yokobond

Downloads (saves) and uploads (loads) Scratch project .sb3 files. Use this skill when you need to save a Scratch project to a local file or load a previously saved .sb3 file into the editor.

Automates Scratch programming by injecting blocks directly into the web editor's VM. Use this skill when you need to create or run Scratch programs programmatically.

Add custom SVG or PNG costumes to sprites programmatically via the Scratch VM storage API. Enables creating original characters, shapes, or artwork without using the paint editor UI.

Adds sprites and backdrops from the Scratch built-in library via the editor UI. Use this skill when you need to add pre-made characters, animals, objects, or backgrounds to a Scratch project.

Builds Scratch programs by dragging and dropping blocks from the palette to the script area using Playwright mouse operations. Use this skill when you need to visually assemble Scratch code through the editor UI rather than injecting via the VM.

Reads and summarizes the code of the Scratch project currently loaded in the editor. Use this skill when you need to inspect what sprites, scripts, and blocks exist in the project before making changes.

Build a Scratch program from a user prompt using vibe coding, then distill the novel techniques into a new reusable SKILL.md. Use this skill when you want to grow the skills collection with a new pattern discovered during live coding.

Spawn an autonomous sub-agent that implements a test Scratch program using only a newly written skill, then reports whether the skill's documentation is accurate, complete, and sufficient to produce working code.

Pattern for coordinating pen drawing across multiple sprites. Uses a stage-based broadcast to ensure "pen clear" runs once before all sprites begin drawing, preventing partial erasure.

Pattern for storytelling with sequential dialog (message chaining) and simultaneous speech (parallel broadcast). Combines backdrop switching with broadcast messages to create multi-scene conversations between characters.

Use when setting up a new Xcratch extension project and local development environment. Trigger phrases: xcratch-create, scaffold extension, setup-dev, initialize extension repo, local extension setup.

Autonomously debug an Xcratch extension in the scratch-editor dev-server by navigating to https://localhost:8601/?extension=<extensionURL> and loading the extension from https://0.0.0.0:5500/*. Use when: verifying extension loads, checking console errors, inspecting extension blocks in the Scratch editor UI, reproducing runtime failures with a specific extension URL.

Use when debugging an in-development Xcratch extension in VS Code. Trigger phrases: breakpoints not hit, source maps, debug on dev-server, live server HTTPS, extension not loading in editor.