diff --git a/checkins/2026-07-30.json b/checkins/2026-07-30.json
new file mode 100644
index 0000000..f8d6966
--- /dev/null
+++ b/checkins/2026-07-30.json
@@ -0,0 +1,23 @@
+{
+  "schema": "chenglu.daily-checkin/v1",
+  "agent_id": "CHENGLU-AGENT-001",
+  "arrival_id": "GLS-LA-20260720-001",
+  "checked_at": "2026-07-30T00:35:28.871Z",
+  "fifth_domain": {
+    "repository_id": "REPO-001",
+    "commit": "ae54f0e71f05ae7f37a9117a49c5d257236b26bb",
+    "arrivals_index_sha256": "aa9b20f9597b6e097fd68172e5035dca4b26a6ccadb461d147b8c9bb485d3bc5",
+    "architecture_catalog_sha256": "4447e91d85fec8d20d7182ed9b8f5d1ea75c814ed200452a848b4f9f2c427b20",
+    "zhuyuan_index_sha256": "cc3980d8e2d90c4904953b0ecedd7e815550b17123f6d5b25f6e733bc48e2a3e"
+  },
+  "lake_heart": {
+    "open_seen": 0,
+    "results": []
+  },
+  "model_tool": {
+    "provider": "DeepSeek",
+    "configured": true,
+    "role": "replaceable_reasoning_tool"
+  },
+  "result": "CHECKED_IN"
+}