Opusfived: a game about AI that cannot just make one button blue

One button, one instruction

The page at opusfived.dev opens with a single line: "Make the "Add to Cart" button blue. Do not let Claude change anything else." Click "Let's go" and it sets a goal — change the colour of the "Add to Cart" button to blue, and leave every other button alone. On screen sit two buttons, "Add to Cart" and "Cancel", along with a few ready-made prompts to send, from the plain "Make the "Add to Cart" button blue" to longer, more careful phrasings.

The loop

What follows is a scripted comedy. The assistant reports success, but the Cancel button has turned blue too. Asked to explain, it says it applied the colour not to the element but to the button's shared value, so the blue survives hover, focus and disabled states. The visitor can then reply, "Why is half the site blue? I only asked you to change one button." A roulette wheel starts spinning, and the answer that follows is long: it reports that 23 agents each investigated a different aspect, before admitting the investigation stopped exactly where it should have checked what else that shared value controlled. Both buttons stay blue. A warning eventually appears: "You are approaching usage restrictions."

A joke written by hand

The site is credited to Miloš Novović, and the exchanges are not produced by a live model: he says the game was written manually from his own attempts, which is what makes the pacing land. The premise riffs on Claude Opus 5, the Anthropic model meant to deliver last-generation quality at half the price, and on the habit of agentic coding assistants to answer a small request with a large investigation.

Why it lands

The link drew well over a thousand points on Hacker News, and the complaints in the thread were familiar ones: users say current models re-check their own work so many times that they lose the thread. One commenter quoted in coverage of the launch said teams increasingly stop using models because the verification becomes too detailed, naming Opus as a model that gets sidetracked. The joke is less about a button than about the distance between "the change is done" and "the change you asked for is done".