fix(core): reject blank cron prompts

packages/core/src/tools/cron-create.test.ts

@@ -99,6 +99,30 @@ describe('CronCreateTool', () => {
     expect(tasks).toHaveLength(0);
   });
 
+  it.each(['', '   '])('rejects blank prompt %j', (prompt) => {
+    expect(() =>
+      tool.build({
+        cron: '*/5 * * * *',
+        prompt,
+      }),
+    ).toThrow('Parameter "prompt" must be a non-empty string.');
+    expect(config._scheduler.list()).toHaveLength(0);
+  });
+
+  it('trims the prompt before scheduling the job', async () => {
+    const invocation = tool.build({
+      cron: '*/5 * * * *',
+      prompt: '  check status  ',
+    });
+
+    const result = await invocation.execute(new AbortController().signal);
+
+    expect(result.error).toBeUndefined();
+    const jobs = config._scheduler.list();
+    expect(jobs).toHaveLength(1);
+    expect(jobs[0]!.prompt).toBe('check status');
+  });
+
   it('returns error for invalid cron expression', async () => {
     const invocation = tool.build({
       cron: 'bad cron',

packages/core/src/tools/cron-create.ts

@@ -49,6 +49,7 @@ class CronCreateInvocation extends BaseToolInvocation<
     const scheduler = this.config.getCronScheduler();
     const recurring = this.params.recurring !== false;
     const durable = this.params.durable === true;
+    const prompt = this.params.prompt.trim();
 
     try {
       // Validate cron expression before creating the job
@@ -59,12 +60,8 @@ class CronCreateInvocation extends BaseToolInvocation<
       nextFireTime(this.params.cron, new Date());
 
       const job = durable
-        ? await scheduler.createDurable(
-            this.params.cron,
-            this.params.prompt,
-            recurring,
-          )
-        : scheduler.create(this.params.cron, this.params.prompt, recurring);
+        ? await scheduler.createDurable(this.params.cron, prompt, recurring)
+        : scheduler.create(this.params.cron, prompt, recurring);
 
       const display = humanReadableCron(job.cronExpr);
       const returnDisplay = `Scheduled ${job.id} (${display})${durable ? ' [durable]' : ''}`;
@@ -165,6 +162,15 @@ export class CronCreateTool extends BaseDeclarativeTool<
     return new CronCreateInvocation(this.config, params);
   }
 
+  protected override validateToolParamValues(
+    params: CronCreateParams,
+  ): string | null {
+    if (!params.prompt || params.prompt.trim() === '') {
+      return 'Parameter "prompt" must be a non-empty string.';
+    }
+    return null;
+  }
+
   /**
    * Forward the prompt and cadence to the classifier. The scheduled
    * prompt will be enqueued and executed against the agent at fire-time,