2048 · gpt-5.6-terra
Output generated Cost / run $0.1123 Runtime 107.0s
Prompt for this run
Build a playable 2048 game using HTML elements and CSS with a 4 by 4 board. 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: - Arrow keys slide tiles toward the selected edge. Adjacent equal tiles merge once per tile per move, and the score increases by the value of each new merged tile. - For example, moving [2, 2, 2, 2] left produces [4, 4, 0, 0], not [8, 0, 0, 0]. Moving [2, 2, 4, 0] left produces [4, 4, 0, 0]. These examples describe the move before spawning a new tile. - Start with two tiles. After a move that changes the board, spawn exactly one tile in an empty cell: 2 with 90% probability, otherwise 4. Do not spawn after an unchanged move. - Animate movement and merging without allowing rapid input to corrupt board state. Prevent arrow keys from scrolling the page. - Show score, a win message on reaching 2048, and Game Over only when no valid move remains. Provide New Game to reset board and score; allow continuing after a win. Verify: Play a short sequence of arrow-key moves and check that tiles slide, a valid move adds a tile, and any observed merge updates the score by its merged value. Use New Game and check that the board returns to two tiles with a reset score.
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 · 40 messages
Build a playable 2048 game using HTML elements and CSS with a 4 by 4 board. 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: - Arrow keys slide tiles toward the selected edge. Adjacent equal tiles merge once per tile per move, and the score increases by the value of each new merged tile. - For example, moving [2, 2, 2, 2] left produces [4, 4, 0, 0], not [8, 0, 0, 0]. Moving [2, 2, 4, 0] left produces [4, 4, 0, 0]. These examples describe the move before spawning a new tile. - Start with two tiles. After a move that changes the board, spawn exactly one tile in an empty cell: 2 with 90% probability, otherwise 4. Do not spawn after an unchanged move. - Animate movement and merging without allowing rapid input to corrupt board state. Prevent arrow keys from scrolling the page. - Show score, a win message on reaching 2048, and Game Over only when no valid move remains. Provide New Game to reset board and score; allow continuing after a win. Verify: Play a short sequence of arrow-key moves and check that tiles slide, a valid move adds a tile, and any observed merge updates the score by its merged value. Use New Game and check that the board returns to two tiles with a reset score.
thinking
**Considering game over conditions** I need to think about game mechanics, specifically when a game ends. It seems game over happens when there are no valid moves left after spawning a new piece. But if two new pieces appear, it might trigger an impossible game over situation. So I should generate a complete list of scenarios to ensure everything's covered. Making sure I understand these mechanics is crucial to avoid frustrating players!
index.html (8854 bytes)Successfully wrote to index.html
thinking
{"action":"reload","x":0,"y":0,"toX":0,"toY":0,"text":"","delta":0}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":"2048\nSCORE\n0\nNew Game\n\nJoin the numbers and get to the 2048 tile!\n\n2\n2\n\nUse the arrow keys to move tiles.","images":"attached"}
thinking
**Testing tile movement** I need to test key movements for the tiles. When two tiles of the same color collide and move left, I should see if the score increases without merging. After that, I want to check if moving up allows for potential merging. There might be some randomness involved that we can inspect, so I’ll keep an eye on how all these movements and interactions affect the game mechanics. Let’s see what happens!
{"action":"key","x":0,"y":0,"toX":0,"toY":0,"text":"ArrowLeft","delta":0}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":"2048\nSCORE\n0\nNew Game\n\nJoin the numbers and get to the 2048 tile!\n\n2\n2\n\nUse the arrow keys to move tiles.","images":"attached"}
thinking
{"action":"screenshot","x":0,"y":0,"toX":0,"toY":0,"text":"","delta":0}Frame 1, +1ms
[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":"2048\nSCORE\n0\nNew Game\n\nJoin the numbers and get to the 2048 tile!\n\n2\n2\n\nUse the arrow keys to move tiles.","images":"attached"}
thinking
**Figuring out tool keys** I need to clarify if potential tool keys need something like "ARROWLEFT." It’s a bit unclear if the browser documentation suggests it should be typed as "ArrowLeft." Okay, but wait, I shouldn't forget about the timestamp. I think I should just click on the game and then find the key I need from there. It’s about piecing together what fits into the overall context correctly.
