diff --git a/scripts/check_freshness.py b/scripts/check_freshness.py
index fac97bc71..55fa8a67e 100644
--- a/scripts/check_freshness.py
+++ b/scripts/check_freshness.py
@@ -58,6 +58,7 @@ from common import (  # noqa: E402
     list_registered_platforms,
     load_emulator_profiles,
     load_platform_registry,
+    require_directory,
     upstream_profile_index,
     write_text_atomic,
     yaml_load,
@@ -1789,6 +1790,7 @@ def main() -> int:
     if unknown:
         parser.error(unknown_areas_message(unknown))
 
+    require_directory(args.platforms_dir, "--platforms-dir")
     platforms_dir = Path(args.platforms_dir)
     profiles = load_emulator_profiles(args.emulators_dir, skip_aliases=False)
     findings: list[Finding] = []
diff --git a/scripts/check_release.py b/scripts/check_release.py
index e53e5b560..4fc8c1932 100644
--- a/scripts/check_release.py
+++ b/scripts/check_release.py
@@ -33,7 +33,7 @@ from pathlib import Path
 sys.path.insert(0, os.path.dirname(__file__))
 from build_port import ARCHIVES
 from check_release_assets import digests_of
-from common import list_release_pack_platforms
+from common import list_release_pack_platforms, require_directory
 from largefiles import LARGE_FILES_REPO
 from release_record import RECORD, load_record
 
@@ -208,6 +208,7 @@ def main() -> int:
     )
     parser.add_argument("--json", action="store_true", help="JSON output")
     args = parser.parse_args()
+    require_directory(args.platforms_dir, "--platforms-dir")
 
     record = load_record(args.record)
     tag = args.tag or record.get("tag")
diff --git a/scripts/common.py b/scripts/common.py
index 7e78ead96..a8833cecf 100644
--- a/scripts/common.py
+++ b/scripts/common.py
@@ -508,7 +508,7 @@ def list_registered_platforms(
     """
     registry_path = os.path.join(platforms_dir, "_registry.yml")
     if not os.path.exists(registry_path):
-        raise FileNotFoundError(f"no platform registry at {registry_path}")
+        raise InputMissing(f"no platform registry at {registry_path}")
     with open(registry_path) as f:
         registry = yaml_load(f) or {}
     platforms = []
diff --git a/scripts/generate_truth.py b/scripts/generate_truth.py
index 37e2728fc..ac5856667 100644
--- a/scripts/generate_truth.py
+++ b/scripts/generate_truth.py
@@ -21,6 +21,7 @@ from common import (
     load_emulator_profiles,
     load_platform_config,
     load_target_config,
+    require_directory,
     require_platform,
     require_yaml,
     truth_target_dir,
@@ -72,6 +73,7 @@ def parse_args(argv: list[str] | None = None) -> argparse.Namespace:
 
 def main(argv: list[str] | None = None) -> None:
     args = parse_args(argv)
+    require_directory(args.platforms_dir, "--platforms-dir")
 
     registry_path = os.path.join(args.platforms_dir, "_registry.yml")
     with open(registry_path) as f:
diff --git a/scripts/release_notes.py b/scripts/release_notes.py
index 3ff155eee..cf3903cae 100644
--- a/scripts/release_notes.py
+++ b/scripts/release_notes.py
@@ -26,6 +26,7 @@ from common import (
     list_release_pack_platforms,
     load_platform_config,
     load_platform_registry,
+    require_directory,
     write_text_atomic,
 )
 from siteguides import install_command
@@ -162,6 +163,7 @@ def main() -> int:
     parser.add_argument("--output", required=True, type=Path,
                         help="notes file to write, passed to gh release create --notes-file")
     args = parser.parse_args()
+    require_directory(args.platforms_dir, "--platforms-dir")
 
