Mario-style platformer · claude-sonnet-5.5

Output generated Cost / run $0.1152 Runtime 58.9s

Prompt for this run

Using the pre-provided phaser.min.js (global Phaser), build a playable side-scrolling platformer in the classic Mario style: run and jump across scrolling platforms, stomp enemies, collect coins, and reach a goal flag. Use ONLY procedurally generated graphics, no external image or audio assets.

⛨ sandboxed Open in new tab ↗

TAKE IT TO CODE

A single self-contained HTML file — copy it and open in any browser, or reuse the prompt with your own pi-agent run.

RUN

modelclaude-sonnet-5.5

vendorAnthropic · Claude

harnesspi 0.87.1 · browser iteration

generated2026-10-05

METRICS

runtime58.9s

tokens in64k

tokens out6.7k

cached48k

cost / run$0.1152

Transcript · 18 messages

system

user

assistant

→ bash {"command":"ls -la; head -c 200 phaser.min.js | head -3"}

toolResult

total 1168 drwx------ 3 node node 4096 Oct 5 05:21 . drwxrwxrwt 6 root root 4096 Oct 5 05:21 .. drwxr-xr-x 3 node node 4096 Oct 5 05:21 .home -rw-r--r-- 1 node node 1181917 Oct 5 05:21 phaser.min.js !function(t,e){"object"==typeof exports&&"object"==typeof module?module.exports=e():"function"==typeof define&&define.amd?define("Phaser",[],e):"object"==typeof exports?exports.Phaser=e():t.Phaser=e()

assistant

thinking

I'm planning a compact platformer with a 4800x450 world, arcade physics, generated textures for tiles and sprites, ground segments with gaps, floating platforms, patrolling enemies, coins, a flag goal, and lives/score/restart logic.

Player will have variable jump height with coyote time, arrow/WASD controls, and stomp detection based on falling velocity and vertical position relative to enemies. I'll skip touch controls and use a simple try-wrapped oscillator beep for sound instead of relying on Phaser's audio system.

→ bash

{"command":"cat > index.html <<'E'\n<!DOCTYPE html><html><head><meta charset=\"utf-8\"><title>Super Platformer</title>\n<style>html,body{mar

→ browser {"action":"screenshot"}

toolResult

(no output)

toolResult

Frame 1, +0ms

[Browser image supplied to model]

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing.","error: Unexpected token ','"],"dom":"","images":"attached"}

assistant

thinking

I'm scanning through the code line by line looking for the syntax error causing the unexpected comma token, checking fillRect calls, ternary expressions, and object definitions for a stray comma.

→ bash

{"command":"sed -n '/<script>/,/<\\/script>/p' index.html | sed '1d;$d' > /tmp/t.js; node --check /tmp/t.js 2>&1 | head"}

toolResult

/tmp/t.js:43 }, ^ SyntaxError: Unexpected token ',' at wrapSafe (node:internal/modules/cjs/loader:1804:18) at checkSyntax (node:internal/main/check_syntax:76:3) Node.js v24.18.0

assistant

Class methods can't be separated by commas.

→ bash

{"command":"sed -i -E 's/^\\},$/}/' index.html; sed -n '/<script>/,/<\\/script>/p' index.html | sed '1d;$d' > /tmp/t.js; node --check /tmp/t

→ browser {"action":"reload"}

toolResult

/tmp/t.js:44 plat(x,y,w,h,t){const s=this.add.tileSprite(x,y,w,h,t).setOrigin(0,0);this.physics.add.existing(s,true);this.solid.add(s);}, ^ SyntaxError: Unexpected token ',' at wrapSafe (node:internal/modules/cjs/loader:1804:18) at checkSyntax (node:internal/main/check_syntax:76:3) Node.js v24.18.0

toolResult

Frame 1, +0ms

[Browser image supplied to model]

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing.","error: Unexpected token ','"],"dom":"","images":"attached"}

assistant

→ bash

{"command":"sed -i -E 's/^(plat|makeTex|hit|die|win)(\\(.*)\\},$/\\1\\2}/; s/^(plat\\(.*\\);\\}),$/\\1/' index.html; sed -i -E '/^(plat|make

toolResult

(no output)

assistant

→ browser {"action":"reload"}

→ browser {"action":"key","text":"ArrowRight"}

toolResult

Frame 1, +0ms

[Browser image supplied to model]

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing.","log: %c %c %c %c %c Phaser v3.80.1 (WebGL | Web Audio) %c https://phaser.io background: #ff0000 background: #ffff00 background: #00ff00 background: #00ffff color: #ffffff; background: #000000 background: transparent","warning: [.WebGL-0x1e7400158800]GL Driver Message (OpenGL, Performance, GL_CLOSE_PATH_NV, High): GPU stall due to ReadPixels","warning: [.WebGL-0x1e7400158800]GL Driver Message (OpenGL, Performance, GL_CLOSE_PATH_NV, High): GPU stall due to ReadPixels","warning: [.WebGL-0x1e7400158800]GL Driver Message (OpenGL, Performance, GL_CLOSE_PATH_NV, High): GPU stall due to ReadPixels","warning: [.WebGL-0x1e7400158800]GL Driver Message (OpenGL, Performance, GL_CLOSE_PATH_NV, High): GPU stall due to ReadPixels (this message will no longer repeat)"],"dom":"","images":"attached"}

toolResult

Frame 1, +0ms

[Browser image supplied to model]

assistant

I've built the platformer in `/tmp/job-euYeDk/index.html`. It loads, renders and shows no script errors, but I only checked the first screen. I didn't play it through, so jumping, stomping, coin pickup and the flag are untested. The first screenshot showed the hero, two enemies, coins, brick platforms and the HUD. The first load failed on a syntax error: I had put commas between class methods. After I removed them it ran. I sent one right-arrow key press and didn't screenshot the result. - **Controls:** arrow keys or A/D to move, and up, W or Space to jump. R restarts. - **Level:** it scrolls across a 5200-pixel world with gaps in the ground, floating brick platforms and a staircase before the goal. - **Goal:** a flagpole and castle sit at the end of the level. - **Pickups and enemies:** there are 31 coins and 14 walking enemies. Stomping an enemy from above scores 200 and bounces you. Touching one from the side, or falling into a gap, costs a life. - **Lives:** you start with 3. At zero lives you get a game-over screen, and R or Space restarts. - **Winning:** reaching the flagpole lowers the flag and walks you to the castle. The win screen shows your score. - **Graphics and sound:** all graphics are drawn in code, and the sound effects are generated in the browser. There are no external assets.