CHOP FIRST, a free browser car racing game I built with AI, just got its biggest update. Until now every race in the game was against a ghost, either your own best lap or a friend’s recorded run in the 24 hour time attack. That changes with Arcade, a new mode that puts an AI driver on the grid instead. His name is Ananse, and getting him to actually drive well took three different Claude models, ending with Claude Fable 5, back in my toolbox for the first time since its export control suspension.

If you have not tried CHOP FIRST yet: it is a browser car racing game built with Next.js and React Three Fiber, no install and no account required. You choose from four cars and three circuits, an alpine touge, the streets of Accra, and a neon highway in orbit, then set a time and send the link to friends. Your friends have 24 hours to ‘chop it’ (which is pidgin for winning something) before the challenge expires. The last update added Day, Dusk, and Night driving to the tracks, a live gap timer, and medal tiers. This one adds an entirely new way to race.

What’s is The Arcade Mode

Its a race against an AI rival with personality. The Time Attack races you against a ghost, a translucent replay of an actual lap someone already drove. Arcade puts a real opponent on the track with you instead. Ananse, named after the trickster spider from Ghanaian folklore, drives a purple and gold coupe, reads the road every frame, brakes and boosts based on what is actually happening in the race, and talks trash the entire way down.

The first version of Ananse just got wrecked if you rammed him. Now a hard hit puts him into a short push mode. He absorbs the crash, then comes back at you with a boost the moment the road opens. I tested this by simulating a player spinning him out every ten seconds for three minutes, 22 spins total. He recovered every single time, worst case under a second and a half.

Three difficulty moods. Once Ananse was actually driving properly (more on that below), one difficulty was not enough. I could beat him too easily, and a beginner would not have stood a chance either way. Arcade now opens with a choice. Cruising hangs back and almost never boosts, built for new drivers. Race Pace is the honest fight, always close, always beatable, holding an average gap of about 19 metres in testing. Full Trickster runs at gold medal pace, brakes late, and boosts on sight, beating a simulated gold medal lap by 215 metres. Same AI brain underneath all three. Only his appetite for risk changes, which is why he still feels like the same character instead of three different robots.

A couple of confusing bugs got cleaned up too. The Time Attack ghost used to sneak into Arcade races, and an Arcade win could quietly overwrite the real personal best. The two modes now run fully separate, down to their own finish screens. Ananse also got a wardrobe fix. The image model that first drew him invented a fake sponsor patch. His racing suit now reads CHOP FIRST with real patches for Explorer 233 and The August Dispatch.

How Claude Fable 5 Finished the Job Sonnet and Opus Started

I built the first version of Ananse on Sonnet 4.6, my daily driver for vibe coding projects. But the physics did not hold. Touch the guardrail even slightly and the car would lock against it, glued in place, unable to peel away while the throttle stayed pinned.

So I moved to Opus 4.8 next. It fixed the wall problem, and fixed a second issue where Ananse steered like he was arm wrestling the wheel, holding acute positions instead of tapping them the way a human does, which kept tripping the drift physics. His steering corrections dropped from about 1.5 direction flips per second to 0.23, and the drift flicker that caused it went from 40 percent of frames to zero. But a third bug would not budge. Ananse would sprint to 180 km/h, slam the brakes down to 29, crawl through a gentle bend, then sprint again, like a nervous learner on every single corner.

That is where Claude Fable 5 came in, and the timing mattered. Fable 5 originally helped get CHOP FIRST built in the first place back in June, before the US government ordered Anthropic to suspend access to it and Mythos 5 over export controls on June 12. I finished the last update on Opus instead. Access was restored July 1, and Anthropic issued a credit to affected users, which is what I used to bring Fable 5 back into the workflow for this fix.

Instead of guessing at the bend problem again, we ran the game’s actual physics in Claude Code. The simulation showed it clearly. The track stores a number describing how sharp each curve is, but it is a value scaled for drawing the road, not real geometry, and it runs about 70 times larger than the actual angle. Ananse was reading every gentle sweeper on the mountain as a hairpin. Once we measured the road’s real curvature and asked a simple physics question at each point, how fast can this car actually take this bend, lap time dropped from 70 seconds to 45 on the spot. That fix is also what made building three honest difficulty levels possible. You cannot tune a mood system on top of physics that do not work yet.

Late Addition: Before pushing the changes to the game, i used Opus 5 to improve the UI and some features, but i’ll talk about that on my review of Opus 5 in a separate blog.

Try Arcade Mode

CHOP FIRST is free at chop-first.vercel.app, no install, no account. Pick Arcade, choose your difficulty, and see if you can get Ananse to stop talking. The in game feedback button goes straight to me if something breaks or you have an idea for what is next.

I am already thinking about where Arcade goes from here, whether that is more AI drivers with their own personalities, or actual people racing each other live instead of asynchronously. Either way, it’ll show up here first.

FAQ

Does Ananse drive differently at each difficulty, or is he a different AI at each level? Same brain at every level. Cruising, Race Pace, and Full Trickster all run the identical driving model, only his aggression, braking points, and boost frequency change between them.

What is rubber banding in a racing game, and does Ananse use it? Rubber banding ties an AI opponent’s pace to how close the player is, so the race stays tight instead of turning into a runaway or a procession. Done badly it feels like cheating, an AI that teleports back to you no matter what you do. Ananse has a real skill ceiling and floor at every difficulty, so he never breaks that rule, he just plays closer to one edge or the other depending on the mood you pick.