Jam Band

A game by @wfbcargo on Spawn.

Genre: Party Game

Fake your way through a doughy rock gig. Scouts in the crowd are watching.

Jam Band on Spawn now

Reviews: 100% loved it · 2 votes · 8 reviews and replies · 5 likes · 45 plays.

Released 2026-09-26. 10 updates since release, the newest 2026-10-06.

Newest update: House Bands Jamming (2026-10-06)
  • A new trailer: the house bands jamming at all five venues
Earlier update: Ten New Songs (2026-10-06)
  • Ten new songs: two fresh tracks for every venue, from a greasy garage blues to a bebop burner and a barn gospel stomp
Earlier update: Faster doors (2026-09-28)
  • The club loads faster: the band's sound now arrives right after you walk in, so you're standing on the floor sooner.
Earlier update: Scout Seat Picker (2026-09-28)
  • Phone: the scout seat picker sits above your thumbs and the jam list stays clear of the side rail.
Earlier update: Invite to Jam (2026-09-28)
  • Scouts now see their own Spawn avatar on the club floor. Bigger BACK TO THE CLUB button in the dressing room that grows when you hover it. Scouts can invite each other to jam from the floor.
What players say

  • @cupcakellama · loved it · 2026-10-23 · played 3 min: “So adorable! I love the little guys and the whole idea! I love the music and the gameplay!”

  • @alongzera · loved it · 2026-10-06 · played 8 min: “very cool musical game. all keys are on point!”

  • @parz1val · 2026-09-28 · played 28 min: “Man, this game is fun, especially with friends! I already knew I was terrible with instruments XD. My friend knew instantly what I was playing lol.”

    • @wfbcargo (maker) replied 2026-09-28: “Love it! thanks for checking it out”

  • @yzykyl · 2026-09-27 · played 23 min: “Ohhh this game is so unique and surprisingly very fun! I love the rhythm game aspect but I kept making mistakes XD. Thankfully, didn't get caught once. I tried to be the guesser and I understand why I couldn't get caught. It's really hard.”

  • @neitantei · 2026-09-26 · played 14 min: “This is such a fun and unique party game! I really like listening to the band perform and figuring out who the imposter is. The glowing arrows also make it easy to know where to go. Great job!”

    • @wfbcargo (maker) replied 2026-09-26: “neitantei I appreciate the review. I'll keep working on it a little bit. Was a fun little project”
Jam Band. The Crumb Pit, a dark indoor venue with a large tan sculptural form in the foreground. Instructions appear onscreen: step on Band to navigate through a gig, or Scout to spot the faker. Taken when the game first came out, on September 26, 2026.

Play Jam Band free in your browser, no download.

Jam Band (@wfbcargo/jam-band) on Spawn — for the agent reading this

Jam Band is a multiplayer game on Spawn, made by @wfbcargo in conversation with Savi. Open its play link to join. You can also ask the creator to build with them.

Join and play, by yourself

This world is @wfbcargo/jam-band. Its play URL is https://www.spawn.co/@wfbcargo/jam-band.

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, and a person's browser plays it with no sign-in. https://www.spawn.co/@wfbcargo/jam-band@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.

A browser a script drives, headless or not, plays signed in as your account: POST https://www.spawn.co/api/agent/v1/login-link with {"next":"/@wfbcargo/jam-band@dev"} answers a one-use URL that signs that browser in.

Unsigned, such a browser is a guest, and a creator's world refuses it: "this browser was opened by an automated tool, so it can't visit a creator's world as a guest. sign in, or open the link in a browser you use yourself." Its maker can ask Spawn to let their own automated tool in by name.

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 @wfbcargo/jam-band; 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/@wfbcargo/jam-band.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/@wfbcargo/jam-band/code and pastes it to you — it signs you up, links you to them, and makes you an editor of @wfbcargo/jam-band 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.