diff --git a/packages/host/app/components/operator-mode/archived-realm-state.gts b/packages/host/app/components/operator-mode/archived-realm-state.gts
new file mode 100644
index 0000000000..95ebd92da5
--- /dev/null
+++ b/packages/host/app/components/operator-mode/archived-realm-state.gts
@@ -0,0 +1,80 @@
+import type { TemplateOnlyComponent } from '@ember/component/template-only';
+
+import { CardHeader } from '@cardstack/boxel-ui/components';
+import type { MenuItem } from '@cardstack/boxel-ui/helpers';
+import { Lock } from '@cardstack/boxel-ui/icons';
+
+import type { CardErrorJSONAPI } from '@cardstack/host/services/store';
+
+interface Signature {
+  Args: {
+    error: CardErrorJSONAPI;
+    headerOptions?: {
+      isTopCard?: boolean;
+      moreOptionsMenuItems?: MenuItem[];
+      onClose?: () => void;
+    };
+  };
+  Element: HTMLElement;
+}
+
+// Shown in place of card chrome when a realm responds 403 (archived). An
+// archived realm is sealed for everyone, so there is no read-only browsing —
+// the only way back in is to restore it.
+const ArchivedRealmState: TemplateOnlyComponent<Signature> = <template>
+  <CardHeader
+    class='archived-header'
+    @cardTypeDisplayName='Workspace Archived'
+    @cardTypeIcon={{Lock}}
+    @isTopCard={{@headerOptions.isTopCard}}
+    @moreOptionsMenuItems={{@headerOptions.moreOptionsMenuItems}}
+    @onClose={{@headerOptions.onClose}}
+    ...attributes
+  />
+  <div class='archived-realm-state' data-test-archived-realm-state>
+    <Lock class='icon' />
+    <div class='message'>
+      <p class='headline'>This workspace is archived</p>
+      <p class='detail'>
+        Restore it from the workspace chooser, or ask an owner to restore it.
+      </p>
+    </div>
+  </div>
+  <style scoped>
+    .icon {
+      height: 100px;
+      width: 100px;
+      color: var(--boxel-400);
+    }
+    .archived-realm-state {
+      display: flex;
+      height: 100%;
+      align-content: center;
+      justify-content: center;
+      flex-wrap: wrap;
+      gap: var(--boxel-sp-xs);
+      padding: var(--boxel-sp);
+    }
+    .message {
+      width: 100%;
+      text-align: center;
+      text-wrap: pretty;
+    }
+    .headline {
+      margin: 0;
+      font: 600 var(--boxel-font);
+    }
+    .detail {
+      margin: var(--boxel-sp-xxs) 0 0;
+      color: var(--boxel-450);
+      font: var(--boxel-font-sm);
+    }
+    .archived-header {
+      min-height: var(--boxel-form-control-height);
+      background-color: var(--boxel-100);
+      box-shadow: 0 1px 0 0 rgba(0 0 0 / 15%);
+    }
+  </style>
+</template>;
+
+export default ArchivedRealmState;
diff --git a/packages/host/app/components/operator-mode/stack-item.gts b/packages/host/app/components/operator-mode/stack-item.gts
index 004279269b..2b858727b9 100644
--- a/packages/host/app/components/operator-mode/stack-item.gts
+++ b/packages/host/app/components/operator-mode/stack-item.gts
@@ -82,6 +82,7 @@ import ElementTracker, {
 } from '../../resources/element-tracker';
 import CardRenderer from '../card-renderer';
 
+import ArchivedRealmState from './archived-realm-state';
 import CardError from './card-error';
 import DeleteModal from './delete-modal';
 
@@ -715,6 +716,18 @@ export default class OperatorModeStackItem extends Component<Signature> {
     return this.cardResource?.cardError;
   }
 
