Hi everyone,
I’ve built a open-source skill that generates complete, valid SquareLine Studio project files directly from Claude / Antigravity / Cursor based on the code you are writing and a description of the UI you want.
Instead of starting from scratch for every panel, label, arc, and button in the visual editor, you describe the interface in your AI code harness and the skill writes the `.spj`, `.sll`, and `Themes.slt` files directly. You open the folder in SLS, and it should just work — all screens, widgets, layouts, events, and styles are in place, ready to refine visually and export.
What it generates
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Multi-screen projects with parent-child widget hierarchies
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20+ LVGL widget types (panels, labels, buttons, arcs, sliders, dropdowns, switches, charts, rollers, checkboxes, spinboxes, etc.)
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Flex and Grid layout configurations with alignment, gap, wrap, and flow
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Screen transition events with correct `Call`/`CallC` templates
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Styles — backgrounds, gradients, borders, opacity, fonts (Montserrat 8–48)
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Correct GUID generation, `nidcnt` tracking, and all required `Style_*` part nodes
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Font generation from TTFs
The generated project files are structurally identical to what SLS would produce. Every widget includes its required property nodes, GUIDs are unique, and the `.sll` metadata is consistent with the `.spj` info block.
How it works
It’s an AI agent “skill” — a set of instructions and reference documents that teaches Claude Code, Google Antigravity or any other harness you might be using how the SLS project file format works. The skill includes:
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A comprehensive format specification covering the `.spj` JSON schema
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Widget property catalogues for every supported widget type
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A Python widget builder API that handles GUID generation, nid tracking, and the tricky format details (like `Layout_type` always being `“No_layout”` in `strval` even when FLEX is active, or gradient colors using 3 values instead of 4)
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A project validator that checks GUID uniqueness, nidcnt consistency, and free-tier limits before you open the project
Board support
The skill works with any board SLS supports. It indexes `.slb` board packs directly from your local SLS installation to get the exact board string, resolution, shape, and LVGL version — so the generated `.sll` always matches an installed board. Tested with CrowPanel, MaTouch, M5Stack, Arduino TFT_eSPI, and the SDL desktop simulator.
Free-tier aware
It validates against the Personal license limits (10 screens, 150 widgets, 1 component, 5 global colours, 2 themes) and includes widget budget planning guidance. If a design naturally needs more than 10 screens, it suggests consolidation strategies like tab views and show/hide panels.
Example workflow
Prompt:
“Create a 3-screen SLS project for a CrowPanel 7.0-inch: a dashboard with temperature and humidity arcs, a settings screen with brightness slider and WiFi SSID input, and a status screen showing connection state.”
Result: A complete project folder with all three screens, widgets positioned and styled, screen transition events wired up, ready to open in SLS.
Issues / Feedback
The skill knows how to raise issues on the skill repo so just tell the skill what you think the problem is and your agent should be able to file the issue directly for me to take a look at.
Links
This is a side project and I’d genuinely welcome feedback — especially if you spot any format quirks I’ve missed, or widgets that don’t generate correctly. Happy to take issues on GitHub.
Has anyone else tried programmatic approaches to `.spj` generation? I know there’s the CLI export flags for CI/CD, but I haven’t seen anything that generates the project files themselves.
