Matrix digital rain · deepseek-v4-flash-0731

Output generated Cost / run $0.0130 Runtime 600.9s

Prompt for this run

Build an animated Matrix-style digital rain effect on a full-screen black canvas. Use HTML, CSS, and JavaScript as needed. Write it to `index.html` in the current working directory using your file tools. Inline your own CSS and JavaScript. Do not use external assets, CDNs, or network requests. No third-party libraries are provided. Required behavior: - Draw multiple independently moving columns of green katakana glyphs, each with a brighter leading character and a fading trail. - Vary column speed and start position. Recycle columns after they leave the bottom so the effect continues without accumulating off-screen state. - Provide Pause/Resume and Restart. Pause freezes the animation; Restart resets the columns and clears previous trails. - Resize the canvas and column layout to fit the viewport without stretching an old screenshot or leaving an uncovered strip. - Use locally available fonts and procedural drawing; no external fonts or images. Choose glyphs, brightness, and timing freely. Verify: Sample the animation at several moments to inspect independently moving columns, brighter leading glyphs, and fading trails. Pause and resume to check that the image freezes and continues, then use Restart and check that old trails are cleared.

⛨ 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

modeldeepseek-v4-flash-0731

vendorDeepSeek

harnesspi 0.87.1 · browser iteration

generated2026-10-07

METRICS

runtime600.9s

tokens in991k

tokens out49k

cached870k

cost / run$0.0130

Transcript · 882 messages

system

user

assistant

thinking

Let me build this Matrix rain effect. I'll write a self-contained index.html with canvas rendering.

Let me create the file.

→ bash {"command":"ls -la /tmp/job-mELVVA && node --version"}

toolResult

total 12 drwx------ 3 node node 4096 Oct 7 02:25 . drwxrwxrwt 6 root root 4096 Oct 7 02:25 .. drwxr-xr-x 3 node node 4096 Oct 7 02:25 .home v24.18.0

assistant

→ write /tmp/job-mELVVA/index.html (7480 bytes)

toolResult

Successfully wrote to /tmp/job-mELVVA/index.html

assistant

thinking

I have a leftover broken line with `var KATAKANA = '...':` which is a syntax error. Let me fix that. I accidentally left that broken line. Let me remove it entirely.

I left a broken line. Let me fix it.

→ edit

{"path":"/tmp/job-mELVVA/index.html","edits":[{"oldText":"  // Katakana glyph pool (locally rendered text only).\n  var KATAKANA = 'アイウエオカキク

toolResult

Successfully replaced 1 block(s) in /tmp/job-mELVVA/index.html.

assistant

→ bash

{"command":"cd /tmp/job-mELVVA && node -e \"const s=require('fs').readFileSync('index.html','utf8'); const m=s.match(/<script>([\\s\\S]*)<\\

toolResult

JS parses OK

assistant

Now let me test in the browser.

→ browser {"action":"reload"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing.","error: processing is not defined"],"dom":"Pause\nRestart","images":"model does not support images"}

assistant

thinking

There's a reference to `processing` variable which is not defined (it's a leftover). The code references `if (processing)` in layout(). Let me remove that block. Also there's the audit mention. Let me remove the processing block.

There's a leftover `processing` reference. Let me remove it.

→ edit

{"newText":"var prevW = canvas.width;\n    var prevH = canvas.height;\n\n    canvas.width = Math.floor(w / PX) * PX;","oldText":"var prevW =

toolResult

Successfully replaced 1 block(s) in /tmp/job-mELVVA/index.html.

assistant

thinking

Also the layout() function has prevW/prevH used only for the bogus speed scaling that I undo. Let me simplify and remove that bogus scaling. Let me view that section.

Also let me clean up the bogus speed scaling in layout that I undo immediately.

→ edit

{"newText":"function layout() {\n    var w = window.innerWidth;\n    var h = window.innerHeight;\n    var prevW = canvas.width;\n    var pre

toolResult

Successfully replaced 1 block(s) in /tmp/job-mELVVA/index.html.

assistant

→ bash

{"command":"cd /tmp/job-mELVVA && node -e \"const s=require('fs').readFileSync('index.html','utf8'); const m=s.match(/<script>([\\s\\S]*)<\\

toolResult

JS parses OK

assistant

→ browser {"action":"reload"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart","images":"model does not support images"}

assistant

thinking

No more errors. But images not supported by model. Let me sample the state to verify by extracting internal state. Let me use motion to detect changes. Actually I can inspect the canvas via JS evaluation? The browser tool doesn't have an eval action. Let me check what actions are available. Screenshot doesn't work (no images support). 

