diff --git a/src/copilot_usage/vscode_parser.py b/src/copilot_usage/vscode_parser.py
index 153319a..778a98f 100644
--- a/src/copilot_usage/vscode_parser.py
+++ b/src/copilot_usage/vscode_parser.py
@@ -131,8 +131,7 @@ class _VSCodeDiscoveryCache:
     *newest_child_path* / *newest_child_id* store the most recently
     modified immediate child at population time; re-stat'ing this single
     sentinel on a hit detects new window directories added inside an
-    existing session.  *child_ids* is recorded at population time and
-    retained for diagnostics but is not fully rescanned on cache hits.
+    existing session.
 
     **Limitation:** only changes under the cached newest session directory
     are detected by the sentinel.  If a different (older) session directory
@@ -144,7 +143,6 @@ class _VSCodeDiscoveryCache:
     """
 
     root_id: tuple[int, int]  # (st_mtime_ns, st_size) of the logs root
-    child_ids: _ChildIds
     newest_child_path: Path | None  # most-recently-modified session dir
     newest_child_id: tuple[int, int] | None  # its identity at population
     log_paths: tuple[Path, ...]
@@ -298,7 +296,6 @@ def _cached_discover_vscode_logs(base_path: Path | None) -> list[Path]:
         found = sorted(candidate.glob(_GLOB_PATTERN))
         _VSCODE_DISCOVERY_CACHE[candidate] = _VSCodeDiscoveryCache(
             root_id=root_id,
-            child_ids=child_ids,
             newest_child_path=newest_path,
             newest_child_id=newest_id,
             log_paths=tuple(found),
diff --git a/tests/copilot_usage/test_vscode_parser.py b/tests/copilot_usage/test_vscode_parser.py
index b27cfe0..dbdb1fd 100644
--- a/tests/copilot_usage/test_vscode_parser.py
+++ b/tests/copilot_usage/test_vscode_parser.py
@@ -2716,7 +2716,6 @@ def test_cache_invalidated_on_root_mtime_change(self, tmp_path: Path) -> None:
         cached = _VSCODE_DISCOVERY_CACHE[tmp_path]
         _VSCODE_DISCOVERY_CACHE[tmp_path] = _VSCodeDiscoveryCache(
             root_id=(cached.root_id[0] + 1_000_000_000, cached.root_id[1]),
-            child_ids=cached.child_ids,
             newest_child_path=cached.newest_child_path,
             newest_child_id=cached.newest_child_id,
             log_paths=cached.log_paths,
@@ -2753,7 +2752,8 @@ def test_discovery_cache_populated(self, tmp_path: Path) -> None:
         cached = _VSCODE_DISCOVERY_CACHE[tmp_path]
         assert len(cached.log_paths) == 1
         assert cached.root_id == safe_file_identity(tmp_path)
-        assert cached.child_ids == _scan_child_ids(tmp_path)
+        assert cached.newest_child_path is not None
+        assert cached.newest_child_id is not None
 
     def test_new_window_under_existing_session_triggers_rediscovery(
         self, tmp_path: Path
@@ -3267,7 +3267,6 @@ def test_field_reassignment_raises(self) -> None:
         """Assigning to a field after construction raises FrozenInstanceError."""
         cache = _VSCodeDiscoveryCache(
             root_id=(0, 0),
-            child_ids=frozenset(),
             newest_child_path=None,
             newest_child_id=None,
             log_paths=(),