diff --git a/apps/worker/src/run-task/__tests__/run-task.test.ts b/apps/worker/src/run-task/__tests__/run-task.test.ts
index 76e42d9bf..38a25333f 100644
--- a/apps/worker/src/run-task/__tests__/run-task.test.ts
+++ b/apps/worker/src/run-task/__tests__/run-task.test.ts
@@ -23,6 +23,7 @@ const {
   drainSlackMessagesMock,
   existsSyncMock,
   getDecryptedKeyMock,
+  getCustomStdioMcpServersMock,
   getMcpServerConfigsMock,
   harnessManagerInstances,
   hasActiveInstallationMock,
@@ -87,6 +88,7 @@ const {
     .mockResolvedValue({ resumed: false, reason: 'no_pending_messages' }),
   existsSyncMock: vi.fn(),
   getDecryptedKeyMock: vi.fn().mockResolvedValue(undefined),
+  getCustomStdioMcpServersMock: vi.fn().mockResolvedValue({ servers: {} }),
   getMcpServerConfigsMock: vi.fn().mockResolvedValue({ servers: {} }),
   harnessManagerInstances: [] as FakeHarnessManager[],
   hasActiveInstallationMock: vi.fn().mockResolvedValue(false),
@@ -183,6 +185,7 @@ vi.mock('@roomote/sdk/client', () => ({
       hasActiveInstallation: hasActiveInstallationMock,
     },
     mcpConnections: {
+      getCustomStdioMcpServers: getCustomStdioMcpServersMock,
       getMcpServerConfigs: getMcpServerConfigsMock,
       isOrgEnabled: isOrgEnabledMock,
     },
@@ -1691,6 +1694,63 @@ describe('runTask', () => {
     );
   });
 
+  it.each([
+    ['user MCP', getMcpServerConfigsMock],
+    ['custom stdio MCP', getCustomStdioMcpServersMock],
+  ])(
+    'warns the agent when %s configuration cannot be loaded',
+    async (_, fetchMock) => {
+      fetchMock.mockRejectedValueOnce(
+        new Error('integration service unavailable'),
+      );
+
+      await runTask({
+        taskRun: {
+          id: 107,
+          taskId: 'task-107',
+          payloadKind: TaskPayloadKind.StandardTask,
+          harness: 'opencode-server',
+          payload: {},
+          result: null,
+        } as never,
+        envVars: {},
+        workspacePath: '/tmp/workspace',
+        prompt: '',
+        harnessInstructions: undefined,
+        agentInstructions: undefined,
+        environmentConfig: undefined,
+        callbacks: {},
+        context: {},
+        logger: {
+          info: vi.fn(),
+          warn: vi.fn(),
+          error: vi.fn(),
+          log: vi.fn(),
+        } as never,
+        harnessSessionId: undefined,
+        workerEnv: {
+          authToken: 'cloud-token',
+          roomoteAppUrl: 'https://api.example.test',
+          trpcUrl: 'https://web.example.test',
+          buildUserFacingEnv: vi.fn(() => ({
+            HOME: '/tmp/home',
+            PATH: '/usr/bin',
+          })),
+        } as never,
+      });
+
+      expect(createHarnessMock).toHaveBeenCalledTimes(1);
+      const developerInstructionsContent = createHarnessMock.mock.calls[0]?.[0]
+        .developerInstructionsContent as string;
+      expect(developerInstructionsContent).toContain(
+        'Do not conclude that a missing integration or tool is unconfigured.',
+      );
+      expect(developerInstructionsContent).not.toContain(
+        'integration service unavailable',
+      );
+    },
+  );
+
   it('passes the proof browser target to the harness when the environment exposes a browser surface', async () => {
     await runTask({
       taskRun: {
diff --git a/apps/worker/src/run-task/run-task.ts b/apps/worker/src/run-task/run-task.ts
index 36c50b891..c50fa804a 100644
--- a/apps/worker/src/run-task/run-task.ts
+++ b/apps/worker/src/run-task/run-task.ts
@@ -937,6 +937,7 @@ export const runTask = async ({
     // Fetch integration MCP availability. This is best-effort: failures are
     // logged but never block task execution.
     const integrations: IntegrationMcpOptions = {};
+    let mcpConfigurationLoadFailed = false;
 
     try {
       const { servers } = await sdk.mcpConnections.getMcpServerConfigs();
@@ -948,6 +949,7 @@ export const runTask = async ({
       logger.warn(
         `[runTask] Failed to fetch user MCP server configs: ${error instanceof Error ? error.message : String(error)}`,
       );
+      mcpConfigurationLoadFailed = true;
     }
 
     // Deployment-scoped custom stdio MCP servers. Same best-effort posture:
@@ -969,6 +971,7 @@ export const runTask = async ({
       logger.warn(
         `[runTask] Failed to fetch custom stdio MCP server configs: ${error instanceof Error ? error.message : String(error)}`,
       );
+      mcpConfigurationLoadFailed = true;
     }
 
     const slackReplyContext = getSlackReplyContext(taskRun);
@@ -1050,6 +1053,9 @@ export const runTask = async ({
         ),
         harnessInstructions,
         environmentInstructions,
+        mcpConfigurationLoadFailed
+          ? `# Integration availability\n\nRoomote could not load the configured MCP integrations for this task. Do not conclude that a missing integration or tool is unconfigured. Tell the user that integration availability could not be verified for this task, and suggest retrying or asking a deployment admin to check Settings > Integrations.`
+          : undefined,
       ]
         .filter((value): value is string => Boolean(value))
         .join('\n\n') || undefined;