Maintainers already have the hard part: a working repository. The launch work is usually the slow part: a clear preview, a social card, release copy, and a short story that makes the project easy to judge.

RepoTrailer reads the repository itself, finds the real pitch, features, technology signals, install command, and git history, then builds a compact asset kit:

• a 1200×630 social card
• a scene-by-scene browser preview
• short launch copy and a Show HN draft
• a source-grounded JSON storyboard
• an optional 18–25 second MP4 rendered with HyperFrames

The default path is local-first and source-grounded. It does not invent stars, downloads, benchmarks, or adoption numbers.

Quick start

Run the CLI from npm:

npx --yes repotrailer .

The default command generates the full kit and renders trailer.mp4. For the fast static pass only:

npx --yes repotrailer . --no-video

Point it at any public GitHub repository:

npx --yes repotrailer owner/repo
npx --yes repotrailer https://github.com/owner/repo

During development from a checkout:

node bin/repotrailer.js . --out ./repotrailer-out --no-video

Open repotrailer-out/index.html.

What you get

| File | Purpose | |---|---| | index.html | Responsive scene preview before spending time rendering | | social-card.svg | README hero, Open Graph image, and launch graphic | | launch-copy.md | Short post, Show HN draft, README snippet, and topics | | repotrailer.json | Auditable repository facts, palette, and timed storyboard | | hyperframes/ | Editable HyperFrames HTML composition and visual identity | | trailer.mp4 | 1920×1080 HyperFrames render at 30fps |

If RepoTrailer saves you a launch asset or helps explain a repository faster, star the project so the next release can focus on the workflows people actually use.

Examples

RepoTrailer has been smoke-tested on different kinds of public repositories:

| Repository | What it shows | |---|---| | sindresorhus/ky | TypeScript library with a concise API story | | Textualize/rich | Python project with visual terminal output | | BurntSushi/ripgrep | CLI tool with a strong installation beat |

See the generated cards in docs/examples.md.

There is also a GitHub Pages landing page: https://howong217-ui.github.io/repotrailer/.

Why this one

Local-first. Local repositories stay local. Public GitHub URLs are cloned to a temporary directory.

No account setup. The first useful result does not require a hosted service or API key.

Facts before flair. Every claim comes from the README, package metadata, file tree, or git history. Missing facts stay missing.

Preview before render. Fix the story and layout in a browser first. Video rendering should be the last step, not the debugging loop.

Automation-ready. The GitHub Action, manifest, and plugin skill let other tools generate and inspect the same assets without changing the evidence rules.

CLI

repotrailer [path | owner/repo | GitHub URL] [options]

-o, --out <directory>   Output directory
    --title <text>      Override the detected project title
    --tagline <text>    Override the detected tagline
    --install <command> Override the detected install command
    --accent <hex>      Accent color for generated assets
    --quality <level>   Video quality: draft, standard, high
    --workers <number>  Render workers, from 1 to 8
    --no-video          Skip MP4 rendering
    --json              Print the manifest path only

Examples:

repotrailer . --tagline "Your README deserves launch assets"
repotrailer owner/repo --accent "#7c5cff" --out ./launch
repotrailer . --quality draft --workers 1

How it works

1. Resolve a local directory or shallow-clone a public GitHub repository.
2. Read README, package metadata, source extensions, and git history.
3. Build a sub-25-second story: hook, three benefits, proof, install, outro.
4. Generate the preview, social card, copy, and machine-readable manifest.
5. Render the approved storyboard with HyperFrames when video is enabled.

The analyzer uses Node.js standard library only. Video rendering invokes HyperFrames and requires Chrome/Chromium plus FFmpeg; HyperFrames can provision its browser automatically. A static launch kit remains available without that toolchain by passing --no-video.

Automation and agents

The repository includes a plugin skill and machine-readable output for local automation:

@repotrailer create a launch kit for this repository

The skill calls the CLI, checks the generated manifest, opens the preview, and returns the assets. It is instructed not to post launch copy or fabricate metrics.

Machine-readable project facts and guardrails are available in llms.txt.

GitHub Action

Generate a static launch kit as a workflow artifact:

- uses: howong217-ui/[email protected]
  with:
    source: .
    output: repotrailer-out

Development

Requires Node.js 22 or newer.

npm test
npm run check
npm run demo
npm run growth

The demo output is generated from examples/demo-repo.

Roadmap

• [x] Local repository and public GitHub URL analysis
• [x] Responsive browser storyboard
• [x] Pure SVG social card
• [x] Source-grounded launch copy
• [x] Automation and agent skill
• [x] HyperFrames MP4 rendering
• [ ] Portrait and square trailer formats
• [ ] Optional product screenshot capture
• [x] GitHub Action artifact upload

Contributing

Small, source-grounded improvements are welcome. Read CONTRIBUTING.md before opening a pull request.

License

MIT