthesizedExpression(node)
+      ) {
+        node = node.expression;
+      }
+      return ts.isIdentifier(node) ? node.text : null;
+    };
+    let mutated = false;
+    const visit = node => {
+      if (mutated) return;
+      if (
+        ts.isBinaryExpression(node) &&
+        node.operatorToken.kind >= ts.SyntaxKind.FirstAssignment &&
+        node.operatorToken.kind <= ts.SyntaxKind.LastAssignment &&
+        !ts.isIdentifier(node.left) &&
+        rootOf(node.left) === name
+      ) {
+        mutated = true;
+      } else if (
+        (ts.isPrefixUnaryExpression(node) ||
+          ts.isPostfixUnaryExpression(node)) &&
+        (node.operator === ts.SyntaxKind.PlusPlusToken ||
+          node.operator === ts.SyntaxKind.MinusMinusToken) &&
+        !ts.isIdentifier(node.operand) &&
+        rootOf(node.operand) === name
+      ) {
+        mutated = true;
+      } else if (
+        ts.isDeleteExpression(node) &&
+        rootOf(node.expression) === name
+      ) {
+        mutated = true;
+      } else if (
+        ts.isCallExpression(node) &&
+        ts.isPropertyAccessExpression(node.expression) &&
+        MUTATING_METHOD.test(node.expression.name.text) &&
+        rootOf(node.expression.expression) === name
+      ) {
+        mutated = true;
+      }
+      ts.forEachChild(node, visit);
+    };
+    visit(source);
+    return mutated;
+  };
+
+  for (const statement of source.statements) {
+    if (ts.isVariableStatement(statement)) {
+      const isLet = (statement.declarationList.flags & ts.NodeFlags.Let) !== 0;
+      const isDeclare = statement.modifiers?.some(
+        m => m.kind === ts.SyntaxKind.DeclareKeyword,
+      );
+      for (const declaration of statement.declarationList.declarations) {
+        if (!ts.isIdentifier(declaration.name)) continue;
+        const name = declaration.name.text;
+        if (hasExport(statement)) exported.add(name);
+        const init = declaration.initializer;
+        const typeText = declaration.type?.getText(source) ?? '';
+        if (
+          (init &&
+            ts.isCallExpression(init) &&
+            init.expression.getText(source) === 'Symbol') ||
+          (isDeclare && /unique symbol/.test(typeText))
+        ) {
+          candidates.set(name, 'symbol');
+        } else if (init && ts.isNewExpression(init)) {
+          const ctor = init.expression.getText(source);
+          // A collection with fixed contents that nothing changes, or one
+          // typed read-only, is a constant, not a registry.
+          const isConstant =
+            /^Readonly/.test(typeText) ||
+            ((init.arguments?.length ?? 0) > 0 && !isMutated(name));
+          if (COLLECTION.test(ctor) && !isConstant) {
+            const keyType =
+              init.typeArguments?.[0]?.getText(source) ??
+              typeText.match(/^\w+<\s*(\w+)/)?.[1] ??
+              '';
+            candidates.set(
+              name,
+              DOCUMENT_KEY.test(keyType) ? 'document-registry' : 'registry',
+            );
+          }
+        } else if (isLet) {
+          candidates.set(name, 'registry');
+        } else if (
+          init &&
+          (ts.isObjectLiteralExpression(init) ||
+            ts.isArrayLiteralExpression(init)) &&
+          !/^Readonly/.test(typeText) &&
+          isMutated(name)
+        ) {
+          // An object or array literal that the module changes holds state
+          // like a collection does.
+          candidates.set(name, 'registry');
+        }
+        if (
+          init &&
+          (ts.isArrowFunction(init) || ts.isFunctionExpression(init))
+        ) {
+          scopes.set(name, {node: init, isType: false});
+        }
+      }
+    } else if (
+      (ts.isFunctionDeclaration(statement) ||
+        ts.isClassDeclaration(statement)) &&
+      statement.name
+    ) {
+      scopes.set(statement.name.text, {node: statement, isType: false});
+      if (hasExport(statement)) exported.add(statement.name.text);
+    } else if (
+      ts.isInterfaceDeclaration(statement) ||
+      ts.isTypeAliasDeclaration(statement)
+    ) {
+      scopes.set(statement.name.text, {node: statement, isType: true});
+      if (hasExport(statement)) exported.add(statement.name.text);
+    } else if (
+      ts.isExportDeclaration(statement) &&
+      !statement.moduleSpecifier &&
+      statement.exportClause &&
+      ts.isNamedExports(statement.exportClause)
+    ) {
+      for (const element of statement.exportClause.elements) {
+        exported.add((element.propertyName ?? element.name).text);
+      }
+    } else if (
+      ts.isExportAssignment(statement) &&
+      ts.isIdentifier(statement.expression)
+    ) {
+      exported.add(statement.expression.text);
+    }
+  }
+  if (candidates.size === 0) return [];
+
+  /**
+   * The candidates a node uses (and whether each is a computed key in a
+   * type), and the top-level scopes it refers to.
