diff --git a/packages/platform-apple/src/readiness/runtime.test.ts b/packages/platform-apple/src/readiness/runtime.test.ts
index 44b87cab42..162d0ae3f4 100644
--- a/packages/platform-apple/src/readiness/runtime.test.ts
+++ b/packages/platform-apple/src/readiness/runtime.test.ts
@@ -196,11 +196,17 @@ test('a boot confirmed only after the deadline is a boot_timeout, and the confir
 });
 
 test('without a startup deadline the boot wait keeps its default budget', async () => {
-  const { host, calls } = coldSimulatorHost({});
+  vi.useFakeTimers();
+  try {
+    vi.setSystemTime(1_000_000);
+    const { host, calls } = coldSimulatorHost({});
 
-  await ensureAppleReady(host, simulator(), new AbortController().signal);
+    await ensureAppleReady(host, simulator(), new AbortController().signal);
 
-  expect(calls.find((call) => call.args.includes('bootstatus'))?.timeoutMs).toBe(120_000);
+    expect(calls.find((call) => call.args.includes('bootstatus'))?.timeoutMs).toBe(120_000);
+  } finally {
+    vi.useRealTimers();
+  }
 });
 
 test('physical readiness forwards the request signal to the focused host port', async () => {
diff --git a/scripts/check-affected/checks.ts b/scripts/check-affected/checks.ts
index a68e03a8f3..9e681cae39 100644
--- a/scripts/check-affected/checks.ts
+++ b/scripts/check-affected/checks.ts
@@ -10,7 +10,6 @@
 // agent reads before skipping a check locally cannot go stale.
 
 import { ALL_CHECKS, type CheckId } from './model.ts';
-import { DEFAULT_VITEST_MAX_WORKERS } from '../lib/vitest-concurrency.ts';
 
 export type CheckKind =
   | { readonly type: 'script'; readonly script: string }
@@ -183,16 +182,7 @@ export function resolveCommand(
   changedFiles: readonly string[] = [],
 ): string[] {
   if (spec.kind.type === 'vitest-related') {
-    return [
-      'pnpm',
-      'exec',
-      'vitest',
-      'related',
-      '--run',
-      '--passWithNoTests',
-      `--maxWorkers=${DEFAULT_VITEST_MAX_WORKERS}`,
-      ...changedFiles,
-    ];
+    return ['pnpm', 'exec', 'vitest', 'related', '--run', '--passWithNoTests', ...changedFiles];
   }
   const { script } = spec.kind;
   if (!(script in scripts)) {
diff --git a/scripts/check-affected/model.test.ts b/scripts/check-affected/model.test.ts
index 9ab6d81f36..4fd46c2c12 100644
--- a/scripts/check-affected/model.test.ts
+++ b/scripts/check-affected/model.test.ts
@@ -4,7 +4,6 @@ import path from 'node:path';
 import { test } from 'node:test';
 import { fileURLToPath } from 'node:url';
 import { assertCatalogComplete, CHECK_CATALOG, resolveCommand } from './checks.ts';
-import { DEFAULT_VITEST_MAX_WORKERS } from '../lib/vitest-concurrency.ts';
 import { ALL_CHECKS, selectChecks, type CheckId, type SelectInput } from './model.ts';
 
 function plan(changedFiles: string[], extra: Partial<SelectInput> = {}) {
@@ -347,10 +346,16 @@ test('vitest-related delegates changed paths to Vitest instead of modeling proje
     'related',
     '--run',
     '--passWithNoTests',
-    `--maxWorkers=${DEFAULT_VITEST_MAX_WORKERS}`,
     'src/a.ts',
     'test/fixture.ts',
   ]);
+  assert.equal(
+    resolveCommand(related, {}, 'origin/main', ['src/a.ts']).some((arg) =>
+      arg.startsWith('--maxWorkers='),
+    ),
+    false,
+    'worker sizing belongs to vitest.config.ts',
+  );
 });
 
 // Guards the catalog against reality, not fixtures: the self-test above uses a
diff --git a/scripts/check-affected/run.test.ts b/scripts/check-affected/run.test.ts
index 52de0069f0..97863e798a 100644
--- a/scripts/check-affected/run.test.ts
+++ b/scripts/check-affected/run.test.ts
@@ -11,7 +11,6 @@ import { test } from 'node:test';
 import { runCmdSync } from '@agent-device/host-kit/command';
 import { STALE_NODE_MODULES_MESSAGE } from './lockfile-install-sync.ts';
 import { CHECK_CATALOG } from './checks.ts';
-import { DEFAULT_VITEST_MAX_WORKERS } from '../lib/vitest-concurrency.ts';
 import { selectChecks } from './model.ts';
 import { type CommandExecutor, readChangedFiles, runChecks } from './run.ts';
 
@@ -161,16 +160,7 @@ test('runChecks passes the selector change set to Vitest related', async () => {
   assert.equal(code, 0);
   assert.deepEqual(
     executed.find((command) => command.includes('related')),
-    [
-      'pnpm',
-      'exec',
-      'vitest',
-      'related',
-      '--run',
-      '--passWithNoTests',
-      `--maxWorkers=${DEFAULT_VITEST_MAX_WORKERS}`,
-      ...changedFiles,
-    ],
+    ['pnpm', 'exec', 'vitest', 'related', '--run', '--passWithNoTests', ...changedFiles],
   );
 });
 
@@ -205,7 +195,7 @@ test('runChecks skips GitHub-authoritative checks and passes when locals succeed
   }
 });
 
-test('runChecks leaves coverage to CI and runs capped related tests once', async () => {
+test('runChecks leaves coverage to CI and runs related tests once through Vitest config', async () => {
   const executed: string[][] = [];
   const execute: CommandExecutor = async (command) => {
     executed.push(command);
@@ -222,7 +212,11 @@ test('runChecks leaves coverage to CI and runs capped related tests once', async
     !related[0]?.includes('--coverage'),
     'coverage instrumentation stays GitHub-authoritative; the local run must not add it',
   );
-  assert.ok(related[0]?.includes(`--maxWorkers=${DEFAULT_VITEST_MAX_WORKERS}`));
+  assert.equal(
+    related[0]?.some((arg) => arg.startsWith('--maxWorkers=')),
+    false,
+    'worker sizing belongs to vitest.config.ts',
+  );
   assert.ok(
     executed.findIndex((command) => command.includes('test:integration:node')) <
       executed.findIndex((command) => command.includes('related')),