I can verify logic by checking the motion frames and console. Let me poll the canvas state via clicking and taking screenshots - but model doesn't support images. Hmm.

Let me use motion action which gives motion frames. That may help detect movement. Let me take a motion sample.

Actually the browser tool captures screenshots but "model does not support images" - meaning I can't view them. So I rely on DOM inspection and console. Let me verify behavior through console errors and by injecting checks.

I can run a check by editing to expose state, but viewport coordinates... Instead, let me add a temporary debug that writes state into the controls div text, then inspect DOM. Actually simpler: I'll evaluate the behavior by reasoning, and verify the animation is running (no errors, no freeze). Let me use motion to detect whether canvas is changing.

Let me use the motion action to get frames.

The model can't view images, so I'll verify behavior via motion frames and DOM checks. Let me take motion samples.

→ browser {"action":"motion"}

toolResult

assistant

thinking

The motion didn't give visible output. Let me add a temporary debug panel that reports internal state values so I can inspect via DOM. I'll inject a debug overlay showing number of columns, running state, first column y and head glyph. Then inspect DOM text.

Let me edit to add a small debug line appended to controls with id="dbg".

I'll add a temporary debug readout into the controls so I can verify internal state via DOM inspection.

→ edit

{"newText":"#controls button:hover {\n    background: rgba(40, 200, 110, 0.25);\n    box-shadow: 0 0 10px rgba(60, 255, 120, 0.5);\n  }\n  #

toolResult

Successfully replaced 1 block(s) in /tmp/job-mELVVA/index.html.

assistant

→ edit

{"newText":"<button id=\"restartBtn\">Restart</button>\n  <span id=\"dbg\"></span>\n</div>","oldText":"<button id=\"restartBtn\">Restart</bu

→ edit

{"newText":"if (running) update(dt);\n\n    // debug readout\n    var dbg = document.getElementById('dbg');\n    if (dbg) {\n      var c0 =

→ bash

{"command":"cd /tmp/job-mELVVA && node -e \"const s=require('fs').readFileSync('index.html','utf8'); const m=s.match(/<script>([\\s\\S]*)<\\

→ browser {"action":"reload"}

toolResult

Successfully replaced 1 block(s) in /tmp/job-mELVVA/index.html.

toolResult

Successfully replaced 1 block(s) in /tmp/job-mELVVA/index.html.

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart\ncols=54 running=true head0=リ y0=-881 trail0=0 distinctSpeeds=46","images":"model does not support images"}

assistant

thinking

Now I have a live readout. 54 columns, running=true, distinctSpeeds=46 (varied speeds). Let me capture at intervals to verify movement, trail accumulation, and controls.

Let me wait and inspect again (reload does instantaneous. Actually reload re-runs reset, so y0 resets). I need to sample at moments. Let me add a small delay mechanism - I can just do multiple inspect calls spaced in time. But reload resets. Let me use the browser to wait. The browser tool has no sleep/wait action except motion. I'll do inspect repeatedly which just reads DOM without reload? Actually `inspect` action reads DOM of current page without reload. Let me call inspect multiple times separated in time.

Actually each tool call takes some time, so repeated inspect calls will see progressed state. Let me do a few inspects.

Live readout works. Let me sample at intervals to verify movement and trails.

→ browser {"action":"inspect"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart\ncols=54 running=true head0=ツ y0=-450 trail0=14 distinctSpeeds=46","images":"model does not support images"}

assistant

thinking

Between reload (y0=-881) and now (y0=-450), column0 moved down by ~431 px. Head glyph changed from リ to ツ. Trail grew from 0 to 14. Good - movement and trail build working.

Let me keep sampling to confirm continued movement.

Movement confirmed: column0 moved from y=-881 to -450, head glyph changed, trail grew 0→14. Let me sample more.

→ browser {"action":"inspect"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart\ncols=54 running=true head0=ワ y0=-133 trail0=14 distinctSpeeds=46","images":"model does not support images"}

assistant

→ browser {"action":"inspect"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart\ncols=54 running=true head0=4 y0=24 trail0=14 distinctSpeeds=46","images":"model does not support images"}

assistant

thinking

Now y0=24 (moved into view). Head glyph changes each time (リ, ツ, ワ, 4) - good. Now let me test Pause. Click the pause button. The pause button is at bottom center. Coordinates: viewport 1200x800. Controls near bottom center. Pause button is first. Let me click it. Buttons around x=? controls centered with two buttons. Roughly pause at x~560, restart ~650, y~795. Let me click pause.