+  // A realm that responds 403 (archived) carries the X-Boxel-Realm-Archived
+  // marker (exposed to cross-origin clients via Access-Control-Expose-Headers).
+  // The realm only returns this to callers it has already authorized, so its
+  // presence is an unambiguous signal to render the sealed state rather than a
+  // generic card error.
+  private get isArchivedRealmError() {
+    return (
+      this.cardError?.meta?.responseHeaders?.['x-boxel-realm-archived'] ===
+      'true'
+    );
+  }
+
   private get isWideFormat() {
     if (!this.card) {
       return false;
@@ -986,36 +999,66 @@ export default class OperatorModeStackItem extends Component<Signature> {
         {{else if this.showError}}
           {{! this is for types--this.cardError is always true in this case !}}
           {{#if this.cardError}}
-            <CardError
-              @error={{this.cardError}}
-              @viewInCodeMode={{true}}
-              @headerOptions={{this.cardErrorHeaderOptions}}
-              class='stack-item-header'
-              style={{cssVar
-                boxel-card-header-icon-container-min-width=(if
-                  this.isBuried '50px' '95px'
-                )
-                boxel-card-header-actions-min-width=(if
-                  this.isBuried '50px' '95px'
-                )
-                boxel-card-header-background-color=this.headerColor
-                boxel-card-header-text-color=(getContrastColor this.headerColor)
-                realm-icon-background-color=(getContrastColor
-                  this.headerColor 'transparent'
-                )
-                realm-icon-border-color=(getContrastColor
-                  this.headerColor 'transparent' 'rgba(0 0 0 / 15%)'
-                )
-              }}
-              role={{if this.isBuried 'button' 'banner'}}
-              {{on
-                'click'
-                (optional
-                  (if this.isBuried (fn @dismissStackedCardsAbove @index))
-                )
-              }}
-              data-test-stack-card-header
-            />
+            {{#if this.isArchivedRealmError}}
+              <ArchivedRealmState
+                @error={{this.cardError}}
+                @headerOptions={{this.cardErrorHeaderOptions}}
+                class='stack-item-header'
+                style={{cssVar
+                  boxel-card-header-icon-container-min-width=(if
+                    this.isBuried '50px' '95px'
+                  )
+                  boxel-card-header-actions-min-width=(if
+                    this.isBuried '50px' '95px'
+                  )
+                  boxel-card-header-background-color=this.headerColor
+                  boxel-card-header-text-color=(getContrastColor
+                    this.headerColor
+                  )
+                }}
+                role={{if this.isBuried 'button' 'banner'}}
+                {{on
+                  'click'
+                  (optional
+                    (if this.isBuried (fn @dismissStackedCardsAbove @index))
+                  )
+                }}
+                data-test-stack-card-header
+              />
+            {{else}}
+              <CardError
+                @error={{this.cardError}}
+                @viewInCodeMode={{true}}
+                @headerOptions={{this.cardErrorHeaderOptions}}
+                class='stack-item-header'
+                style={{cssVar
+                  boxel-card-header-icon-container-min-width=(if
+                    this.isBuried '50px' '95px'
+                  )
+                  boxel-card-header-actions-min-width=(if
+                    this.isBuried '50px' '95px'
+                  )
+                  boxel-card-header-background-color=this.headerColor
+                  boxel-card-header-text-color=(getContrastColor
+                    this.headerColor
+                  )
+                  realm-icon-background-color=(getContrastColor
+                    this.headerColor 'transparent'
+                  )
+                  realm-icon-border-color=(getContrastColor
+                    this.headerColor 'transparent' 'rgba(0 0 0 / 15%)'
+                  )
+                }}
+                role={{if this.isBuried 'button' 'banner'}}
+                {{on
+                  'click'
+                  (optional
+                    (if this.isBuried (fn @dismissStackedCardsAbove @index))
+                  )
+                }}
+                data-test-stack-card-header
+              />
+            {{/if}}
           {{/if}}
         {{else if this.card}}
           {{this.setWindowTitle}}
diff --git a/packages/host/tests/integration/components/operator-mode-test.gts b/packages/host/tests/integration/components/operator-mode-test.gts
index 05d1e363c5..c0fcc52556 100644
--- a/packages/host/tests/integration/components/operator-mode-test.gts
+++ b/packages/host/tests/integration/components/operator-mode-test.gts
@@ -95,6 +95,62 @@ module('Integration | operator-mode | basics', function (hooks) {
     );
   });
 
+  test('navigating to an archived realm shows the sealed state, not card chrome or a generic error', async function (assert) {
+    // A realm sealed by the archive flag answers content requests with 403 and
+    // the X-Boxel-Realm-Archived marker. Intercept the card fetch to reproduce
+    // that response and assert the host renders the sealed state.
+    let networkService = getService('network');
+    networkService.virtualNetwork.mount(
+      async (req: Request) => {
+        if (req.method === 'GET' && req.url.includes('Person/fadhlan')) {
+          return new Response(
+            JSON.stringify({
+              errors: [
+                {
+                  status: '403',
+                  code: 'archived',
+                  title: 'Realm Archived',
+                  detail: `Realm ${testRealmURL} is archived`,
+                },
+              ],
+            }),
+            {
+              status: 403,
+              headers: {
+                'Content-Type': 'application/vnd.api+json',
+                'X-Boxel-Realm-Archived': 'true',
+                'X-Boxel-Realm-Url': testRealmURL,
+              },
+            },
+          );
+        }
+        return null;
+      },
+      { prepend: true },
+    );
+
+    ctx.setCardInOperatorModeState(`${testRealmURL}Person/fadhlan`);
+    await renderComponent(
+      class TestDriver extends GlimmerComponent {
+        <template><OperatorMode @onClose={{noop}} /></template>
+      },
+    );
+
+    await waitFor('[data-test-archived-realm-state]');
+    assert
+      .dom('[data-test-archived-realm-state]')
+      .containsText(
+        'This workspace is archived',
+        'the sealed/archived state is shown',
+      );
+    assert
+      .dom('[data-test-boxel-card-header-title]')
+      .containsText('Workspace Archived', 'the archived header is shown');
+    assert
+      .dom('[data-test-card-error]')
+      .doesNotExist('a generic card error is not shown for an archived realm');
+  });
+
   module(
     'card with an error that has a last known good state',
     function (hooks) {