+   */
+  const usesIn = node => {
+    /** @type {Map<string, boolean>} */
+    const used = new Map();
+    const refers = new Set();
+    const visit = child => {
+      if (ts.isIdentifier(child)) {
+        if (candidates.has(child.text)) {
+          const parent = child.parent;
+          const asTypeKey =
+            parent &&
+            ts.isComputedPropertyName(parent) &&
+            (ts.isPropertySignature(parent.parent) ||
+              ts.isMethodSignature(parent.parent));
+          used.set(child.text, Boolean(used.get(child.text) || asTypeKey));
+        }
+        if (scopes.has(child.text)) refers.add(child.text);
+      }
+      ts.forEachChild(child, visit);
+    };
+    visit(node);
+    return {used, refers};
+  };
+  const uses = new Map(
+    [...scopes].map(([name, scope]) => [name, usesIn(scope.node)]),
+  );
+
+  // A function the module hands to another module at load, such as a
+  // callback it installs, acts for the module as an export does.
+  const handedOut = new Set();
+  for (const statement of source.statements) {
+    if (
+      ts.isExpressionStatement(statement) ||
+      (ts.isVariableStatement(statement) &&
+        statement.declarationList.declarations.some(
+          declaration =>
+            declaration.initializer &&
+            ts.isCallExpression(declaration.initializer),
+        ))
+    ) {
+      for (const name of usesIn(statement).refers) {
+        if (!exported.has(name) && !scopes.get(name).isType) {
+          handedOut.add(name);
+        }
+      }
+    }
+  }
+
+  const rootName = root =>
+    exported.has(root)
+      ? `the exported ${root}`
+      : `${root}, which the module hands out at load,`;
+  /** @type {Map<string, string>} name -> why it crosses modules */
+  const found = new Map();
+  for (const root of [...[...exported].sort(), ...[...handedOut].sort()]) {
+    const scope = scopes.get(root);
+    if (!scope) continue;
+    if (scope.isType) {
+      for (const [name, asTypeKey] of uses.get(root).used) {
+        if (
+          candidates.get(name) === 'symbol' &&
+          asTypeKey &&
+          !found.has(name)
+        ) {
+          found.set(name, `keys the exported type ${root}`);
+        }
+      }
+      continue;
+    }
+    // Everything the exported function reaches through the module's own
+    // functions acts for it.
+    const reached = new Set([root]);
+    const queue = [root];
+    while (queue.length) {
+      const next = queue.pop();
+      for (const name of uses.get(next)?.refers ?? []) {
+        if (!reached.has(name) && !scopes.get(name).isType) {
+          reached.add(name);
+          queue.push(name);
+        }
+      }
+    }
+    for (const name of reached) {
+      for (const used of uses.get(name).used.keys()) {
+        if (found.has(used)) continue;
+        found.set(
+          used,
+          candidates.get(used) === 'document-registry'
+            ? `a per-document store ${rootName(root)} uses`
+            : candidates.get(used) === 'symbol'
+              ? `read or written by ${rootName(root)}`
+              : `module state ${rootName(root)} uses`,
+        );
+      }
+    }
+  }
+  // A per-document store counts even when no export reaches it: the
+  // components of the package and of a copy share the document.
+  for (const [name, kind] of candidates) {
+    if (kind === 'document-registry' && !found.has(name)) {
+      found.set(name, 'a per-document store in module scope');
+    }
+  }
+  return [...found].map(([name, why]) => ({
+    file,
+    name,
+    kind: candidates.get(name) === 'symbol' ? 'symbol' : 'registry',
+    why,
+  }));
+}
+
+/** Every hit in the shipped source. */
+export function findAll() {
+  return sourceFiles().flatMap(findInFile);
+}
diff --git a/scripts/shared-identity.test.mjs b/scripts/shared-identity.test.mjs
new file mode 100644
index 0000000000000..c6199f0817768
--- /dev/null
+++ b/scripts/shared-identity.test.mjs
@@ -0,0 +1,119 @@
+// Copyright (c) Meta Platforms, Inc. and affiliates.
