diff --git a/nanobot/agent/loop.py b/nanobot/agent/loop.py
index 0ae4e23de..afe62ca28 100644
--- a/nanobot/agent/loop.py
+++ b/nanobot/agent/loop.py
@@ -144,7 +144,9 @@ class AgentLoop:
         self.tools.register(MessageTool(send_callback=self.bus.publish_outbound))
         self.tools.register(SpawnTool(manager=self.subagents))
         if self.cron_service:
-            self.tools.register(CronTool(self.cron_service, default_timezone=timezone or "UTC"))
+            self.tools.register(
+                CronTool(self.cron_service, default_timezone=self.context.timezone or "UTC")
+            )
 
     async def _connect_mcp(self) -> None:
         """Connect to configured MCP servers (one-time, lazy)."""
diff --git a/tests/agent/test_loop_cron_timezone.py b/tests/agent/test_loop_cron_timezone.py
new file mode 100644
index 000000000..7738d3043
--- /dev/null
+++ b/tests/agent/test_loop_cron_timezone.py
@@ -0,0 +1,27 @@
+from pathlib import Path
+from unittest.mock import MagicMock
+
+from nanobot.agent.loop import AgentLoop
+from nanobot.agent.tools.cron import CronTool
+from nanobot.bus.queue import MessageBus
+from nanobot.cron.service import CronService
+
+
+def test_agent_loop_registers_cron_tool_with_configured_timezone(tmp_path: Path) -> None:
+    bus = MessageBus()
+    provider = MagicMock()
+    provider.get_default_model.return_value = "test-model"
+
+    loop = AgentLoop(
+        bus=bus,
+        provider=provider,
+        workspace=tmp_path,
+        model="test-model",
+        cron_service=CronService(tmp_path / "cron" / "jobs.json"),
+        timezone="Asia/Shanghai",
+    )
+
+    cron_tool = loop.tools.get("cron")
+
+    assert isinstance(cron_tool, CronTool)
+    assert cron_tool._default_timezone == "Asia/Shanghai"