diff --git a/test/e2e/live/mcp-bridge-hermes-lifecycle.ts b/test/e2e/live/mcp-bridge-hermes-lifecycle.ts
index 5044cc5e31a..541ca88eebc 100644
--- a/test/e2e/live/mcp-bridge-hermes-lifecycle.ts
+++ b/test/e2e/live/mcp-bridge-hermes-lifecycle.ts
@@ -189,6 +189,44 @@ export async function assertHermesManagedAddSurvivesLockedGatewayRestartAndState
   expectExitZero(shieldsDown, "unlock Hermes config for remaining managed MCP lifecycle");
 }
 
+/**
+ * Rebuild can outlive the inherited Shields-down timer and correctly return
+ * with lockdown restored. Normalize the posture first so an already-down
+ * sandbox cannot retain an almost-expired timer, then open a fresh window for
+ * the final managed MCP mutation.
+ */
+export async function reopenHermesMcpMaintenanceWindow(
+  host: HostCliClient,
+  sandboxName: string,
+): Promise<void> {
+  const shieldsUp = await host.nemoclaw([sandboxName, "shields", "up"], {
+    artifactName: "hermes-mcp-shields-up-before-post-rebuild-remove",
+    env: buildAvailabilityProbeEnv(),
+    redactionValues: [HOST_SECRET, ROTATED_HOST_SECRET],
+    timeoutMs: 3 * 60_000,
+  });
+  expectExitZero(shieldsUp, "normalize Hermes shields before post-rebuild MCP removal");
+
+  const shieldsDown = await host.nemoclaw(
+    [
+      sandboxName,
+      "shields",
+      "down",
+      "--timeout",
+      "15m",
+      "--reason",
+      "Post-rebuild MCP removal E2E",
+    ],
+    {
+      artifactName: "hermes-mcp-shields-down-before-post-rebuild-remove",
+      env: buildAvailabilityProbeEnv(),
+      redactionValues: [HOST_SECRET, ROTATED_HOST_SECRET],
+      timeoutMs: 3 * 60_000,
+    },
+  );
+  expectExitZero(shieldsDown, "open a fresh Hermes MCP maintenance window after rebuild");
+}
+
 /**
  * Inject a first-reload failure around the packaged transaction helper, then
  * require its real rollback reload to restore the prior config, both integrity
diff --git a/test/e2e/live/mcp-bridge.test.ts b/test/e2e/live/mcp-bridge.test.ts
index 3524d9119d9..1cc045d5a4f 100644
--- a/test/e2e/live/mcp-bridge.test.ts
+++ b/test/e2e/live/mcp-bridge.test.ts
@@ -38,6 +38,7 @@ import {
   assertHermesManagedAddSurvivesLockedGatewayRestartAndStateLayout,
   assertHermesReloadRollback,
   assertHermesRemovalSurvivesGatewayRestart,
+  reopenHermesMcpMaintenanceWindow,
 } from "./mcp-bridge-hermes-lifecycle.ts";
 import {
   buildMcpBridgeExactMainEnv,
@@ -1226,6 +1227,7 @@ mcpBridgeShardTest("hermes")(
       artifactName: "hermes-real-mcp-tool-call-after-rebuild",
       expectedSecret: ROTATED_HOST_SECRET,
     });
+    await reopenHermesMcpMaintenanceWindow(host, HERMES_SANDBOX_NAME);
     await removeBridgeAndAssertEmpty(host, sandbox, {
       agent: "hermes",
       adapter: "hermes-config",
diff --git a/test/e2e/support/mcp-bridge-hermes-lifecycle.test.ts b/test/e2e/support/mcp-bridge-hermes-lifecycle.test.ts
index a39d2a25223..bb87a202d11 100644
--- a/test/e2e/support/mcp-bridge-hermes-lifecycle.test.ts
+++ b/test/e2e/support/mcp-bridge-hermes-lifecycle.test.ts
@@ -3,8 +3,55 @@
 
 import { describe, expect, it } from "vitest";
 
-import { SandboxClient } from "../fixtures/clients/sandbox.ts";
-import { assertHermesReloadRollback } from "../live/mcp-bridge-hermes-lifecycle.ts";
+import { type CommandRunner, HostCliClient, SandboxClient } from "../fixtures/clients/index.ts";
+import type {
+  ShellProbeResult,
+  ShellProbeRunOptions,
+  TrustedShellCommand,
+} from "../fixtures/shell-probe.ts";
+import {
+  assertHermesReloadRollback,
+  reopenHermesMcpMaintenanceWindow,
+} from "../live/mcp-bridge-hermes-lifecycle.ts";
+
+interface RunnerCall {
+  command: string;
+  args: string[];
+  options?: ShellProbeRunOptions;
+}
+
+function shellResult(exitCode = 0): ShellProbeResult {
+  return {
+    command: [],
+    exitCode,
+    signal: null,
+    timedOut: false,
+    stdout: "",
+    stderr: "",
+    artifacts: {
+      stdout: "/tmp/stdout",
+      stderr: "/tmp/stderr",
+      result: "/tmp/result",
+    },
+  };
+}
+
+class RecordingRunner implements CommandRunner {
+  readonly calls: RunnerCall[] = [];
+  private readonly responses: ShellProbeResult[];
+
+  constructor(responses: ShellProbeResult[] = []) {
+    this.responses = [...responses];
+  }
+
+  async run(
+    command: TrustedShellCommand,
+    options?: ShellProbeRunOptions,
+  ): Promise<ShellProbeResult> {
+    this.calls.push({ command: command.command, args: [...command.args], options });
+    return this.responses.shift() ?? shellResult();
+  }
+}
 
 function sandboxWithInspectionState(state: string): SandboxClient {
   return new SandboxClient({
@@ -48,3 +95,55 @@ describe("Hermes MCP live rollback inspection", () => {
     });
   });
 });
+
+describe("Hermes MCP post-rebuild maintenance", () => {
+  it("opens a fresh Shields-down timer before the final config mutation", async () => {
+    const runner = new RecordingRunner();
+    const host = new HostCliClient(runner, { cliPath: "nemoclaw" });
+
+    await reopenHermesMcpMaintenanceWindow(host, "hermes-e2e");
+
+    expect(runner.calls).toEqual([
+      expect.objectContaining({
+        command: "nemoclaw",
+        args: ["hermes-e2e", "shields", "up"],
+        options: expect.objectContaining({
+          artifactName: "hermes-mcp-shields-up-before-post-rebuild-remove",
+          timeoutMs: 3 * 60_000,
+        }),
+      }),
+      expect.objectContaining({
+        command: "nemoclaw",
+        args: [
+          "hermes-e2e",
+          "shields",
+          "down",
+          "--timeout",
+          "15m",
+          "--reason",
+          "Post-rebuild MCP removal E2E",
+        ],
+        options: expect.objectContaining({
+          artifactName: "hermes-mcp-shields-down-before-post-rebuild-remove",
+          timeoutMs: 3 * 60_000,
+        }),
+      }),
+    ]);
+  });
+
+  it("keeps Shields up when posture normalization fails", async () => {
+    const runner = new RecordingRunner([shellResult(1)]);
+    const host = new HostCliClient(runner, { cliPath: "nemoclaw" });
+
+    await expect(reopenHermesMcpMaintenanceWindow(host, "hermes-e2e")).rejects.toThrow(
+      "normalize Hermes shields before post-rebuild MCP removal failed: exit=1",
+    );
+
+    expect(runner.calls).toEqual([
+      expect.objectContaining({
+        command: "nemoclaw",
+        args: ["hermes-e2e", "shields", "up"],
+      }),
+    ]);
+  });
+});