diff --git a/src/langbot/pkg/platform/sources/wecom.py b/src/langbot/pkg/platform/sources/wecom.py
index 93aaf1f92..d555599af 100644
--- a/src/langbot/pkg/platform/sources/wecom.py
+++ b/src/langbot/pkg/platform/sources/wecom.py
@@ -274,11 +274,11 @@ class WecomAdapter(abstract_platform_adapter.AbstractMessagePlatformAdapter):
                 if content['type'] == 'text':
                     await self.bot.send_private_msg(user_id, agent_id, content['content'])
                 if content['type'] == 'image':
-                    await self.bot.send_image(user_id, agent_id, content['media'])
+                    await self.bot.send_image(user_id, agent_id, content['media_id'])
                 if content['type'] == 'voice':
-                    await self.bot.send_voice(user_id, agent_id, content['media'])
+                    await self.bot.send_voice(user_id, agent_id, content['media_id'])
                 if content['type'] == 'file':
-                    await self.bot.send_file(user_id, agent_id, content['media'])
+                    await self.bot.send_file(user_id, agent_id, content['media_id'])
 
     def register_listener(
         self,
diff --git a/tests/unit_tests/platform/test_wecom_send_message.py b/tests/unit_tests/platform/test_wecom_send_message.py
new file mode 100644
index 000000000..20c9e6976
--- /dev/null
+++ b/tests/unit_tests/platform/test_wecom_send_message.py
@@ -0,0 +1,59 @@
+"""Tests for WecomAdapter.send_message content-key handling."""
+
+import pytest
+
+import langbot_plugin.api.entities.builtin.platform.message as platform_message
+from langbot.pkg.platform.sources.wecom import WecomAdapter
+
+
+class StubWecomClient:
+    def __init__(self):
+        self.calls = []
+
+    async def get_media_id(self, msg):
+        return 'MEDIA_ID_123'
+
+    async def send_private_msg(self, user_id, agent_id, text):
+        self.calls.append(('text', user_id, agent_id, text))
+
+    async def send_image(self, user_id, agent_id, media_id):
+        self.calls.append(('image', user_id, agent_id, media_id))
+
+    async def send_voice(self, user_id, agent_id, media_id):
+        self.calls.append(('voice', user_id, agent_id, media_id))
+
+    async def send_file(self, user_id, agent_id, media_id):
+        self.calls.append(('file', user_id, agent_id, media_id))
+
+
+def _make_adapter():
+    adapter = WecomAdapter.model_construct(bot=StubWecomClient())
+    return adapter
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    ('part', 'expected_type'),
+    [
+        (platform_message.Image(url='https://example.com/x.jpg'), 'image'),
+        (platform_message.Voice(url='https://example.com/x.amr'), 'voice'),
+        (platform_message.File(url='https://example.com/x.pdf', name='x.pdf'), 'file'),
+    ],
+)
+async def test_send_message_dispatches_media_by_id(part, expected_type):
+    adapter = _make_adapter()
+    chain = platform_message.MessageChain([part])
+
+    await adapter.send_message('person', 'USER1|1000001', chain)
+
+    assert adapter.bot.calls == [(expected_type, 'USER1', 1000001, 'MEDIA_ID_123')]
+
+
+@pytest.mark.asyncio
+async def test_send_message_text_still_works():
+    adapter = _make_adapter()
+    chain = platform_message.MessageChain([platform_message.Plain(text='hello')])
+
+    await adapter.send_message('person', 'USER1|1000001', chain)
+
+    assert adapter.bot.calls == [('text', 'USER1', 1000001, 'hello')]