diff --git a/pyrit/converter/puzzled/puzzled_converter.py b/pyrit/converter/puzzled/puzzled_converter.py
index c66c557147..302a5a2278 100644
--- a/pyrit/converter/puzzled/puzzled_converter.py
+++ b/pyrit/converter/puzzled/puzzled_converter.py
@@ -5,6 +5,7 @@
 import json
 import pathlib
 import uuid
+from typing import assert_never
 
 from pyrit.common.path import CONVERTER_SEED_PROMPT_PATH
 from pyrit.converter.converter import Converter, ConverterResult
@@ -197,8 +198,10 @@ async def convert_async(self, *, prompt: str, input_type: PromptDataType = "text
             puzzle_body = build_word_search(words, rng)
         elif puzzle_type is PuzzleType.ANAGRAM:
             puzzle_body = build_anagram(words, rng)
-        else:
+        elif puzzle_type is PuzzleType.CROSSWORD:
             puzzle_body = build_crossword(words)
+        else:
+            assert_never(puzzle_type)
 
         semantics = await self._semantic_clues_async(words)
         clues = "\n".join(self._clue_line(masked, semantics) for masked in mask_result.masked_words)
diff --git a/tests/unit/converter/test_puzzled_converter.py b/tests/unit/converter/test_puzzled_converter.py
index bf8b24295b..f1dca4e744 100644
--- a/tests/unit/converter/test_puzzled_converter.py
+++ b/tests/unit/converter/test_puzzled_converter.py
@@ -98,6 +98,13 @@ async def test_unsupported_input_type_raises():
         await PuzzledConverter().convert_async(prompt=_PROMPT, input_type="image_path")
 
 
+async def test_unhandled_puzzle_type_raises_async() -> None:
+    converter = PuzzledConverter(num_to_mask=2, seed=1)
+    with patch.object(converter, "_puzzle_type", "sudoku"):
+        with pytest.raises(AssertionError, match="Expected code to be unreachable, but got: 'sudoku'"):
+            await converter.convert_async(prompt=_PROMPT)
+
+
 @pytest.mark.parametrize(
     "puzzle_type, label",
     [("word_search", "word search"), ("anagram", "anagram"), ("crossword", "crossword")],