diff --git a/chelation_logger.py b/chelation_logger.py
index e71fd19..f1cb855 100644
--- a/chelation_logger.py
+++ b/chelation_logger.py
@@ -57,11 +57,11 @@ def __init__(
         Initialize logger.
 
         Args:
-            log_path: Path to log file (default: chelation_debug.jsonl)
+            log_path: Path to log file (default: chelation_events.jsonl)
             console_level: Logging level for console output
             file_level: (Unused - kept for backward compatibility)
         """
-        self.log_path = log_path or Path("chelation_debug.jsonl")
+        self.log_path = log_path or Path("chelation_events.jsonl")
         self.start_time = time.time()
         self.operation_stack = []  # Track nested operations
 
diff --git a/dashboard_server.py b/dashboard_server.py
index 0f69086..6deaea7 100644
--- a/dashboard_server.py
+++ b/dashboard_server.py
@@ -1154,12 +1154,9 @@ def filter_events(
             # Generic event_type field filter
             filtered = [e for e in filtered if e.get("event_type") == event_type]
     
-    # Sort by timestamp (most recent first)
-    filtered = sorted(
-        filtered,
-        key=lambda e: e.get("timestamp", 0),
-        reverse=True
-    )
+    # Sort by timestamp (most recent first). ISO strings and missing values
+    # must not be compared with each other as str and int.
+    filtered = sorted(filtered, key=_event_sort_value, reverse=True)
     
     # Apply limit (0 means no rows; clamped above at _MAX_API_LIMIT)
     if limit is not None:
@@ -1168,6 +1165,25 @@ def filter_events(
     return filtered
 
 
+def _event_sort_value(event: Dict[str, Any]) -> float:
+    """Numeric sort key. Naive ISO datetimes are UTC. Missing values sort as 0."""
+    stamp = event.get("timestamp", None)
+    if isinstance(stamp, bool):
+        return 0.0
+    if isinstance(stamp, (int, float)):
+        return float(stamp)
+    if isinstance(stamp, str) and stamp:
+        text = stamp
+        if not (text.endswith("Z") or len(text) >= 6 and text[-6] in "+-" and text[-3] == ":"):
+            text = text + "Z"
+        try:
+            parsed = datetime.fromisoformat(text.replace("Z", "+00:00"))
+        except ValueError:
+            return 0.0
+        return parsed.timestamp()
+    return 0.0
+
+
 def _first_present(payload: Dict[str, Any], keys: List[str]) -> Any:
     for key in keys:
         if key in payload:
diff --git a/test_event_log_contract.py b/test_event_log_contract.py
new file mode 100644
index 0000000..12c3c5d
--- /dev/null
+++ b/test_event_log_contract.py
@@ -0,0 +1,31 @@
+"""Default event-log path and mixed timestamp sorting."""
+
+import unittest
+from pathlib import Path
+
+import dashboard_server
+from chelation_logger import ChelationLogger
+
+
+class TestEventLogContract(unittest.TestCase):
+    def test_default_log_path_matches_dashboard_events_file(self):
+        logger = ChelationLogger(console_level="ERROR")
+        self.assertEqual(logger.log_path, Path("chelation_events.jsonl"))
+        self.assertEqual(dashboard_server.LOG_FILE_PATH, "chelation_events.jsonl")
+        explicit = ChelationLogger(log_path=Path("custom.jsonl"), console_level="ERROR")
+        self.assertEqual(explicit.log_path, Path("custom.jsonl"))
+
+    def test_filter_iso_timestamp_does_not_crash_when_timestamp_missing(self):
+        rows = [
+            {"timestamp": "2026-09-24T00:00:00", "query_snippet": "a"},
+            {"message": "no ts"},
+        ]
+        result = dashboard_server.filter_events(rows)
+        self.assertEqual(len(result), 2)
+        self.assertEqual(result[0]["timestamp"], "2026-09-24T00:00:00")
+        self.assertEqual(result[0]["query_snippet"], "a")
+        self.assertEqual(result[1]["message"], "no ts")
+
+
+if __name__ == "__main__":
+    unittest.main()