diff --git a/fixit/cli.py b/fixit/cli.py
index 632cf17..b5ecd6d 100644
--- a/fixit/cli.py
+++ b/fixit/cli.py
@@ -44,25 +44,29 @@ def build_parser() -> argparse.ArgumentParser:
 
 
 def main(argv=None) -> int:
-    args = build_parser().parse_args(argv)
-    if args.command == "wc":
-        print(f"words={wordcount.count_words(args.text)} "
-              f"lines={wordcount.count_lines(args.text)} "
-              f"chars={wordcount.count_chars(args.text)}")
-    elif args.command == "convert":
-        print(CONVERSIONS[args.kind](args.value))
-    elif args.command == "password":
-        print(password.generate(args.length, use_symbols=args.symbols))
-    elif args.command == "uuid":
-        for _ in range(args.count):
-            print(uuid.uuid4())
-    elif args.command == "json":
-        print(jsonfmt.format_json(args.raw))
-    elif args.command == "palindrome":
-        print(textutils.is_palindrome(args.text))
-    elif args.command == "reverse":
-        print(textutils.reverse_words(args.text))
-    return 0
+    try:
+        args = build_parser().parse_args(argv)
+        if args.command == "wc":
+            print(f"words={wordcount.count_words(args.text)} "
+                f"lines={wordcount.count_lines(args.text)} "
+                f"chars={wordcount.count_chars(args.text)}")
+        elif args.command == "convert":
+            print(CONVERSIONS[args.kind](args.value))
+        elif args.command == "password":
+            print(password.generate(args.length, use_symbols=args.symbols))
+        elif args.command == "uuid":
+            for _ in range(args.count):
+                print(uuid.uuid4())
+        elif args.command == "json":
+            print(jsonfmt.format_json(args.raw))
+        elif args.command == "palindrome":
+            print(textutils.is_palindrome(args.text))
+        elif args.command == "reverse":
+            print(textutils.reverse_words(args.text))
+        return 0
+    except ValueError as e:
+        print(str(e), file=sys.stderr)
+        return 1
 
 
 if __name__ == "__main__":
diff --git a/fixit/jsonfmt.py b/fixit/jsonfmt.py
index 544dd66..965935c 100644
--- a/fixit/jsonfmt.py
+++ b/fixit/jsonfmt.py
@@ -3,6 +3,9 @@
 
 
 def format_json(raw: str, indent: int = 2) -> str:
-    """Return pretty-printed JSON."""
-    data = json.loads(raw)
-    return json.dumps(data, indent=indent)
+    try:
+        """Return pretty-printed JSON."""
+        data = json.loads(raw)
+        return json.dumps(data, indent=indent)
+    except json.JSONDecodeError:
+        raise ValueError("Invalid JSON")
diff --git a/fixit/password.py b/fixit/password.py
index 8105c71..7ff6e59 100644
--- a/fixit/password.py
+++ b/fixit/password.py
@@ -5,6 +5,8 @@
 
 def generate(length: int = 12, use_digits: bool = True, use_symbols: bool = False) -> str:
     """Return a random password of the given length."""
+    if length <= 0:
+        raise ValueError("Password length must be greater then 0!")
     chars = string.ascii_letters
     if use_digits:
         chars += string.digits
diff --git a/tests/test_errors.py b/tests/test_errors.py
new file mode 100644
index 0000000..0c62904
--- /dev/null
+++ b/tests/test_errors.py
@@ -0,0 +1,7 @@
+from fixit import cli
+
+def test_invalid_json_returns_1():
+    assert cli.main(["json", "{bad"]) == 1
+
+def test_invalid_password_returns_1():
+    assert cli.main(["password", "--length", "0"]) == 1
\ No newline at end of file
diff --git a/tests/test_jsonfmt.py b/tests/test_jsonfmt.py
index 6a08346..b850f8e 100644
--- a/tests/test_jsonfmt.py
+++ b/tests/test_jsonfmt.py
@@ -6,7 +6,6 @@ def test_format_json():
     assert format_json('{"a":1}') == '{\n  "a": 1\n}'
 
 
-@pytest.mark.xfail(reason="Known bug: invalid JSON raises a raw traceback instead of a friendly error")
 def test_invalid_json_friendly_error():
     with pytest.raises(ValueError, match="Invalid JSON"):
         format_json("{not json")
diff --git a/tests/test_password.py b/tests/test_password.py
index 04316ec..ceae252 100644
--- a/tests/test_password.py
+++ b/tests/test_password.py
@@ -10,7 +10,6 @@ def test_no_digits():
     assert not any(c.isdigit() for c in generate(50, use_digits=False))
 
 
-@pytest.mark.xfail(reason="Known bug: length < 1 is not validated")
 def test_invalid_length():
     with pytest.raises(ValueError):
         generate(0)