diff --git a/homeassistant/components/backup/websocket.py b/homeassistant/components/backup/websocket.py
index 04b16bad304..375ee4c04ee 100644
--- a/homeassistant/components/backup/websocket.py
+++ b/homeassistant/components/backup/websocket.py
@@ -226,7 +226,7 @@ async def backup_agents_info(
     connection.send_result(
         msg["id"],
         {
-            "agents": [{"id": agent_id} for agent_id in manager.backup_agents],
+            "agents": [{"agent_id": agent_id} for agent_id in manager.backup_agents],
             "syncing": manager.syncing,
         },
     )
@@ -254,7 +254,7 @@ async def backup_agents_list_backups(
 @websocket_api.websocket_command(
     {
         vol.Required("type"): "backup/agents/download",
-        vol.Required("agent"): str,
+        vol.Required("agent_id"): str,
         vol.Required("backup_id"): str,
         vol.Required("slug"): str,
     }
@@ -269,9 +269,9 @@ async def backup_agents_download(
     manager = hass.data[DATA_MANAGER]
     await manager.load_platforms()
 
-    if not (agent := manager.backup_agents.get(msg["agent"])):
+    if not (agent := manager.backup_agents.get(msg["agent_id"])):
         connection.send_error(
-            msg["id"], "unknown_agent", f"Agent {msg['agent']} not found"
+            msg["id"], "unknown_agent", f"Agent {msg['agent_id']} not found"
         )
         return
     try:
diff --git a/tests/components/backup/snapshots/test_websocket.ambr b/tests/components/backup/snapshots/test_websocket.ambr
index 427748083a2..2dc35469778 100644
--- a/tests/components/backup/snapshots/test_websocket.ambr
+++ b/tests/components/backup/snapshots/test_websocket.ambr
@@ -43,7 +43,7 @@
     'result': dict({
       'agents': list([
         dict({
-          'id': 'domain.test',
+          'agent_id': 'domain.test',
         }),
       ]),
       'syncing': False,
@@ -58,7 +58,7 @@
     'result': dict({
       'agents': list([
         dict({
-          'id': 'domain.test',
+          'agent_id': 'domain.test',
         }),
       ]),
       'syncing': False,
diff --git a/tests/components/backup/test_websocket.py b/tests/components/backup/test_websocket.py
index 265de55f855..5fee1870c10 100644
--- a/tests/components/backup/test_websocket.py
+++ b/tests/components/backup/test_websocket.py
@@ -506,7 +506,7 @@ async def test_agents_download(
         {
             "type": "backup/agents/download",
             "slug": "abc123",
-            "agent": "domain.test",
+            "agent_id": "domain.test",
             "backup_id": "abc123",
         }
     )
@@ -534,7 +534,7 @@ async def test_agents_download_exception(
         {
             "type": "backup/agents/download",
             "slug": "abc123",
-            "agent": "domain.test",
+            "agent_id": "domain.test",
             "backup_id": "abc123",
         }
     )
@@ -558,7 +558,7 @@ async def test_agents_download_unknown_agent(
         {
             "type": "backup/agents/download",
             "slug": "abc123",
-            "agent": "domain.test",
+            "agent_id": "domain.test",
             "backup_id": "abc123",
         }
     )