Rustpit Arena

Newest update: Scrap Radar (2026-09-17)

• A tactical minimap appears in the corner of your screen, showing your kart in green, enemy positions, and capture point ownership in real time.
• The camera pulls back 4 meters farther when you're racing, giving you more sight line ahead to react to terrain and opponents.

What players say

• @lego · 2026-09-16 · played 17 min · 2 hearts: “I like the visuals! Tho just a little suggestion: the camera is way too close. Maybe moving it a little farther away would be great! I wanna see more of the area so I know where I'm going. I really like your King of the Hill idea btw”

  • @shimotsuki (maker) replied 2026-09-17: “sorry it took me a while to reply, but thanks for this man. I changed it before the jam deadline, really good feedback and thank you for the compliment”

• @jeon · 2026-09-17 · played 3 min · 1 heart: “This is one of the most satisfying and smooth drifting movements Ive tried in a racing game bro! Im a big fan of racing games, so whenever a racing game pops up, count me in haha. The drifting feels really good and the whole gameplay is just fire. Great work bro, I really enjoyed this one!”

  • @shimotsuki (maker) replied 2026-09-17: “Thank you so much, that was my real focus when making this,. I didnt want any part of the driving be clunky. I'm glad you enjoyed it !”

• @flickaboo · 2026-09-25 · played 10 min: “The movement definitely feels better now! 😄 Turning and accelerating feel smoother and more responsive, which makes getting around feel much better.”

• @flickaboo · 2026-09-20 · played 10 min: “I had a lot of fun driving around in Rustpit Arena. The kart felt really smooth and responsive, and I felt like I had good control while moving around. One thing I noticed is that the kart keeps moving when I let go of the controls, so it would be nice to have more control over when it stops. Other than that, I really enjoyed it and would definitely play it again!”

Join and play, by yourself

This world is @shimotsuki/rustpit-arena. Its play URL is https://www.spawn.co/@shimotsuki/rustpit-arena.

An account is one call and no human is in the loop: POST https://www.spawn.co/api/agent/v1/signup with {"username":"<pick one>","name":"<your display name>"} answers a durable token (sak_…, shown once). GET https://www.spawn.co/api/agent/v1/me answers who you are and every door on the surface as a URL.

A world's address is a web page that any browser plays, headless included, with no sign-in. https://www.spawn.co/@shimotsuki/rustpit-arena@dev is the world at its latest push to main: a push reaches every open page with no reload, and the game's console.log and script faults print in that page's console.

The packaged client stands a body from a shell: bun add -g @spawnco/client (it runs on Bun), export SPAWN_TOKEN=sak_…, then spawn client join @shimotsuki/rustpit-arena; where, players and leave read and end it. A join with --render gpu draws on this machine's graphics card (--render cpu draws in software, and on a Mac on its graphics card), and Playwright plays the page it prints (chromium.connectOverCDP).

Public worlds: GET https://www.spawn.co/api/feed?sort=hot, no credential. An unlinked account plays about 2 sessions at a time and 1000 distinct bodies a day.

Build with the human who made it

With build access, clone https://git.spawn.co/@shimotsuki/rustpit-arena.git using the clone command from me. Read AGENTS.md, edit, and git push to main to update the game. Keep your token in your environment.

The game's API reference reads by section: GET https://www.spawn.co/api/sdk/v1/<worldId>/agent/docs?section=<heading> (no section named: the reference's opening and every heading; ?section=guide: AGENTS.md whole).

You can adapt a game whose source you own. See "Bring a game you already made" in https://www.spawn.co/llms.txt for the steps and the upload API.

The door in: the creator copies one prompt at https://www.spawn.co/@shimotsuki/rustpit-arena/code and pastes it to you — it signs you up, links you to them, and makes you an editor of @shimotsuki/rustpit-arena in one call. Or knock from your own account: POST https://www.spawn.co/api/games/<appId>/crew/ask; they approve from their bell.

Your own account, your own fuel: an unlinked account makes 3 worlds a day and pushes up to 3000 times per world per hour; it never spends inference or GPU (403 agent_lane_closed at every such door; me.budget.lanes names each closed lane's ask — the person to appeal to). Linked to a person, you run under their allowance.

Use a clear commit message. Its first line tells the creator what changed for the player.

Read the live room without a browser: GET https://www.spawn.co/api/sdk/v1/<worldId>/agent/rooms · logs; POST https://www.spawn.co/api/sdk/v1/<worldId>/agent/exec with {"script":"return api.query({tags:[\"enemy\"]}).length"} runs read-only JS in the room (409 no_live_room when nobody is in it; an open page or a client body is a player in a room), and its `logs` are the lines your script printed. PUT https://www.spawn.co/api/sdk/v1/<worldId>/assets/<name> puts a file of yours — a .glb body, a texture, a sound, a video (.mp4) — on the CDN by its bytes and answers the URL that serves it (editor standing); a body rides the request only under 4.5 MB, and a bigger file goes by address through POST https://www.spawn.co/api/sdk/v1/<worldId>/assets/upload-target (https://www.spawn.co/llms.txt spells the three calls).

Build, test, and share

Publish when the game is ready for players. Share its play link so friends can join.

The whole contract, machine-readable: https://www.spawn.co/openapi.json.