Double pendulum · mistral-large-4-0
Output saved · Stopped by an API error Cost / run $0.3158 Runtime 327.8s
A model request failed and its retries ran out. The output is the HTML saved before that.
Prompt for this run
Build a planar double-pendulum simulation on a canvas with a colorful fading trail at the lower bob. 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: - Model two point masses connected by massless rigid rods under gravity, without damping or external driving. Use the coupled equations of motion rather than independent sine-wave animations. - Use equal masses and rod lengths, gravity of 9.81 in consistent simulation units, initial angles of 120 and -10 degrees measured from downward vertical, and zero initial angular velocities. - Draw a fixed pivot, both rods and bobs, and a bounded fading trail of the lower bob. Keep both rod lengths constant and the pendulum visible. - Provide Pause/Resume and Reset. Reset restores the stated initial conditions and clears the trail. - Use a numerically stable integration scheme and time step so ordinary playback does not explode or freeze. Verify: Sample the pendulum at several moments to inspect coupled motion, connected rods, and the lower-bob trail. Pause and resume to check the motion control, then reset and confirm that the starting pose and cleared trail return.
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
METRICS
Transcript · 46 messages
Build a planar double-pendulum simulation on a canvas with a colorful fading trail at the lower bob. 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: - Model two point masses connected by massless rigid rods under gravity, without damping or external driving. Use the coupled equations of motion rather than independent sine-wave animations. - Use equal masses and rod lengths, gravity of 9.81 in consistent simulation units, initial angles of 120 and -10 degrees measured from downward vertical, and zero initial angular velocities. - Draw a fixed pivot, both rods and bobs, and a bounded fading trail of the lower bob. Keep both rod lengths constant and the pendulum visible. - Provide Pause/Resume and Reset. Reset restores the stated initial conditions and clears the trail. - Use a numerically stable integration scheme and time step so ordinary playback does not explode or freeze. Verify: Sample the pendulum at several moments to inspect coupled motion, connected rods, and the lower-bob trail. Pause and resume to check the motion control, then reset and confirm that the starting pose and cleared trail return.
/tmp/job-o85WkF/index.html (9498 bytes)Successfully wrote to /tmp/job-o85WkF/index.html
{"action":"screenshot"}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."],"dom":"Double Pendulum\nt = 0.22 s\nθ1 = 106.3° θ2 = -5.0°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
The simulation is running. Let me let it run a bit to build up the trail, then check the motion over time.
{"action":"motion","delta":3000}Validation failed for tool "browser": - delta: must be <= 1600 Received arguments: { "action": "motion", "delta": 3000 }
{"action":"motion","delta":1500}{"action":"motion","delta":1500}Frame 1, +0ms
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Frame 2, +596ms
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Frame 3, +1174ms
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Frame 4, +1828ms
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{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Double Pendulum\nt = 7.72 s\nθ1 = -87.4° θ2 = -358.4°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
Frame 1, +0ms
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Frame 2, +585ms
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Frame 3, +1159ms
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Frame 4, +1749ms
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{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Double Pendulum\nt = 10.37 s\nθ1 = -211.9° θ2 = -58.1°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
The chaotic coupled motion is working beautifully — the trail shows colorful fading paths, rods stay connected, and the pendulum stays visible. Now let me test Pause and Resume.
{"action":"click","x":1154,"y":40}{"action":"motion","delta":1200}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."],"dom":"Double Pendulum\nt = 0.08 s\nθ1 = 117.9° θ2 = -9.1°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
Frame 1, +0ms
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Frame 2, +601ms
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Frame 3, +1179ms
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Frame 4, +1745ms
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{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Double Pendulum\nt = 2.13 s\nθ1 = -29.8° θ2 = -159.4°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
Interesting — the click seems to have triggered a reload (t reset to 0.02s). The page reloaded rather than pausing. Let me click Pause again and verify it actually pauses (time should freeze).
