diff --git a/src/repodock/detect.py b/src/repodock/detect.py
index b5b9859..53d1365 100644
--- a/src/repodock/detect.py
+++ b/src/repodock/detect.py
@@ -162,7 +162,11 @@ def _node(root: Path, win: bool) -> list[Candidate]:
         pkg = json.loads(_read(pkg_path))
     except ValueError:
         pkg = {}
-    scripts = pkg.get("scripts") or {}
+    if not isinstance(pkg, dict):
+        return []
+    scripts = pkg.get("scripts")
+    if not isinstance(scripts, dict):
+        scripts = {}
     if (root / "pnpm-lock.yaml").exists():
         pm, install = "pnpm", "pnpm install"
     elif (root / "yarn.lock").exists():
@@ -175,12 +179,12 @@ def _node(root: Path, win: bool) -> list[Candidate]:
     common = dict(kind="node", tool=pm, deps=install if has_deps else None, deps_marker="node_modules" if has_deps else None)
     out = []
     for name in ("dev", "start", "serve", "preview", "develop"):
-        if name in scripts:
+        if isinstance(scripts.get(name), str) and scripts[name].strip():
             cmd = f"{pm} start" if name == "start" and pm in ("npm", "yarn") else f"{pm} run {name}"
             out.append(Candidate(f"{pm} {'start' if name == 'start' else 'run ' + name}", cmd, notes=[f"runs: {scripts[name]}"], **common))
     if not out:
         main = pkg.get("main")
-        for entry in ([main] if main else []) + ["index.js", "server.js", "app.js", "main.js"]:
+        for entry in ([main] if isinstance(main, str) and main else []) + ["index.js", "server.js", "app.js", "main.js"]:
             if entry and (root / entry).is_file():
                 out.append(Candidate(f"node {entry}", f"node {q(entry)}", **{**common, "tool": "node"}))
                 break
@@ -195,10 +199,15 @@ def _deno(root: Path, win: bool) -> list[Candidate]:
         if (root / name).is_file():
             text = re.sub(r"^\s*//.*$", "", _read(root / name), flags=re.M)
             try:
-                tasks = (json.loads(text).get("tasks") or {})
+                config = json.loads(text)
+                tasks = config.get("tasks") if isinstance(config, dict) else {}
+                if not isinstance(tasks, dict):
+                    tasks = {}
             except ValueError:
                 tasks = {}
-            return [Candidate(f"deno task {t}", f"deno task {t}", "deno", tool="deno") for t in ("dev", "start") if t in tasks]
+            # Deno supports both command strings and task objects (including dependency-only tasks).
+            return [Candidate(f"deno task {t}", f"deno task {t}", "deno", tool="deno") for t in ("dev", "start")
+                    if isinstance(tasks.get(t), dict) or (isinstance(tasks.get(t), str) and tasks[t].strip())]
     return []
 
 
diff --git a/tests/test_detect.py b/tests/test_detect.py
index 5d4f9a9..7b772e0 100644
--- a/tests/test_detect.py
+++ b/tests/test_detect.py
@@ -41,6 +41,27 @@ def test_node_without_scripts(self):
         c = self.first({"package.json": json.dumps({"main": "lib/app.js"}), "lib/app.js": ""})
         self.assertEqual(c.command, "node lib/app.js")
 
+    def test_invalid_node_metadata_does_not_hide_other_project_types(self):
+        for value in (None, [], True, 42, "not a package"):
+            with self.subTest(value=value):
+                found = detect(self.repo({"package.json": json.dumps(value), "main.py": "print('hello')"}), "linux")
+                self.assertTrue(any(c.kind == "python" for c in found))
+        for scripts in ([], "dev", 42, {"dev": None}, {"dev": []}, {"dev": "  "}):
+            with self.subTest(scripts=scripts):
+                found = detect(self.repo({"package.json": json.dumps({"scripts": scripts, "main": 42}), "index.js": ""}), "linux")
+                self.assertEqual([c.command for c in found], ["node index.js"])
+
+    def test_invalid_deno_metadata_does_not_hide_other_project_types(self):
+        for value in (None, [], True, {"tasks": []}, {"tasks": 42}, {"tasks": {"dev": None}}):
+            with self.subTest(value=value):
+                found = detect(self.repo({"deno.json": json.dumps(value), "main.py": "print('hello')"}), "linux")
+                self.assertTrue(any(c.kind == "python" for c in found))
+                self.assertFalse(any(c.kind == "deno" for c in found))
+        c = self.first({"deno.json": json.dumps({"tasks": {"dev": {"command": "deno run main.ts"}}})})
+        self.assertEqual(c.command, "deno task dev")
+        c = self.first({"deno.json": json.dumps({"tasks": {"dev": {"dependencies": ["client", "server"]}}})})
+        self.assertEqual(c.command, "deno task dev")
+
     def test_python_entry_with_requirements(self):
         c = self.first({"requirements.txt": "requests\n", "main.py": "print(1)"})
         self.assertEqual(c.command, "{python} main.py")