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 802a63ff..2c8d7c52 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
@@ -245,6 +245,15 @@ def _read_mode_table() -> dict[str, str]:
         LOWERCASE_F_FIELD_CATEGORY,
     }
 )
+HARD_CATEGORIES: frozenset[str] = frozenset(
+    {
+        TOOL_README_CATEGORY,
+        TOOL_CAPABILITY_CATEGORY,
+        CAPABILITY_SYNC_CATEGORY,
+        INJECTION_GUARD_CATEGORY,
+    }
+)
+ALL_CATEGORIES = HARD_CATEGORIES | SOFT_CATEGORIES
 
 # ---------------------------------------------------------------------------
 # Injection-guard constants (Pattern 4)
@@ -1648,8 +1657,19 @@ def main(argv: list[str] | None = None) -> int:
         action="store_true",
         help="Promote SOFT categories (advisory) to hard failures.",
     )
+    parser.add_argument(
+        "--list-categories",
+        action="store_true",
+        help="Print every violation category name (SOFT ones marked) and exit.",
+    )
     args = parser.parse_args(argv)
 
+    if args.list_categories:
+        for category in sorted(ALL_CATEGORIES):
+            suffix = " (advisory)" if category in SOFT_CATEGORIES else ""
+            print(f"{category}{suffix}")
+        return 0
+
     skip = {c.strip() for c in args.skip_categories.split(",") if c.strip()}
     violations = run_validation()
     filtered = [v for v in violations if v.category not in skip]
diff --git a/tools/skill-and-tool-validator/tests/test_validator.py b/tools/skill-and-tool-validator/tests/test_validator.py
index 4998f415..62325119 100644
--- a/tools/skill-and-tool-validator/tests/test_validator.py
+++ b/tools/skill-and-tool-validator/tests/test_validator.py
@@ -28,9 +28,11 @@
     _MODE_TAXONOMY,
     _OFF_MODES,
     _PRIVACY_EXTERNAL_CONTENT_MODES,
+    ALL_CATEGORIES,
     ALLOWED_MODES,
     FORBIDDEN_PATTERNS,
     GH_LIST_CATEGORY,
+    HARD_CATEGORIES,
     INJECTION_GUARD_CALLOUT_SENTINEL,
     INJECTION_GUARD_CATEGORY,
     INJECTION_GUARD_TODO_CATEGORY,
@@ -1391,6 +1393,10 @@ def test_lowercase_f_field_in_soft_categories(self) -> None:
 
 
 class TestSoftCategories:
+    def test_all_categories_is_union_of_hard_and_soft(self) -> None:
+        assert ALL_CATEGORIES == HARD_CATEGORIES | SOFT_CATEGORIES
+        assert HARD_CATEGORIES.isdisjoint(SOFT_CATEGORIES)
+
     def test_soft_categories_set(self) -> None:
         assert PRINCIPLE_CATEGORY in SOFT_CATEGORIES
         assert TRIGGER_PRESERVATION_CATEGORY in SOFT_CATEGORIES
@@ -1879,6 +1885,13 @@ def _make_valid_skill(root: Path, name: str) -> Path:
 
 
 class TestMain:
+    def test_list_categories(self, capsys: pytest.CaptureFixture[str]) -> None:
+        rc = main(["--list-categories"])
+        assert rc == 0
+        out = capsys.readouterr().out
+        expected = [f"{c} (advisory)" if c in SOFT_CATEGORIES else c for c in sorted(ALL_CATEGORIES)]
+        assert out.strip().splitlines() == expected
+
     def test_returns_0_when_no_violations(self, tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
         root = _skill_root(tmp_path)
         _make_valid_skill(root, "my-skill")