A multi-device preview Chrome extension built from one screenshot

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A Chrome extension for previewing a site on several devices at once, which keeps each device in the same logical state rather than mirroring clicks, so a desktop menu and a mobile hamburger stay in step. Claude Fable 5.2 built it between 5:45pm and midnight from a screenshot of an existing tool and a paragraph on what bothered its maker.

Claude wrote all the code, tested it in headless Chrome and found a bug its maker would have missed: Chrome throttles off-screen frames, so animations on those devices never finished. It also listed what it had not checked.

The maker still had to step in: the first interface looked nothing like the screenshot, its first name was already taken, and it flagged 86 normal buttons as too small until the check was tuned.