{"action":"click","x":600,"y":400,"toX":0,"toY":0,"text":"","delta":0}{"command":"grep -n \"oldNodes\\|existing\\|board;\" index.html","timeout":10}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":"2048\nSCORE\n0\nNew Game\n\nJoin the numbers and get to the 2048 tile!\n\n2\n2\n\nUse the arrow keys to move tiles.","images":"attached"}
74: const oldNodes=new Map([...tilesEl.children].map((e,i)=>[i,e])); 77: const existing=[...tilesEl.children]; board; // state is already safe while animation runs
thinking
**Cleaning up code** I need to address some dead code in my project; it's cluttering things up, and it’s important to tidy that up first. After that, I'll focus on the key areas that require attention. I really want to make sure I’m streamlining everything effectively, so getting rid of unnecessary code will help improve the overall functionality. I'm curious how it'll all come together once I finish this crucial step.
{"action":"key","x":0,"y":0,"toX":0,"toY":0,"text":"ARROWLEFT","delta":0}keyboard.press: Unknown key: "ARROWLEFT"
thinking
**Evaluating key recognition issues** I noticed that ArrowLeft was recognized earlier, but there could be an issue with the timer not advancing alongside the screenshots. It seems like the browser might be advancing motion frames instead. However, the initial key action doesn't appear to cause any changes—this could be related to a game overlay problem. I think it would be worth testing by repeating the key input and checking the browser motion again to see what happens.
{"action":"key","x":0,"y":0,"toX":0,"toY":0,"text":"ArrowLeft","delta":0}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":"2048\nSCORE\n0\nNew Game\n\nJoin the numbers and get to the 2048 tile!\n\n2\n2\n\nUse the arrow keys to move tiles.","images":"attached"}
thinking
{"action":"key","x":0,"y":0,"toX":0,"toY":0,"text":"ArrowUp","delta":0}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":"2048\nSCORE\n0\nNew Game\n\nJoin the numbers and get to the 2048 tile!\n\n2\n2\n\nUse the arrow keys to move tiles.","images":"attached"}
thinking
{"action":"motion","x":0,"y":0,"toX":0,"toY":0,"text":"","delta":0}Frame 1, +0ms
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Frame 2, +526ms
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Frame 3, +1063ms
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Frame 4, +1595ms
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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":"2048\nSCORE\n0\nNew Game\n\nJoin the numbers and get to the 2048 tile!\n\n2\n2\n2\n\nUse the arrow keys to move tiles.","images":"attached"}
thinking
{"path":"index.html","edits":[{"oldText":" if(other && !other.merged && other.value===tile.value) { other.merged=true; other.value*=2; Successfully replaced 2 block(s) in index.html.
thinking
**Evaluating code variables** I noticed that my variable `other` is still assigned to the previous key, which is fine since it's unused. I'm thinking the new coordinates I check could fall outside the assigned range, which could lead to a situation with no occupancy. Initially, at row 0 with a downward direction, `other` is undefined at the first. In the second iteration, row 3 loops at row 1, and it seems to work when checking ahead at row 0. I'll test the reload process next.
{"action":"reload","x":0,"y":0,"toX":0,"toY":0,"text":"","delta":0}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":"2048\nSCORE\n0\nNew Game\n\nJoin the numbers and get to the 2048 tile!\n\n2\n2\n\nUse the arrow keys to move tiles.","images":"attached"}
thinking
**Testing movement and merges** I'm mulling over different random moves, thinking about using ArrowLeft and then Up for positions. It seems that with ArrowUp, there might not be a merge in the same column. I could test the Left move to see if it yields valid tile distribution on the board. Then, I could analyze how likely it is for two rows to merge, especially if I move left first and then up. Let’s focus on these movements and see what happens!
