diff --git a/apps/server/src/mcp/toolkits/previewControls/handlers.test.ts b/apps/server/src/mcp/toolkits/previewControls/handlers.test.ts
index 4cd06bc4233b..62840dd21e6e 100644
--- a/apps/server/src/mcp/toolkits/previewControls/handlers.test.ts
+++ b/apps/server/src/mcp/toolkits/previewControls/handlers.test.ts
@@ -4,8 +4,10 @@ import { expect, it } from "@effect/vitest";
 import {
   DEFAULT_SERVER_SETTINGS,
   EnvironmentId,
+  PreviewAutomationControlInterruptedError,
   ProjectId,
   ProviderInstanceId,
+  SERVER_BROWSER_AUTOMATION_CLIENT_ID,
   ThreadId,
 } from "@t3tools/contracts";
 import { resolveProjectSettings } from "@t3tools/shared/projectSettings";
@@ -101,3 +103,86 @@ it.effect.each([
     }),
   ),
 );
+
+it.effect("close reports why the server browser refused to close a tab", () =>
+  Effect.scoped(
+    Effect.gen(function* () {
+      const threadId = ThreadId.make("preview-controls-thread");
+      const scope: McpInvocationContext.McpInvocationScope = {
+        environmentId: EnvironmentId.make("preview-controls-environment"),
+        requestNamespace: "preview-controls-provider-session",
+        thread: {
+          threadId,
+          providerSessionId: "preview-controls-provider-session",
+          providerInstanceId: ProviderInstanceId.make("codex"),
+        },
+        client: undefined,
+        capabilities: new Set(["preview"]),
+        issuedAt: 0,
+      };
+      const manager = yield* Preview.make.pipe(
+        Effect.provide(
+          Layer.merge(
+            ServerConfig.layerTest(process.cwd(), { prefix: "t3-preview-controls-" }).pipe(
+              Layer.provide(NodeServices.layer),
+            ),
+            NodeCrypto.layer,
+          ),
+        ),
+      );
+      const tab = yield* manager.open({
+        threadId,
+        url: "http://localhost:3000",
+        runtime: "server",
+      });
+      const layerDependencies = Layer.mergeAll(
+        Layer.mock(PreviewAutomationBroker.PreviewAutomationBroker)({
+          invoke: () =>
+            Effect.fail(
+              new PreviewAutomationControlInterruptedError({
+                operation: "close",
+                environmentId: scope.environmentId,
+                threadId,
+                providerSessionId: "preview-controls-provider-session",
+                providerInstanceId: ProviderInstanceId.make("codex"),
+                clientId: SERVER_BROWSER_AUTOMATION_CLIENT_ID,
+                connectionId: "server-browser-connection",
+                requestId: "close-request",
+                tabId: tab.tabId,
+                timeoutMs: 1_000,
+                remoteTag: "PreviewAutomationControlInterruptedError",
+                remoteMessageLength: 0,
+                cause: null,
+                reason: "agentMismatch",
+              }),
+            ),
+        }),
+        Layer.succeed(Preview.PreviewManager, manager),
+        Layer.succeed(McpInvocationContext.McpInvocationContext, scope),
+        McpToolAccessTestkit.liveThreadsLayer,
+        Layer.mock(ServerSettings.ServerSettingsService)({
+          getSettings: Effect.succeed({
+            ...DEFAULT_SERVER_SETTINGS,
+            enableAgentBrowserAccess: true,
+          }),
+        }),
+      );
+      const toolkit = yield* PreviewControlsToolkit.pipe(
+        Effect.provide(
+          McpToolAccess.HandlersLayer.layer(PreviewControlsHandlers.layer).pipe(
+            Layer.provide(layerDependencies),
+          ),
+        ),
+      );
+
+      const closed = yield* toolkit
+        .handle("t3_preview_close", { tabId: tab.tabId })
+        .pipe(Stream.unwrap, Stream.runCollect, Effect.provide(layerDependencies));
+
+      expect(closed.at(-1)?.result).toMatchObject({
+        _tag: "PreviewAutomationControlInterruptedError",
+        reason: "agentMismatch",
+      });
+    }),
+  ),
+);
diff --git a/apps/server/src/mcp/toolkits/previewControls/handlers.ts b/apps/server/src/mcp/toolkits/previewControls/handlers.ts
index bdb2bad2ad6e..f0b011f5c3b2 100644
--- a/apps/server/src/mcp/toolkits/previewControls/handlers.ts
+++ b/apps/server/src/mcp/toolkits/previewControls/handlers.ts
@@ -33,9 +33,7 @@ export const layer = McpToolAccess.toLayer(PreviewControlsToolkit, {
         sessions.some((session) => session.tabId === input.tabId && session.runtime === "server")
       ) {
         const broker = yield* PreviewAutomationBroker.PreviewAutomationBroker;
-        yield* broker
-          .invoke({ scope, operation: "close", input: {}, tabId: input.tabId })
-          .pipe(Effect.mapError(unavailable));
+        yield* broker.invoke({ scope, operation: "close", input: {}, tabId: input.tabId });
         return {};
       }
       yield* manager
diff --git a/apps/server/src/mcp/toolkits/previewControls/tools.ts b/apps/server/src/mcp/toolkits/previewControls/tools.ts
index 2a14ee7b5e64..8bc2ccd31c18 100644
--- a/apps/server/src/mcp/toolkits/previewControls/tools.ts
+++ b/apps/server/src/mcp/toolkits/previewControls/tools.ts
@@ -1,7 +1,7 @@
 import {
   NonNegativeInt,
   OrchestratorMcpFailure,
-  PreviewAutomationUnavailableError,
+  PreviewAutomationError,
   PreviewListResult,
   PreviewTabId,
 } from "@t3tools/contracts";
@@ -13,7 +13,7 @@ import * as PreviewAutomationBroker from "../../PreviewAutomationBroker.ts";
 import * as McpInvocationContext from "../../McpInvocationContext.ts";
 
 const shared = {
-  failure: Schema.Union([OrchestratorMcpFailure, PreviewAutomationUnavailableError]),
+  failure: Schema.Union([PreviewAutomationError, OrchestratorMcpFailure]),
   failureMode: "return" as const,
   dependencies: [
     McpInvocationContext.McpInvocationContext,