I was able to test Anthropic’s newest welterweight class model, Sonnet 5, on the one-shot “make me a game” agentic prompt I had developed in my last post. I’ll go into more detail about the prompt after the Independence Day holiday,.

Briefly, the prompt instructs a single agent in a single context to create a basic Asteroids game, then come up with 20 fun new features all on its own, and iterate on them one by one, using Playwright autonomously to take screen captures of the game to validate the graphics.

The full prompt is here, and includes guidance to the LLM on code architecture, testing, and choosing new features : https://github.com/rgmarquez/devrep20-claude-sonnet-5/blob/main/notes/prompt.md

I’ll analyze the pros and cons of the one-shot prompt versus the much more structured feature orchestrator agentic pipeline I had been using before the (on again, off again) release of Claude Fable. I’ll also discuss some interesting observations and challenges I noted while watching Sonnet 5 iterate on the features, including intuitions on what fully agentic LLM pipelines may struggle with in the future, and the high token and money costs of fully agentic flows such as this one.

But for now, I present you Claude Sonnet 5’s solution.

The game can be played in a web browser here : https://rgmarquez.github.io/devrep20-claude-sonnet-5/

The actual GitHub repository can be found here : https://github.com/rgmarquez/devrep20-claude-sonnet-5