{"action":"key","x":0,"y":0,"toX":0,"toY":0,"text":"ArrowLeft","delta":0}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":"2048\nSCORE\n0\nNew Game\n\nJoin the numbers and get to the 2048 tile!\n\n2\n2\n\nUse the arrow keys to move tiles.","images":"attached"}
{"action":"motion","x":0,"y":0,"toX":0,"toY":0,"text":"","delta":0}Frame 1, +0ms
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Frame 2, +582ms
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Frame 3, +1106ms
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Frame 4, +1637ms
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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":"2048\nSCORE\n0\nNew Game\n\nJoin the numbers and get to the 2048 tile!\n\n2\n2\n2\n\nUse the arrow keys to move tiles.","images":"attached"}
thinking
**Evaluating merging options** I’m thinking about merging two items in column 0 with three tiles, and that would give a score of 4. It seems like a straightforward strategy, but I need to consider how this will affect the overall game dynamic. I wonder if this will create more opportunities or if it could backfire. Letting two tiles combine might seem simple, but the implications could be more complex than I realize!
{"action":"key","x":0,"y":0,"toX":0,"toY":0,"text":"ArrowUp","delta":0}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":"2048\nSCORE\n4\nNew Game\n\nJoin the numbers and get to the 2048 tile!\n\n2\n2\n2\n\nUse the arrow keys to move tiles.","images":"attached"}
thinking
**Considering animation timing** I'm thinking about the animation timing and how it shows two seconds for actions that aren't merged. I'm curious if the final rendering will correct that timing issue. It seems like there's room for improvement here, and I want to ensure everything flows smoothly in the end. It's interesting how small timing adjustments can make a big difference in overall animation. Let's keep an eye on how that works out in the final product!
{"action":"motion","x":0,"y":0,"toX":0,"toY":0,"text":"","delta":0}Frame 1, +0ms
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Frame 2, +530ms
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Frame 3, +1055ms
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Frame 4, +1580ms
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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":"2048\nSCORE\n4\nNew Game\n\nJoin the numbers and get to the 2048 tile!\n\n4\n2\n2\n\nUse the arrow keys to move tiles.","images":"attached"}
thinking
**Testing game reset** I'm focused on testing the new game, making sure to reset the board to 2 and setting the score to 0. The goal here is to ensure everything works smoothly after these adjustments. Clicking to reset is the next step to see if it responds correctly. I'm curious to find out if everything functions as expected without any glitches! Let's see how it goes.
{"action":"click","x":792,"y":111,"toX":0,"toY":0,"text":"","delta":0}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":"2048\nSCORE\n0\nNew Game\n\nJoin the numbers and get to the 2048 tile!\n\n2\n2\n\nUse the arrow keys to move tiles.","images":"attached"}
thinking
**Addressing game issues** I need to fix animation 4, and I think the ending from the second source could overlap. The main issue seems to be that the win message shows only after spawning. If merged to 2048, it might be best to spawn before the overlay. I'm noticing that when the game reaches a win and then game over, only the win shows. After hitting continue, the win hides without showing game over, so if there are no valid moves, I need to ensure the game over displays clearly.**Improving game mechanics** I need to implement game version increments, reset, and capture tokens during moves. The timeout checks should ensure that if the version doesn't match the turn, it returns. That's straightforward. I'll add a variable for gameId set to 0, and then increment it on reset. For the move, I'll use the current gameId, plus set a timeout callback that returns if there's a mismatch. Also, I should make sure that the previous timeout doesn’t interfere if it’s marked as busy.
{"path":"index.html","edits":[{"oldText":" let board=[], score=0, nextId=1, busy=false, won=false, stopped=false;","newText":" let board=[Successfully replaced 5 block(s) in index.html.
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{"action":"reload","x":0,"y":0,"toX":0,"toY":0,"text":"","delta":0}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":"2048\nSCORE\n0\nNew Game\n\nJoin the numbers and get to the 2048 tile!\n\n4\n2\n\nUse the arrow keys to move tiles.","images":"attached"}
Implemented the playable 2048 game in `index.html`. Checked in browser: - Initial board starts with exactly two tiles and score 0. - Arrow-key moves slide tiles and add one new tile after a valid move. - Observed a merge into 4 and confirmed the score increased by 4. - New Game reset the score and returned the board to two tiles. - Console showed no app errors (only the sandbox iframe warning). Also included movement/merge animations, input locking during animation, page-scroll prevention for arrow keys, win/continue UI, and game-over detection.