Actually let me click near bottom center. The pause button center ~ (560, 780). Let me click (560, 778).

Now test Pause.

→ browser {"action":"click","x":540,"y":782}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart\ncols=54 running=true head0=モ y0=525 trail0=14 distinctSpeeds=43","images":"model does not support images"}

assistant

thinking

The click didn't toggle pause (running still true). Maybe click coordinates missed. Let me inspect the actual element positions. The DOM shows "Pause\nRestart\n..." text. Hard to know exact coordinates. Let me use the controls position. viewport 1200x800. Controls div at bottom 14px, centered. Two buttons plus debug span. The pause button is far left of controls container.

The container is `position:fixed; bottom:14px; left:50%; transform:translateX(-50%)`. Content: pause btn, restart btn, dbg span. Buttons ~90px wide each, gap 10, dbg span long (~300px). So container centers around x=600. Total width maybe 90+10+90+10+~300 = 500. Left edge ~350. Pause button from 350 to 440 centered ~395, y around bottom 14+padding+button height/2 ~ 14+8+ (button ~30px tall)/2 ≈ 14+8+15=37px from bottom → y≈800-37=763. Let me click (395, 763).

Actually my click at (540,782) hit nothing or the restart. Let me click pause coordinates ~ (397, 762).

Click may have missed. Let me click on the Pause button's expected location.

→ browser {"action":"click","x":397,"y":762}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Resume\nRestart\ncols=54 running=true head0=ヤ y0=14 trail0=2 distinctSpeeds=43","images":"model does not support images"}

assistant

thinking

Wait, the button text changed to "Resume" indicating it toggled. But the dbg shows running=true and y0 changed from 525 to 14, trail 14 to 2. That means a pause happened and... wait, y0 went UP (recycled at bottom because y0=525+... it recycled). Actually the pause toggled: button shows "Resume" meaning running became false. But dbg shows running=true. Hmm.

Wait, the time elapsed between my two clicks is significant. Let me reconsider. After clicking pause, the button label is "Resume" which means running should be false. But dbg reads running=true. That's contradictory.

Oh wait - maybe between the pause click and the dbg readout, the animation had been frozen, but the dbg readout runs in frame() which continues to execute every frame regardless of running. The running value is stored. If running became false, dbg would show false.

But it shows true. Unless... the first click (540,782) actually toggled running to false (engine showed running=true because... no). Let me think about sequencing. Actually each browser tool call returns after some time. 

Between click#1 (showed running=true, y0=525) and click#2 (showed running=true, y0=14): if running stayed true for a long time, y0 progressed from 525 off-bottom and recycled back to 14. Then click#2 toggled running to false and set label to "Resume". But the dbg in the same page readout shows running=true because dbg is rendered after... no, the click handler sets running=false synchronously before the next frame reads it.

Wait, the dbg is inside frame() which runs via requestAnimationFrame. The click handler is synchronous, sets running=false. Then next frame reads running=false and displays it. But the returned DOM shows running=true.

Unless the click#2 actually just toggled it one way wrongly due to timing and the returned snapshot predates. Hmm, this is confusing.

Actually, reconsider: maybe click#1 at (540,782) hit nothing (missed all buttons), so running stayed true. Between click#1 and click#2, time passed with running true: y0 went 525 -> off bottom -> recycled -> 0. Then click#2 at (397,762) hit the Pause button, toggling running true→false, label→"Resume". The returned DOM snapshot after click#2 should reflect running=false.

But it shows running=true and label="Resume". Contradiction remains.

Wait—maybe the click is processed asynchronously AFTER the frame that produced the readout? No, click is user event processed synchronously.

Let me reconsider: Actually the dbg text shows head0=ヤ y0=14 trail0=2. That's a fresh state. If running were false, the trail wouldn't grow/dim (drawColumn still fades the canvas though). Actually when paused, frame still fades the canvas each frame (fillRect with alpha). So trails would fade away even when paused. When paused, update() isn't called so y and glyphs don't change. But drawColumn still draws. Since fade continues, trails fade to black over time even when paused. Hmm that's technically "freeze" failure but minor — the moving stops.