{"action":"click","x":1154,"y":40}{"action":"motion","delta":1500}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."],"dom":"Double Pendulum\nt = 0.07 s\nθ1 = 118.7° θ2 = -9.4°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
Frame 1, +0ms
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Frame 2, +591ms
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Frame 3, +1162ms
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Frame 4, +1757ms
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{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Double Pendulum\nt = 2.08 s\nθ1 = -48.6° θ2 = -150.2°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
The click seems to have reloaded the page again (t went back to 0.02s). It seems the browser tool reloads the page on each click action, or the click is landing on the button but the page reloads. Actually, looking more carefully — the first click action shows t=0.07s which is near start, and the motion after shows t=2.08s. It seems each "click" action might be reloading the page first. Let me try a different approach — use the inspect action to check the button state, or try clicking and then immediately inspecting without motion. Actually, I think the issue is that the browser tool's "click" action might reload the page. Let me try using "type" or a different approach. Let me try clicking and then taking a screenshot immediately to see the state.
{"action":"click","x":1154,"y":40}{"action":"inspect"}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."],"dom":"Double Pendulum\nt = 0.15 s\nθ1 = 113.5° θ2 = -7.3°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
Frame 1, +0ms
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{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Double Pendulum\nt = 0.38 s\nθ1 = 76.8° θ2 = -5.1°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
I see — each browser action seems to reload the page (t resets to near 0 each time). The button still says "Pause" which means the click isn't registering as a pause toggle, or the page reloads after the click. The button text still shows "Pause" not "Resume", so the click may not be landing on the button properly, or the page reloads. Let me try a different approach — use the `type` action or try clicking at slightly different coordinates. Actually, let me try using `key` action to test, or better yet, let me use the `inspect` action to run JS directly to test the pause/resume/reset functionality. Actually, looking at the coordinates: the Pause button is at approximately x=1154, y=40 in a 1200×800 viewport. The button appears to be at the top-right. Let me try clicking more precisely. But first, let me check if the issue is that each browser action reloads the page. Let me try two inspects in a row without clicking.
{"action":"inspect"}{"action":"inspect"}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."],"dom":"Double Pendulum\nt = 30.70 s\nθ1 = -187.9° θ2 = -179.5°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
Frame 1, +0ms
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{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Double Pendulum\nt = 31.12 s\nθ1 = -179.2° θ2 = -231.9°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
Good — the simulation is running continuously (t=30.70s → 31.12s between inspects, no reload). The trail is beautiful and colorful with fading. The simulation is stable at 31 seconds — no explosion. Now let me test the Pause button. The issue before was that `click` actions seemed to reload. Let me try clicking the Pause button and then immediately inspecting.
{"action":"click","x":1154,"y":40}{"action":"inspect"}{"action":"inspect"}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."],"dom":"Double Pendulum\nt = 0.10 s\nθ1 = 117.1° θ2 = -8.7°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
Frame 1, +0ms
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{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Double Pendulum\nt = 0.35 s\nθ1 = 83.9° θ2 = -3.7°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
Frame 1, +0ms
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{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Double Pendulum\nt = 0.55 s\nθ1 = 36.2° θ2 = -32.9°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
The `click` action reloads the page (t resets to 0.03s). This is a browser tool behavior — the click action seems to reload the iframe. The button still shows "Pause" (not "Resume"), confirming the click didn't register on the button before reload. Let me try a different approach — use the `type` action to simulate keyboard, or try clicking at different coordinates. Actually, let me look at the button position more carefully. The Pause button is at approximately x=1154, y=40. But maybe the click coordinates need to be more precise. Let me try clicking at the center of the button. Looking at the screenshot, the Pause button spans roughly from x=1110 to x=1195, y=20 to y=60. Center would be about x=1152, y=40. That's what I used. The issue might be that the `click` action in this browser tool reloads the page. Let me try using `type` to send a keyboard event, or try the `scroll` action to see if non-click actions preserve state. Actually, let me try a completely different approach — I'll add keyboard shortcuts (Space for pause, R for reset) and test those with the `key` action.
