diff --git a/backend/api/server.py b/backend/api/server.py
index b815ee0..67d2751 100644
--- a/backend/api/server.py
+++ b/backend/api/server.py
@@ -4903,7 +4903,7 @@ def _list_admin_accounts(
                 child_session_count += 1
             else:
                 visible_session_count += 1
-            row_tool_calls = int(data.get('tool_calls') or 0)
+            row_tool_calls = _admin_session_tool_call_count(data)
             tool_calls += row_tool_calls
             usage = data.get('usage') if isinstance(data.get('usage'), dict) else {}
             row_input_tokens = int(usage.get('input_tokens') or 0)
@@ -5061,6 +5061,49 @@ def _admin_daily_series(buckets: dict[str, dict[str, Any]]) -> list[dict[str, An
     return [buckets[key] for key in sorted(buckets)]
 
 
+def _admin_session_tool_call_count(data: dict[str, Any]) -> int:
+    raw_value = data.get('tool_calls')
+    raw_count = raw_value if isinstance(raw_value, int) else 0
+    if raw_count < 0:
+        raw_count = 0
+    file_history = data.get('file_history')
+    file_history_count = len(file_history) if isinstance(file_history, list) else 0
+    message_count = max(
+        _admin_count_tool_calls_in_items(data.get('messages')),
+        _admin_count_tool_calls_in_items(data.get('turns')),
+    )
+    derived_count = max(file_history_count, message_count)
+    if raw_count == 0 and derived_count:
+        return derived_count
+    # Some historical session files contain corrupted cumulative values here.
+    # Prefer a conservative derived count when the stored number is wildly
+    # larger than the persisted tool history/message structure can support.
+    if derived_count and raw_count > max(5000, derived_count * 20 + 100):
+        return derived_count
+    return raw_count
+
+
+def _admin_count_tool_calls_in_items(value: Any) -> int:
+    if not isinstance(value, list):
+        return 0
+    count = 0
+    for item in value:
+        if not isinstance(item, dict):
+            continue
+        tool_calls = item.get('tool_calls')
+        if isinstance(tool_calls, list):
+            count += len(tool_calls)
+        content = item.get('content')
+        if isinstance(content, list):
+            for block in content:
+                if not isinstance(block, dict):
+                    continue
+                block_type = str(block.get('type') or '')
+                if block_type in {'tool_use', 'tool-call', 'tool_call'}:
+                    count += 1
+    return count
+
+
 def _merge_admin_daily_series(
     series_items: Iterable[list[dict[str, Any]]],
 ) -> list[dict[str, Any]]: