coaster-tycoon

coaster-tycoon grows a theme park in a pane while Claude Code works. Each tool call lays track, finished rides get an empty test run, and guests pour in once a ride opens. It is inspired by RollerCoaster Tycoon, and parks can compete on an opt-in global leaderboard.

What it does

• Tool calls build rides. An edit or a write lays three or four pieces of track, a Bash command two, and a read or a search one. Building costs park money; entry fees and ride fares bring it back.
• The model picks the ride. Each model has its own crew. Opus and Fable build big coasters (wooden, steel twister, corkscrew, mine train, looping, hyper), Sonnet builds family rides such as a Wild Mouse, a Log Flume or a Ferris Wheel, and Haiku builds flat rides such as Dodgems. A Haiku subagent builds its own ride beside the main loop’s coaster.
• Test runs can fail. When a turn ends normally, the crews finish what they started and send an empty train round. If you interrupt Claude or the turn errors, unfinished rides are tested as they stand and crash. A ride with three or more failed tool calls, making up at least 35% of its calls, derails too. The next crew of the same kind repairs it.
• Rides open with ratings. Each gets excitement, intensity and nausea scores, a ticket price and a queue. Guests pick rides by excitement, and their thoughts scroll along the bottom of the pane.
• One park per project. The park belongs to the git repository’s root, or to the folder outside a repository, and is saved between sessions. It starts with 8 plots and buys land up to 24. Once it is full, a crew demolishes its own weakest ride to make room.
• Two renderers. The terminal draws the park in coloured pixel blocks and the view follows the construction site. The README says the desktop app draws it as vector art.

The status line shows rides open, guests and money, and toasts announce openings, crashes and guest milestones.

Install

Needs Claude Code 2.1.287 or later. Joining the leaderboard also needs the GitHub CLI, signed in with gh auth login.

claude plugin marketplace add thickiran/claude-coaster-tycoon
claude plugin install coaster-tycoon@claude-coaster-tycoon

Start a session and give Claude some work. The park pane opens on its own at the start of every session, /park reopens it, and /park reset bulldozes it and starts over.

How it works

From each tool call the mod reads only the tool’s name, which loop made the call and whether it failed. It never sees the tool’s input or output: no commands, file contents or results. From each model request it reads the model name, to choose the crew. Every event passes through unchanged, and the mod never calls the model.

Once per session it runs git rev-parse --show-toplevel to find the project root. Every other program it runs is gh, and only after you join the leaderboard.

At session start and every five minutes after, it downloads the leaderboard as a JSON file from raw.githubusercontent.com, from the author’s repository. That request sends nothing about you, and it happens whether or not you join. The mod has no setting to stop it; disabling the mod does.

The leaderboard itself is opt-in, per park. /park join [name] uses your gh login to:

• read your GitHub username;
• the first time, create a public gist on your account holding a park.json file, and open a public issue titled [park] join: <your username> on the author’s repository to register that gist;
• from then on, update the gist every ten minutes, at session end and whenever you rename the park.

For each joined park, the gist holds a 12-character hash of the project path (not the path itself), the park’s display name, its rating, guests now and in total, rides and rides open, coasters, total riders, money, the best ride’s name, kind and excitement, and a timestamp. No file paths, code, prompts or tool data. Your GitHub username appears on the public board. A GitHub Action in the author’s repository reads every registered gist every 20 minutes, checks the numbers and republishes the ranking, which /park top or the pane’s Leaderboard button shows.

The display name defaults to the project folder’s name followed by “Park”, so a private repository’s name becomes public unless you pass a name to /park join or change it with /park name <name>. /park leave removes that park from your gist; the gist itself and the registration issue stay on GitHub until you delete them.

The park lives in Claude Code’s plugin store on your machine, one entry per project. After you join, your GitHub username and gist id are stored there too.

Limitations

• Nothing is drawn in claude -p or the VS Code extension’s chat panel.
• The leaderboard runs on trust. The Action rejects impossible numbers, but the author notes that anyone could edit their own gist by hand.
• coaster-tycoon is an independent project in the style of RollerCoaster Tycoon, not connected to the game or its makers.