diff --git a/test/model/Account.test.ts b/test/model/Account.test.ts
index 4b81db7..70f07d6 100644
--- a/test/model/Account.test.ts
+++ b/test/model/Account.test.ts
@@ -889,6 +889,86 @@ const validAccount = (): Record<string, unknown> => ({
 
 describe('Account.Schema', () => {
   describe('field inventory', () => {
+    /**
+     * Exhaustive key inventory.
+     *
+     * The `toContain` checks below name 22 of these 55 keys, which makes them a
+     * spot-check rather than an inventory: a field deleted from the schema and
+     * not named in one of those lists is invisible to them. It is also invisible
+     * to {@link Account.SchemaOutput}, because that proof is assignability-based
+     * and `z.looseObject` infers a `[x: string]: unknown` index signature — an
+     * *optional* interface property is satisfied structurally whether or not the
+     * schema still declares it, so only the removal of a *required* field is a
+     * compile error.
+     *
+     * A field silently dropped from the schema is not a cosmetic loss. The field
+     * stops being validated entirely and falls through to the loose-object
+     * passthrough, where any value is accepted, while {@link Account.Interface}
+     * continues to promise it was checked. This assertion is what makes that a
+     * failure, and it is deliberately a literal list rather than anything
+     * derived from `Schema.shape`, which would delete itself alongside the field
+     * and pass.
+     */
+    it('should declare exactly these 55 fields, so a silently dropped field fails here', () => {
+      expect(Object.keys(Account.Schema.shape).sort()).toEqual([
+        'alias',
+        'appToPersonUseCase',
+        'area',
+        'authorizedRepresentative1',
+        'authorizedRepresentative2',
+        'automaticHeader',
+        'backup',
+        'bca',
+        'brandType',
+        'businessIndustry',
+        'businessName',
+        'businessRegionsOfOperations',
+        'businessRegistrationIdentifier',
+        'businessRegistrationNumber',
+        'businessType',
+        'city',
+        'companyType',
+        'counted',
+        'country',
+        'created',
+        'description',
+        'domain',
+        'domainOk',
+        'domainTimestamp',
+        'estimatedVolume',
+        'expiry',
+        'id',
+        'image',
+        'imageURL',
+        'language',
+        'links',
+        'name',
+        'pending',
+        'postalCode',
+        'ready',
+        'sampleMessage1',
+        'sampleMessage2',
+        'sampleMessage3',
+        'sampleMessage4',
+        'sampleMessage5',
+        'sender',
+        'sending',
+        'status',
+        'stockExchange',
+        'stockTicker',
+        'street1',
+        'street2',
+        'tollFreeUseCase',
+        'type',
+        'uid',
+        'updated',
+        'useCaseDescription',
+        'useCaseDescriptionCTA',
+        'useName',
+        'utcOffset',
+      ]);
+    });
+
     it('should declare the account fields alongside the inherited audit and queue fields', () => {
       const keys = Object.keys(Account.Schema.shape);
       for (const field of ['id', 'backup', 'created', 'updated', 'expiry']) {
diff --git a/test/model/EventData.test.ts b/test/model/EventData.test.ts
index 96ec324..18525e7 100644
--- a/test/model/EventData.test.ts
+++ b/test/model/EventData.test.ts
@@ -303,6 +303,63 @@ const validEvent = (): Record<string, unknown> => ({
 
 describe('EventData.Schema', () => {
   describe('field inventory', () => {
+    /**
+     * Exhaustive key inventory.
+     *
+     * The `toContain` checks below name 18 of these 37 keys, so a field deleted
+     * from the schema and absent from those lists passes them. It also passes
+     * {@link EventData.SchemaOutput}: that proof is assignability-based, and the
+     * `[x: string]: unknown` index signature `z.looseObject` infers satisfies an
+     * *optional* interface property whether or not the schema declares it.
+     *
+     * A dropped field stops being validated and falls through to the
+     * loose-object passthrough, accepting any value, while
+     * {@link EventData.Interface} still promises it was checked. The list is
+     * literal on purpose — deriving it from `Schema.shape` would shrink with the
+     * deletion and assert nothing.
+     */
+    it('should declare exactly these 37 fields, so a silently dropped field fails here', () => {
+      expect(Object.keys(EventData.Schema.shape).sort()).toEqual([
+        'account',
+        'amount',
+        'area',
+        'backup',
+        'blocks',
+        'booked',
+        'checkout',
+        'clicks',
+        'country',
+        'created',
+        'currency',
+        'description',
+        'duration',
+        'endTime',
+        'expiry',
+        'frequency',
+        'geohash',
+        'hosts',
+        'id',
+        'language',
+        'latitude',
+        'limit',
+        'location',
+        'longitude',
+        'media',
+        'name',
+        'placeId',
+        'placeName',
+        'runHour',
+        'startTime',
+        'status',
+        'type',
+        'uid',
+        'updated',
+        'users',
+        'utcOffset',
+        'views',
+      ]);
+    });
+
     it('should declare the event fields alongside the inherited audit and place fields', () => {
       const keys = Object.keys(EventData.Schema.shape);
       for (const field of ['name', 'account', 'blocks', 'startTime', 'endTime', 'runHour', 'limit', 'amount']) {