diff --git a/src/commands/schedule.test.ts b/src/commands/schedule.test.ts
index 976a143d..1c70e054 100644
--- a/src/commands/schedule.test.ts
+++ b/src/commands/schedule.test.ts
@@ -3,7 +3,7 @@ import { tmpdir } from 'node:os';
 import { join } from 'node:path';
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 import { ApiError } from '../lib/errors.js';
-import { type CliSchedule, createScheduleCommand, runGet, runList } from './schedule.js';
+import { type CliSchedule, createScheduleCommand, runGet, runList, runUpdate } from './schedule.js';
 
 const SCHEDULE_FIXTURE: CliSchedule = {
   scheduleId: 'sch_b3c91efa',
@@ -427,3 +427,27 @@ describe('runGet', () => {
     ).rejects.toBeInstanceOf(ApiError);
   });
 });
+
+describe('runUpdate --name validation', () => {
+  it('rejects an empty --name instead of sending it to the server', async () => {
+    const fetchImpl = vi.fn();
+    await expect(
+      runUpdate(
+        { ...BASE, output: 'json', scheduleId: 'sch_1', name: '' },
+        { fetchImpl: fetchImpl as unknown as typeof globalThis.fetch, stdout: () => {}, stderr: () => {} },
+      ),
+    ).rejects.toMatchObject({ code: 'VALIDATION_ERROR', exitCode: 5 });
+    expect(fetchImpl).not.toHaveBeenCalled();
+  });
+
+  it('rejects a whitespace-only --name', async () => {
+    const fetchImpl = vi.fn();
+    const err = await runUpdate(
+      { ...BASE, output: 'json', scheduleId: 'sch_1', name: '   ' },
+      { fetchImpl: fetchImpl as unknown as typeof globalThis.fetch, stdout: () => {}, stderr: () => {} },
+    ).catch((caught: unknown) => caught);
+    expect(err).toMatchObject({ code: 'VALIDATION_ERROR', exitCode: 5 });
+    expect((err as { nextAction: string }).nextAction).toContain('--name must not be empty');
+    expect(fetchImpl).not.toHaveBeenCalled();
+  });
+});
diff --git a/src/commands/schedule.ts b/src/commands/schedule.ts
index 65b15093..60b5f646 100644
--- a/src/commands/schedule.ts
+++ b/src/commands/schedule.ts
@@ -395,6 +395,10 @@ export async function runUpdate(
   }
   const environment = normalizeScheduleEnvironmentName(opts.env);
 
+  if (opts.name !== undefined && opts.name.trim().length === 0) {
+    throw localValidationError('--name must not be empty');
+  }
+
   const body: UpdateScheduleRequest = {
     ...(opts.name !== undefined ? { name: opts.name } : {}),
     ...(environment !== undefined ? { environment } : {}),