     record = release_record.load_record(args.record)
     if not record.get("packs"):
diff --git a/scripts/validate_pr.py b/scripts/validate_pr.py
index cbc6fa1bd..cae324e65 100644
--- a/scripts/validate_pr.py
+++ b/scripts/validate_pr.py
@@ -34,6 +34,7 @@ from common import (
     load_emulator_profiles,
     load_platform_config,
     parse_md5_list,
+    require_directory,
 )
 from hashing import parse_hash_list
 from nativemode import digest_algorithm
@@ -798,6 +799,7 @@ def main() -> None:
     if os.path.realpath(os.getcwd()) != os.path.realpath(REPO_ROOT):
         args.files = [os.path.abspath(f) for f in args.files]
     work_from_repo_root(args, parser, ["db", "platforms_dir", "emulators_dir"])
+    require_directory(args.platforms_dir, "--platforms-dir")
 
     files = _files_to_validate(args, parser)
     if not files:
diff --git a/scripts/validate_site.py b/scripts/validate_site.py
index c922ad414..6db66bc09 100644
--- a/scripts/validate_site.py
+++ b/scripts/validate_site.py
@@ -499,6 +499,9 @@ def main() -> None:
         help="stop listing after this many errors (default: %(default)s)",
     )
     args = parser.parse_args()
+    from common import require_directory  # noqa: PLC0415
+
+    require_directory(str(args.platforms_dir), "--platforms-dir")
 
     try:
         issues = validate_site(Path(args.site_dir), args.base, args.platforms_dir, args.record)
diff --git a/tests/test_system_selection.py b/tests/test_system_selection.py
index 56c16cba1..3d554abf3 100644
--- a/tests/test_system_selection.py
+++ b/tests/test_system_selection.py
@@ -331,6 +331,50 @@ class AMissingProfileDirIsRefused(unittest.TestCase):
         self.assertEqual(after, before)
 
 
+class AMissingPlatformsDirIsRefused(unittest.TestCase):
+    """`verify.py --platforms-dir noplat` ended on a FileNotFoundError at the
+    bottom of a stack trace, and validate_pr read it as no platform at all
+    and exited 0."""
+
+    EXTRA = {
+        "auto_fetch": ["--all", "--dry-run"],
+        "check_release": ["--tag", "v1"],
+        "diff_truth": ["--all"],
+        "export_native": ["--all", "--output-dir", "{out}"],
+        "generate_pack": ["--platform", "retroarch", "--offline", "--output-dir", "{out}"],
+        "generate_site": ["--docs-dir", "{out}"],
+        "generate_truth": ["--all", "--output-dir", "{out}"],
+        "release_notes": ["--whats-new", "{notes}", "--output", "{out}/notes.md"],
+        "release_record": ["{out}", "--tag", "v1"],
+        "romset_dat_importer": ["--source", "mame", "--pack", "{dat}", "--output", "{out}/r.json"],
+        "validate_pr": ["bios/Sony/PlayStation/scph5501.bin"],
+        "validate_site": ["--site-dir", "{out}"],
+        "verify": ["--platform", "retroarch"],
+    }
+
+    def test_every_script_taking_a_platforms_dir_refuses_a_missing_one(self):
+        scratch = tempfile.TemporaryDirectory(dir=REPO_ROOT / "tmp")
+        self.addCleanup(scratch.cleanup)
+        root = Path(scratch.name)
+        (root / "empty.dat").write_bytes(b"")
+        (root / "notes.md").write_text("Notes.\n")
+        values = {"out": str(root / "out"), "dat": str(root / "empty.dat"),
+                  "notes": str(root / "notes.md")}
+        taking = _scripts_taking("--platforms-dir")
+        self.assertGreater(len(taking), 15)
+        for path in taking:
+            extra = [arg.format(**values) for arg in self.EXTRA.get(path.stem, [])]
+            with self.subTest(script=path.stem):
+                proc = subprocess.run(
+                    [*_command(path), "--platforms-dir", "nosuch", *extra],
+                    capture_output=True, text=True, cwd=str(REPO_ROOT), timeout=600,
+                    check=False, env={**os.environ, "RETROBIOS_OFFLINE": "1"},
+                )
+                self.assertNotEqual(proc.returncode, 0, proc.stdout[-500:])
+                self.assertNotIn("Traceback", proc.stderr, proc.stderr[-1500:])
+                self.assertRegex(proc.stderr, r"ERROR: .*nosuch")
+
+
 class StrictVerifyFailsOnACriticalMiss(unittest.TestCase):
     """verify exited 0 with a required file missing on an md5 platform, so
     the pipeline printed "verify OK" over a pack the frontend rejects."""