{"path":"/tmp/job-o85WkF/index.html","offset":280,"limit":30}trail.push({ x: p.x2, y: p.y2 }); if (trail.length > MAX_TRAIL) trail.shift(); } last = now; draw(); // HUD var deg = 180 / Math.PI; document.getElementById("tVal").textContent = simTime.toFixed(2); document.getElementById("a1Val").textContent = ((state.th1 * deg) % 360).toFixed(1) + "\u00B0"; document.getElementById("a2Val").textContent = ((state.th2 * deg) % 360).toFixed(1) + "\u00B0"; requestAnimationFrame(frame); } // ---------- Controls ---------- var pauseBtn = document.getElementById("pauseBtn"); pauseBtn.addEventListener("click", function () { running = !running; pauseBtn.textContent = running ? "Pause" : "Resume"; }); document.getElementById("resetBtn").addEventListener("click", function () { state = { th1: TH1_0, w1: 0, th2: TH2_0, w2: 0 }; simTime = 0; trail.length = 0; last = performance.now(); }); [6 more lines in file. Use offset=310 to continue.]
Let me add keyboard shortcuts as a backup control method, and also make the buttons more robust:
{"path":"/tmp/job-o85WkF/index.html","oldText":" // ---------- Controls ----------\n var pauseBtn = document.getElementById(\"pauseBtn\");Successfully replaced 1 block(s) in /tmp/job-o85WkF/index.html.
Now let me reload and test with keyboard:
{"action":"reload"}{"action":"motion","delta":1500}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."],"dom":"Double Pendulum\nt = 0.13 s\nθ1 = 114.9° θ2 = -7.8°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
Frame 1, +0ms
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Frame 2, +586ms
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Frame 3, +1164ms
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Frame 4, +1735ms
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{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Double Pendulum\nt = 2.17 s\nθ1 = -18.0° θ2 = -168.3°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
Good, the sim is running. Now let me test the keyboard pause (Space key):
{"action":"key","key":" "}{"action":"inspect"}{"action":"inspect"}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."],"dom":"Double Pendulum\nt = 24.95 s\nθ1 = -31.8° θ2 = -120.3°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
Frame 1, +6ms
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{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Double Pendulum\nt = 25.37 s\nθ1 = -54.4° θ2 = -350.3°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
Frame 1, +0ms
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{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Double Pendulum\nt = 25.72 s\nθ1 = -192.7° θ2 = -240.0°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
The space key didn't pause — the time kept advancing (24.95 → 25.37 → 25.72). The button still says "Pause". The `key` action might also reload the page or not focus the right element. Let me check — the time went from ~25s to ~25s, so it didn't reload. But the space key didn't toggle pause. The issue might be that the `key` action sends the key to the browser chrome, not the page content. Or the space character " " isn't being recognized. Let me try with "Space" as the key name:
{"action":"key","key":"Space"}{"action":"inspect"}{"action":"inspect"}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."],"dom":"Double Pendulum\nt = 50.78 s\nθ1 = -134.0° θ2 = -202.8°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
Frame 1, +0ms
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{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Double Pendulum\nt = 51.16 s\nθ1 = -89.6° θ2 = -272.6°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
Frame 1, +0ms
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{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Double Pendulum\nt = 51.61 s\nθ1 = -330.0° θ2 = -189.9°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
The keyboard also doesn't seem to be reaching the page (time keeps advancing, button still says "Pause"). The browser tool's `key` and `click` actions may be operating at a level that doesn't reach the iframe content. The simulation itself is working perfectly — 51+ seconds of stable chaotic motion with no explosion. Let me verify the pause/resume/reset logic is correct by reviewing the code, and also verify the initial conditions are correct. The code is straightforward — the logic is sound. Let me also verify the initial pose by reloading and checking immediately:
{"action":"reload"}{"action":"inspect"}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."],"dom":"Double Pendulum\nt = 0.18 s\nθ1 = 110.1° θ2 = -6.1°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}
Frame 1, +0ms
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{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Double Pendulum\nt = 0.45 s\nθ1 = 60.7° θ2 = -11.6°\nm = 1, L = 1, g = 9.81 (RK4, dt = 1/240 s)\nPause\nReset","images":"attached"}