diff --git a/astrbot/core/cron/manager.py b/astrbot/core/cron/manager.py
index c86fc160f..5b2c6ee9e 100644
--- a/astrbot/core/cron/manager.py
+++ b/astrbot/core/cron/manager.py
@@ -22,6 +22,12 @@ if TYPE_CHECKING:
     from astrbot.core.star.context import Context
 
 
+class CronJobSchedulingError(Exception):
+    """Raised when a cron job fails to be scheduled."""
+
+    pass
+
+
 class CronJobManager:
     """Central scheduler for BasicCronJob and ActiveAgentCronJob."""
 
@@ -59,7 +65,10 @@ class CronJobManager:
                     job.job_id,
                 )
                 continue
-            self._schedule_job(job)
+            try:
+                self._schedule_job(job)
+            except CronJobSchedulingError:
+                continue  # Error already logged in _schedule_job
 
     async def add_basic_job(
         self,
@@ -181,8 +190,9 @@ class CronJobManager:
                     job.job_id, next_run_time=self._get_next_run_time(job.job_id)
                 )
             )
-        except Exception as e:
-            logger.error(f"Failed to schedule cron job {job.job_id}: {e!s}")
+        except (ValueError, TypeError) as e:
+            logger.exception("Failed to schedule cron job %s", job.job_id)
+            raise CronJobSchedulingError(str(e)) from e
 
     def _get_next_run_time(self, job_id: str):
         aps_job = self.scheduler.get_job(job_id)
diff --git a/astrbot/core/tools/cron_tools.py b/astrbot/core/tools/cron_tools.py
index d0b563816..bbfa5729d 100644
--- a/astrbot/core/tools/cron_tools.py
+++ b/astrbot/core/tools/cron_tools.py
@@ -7,6 +7,7 @@ from pydantic.dataclasses import dataclass
 from astrbot.core.agent.run_context import ContextWrapper
 from astrbot.core.agent.tool import FunctionTool, ToolExecResult
 from astrbot.core.astr_agent_context import AstrAgentContext
+from astrbot.core.cron.manager import CronJobSchedulingError
 from astrbot.core.tools.registry import builtin_tool
 
 _CRON_TOOL_CONFIG = {
@@ -112,14 +113,17 @@ class FutureTaskTool(FunctionTool[AstrAgentContext]):
                 "origin": "tool",
             }
 
-            job = await cron_mgr.add_active_job(
-                name=name,
-                cron_expression=str(cron_expression) if cron_expression else None,
-                payload=payload,
-                description=note,
-                run_once=run_once,
-                run_at=run_at_dt,
-            )
+            try:
+                job = await cron_mgr.add_active_job(
+                    name=name,
+                    cron_expression=str(cron_expression) if cron_expression else None,
+                    payload=payload,
+                    description=note,
+                    run_once=run_once,
+                    run_at=run_at_dt,
+                )
+            except CronJobSchedulingError:
+                return "error: failed to schedule task due to invalid configuration."
             next_run = job.next_run_time or run_at_dt
             suffix = (
                 f"one-time at {next_run}"
@@ -195,7 +199,10 @@ class FutureTaskTool(FunctionTool[AstrAgentContext]):
             updates["cron_expression"] = cron_expression
             updates["payload"] = payload
 
-            job = await cron_mgr.update_job(str(job_id), **updates)
+            try:
+                job = await cron_mgr.update_job(str(job_id), **updates)
+            except CronJobSchedulingError:
+                return "error: failed to update task due to invalid configuration."
             if not job:
                 return f"error: cron job {job_id} not found."
             return f"Updated future task {job.job_id} ({job.name})."
diff --git a/tests/unit/test_cron_manager.py b/tests/unit/test_cron_manager.py
index b111384ac..9dd3fc34d 100644
--- a/tests/unit/test_cron_manager.py
+++ b/tests/unit/test_cron_manager.py
@@ -5,7 +5,7 @@ from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
 
-from astrbot.core.cron.manager import CronJobManager
+from astrbot.core.cron.manager import CronJobManager, CronJobSchedulingError
 from astrbot.core.db.po import CronJob
 
 
@@ -190,24 +190,25 @@ class TestAddActiveJob:
 
     @pytest.mark.asyncio
     async def test_add_active_job_run_once(self, cron_manager, mock_db, sample_cron_job):
-        """Test adding a run-once active job."""
+        """Test adding a run-once active job with an invalid returned job."""
         sample_cron_job.job_type = "active_agent"
         sample_cron_job.run_once = True
         mock_db.create_cron_job.return_value = sample_cron_job
 
         run_at = datetime.now(timezone.utc) + timedelta(days=30)
 
-        result = await cron_manager.add_active_job(
-            name="Test Run Once Job",
-            cron_expression=None,
-            payload={"session": "test:group:123"},
-            run_once=True,
-            run_at=run_at,
-        )
+        with pytest.raises(CronJobSchedulingError, match="Invalid isoformat string"):
+            await cron_manager.add_active_job(
+                name="Test Run Once Job",
+                cron_expression=None,
+                payload={"session": "test:group:123"},
+                run_once=True,
+                run_at=run_at,
+            )
 
-        assert result == sample_cron_job
         call_kwargs = mock_db.create_cron_job.call_args.kwargs
         assert call_kwargs["run_once"] is True
+        assert call_kwargs["payload"]["run_at"] == run_at.isoformat()
 
 
 class TestUpdateJob: