Agent skill · steipete
proof-video
Add subtitles, captions, narration cues, or zoom to a proof video or PR recording using repo-local capture helpers and a system ffmpeg renderer.
What it needs
About 5k tokens when loaded.
What this skill does
Proof video Use this developer skill for captioned Control UI recordings and native captures. Captions are burned into an MP4; they are visual narration, not synthesized audio. Keep the raw video as evidence, attach the polished MP4, and never commit media or .artifacts/ output. Inspect the entire capture for unrelated or private content before publishing under the PR's existing authorization. Standalone recording From the repository root, save this script as .artifacts/proof-video/record.mts (create the parent directory first), then run node --import tsx .artifacts/proof-video/record.mts. It starts an isolated mocked Control UI, records five captions, a real toolbar zoom, fast-forwarded startup, and an eight-second pause at 4× speed. Every invocation allocates a fresh evidence directory. Use caption(text) to replace the current caption, clearCaption() to end it, zoom(locatorOrRect, { factor: 2, padding: 24, ease: 0.5 }) to start or replace a zoom, and zoomOut() to end it. Rectangles use viewport CSS pixels. Padding expands and clamps the target rectangle; its center determines the zoom focus. speed(factor) changes playback speed until the next call; speed(1) restores normal playback. finish() closes open cues at the finalized video's end, closes the recording context, rasterizes captions, writes cues.json, and returns { dir, videoPath, cuesPath }. The caller closes the browser and server. The helper is test tooling at ui/src/test-helpers/proof-video.ts; production code must not import it. contextOptions carries ordinary Playwright context options, while the helper owns the viewport, recording size, and device scale. Keep narration to one or two short lines; oversized text fails instead of silently clipping. Caption PNGs are transparent viewport-width, 120-pixel-high strips with a centered dark rounded card and 30-pixel system text. Render Use the exact directory printed by the recording: The renderer prints the output path and duration. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills steipete/proof-video