菜单
VHS tape syntax and ffmpeg video handling in readme2demo — how the demo video is generated, the hard-won gotchas, and the duration gate. Use when touching templates/demo.tape.j2, render.py, distill.tape_from_guide, or when a video is short, blank, mis-paced, or fails to render.
用 Codex 或 Claude 帮你安装 复制这段 Prompt，粘贴到 Codex、Claude 或其他助手里，让它检查 Skill 页面并帮你完成安装。
基于 SOC 职业分类
Debug a failed, unverified, or low-quality readme2demo pipeline run. Use when a run fails at any stage, verify won't pass, the demo video is short or missing steps, generated docs lack detail, or the user pastes readme2demo CLI output showing a failure.
Add a new AI agent backend (engine) to readme2demo, or fix parsing for an existing one (claude-code stream-json drift, openhands trajectory changes). Use when adding support for a new coding agent or when transcripts stop parsing after an agent CLI upgrade.
The workflow for turning a newly diagnosed readme2demo run failure into a permanent, tested defense. Use after debug-run identifies a failure mechanism that is not yet in CLAUDE.md's known-failure-classes table.
Docker usage in readme2demo — the base image, hardened sandbox lifecycle, the Docker-socket opt-in, and diagnosing container/daemon failures. Use when touching sandbox.py, images/base/Dockerfile, render.py, verify.py, or when a run fails with a docker/daemon/permission/disk error.
Git and GitHub operations for maintaining the readme2demo repo — branching, conventional commits, PRs, releases, and the never-commit rules. Use when committing, opening a PR, tagging a release, or doing any git/gh operation on this repo.
Python coding standards, testing patterns, and pydantic/typing conventions for the readme2demo codebase. Use when writing or reviewing any Python in src/readme2demo/ or tests/, adding a module, or before committing code changes.
| name | vhs-video |
| description | VHS tape syntax and ffmpeg video handling in readme2demo — how the demo video is generated, the hard-won gotchas, and the duration gate. Use when touching templates/demo.tape.j2, render.py, distill.tape_from_guide, or when a video is short, blank, mis-paced, or fails to render. |
The demo video is built from the FINAL step_by_step.md (render stage, after
tutorial finalizes the guide) so the video follows the published guide
step-for-step. distill.tape_from_guide parses the guide's fenced bash blocks
into TapeCommands; templates/demo.tape.j2 renders the tape; render.py
runs VHS in the base image.
Wait+Screen on output text. It matches only the VISIBLE
buffer; any pattern in longer-than-one-screen output scrolls off and times
the render out. Pace with Wait (blocks until the shell prompt returns, so
the command — build included — has finished) then a short Sleep to read.vhs_quote picks a
delimiter the text doesn't contain: " → ` → '. A string with all
three can't be typed (rare; that step is skipped).Type is single-line. Multi-line commands (heredocs) are typed
LINE-BY-LINE via TapeCommand.lines (Type/Enter per line) so file creation
plays on camera — a real shell reads a heredoc until its terminator.Output demo.mp4 only. A GIF per-frame render of a
multi-minute tape once filled the Docker VM disk. demo.gif is a short
downscaled ffmpeg preview cut from the mp4 afterwards (best-effort, never
gates the stage).cd /work && clear so the guide's own git clone ... .
starts from the empty workspace.render.validate_outputs)expected_min_duration_s sums the tape's Sleeps + typing time; real command
execution (the Waits) only adds on top. A video shorter than ~0.8× that bound
means steps didn't play (stale image, aborted tape) → HARD error, never a
silently short clip. Bounds: 5s..1500s.
render writes tape_coverage.json (guide_steps / tape_steps / dropped) and
prints any dropped step. With heredocs now on camera, a dropped step means a
genuinely ungrounded guide command — investigate, don't ignore.
Used for the gif preview (fps=10,scale=800) and, on the host, ffprobe for
the duration check. Both run inside the base image for the preview; the host
ffprobe check is skipped when ffprobe isn't on PATH.