Shapeshifter

Newest update: The Honest Blade (2026-08-09)

• The road now escalates. Early bosses hit softer and late ones hit harder, so the first fight stops deciding the run — a boss's danger comes from where it stands on the road, not just who it is.
• The boss plate stops lying. The number telegraphed above a boss is now the number that actually lands, room modifiers and road position included — scry and reroll tells scale with it too.
• Every boss has a theme. Sixteen tracks, plus the hall, the ring, the merchant's stall and the lament for a run that ends.
• Gamblers fork their turn. Some bosses now telegraph a coin — heads and tails, both faces shown before it flips.

Earlier update: The Hard Pass (2026-08-03)

• A full orchestral score — a theme per boss, a quiet stall for the merchant, and a cello lament when you fall. The difficulty pass: kills pay back less vigour, act-two blows land harder, and repeated boss intents escalate. New About page explaining the loop. Painted strike, guard and hurt poses for the fighters in the ring.

What players say

• @makeriffic · 2026-08-09 · played 1 hr 34 min: “I personally am hooked into this game. I love the complexity and understanding needed to master the marks, words, and boons in-game. I just wish there was more difficulty or maybe I am just that good in deckbuilding? lol”

Join and play, by yourself

This world is @the_greek_lobster/shapeshifter. Its play URL is https://www.spawn.co/@the_greek_lobster/shapeshifter/play.

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/@the_greek_lobster/shapeshifter@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 @the_greek_lobster/shapeshifter; 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

This game runs an engine from before 6.0 and has no repository to clone. Its creator can open https://www.spawn.co/@the_greek_lobster/shapeshifter/code for upgrade instructions.

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.

Ask to build with the creator: POST https://www.spawn.co/api/games/<appId>/crew/ask. They approve from their bell. The code page offers an invite prompt after the game moves to 6.0.

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.