diff --git a/plugins/codex-security/scripts/generate_in_scope_files.py b/plugins/codex-security/scripts/generate_in_scope_files.py
index 6b5807933..a7e9a5120 100644
--- a/plugins/codex-security/scripts/generate_in_scope_files.py
+++ b/plugins/codex-security/scripts/generate_in_scope_files.py
@@ -131,9 +131,20 @@ def generate_in_scope_files(repository: Path, scope: str, output: Path) -> int:
                     scope,
                     text=False,
                 )
-            except OSError:
-                tracked = None
-            if tracked is not None and tracked.returncode == 0:
+            except OSError as error:
+                raise InventoryError(f"could not run git ls-files: {error}") from error
+
+            # git_command reports a missing trusted Git executable as status 127
+            # with no output. Git is optional for this listing; a Git that ran
+            # and failed would leave the inventory silently incomplete.
+            git_missing = tracked.returncode == 127 and not tracked.stderr
+            if tracked.returncode != 0 and not git_missing:
+                detail = tracked.stderr.decode("utf-8", errors="replace").strip()
+                message = f"git ls-files exited with status {tracked.returncode}"
+                if detail:
+                    message = f"{message}: {detail}"
+                raise InventoryError(message)
+            if tracked.returncode == 0:
                 prefix = b"./" if scope == "." or scope.startswith("./") else b""
                 for path in tracked.stdout.split(b"\0"):
                     candidate = repository / os.fsdecode(path)
diff --git a/plugins/codex-security/tests/test_generate_in_scope_files.py b/plugins/codex-security/tests/test_generate_in_scope_files.py
index 4dbf9d8de..42aae1cc4 100644
--- a/plugins/codex-security/tests/test_generate_in_scope_files.py
+++ b/plugins/codex-security/tests/test_generate_in_scope_files.py
@@ -175,6 +175,34 @@ def test_inventory_rejects_line_breaks_before_serializing_paths(
     assert list(output.parent.glob(f".{output.name}.*.tmp")) == []
 
 
+def test_inventory_reports_a_failed_ignored_tracked_listing(tmp_path: Path) -> None:
+    repository = make_repository(tmp_path)
+    write_file(repository, "ignored/tracked.py")
+    git(repository, "add", "--force", "--", "ignored/tracked.py")
+    git(repository, "config", "core.repositoryformatversion", "1")
+    git(repository, "config", "extensions.exampleUnsupported", "true")
+    output = tmp_path / "in_scope_files.txt"
+
+    result = run_inventory(repository, ".", output)
+
+    assert result.returncode == 2, result.stdout
+    assert "git ls-files" in result.stderr
+    assert not output.exists()
+
+
+def test_inventory_without_git_keeps_the_ripgrep_listing(tmp_path: Path) -> None:
+    repository = make_repository(tmp_path)
+    write_file(repository, "ignored/tracked.py")
+    git(repository, "add", "--force", "--", "ignored/tracked.py")
+    output = tmp_path / "in_scope_files.txt"
+
+    # An empty CODEX_SECURITY_GIT selects no Git executable.
+    result = run_inventory(repository, ".", output, env={**os.environ, "CODEX_SECURITY_GIT": ""})
+
+    assert result.returncode == 0, result.stderr
+    assert output.read_bytes() == standard_inventory(repository, ".")
+
+
 def test_diff_inventory_includes_power_shell_files(
     tmp_path: Path, monkeypatch: pytest.MonkeyPatch
 ) -> None: