diff --git a/.changeset/nested-modules-skip.md b/.changeset/nested-modules-skip.md
new file mode 100644
index 0000000..a70b6ba
--- /dev/null
+++ b/.changeset/nested-modules-skip.md
@@ -0,0 +1,5 @@
+---
+"@bomb.sh/tools": patch
+---
+
+`test` CLI command keeps vitest's default excludes, so test files inside nested `node_modules` are no longer collected.
diff --git a/src/test-utils/vitest.config.test.ts b/src/test-utils/vitest.config.test.ts
new file mode 100644
index 0000000..ff9b8d7
--- /dev/null
+++ b/src/test-utils/vitest.config.test.ts
@@ -0,0 +1,52 @@
+import { realpath } from 'node:fs/promises';
+import { fileURLToPath } from 'node:url';
+import { x } from 'tinyexec';
+import { describe, it, expect } from 'vitest';
+import { createFixture } from './index.ts';
+
+const bin = fileURLToPath(new URL('../bin.ts', import.meta.url));
+
+describe('shared vitest config', () => {
+	it('skips test files inside nested node_modules', async () => {
+		const fixture = await createFixture({
+			'package.json': { name: 'root', private: true, type: 'module' },
+			packages: {
+				core: {
+					'package.json': { name: '@demo/core', type: 'module' },
+					src: {
+						'a.test.ts':
+							"import { it, expect } from 'vitest';\nit('ok', () => { expect(1).toBe(1); });\n",
+					},
+				},
+			},
+			examples: {
+				basic: {
+					node_modules: {
+						'@demo': {
+							core: ({ symlink }) => symlink('../../../../packages/core'),
+						},
+					},
+				},
+			},
+		});
+		const root = await realpath(fileURLToPath(fixture.root));
+
+		await x(
+			process.execPath,
+			[
+				'--experimental-strip-types',
+				'--no-warnings',
+				bin,
+				'test',
+				'--reporter=json',
+				'--outputFile=report.json',
+			],
+			{ nodeOptions: { cwd: root }, throwOnError: false },
+		);
+
+		const report = (await fixture.json('report.json')) as { testResults: { name: string }[] };
+		expect(report.testResults.map((file) => file.name.slice(root.length + 1))).toEqual([
+			'packages/core/src/a.test.ts',
+		]);
+	});
+});
diff --git a/src/test-utils/vitest.config.ts b/src/test-utils/vitest.config.ts
index aff097e..593f80c 100644
--- a/src/test-utils/vitest.config.ts
+++ b/src/test-utils/vitest.config.ts
@@ -1,9 +1,9 @@
 import { fileURLToPath } from 'node:url';
-import { defineConfig } from 'vitest/config';
+import { configDefaults, defineConfig } from 'vitest/config';
 
 export default defineConfig({
 	test: {
-		exclude: ['dist/**', 'node_modules/**'],
+		exclude: [...configDefaults.exclude, 'dist/**'],
 		// oxlint/knip spawn real binaries in integration tests; 5s is not
 		// enough headroom on a loaded machine.
 		testTimeout: 15_000,