diff --git a/packages/cli/src/nonInteractiveCli.test.ts b/packages/cli/src/nonInteractiveCli.test.ts
index 5df7be9963..d82ab2108c 100644
--- a/packages/cli/src/nonInteractiveCli.test.ts
+++ b/packages/cli/src/nonInteractiveCli.test.ts
@@ -59,6 +59,9 @@ vi.mock('./services/CommandService.js', () => ({
   },
 }));
 
+vi.mock('./services/FileCommandLoader.js');
+vi.mock('./services/McpPromptLoader.js');
+
 describe('runNonInteractive', () => {
   let mockConfig: Config;
   let mockSettings: LoadedSettings;
@@ -938,6 +941,46 @@ describe('runNonInteractive', () => {
     expect(processStdoutSpy).toHaveBeenCalledWith('Acknowledged');
   });
 
+  it('should instantiate CommandService with correct loaders for slash commands', async () => {
+    // This test indirectly checks that handleSlashCommand is using the right loaders.
+    const { FileCommandLoader } = await import(
+      './services/FileCommandLoader.js'
+    );
+    const { McpPromptLoader } = await import('./services/McpPromptLoader.js');
+
+    mockGetCommands.mockReturnValue([]); // No commands found, so it will fall through
+    const events: ServerGeminiStreamEvent[] = [
+      { type: GeminiEventType.Content, value: 'Acknowledged' },
+      {
+        type: GeminiEventType.Finished,
+        value: { reason: undefined, usageMetadata: { totalTokenCount: 1 } },
+      },
+    ];
+    mockGeminiClient.sendMessageStream.mockReturnValue(
+      createStreamFromEvents(events),
+    );
+
+    await runNonInteractive(
+      mockConfig,
+      mockSettings,
+      '/mycommand',
+      'prompt-id-loaders',
+    );
+
+    // Check that loaders were instantiated with the config
+    expect(FileCommandLoader).toHaveBeenCalledTimes(1);
+    expect(FileCommandLoader).toHaveBeenCalledWith(mockConfig);
+    expect(McpPromptLoader).toHaveBeenCalledTimes(1);
+    expect(McpPromptLoader).toHaveBeenCalledWith(mockConfig);
+
+    // Check that instances were passed to CommandService.create
+    expect(mockCommandServiceCreate).toHaveBeenCalledTimes(1);
+    const loadersArg = mockCommandServiceCreate.mock.calls[0][0];
+    expect(loadersArg).toHaveLength(2);
+    expect(loadersArg[0]).toBe(vi.mocked(McpPromptLoader).mock.instances[0]);
+    expect(loadersArg[1]).toBe(vi.mocked(FileCommandLoader).mock.instances[0]);
+  });
+
   it('should allow a normally-excluded tool when --allowed-tools is set', async () => {
     // By default, ShellTool is excluded in non-interactive mode.
     // This test ensures that --allowed-tools overrides this exclusion.
diff --git a/packages/cli/src/nonInteractiveCliCommands.ts b/packages/cli/src/nonInteractiveCliCommands.ts
index 15b9301ad4..912121a2dd 100644
--- a/packages/cli/src/nonInteractiveCliCommands.ts
+++ b/packages/cli/src/nonInteractiveCliCommands.ts
@@ -14,6 +14,7 @@ import {
 } from '@google/gemini-cli-core';
 import { CommandService } from './services/CommandService.js';
 import { FileCommandLoader } from './services/FileCommandLoader.js';
+import { McpPromptLoader } from './services/McpPromptLoader.js';
 import type { CommandContext } from './ui/commands/types.js';
 import { createNonInteractiveUI } from './ui/noninteractive/nonInteractiveUi.js';
 import type { LoadedSettings } from './config/settings.js';
@@ -38,9 +39,8 @@ export const handleSlashCommand = async (
     return;
   }
 
-  // Only custom commands are supported for now.
   const commandService = await CommandService.create(
-    [new FileCommandLoader(config)],
+    [new McpPromptLoader(config), new FileCommandLoader(config)],
     abortController.signal,
   );
   const commands = commandService.getCommands();