/youtube-chapters-tags

name: youtube-chapters-tags
description: Stage 4 of the Ben AI publishing chain. Generates chapters with accurate timestamps and a tag string for a Ben van Sprundel video. Pulls the timestamped transcript out of YouTube through Claude in Chrome, finds where each topic actually starts, names chapters to Ben's measured style, flags every outbound video reference that needs a description link, and builds the tag list from the pattern measured across Ben's last 15 published videos. Needs the video to be Unlisted first, because a Studio draft has no caption track. Use when someone says "prepare the chapters", "do the tags", "chapter this video", "what tags should I use", "review the chapters", or shares a video URL and asks for chapters or tags.

YouTube Chapters and Tags

Stage 4. Two deliverables from one video, run independently so either can be asked for alone.

1. **Chapters**: `MM:SS – Title` for the description and YouTube's chapter UI. 2. **Tags**: a tag string matching the pattern measured across Ben's recent videos.

Precondition: the video has to be Unlisted

A Studio draft has **no caption track**. No captions means no timestamped transcript means no chapters. YouTube generates captions only after the video is saved at a real visibility and its checks finish. Private does not work either.

So `youtube-studio-setup` runs first. If the video is still a draft, or Unlisted but not yet captioned, say so plainly and stop. Do not fake chapters from the script, the Notion card, or the outline. Every timestamp has to come from the transcript.

Check for captions before anything else:

const h = await (await fetch('/watch?v=VIDEO_ID')).text();
h.includes('captionTracks')

False means come back later. It usually clears within the same session for a video under 20 minutes.

Workflow A: chapters

1. Pull the timestamped transcript

YouTube is IP-blocked from the sandbox. `youtube-transcript-api` and `curl` both fail; do not retry them. Everything goes through Claude in Chrome.

Use the transcript-panel recipe in `references/chrome-transcript-extraction.md`.

**Do not try to fetch the caption track's `baseUrl` out of `captionTracks`.** It gets blocked, because that URL carries session tokens. Found 2026-08-25. The DOM panel is the working path.

Store the result on `window.__ts`. JS responses cap at about 1000 characters, so read it back in slices of roughly 8 lines. Tabs also die mid-session and take `window` with them, so re-derive rather than assuming state survived.

2. Find the transitions cheaply

Reading 100 segments at 8 lines a call is a dozen round trips. Filter first, read only the windows around each candidate:

const p = /(first|second|thirdly|lastly|and last|best practice|now let me|moving on|
             demo|review|recommend|here above|show you)/i;
window.__ts.map((l,i)=>({i,l})).filter(o=>p.test(o.l)).map(o=>o.i+' '+o.l.slice(0,40)).join('\n')

Then `window.__ts.slice(n-1, n+7)` around each hit to confirm the exact boundary line.

The timestamp marks where the topic **starts being discussed**, not where the transcript block starts. If the transition phrase lands mid-block, take that block's timestamp.

3. Name them

**Read `references/chapter-style.md` before naming anything.** It is measured from the last 15 published videos and it overrides intuition. The corpus is in `references/examples/chapter-corpus-2026-08.md`.

The rule that matters most: a chapter title reads like a video title. It hints at the territory and withholds the payoff. `Best Practice #3`, never `Best Practice 3: Narrate Why`.

Four things worth repeating here:

• `00:00 – Intro` always, zero-padded, en dash U+2013.
• **No `Outro` chapter.** 0 of 15 videos have one.
• **Never chapter a CTA.** The accelerator plug is not a chapter. Start the next chapter after

it ends, not at the block that still contains its tail.

• Counted items take the `#` form: `Best Practice #1`, never `Best Practice 1`. Keep the label

on the noun when the bare noun would not stand alone. Oskar corrected `Practice #1` to `Best Practice #1` on 2026-08-25: the `#` governs the number, not how far the noun gets trimmed.

4. Check before delivering

• `00:00 – Intro` present, en dash, zero-padded.
• No chapter contains the answer to itself.
• No `Outro`.
• 7 to 13 chapters unless the video runs over 40 minutes.
• Last chapter starts between 80 and 95 percent of runtime.
• **Chapters at least 20 seconds apart.** Rule set by Oskar 2026-08-24, tightened from an

earlier 15-second floor. Merge or shift when two transitions land closer, and say which.

Deliver in a fenced code block so it copies cleanly.

5. Flag the video references

Scan for any moment Ben points at another video: "I have a full video on this", "check out the video here above", "link in the description". For each one report the timestamp, the exact quote, and what it is probably about.

The end-card reference in the last 30 seconds is the most common and almost always needs a link. Report it; do not guess which video it is.

Workflow B: tags

**Read `references/tagging-pattern.md`.** It was rebuilt 2026-08-25 from the real `keywords` field of Ben's last 15 videos, and it corrects five rules that the old lost version got wrong. Do not work from memory of the old rules.

The headline corrections, so nobody rebuilds the mistakes:

• Target **420 to 450 characters**, not 480 to 500. No video in the corpus reaches 460.
• 18 to 32 tags, median 26.
• **`Ben AI` is the only near-universal tag** (14 of 15). The other eight "non-negotiable

staples" are topical. `claude cli` appears once in fifteen videos.

• **Business and vertical framings are used**, not cut. `ai for business` appears 6 times.
• **"How to" tags are used** when the title is a how-to. Six appear in the corpus.

A list is mostly permutations of the video's own topic, with a thin brand layer. The measured shape and the modifier set are in the reference.