+
+/**
+ * @file shared-identity.test.mjs
+ * @input The shipped source of the packages swizzle copies from, and
+ *   scripts/shared-identity.baseline.json
+ * @output Fails when a module keeps cross-module identity in module scope
+ *   (a module-local symbol or registry) that the baseline does not list, or
+ *   when the baseline lists one the source no longer has
+ *   (spec:AST-110 FR3, FR7)
+ * @position Node test over source; needs no build
+ */
+
+import fs from 'node:fs';
+import path from 'node:path';
+import {describe, expect, it} from 'vitest';
+
+import {REPO, findAll, findInSource} from './shared-identity.mjs';
+
+const BASELINE = path.join(REPO, 'scripts/shared-identity.baseline.json');
+const FIX =
+  'Keep it under a registered key: sharedKey or realmValue from ' +
+  'packages/core/src/utils/sharedRealm.ts, createSharedContext for a ' +
+  'context, and for a type brand one optional phantom member typed never ' +
+  '(spec:AST-110 FR3).';
+
+describe('cross-module identity in module scope (spec:AST-110 FR3)', () => {
+  it('flags a module-local symbol brand and passes a shared key', () => {
+    const local = findInSource(
+      'brand.ts',
+      [
+        `const brand: unique symbol = Symbol('Brand');`,
+        `export interface Branded { readonly [brand]: true }`,
+        `export function make(): Branded { return {[brand]: true}; }`,
+      ].join('\n'),
+    );
+    expect(local.map(hit => hit.name)).toEqual(['brand']);
+    const shared = findInSource(
+      'brand.ts',
+      [
+        `import {sharedKey} from './sharedRealm';`,
+        `const BRAND = sharedKey('brand', 1);`,
+        `export interface Branded { readonly '@astryxdesign/core/brand/v1'?: never }`,
+        `export function make(): Branded { return {[BRAND]: true} as Branded; }`,
+      ].join('\n'),
+    );
+    expect(shared).toEqual([]);
+  });
+
+  it('flags a module-scope registry an exported function reads', () => {
+    const hits = findInSource(
+      'host.ts',
+      [
+        `let registered: unknown = null;`,
+        `export function registerHost(host: unknown) { registered = host; }`,
+      ].join('\n'),
+    );
+    expect(hits.map(hit => hit.name)).toEqual(['registered']);
+  });
+
+  it('flags state an export reaches through a private helper or an export list, including a literal it changes', () => {
+    const hits = findInSource(
+      'claims.ts',
+      [
+        `const held = new Map<number, string>();`,
+        `const regions: WeakMap<Document, string> = new WeakMap();`,
+        `const claims: Record<string, number[]> = {overflow: []};`,
+        `function remember(id: number) { held.set(id, 'x'); claims.overflow.push(id); }`,
+        `function claim(id: number) { remember(id); }`,
+        `export {claim};`,
+      ].join('\n'),
+    );
+    expect(hits.map(hit => [hit.name, hit.why])).toEqual([
+      ['held', 'module state the exported claim uses'],
+      ['claims', 'module state the exported claim uses'],
+      ['regions', 'a per-document store in module scope'],
+    ]);
+  });
+
+  it('flags state a function the module hands out at load reaches', () => {
+    const hits = findInSource(
+      'route.ts',
+      [
+        `import {installRoute} from './other';`,
+        `const deferred = new WeakMap<object, string>();`,
+        `function announce(scope: object) { deferred.set(scope, 'x'); }`,
+        `installRoute({announce});`,
+      ].join('\n'),
+    );
+    expect(hits.map(hit => hit.name)).toEqual(['deferred']);
+  });
+
+  it('lists every hit in the baseline, and nothing the source no longer has', () => {
+    const baseline = JSON.parse(fs.readFileSync(BASELINE, 'utf8')).entries;
+    const hits = findAll();
+    const found = new Set(hits.map(hit => `${hit.file}:${hit.name}`));
+    const unlisted = hits
+      .filter(hit => !(`${hit.file}:${hit.name}` in baseline))
+      .map(hit => `${hit.file}:${hit.name}: ${hit.why}. ${FIX}`);
+    const stale = Object.keys(baseline).filter(key => !found.has(key));
+    expect(unlisted, 'new module-scope identity').toEqual([]);
+    expect(
+      stale,
+      'baseline entries the source no longer has; delete them',
+    ).toEqual([]);
+  });
+
+  it('gives every allowed entry a reason and every open entry a fix group', () => {
+    const baseline = JSON.parse(fs.readFileSync(BASELINE, 'utf8')).entries;
+    for (const [key, entry] of Object.entries(baseline)) {
+      if (entry.status === 'allowed') {
+        expect(entry.reason, key).toMatch(/\S/);
+      } else {
+        expect(entry.status, key).toBe('open');
+        expect(entry.group, key).toMatch(/\S/);
+      }
+    }
+  });
+});