# Ratstack Tube

> For agents: start with the [agent guide](https://ratstack.sh/llms.txt). Every page is Markdown by default; add `Accept: text/html` for HTML.

New on /news: [Tardigrade 0.55 on Effect 4.1](/news).

## What it does

[Ratstack Tube](/tube) lists videos worth watching while learning this stack.
Most are by the people who build the tools: Effect, Alchemy, XState and Cloudflare engineers.
Each entry has a tier from S to F, a theme, and a take of one to three sentences that names what the viewer learns.

The list lives in `.brain/data/tube.json`.
The `TubeVideo` [schema](/lore/schemas-define-the-boundary) in `apps/web/src/client/tube/data.ts` defines an entry.
The content build reads the file through `apps/site/scripts/tube-pages.ts` and fails on any bad entry.

The page groups videos by theme and orders each theme from S to F.
Inside a tier, the file's order is the editorial order.
The S tier also appears as a numbered "Start here" list at the top.

A thumbnail loads from YouTube's image host.
The player loads from `youtube-nocookie.com`, and only after the reader presses play.
The built page holds no player at all.
Every title links to the video on youtube.com, so a card still works when an image or the player fails.

## The standard

- Titles and channels come from YouTube's oEmbed endpoint. Durations and publish dates come from the video page. Each entry records the date it was checked in `checked`.
- A take says only what its source supports. `basis` records the source: `transcript`, `description` (which includes a chapter list in the description), or `watched-chapters`. Each card shows its check date and basis. A video whose content cannot be confirmed stays off the list.
- The list links and embeds only. It never rehosts a video or a thumbnail.
- `/tube` is the only reader page whose content security policy allows images from `https://i.ytimg.com` and frames from `https://www.youtube-nocookie.com`. Every other page keeps the reader policy unchanged.
- The page says that thumbnails and played videos load from YouTube.
- The content build rejects a missing or long take, an unknown theme or basis, and a duplicate id. It also rejects a URL that is not https or does not point at its own video. Each failure is a fence message that names the entry and the field.

To add a video, append an entry to `.brain/data/tube.json` with facts from YouTube, the date you checked them, and the `basis` you checked the take against, then rebuild.
To remove one, delete its entry.

## How to check

Run the tube tests:

```sh
pnpm --filter @rat-stack/web exec vitest run test/tube.data.test.ts test/tube.story.test.ts test/tube.scene.test.ts test/tube.seam.test.ts test/reader-csp.test.ts
```

They check that ranking orders tiers from S to F and keeps the file's order inside a tier.
They check that one planted fault in a generated list yields one fence message naming its entry and field.
They check that the built page holds no player, that a press loads the `youtube-nocookie.com` player, and that only `/tube` gets the wider policy.

Then read the live page as Markdown:

```sh
curl --silent 'https://ratstack.sh/tube.md' | head -20
```

## Sources

1. [YouTube oEmbed response for one listed video](https://www.youtube.com/oembed?format=json\&url=https://www.youtube.com/watch?v=PxIBWjiv3og)
   YouTube. The endpoint that supplies each entry's title and channel. Accessed 2026-11-08.

## Lore on this page

- [The fence](/lore/the-fence)

## Linked from

- Agent guide → An Effect stack so pure (aspirational) Kit Langton will blush. → [Read page](https://ratstack.sh/llms.txt)

- Change log → What changed in the files served here, newest first. → [Read page](https://ratstack.sh/log)

- Full agent guide → An Effect stack so pure (aspirational) Kit Langton will blush. → [Read page](https://ratstack.sh/llms-full.txt)

- Rat Stack systems | rat-stack → The systems rat-stack ships, the standard each keeps, and how to check it. → [Read page](https://ratstack.sh/systems)

- Source change history (log.md) → The generated change log as Markdown. → [Read page](https://ratstack.sh/log.md)