Ask HN: Tools for Crossword Puzzle Generation?

2 ekorbia 2 9/1/2025, 8:48:38 PM

Hi,

I'm big fan of crossword puzzles such as the New York Times daily crossword and I'd like to build my own crossword puzzle game.

Has anyone had any luck using AI or other tools to speed up the process of building crossword puzzles?

I've used the Phil crossword puzzle maker to export crossword patterns with a few clues and answers in JSON format. Then I've tried various prompts with Claude Sonnet 4 to fill out the rest of the puzzle but I haven't been able to produce a valid crossword puzzle with the across and down words intersecting properly.

Any advice on tools or prompting would be appreciated. Thanks!

Comments (2)

vunderba · 2h ago

I gave a recommendation around LLM crossword generators a while ago, so reposting it:

As someone who has dabbled in AI generated crosswords I found that providing samples of "good crossword clues" (which I curated from historical NYT monday puzzles) as part of the LLM context helped tremendously in generating better clues.

Part of the deep satisfaction in solving a crossword puzzle is the specificity of the answer. It's far more gratifying to answer a question with something like "Hawking" then to answer with "scientist", or answering with "mandelbrot" versus "shape".

So ideally, you want to lean towards "specificity" wherever possible, and use "generics" as filler.

Producing a valid layout is a different situation. Ultimately depends on how strict you are in terms of acceptable layouts. Getting a NYT compatible crossword puzzle is going to be more difficult by virtue of its symmetrical requirements than if you're okay with just laying out sequences of perpendicular intersecting words.

ekorbia · 1h ago

Thanks for the response. I agree that specificity is important.

I provided a few specific clues and answers along with the grid layout, and a theme as context. Ideally this would generate a filled crossword that I could then verify and edit.

Claude would churn, restarting from scratch over and over trying to fill the layout. If I remove the grid layout from the context, I can generate sparse sequences like you mention but these are not very fun to play.