fix: improve robustness of `gemini mcp add` command (#6332)

packages/cli/src/commands/mcp/add.test.ts

@@ -85,4 +85,38 @@ describe('mcp add command', () => {
       },
     );
   });
+
+  it('should handle MCP server args with -- separator', async () => {
+    await parser.parseAsync(
+      'add my-server npx -- -y http://example.com/some-package',
+    );
+
+    expect(mockSetValue).toHaveBeenCalledWith(
+      SettingScope.Workspace,
+      'mcpServers',
+      {
+        'my-server': {
+          command: 'npx',
+          args: ['-y', 'http://example.com/some-package'],
+        },
+      },
+    );
+  });
+
+  it('should handle unknown options as MCP server args', async () => {
+    await parser.parseAsync(
+      'add test-server npx -y http://example.com/some-package',
+    );
+
+    expect(mockSetValue).toHaveBeenCalledWith(
+      SettingScope.Workspace,
+      'mcpServers',
+      {
+        'test-server': {
+          command: 'npx',
+          args: ['-y', 'http://example.com/some-package'],
+        },
+      },
+    );
+  });
 });

packages/cli/src/commands/mcp/add.ts

@@ -130,6 +130,10 @@ export const addCommand: CommandModule = {
   builder: (yargs) =>
     yargs
       .usage('Usage: gemini mcp add [options] <name> <commandOrUrl> [args...]')
+      .parserConfiguration({
+        'unknown-options-as-args': true, // Pass unknown options as server args
+        'populate--': true, // Populate server args after -- separator
+      })
       .positional('name', {
         describe: 'Name of the server',
         type: 'string',
@@ -189,6 +193,13 @@ export const addCommand: CommandModule = {
         describe: 'A comma-separated list of tools to exclude',
         type: 'array',
         string: true,
+      })
+      .middleware((argv) => {
+        // Handle -- separator args as server args if present
+        if (argv['--']) {
+          const existingArgs = (argv.args as Array<string | number>) || [];
+          argv.args = [...existingArgs, ...(argv['--'] as string[])];
+        }
       }),
   handler: async (argv) => {
     await addMcpServer(