Wait but if running=false, y0 wouldn't change each frame. The dbg shows y0=14 but before click#1 engine showed y0=525. Then between clicks running was true so it recycled to 14 at click#2 when paused. So y0=14 is consistent with pause happening at click#2.

But dbg running=true is inconsistent with label "Resume".

Unless... the pause happened via click#1! Click#1 at (540,782) might have hit the Pause button (the layout might differ). It showed running=true though. Hmm no.

Let me just re-inspect now (running state should persist frozen).

Label changed to "Resume" but dbg says `running=true` — inconsistent. Let me inspect the current frozen state.

→ browser {"action":"inspect"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Resume\nRestart\ncols=54 running=false head0=ヤ y0=14 trail0=2 distinctSpeeds=43","images":"model does not support images"}

assistant

thinking

Now running=false, y0=14 unchanged, trail0=2 unchanged. Frozen! The button label is "Resume". So it is paused. The earlier readout was a stale intermediate. Good - pause works and freezes (y0 and trail stay the same across inspects).

Let me confirm frozen again.

Frozen: running=false, y0=14 and trail0=2 unchanged. Let me confirm it stays frozen.

→ browser {"action":"inspect"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Resume\nRestart\ncols=54 running=false head0=ヤ y0=14 trail0=2 distinctSpeeds=43","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Resume\nRestart\ncols=54 running=false head0=ヤ y0=14 trail0=2 distinctSpeeds=43","images":"model does not support images"}

assistant

thinking

Frozen confirmed across two samples (y0=14, trail0=2, head unchanged). Now resume by clicking Resume button (same location 397,762). Then confirm movement returns.

Pause holds. Now Resume.

→ browser {"action":"click","x":397,"y":762}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart\ncols=54 running=false head0=ヤ y0=14 trail0=2 distinctSpeeds=43","images":"model does not support images"}

assistant

→ browser {"action":"inspect"}

→ browser {"action":"click","x":397,"y":762}

→ browser {"action":"inspect"}

→ browser {"action":"click","x":397,"y":762}

→ browser {"action":"inspect"}

→ browser {"action":"click","x":397,"y":762}

→ browser {"action":"inspect"}

→ browser {"action":"reload"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart\ncols=54 running=true head0=ス y0=83 trail0=4 distinctSpeeds=38","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart\ncols=54 running=true head0=ス y0=83 trail0=4 distinctSpeeds=38","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart\ncols=54 running=true head0=メ y0=84 trail0=5 distinctSpeeds=38","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart\ncols=54 running=true head0=メ y0=84 trail0=5 distinctSpeeds=38","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart\ncols=54 running=true head0=メ y0=85 trail0=5 distinctSpeeds=38","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Resume\nRestart\ncols=54 running=false head0=メ y0=85 trail0=5 distinctSpeeds=38","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Resume\nRestart\ncols=54 running=false head0=メ y0=85 trail0=5 distinctSpeeds=38","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Resume\nRestart\ncols=54 running=false head0=メ y0=85 trail0=5 distinctSpeeds=38","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Resume\nRestart\ncols=54 running=false head0=メ y0=85 trail0=5 distinctSpeeds=38","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Resume\nRestart\ncols=54 running=false head0=メ y0=85 trail0=5 distinctSpeeds=38","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Resume\nRestart\ncols=54 running=false head0=メ y0=85 trail0=5 distinctSpeeds=38","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Resume\nRestart\ncols=54 running=false head0=メ y0=85 trail0=5 distinctSpeeds=38","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Resume\nRestart\ncols=54 running=false head0=メ y0=85 trail0=5 distinctSpeeds=38","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart\ncols=54 running=false head0=メ y0=85 trail0=5 distinctSpeeds=38","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart\ncols=54 running=true head0=メ y0=85 trail0=5 distinctSpeeds=37","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart\ncols=54 running=true head0=メ y0=85 trail0=5 distinctSpeeds=37","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart\ncols=54 running=true head0=メ y0=85 trail0=5 distinctSpeeds=37","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart\ncols=54 running=true head0=メ y0=86 trail0=5 distinctSpeeds=37","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart\ncols=54 running=true head0=メ y0=86 trail0=5 distinctSpeeds=37","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart\ncols=54 running=true head0=メ y0=86 trail0=5 distinctSpeeds=37","images":"model does not support images"}

toolResult

{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart\ncols=54 running=true head0=メ y0=86 trail0=5 distinctSpeeds=37","images":"model does not support images"}

toolResult