diff --git a/tools/skill-and-tool-validator/src/skill_and_tool_validator/__init__.py b/tools/skill-and-tool-validator/src/skill_and_tool_validator/__init__.py
index a69caabf..372462fb 100644
--- a/tools/skill-and-tool-validator/src/skill_and_tool_validator/__init__.py
+++ b/tools/skill-and-tool-validator/src/skill_and_tool_validator/__init__.py
@@ -1550,17 +1550,35 @@ def collect_tool_dirs(root: Path | None = None) -> list[Path]:
         return []
 
     dirs = sorted(d for d in base.iterdir() if d.is_dir() and not d.name.startswith("."))
-    tracked_names = _git_tracked_tool_names(repo_root)
-    if tracked_names is None:
+    visible_names = _git_visible_tool_names(repo_root)
+    if visible_names is None:
         return dirs
-    return [d for d in dirs if d.name in tracked_names]
+    return [d for d in dirs if d.name in visible_names]
 
 
-def _git_tracked_tool_names(root: Path) -> set[str] | None:
-    """Return top-level ``tools/<name>`` entries tracked by git, if available."""
+def _git_visible_tool_names(root: Path) -> set[str] | None:
+    """Return top-level ``tools/<name>`` entries git considers non-ignored
+    (tracked *or* untracked-but-not-``.gitignore``d), if git is available.
+
+    Using ``--cached --others --exclude-standard`` — rather than tracked
+    files alone — means a freshly-authored tool directory that has not been
+    ``git add``ed yet is still validated, while gitignored artifact
+    directories (e.g. ``__pycache__``, build output) are excluded.
+    """
     try:
         result = subprocess.run(
-            ["git", "-C", str(root), "ls-files", "-z", "--", str(TOOLS_DIR)],
+            [
+                "git",
+                "-C",
+                str(root),
+                "ls-files",
+                "-z",
+                "--cached",
+                "--others",
+                "--exclude-standard",
+                "--",
+                str(TOOLS_DIR),
+            ],
             check=False,
             stdout=subprocess.PIPE,
             stderr=subprocess.DEVNULL,
diff --git a/tools/skill-and-tool-validator/tests/test_validator.py b/tools/skill-and-tool-validator/tests/test_validator.py
index 7d5130f1..b75d6680 100644
--- a/tools/skill-and-tool-validator/tests/test_validator.py
+++ b/tools/skill-and-tool-validator/tests/test_validator.py
@@ -2611,6 +2611,31 @@ def test_ignored_tool_artifact_directory_skipped(self, tmp_path: Path) -> None:
         violations = list(validate_tools(root))
         assert violations == []
 
+    def test_untracked_tool_directory_still_checked(self, tmp_path: Path) -> None:
+        # A freshly-authored tool directory that has not been ``git add``ed yet
+        # is not gitignored, so it must still be validated. Regression guard: an
+        # earlier tracked-only filter silently dropped such directories.
+        root = _make_tools_root(tmp_path)
+        subprocess.run(["git", "init"], cwd=root, check=True, capture_output=True)
+        (root / ".gitignore").write_text("tools/ignored-artifact/\n", encoding="utf-8")
+
+        untracked_tool = root / "tools" / "brand-new"
+        untracked_tool.mkdir()
+        (untracked_tool / "README.md").write_text(
+            "# tools/brand-new\n\n**Capability:** substrate:framework-dev\n\nNew tool.\n\n" + _VALID_PREREQS,
+            encoding="utf-8",
+        )
+
+        ignored_tool = root / "tools" / "ignored-artifact"
+        ignored_tool.mkdir()
+        (ignored_tool / "junk.txt").write_text("", encoding="utf-8")
+
+        # Only .gitignore is staged; the new tool is deliberately left untracked.
+        subprocess.run(["git", "add", ".gitignore"], cwd=root, check=True, capture_output=True)
+
+        assert [d.name for d in collect_tool_dirs(root)] == ["brand-new"]
+        assert list(validate_tools(root)) == []
+
     def test_tool_missing_readme(self, tmp_path: Path) -> None:
         root = _make_tools_root(tmp_path)
         (root / "tools" / "no-readme").mkdir()