yt-ab

name	yt-ab
description	Use when the user wants to A/B test a YouTube video's title or thumbnail using YouTube Studio's native Test and Compare feature. Generates 3 candidate titles from the transcript and drives Studio via Claude-in-Chrome to set up the test. Triggers on "ab test", "a/b test", "test titles", "test thumbnail", "test and compare", "split test", "best title for this".
user_invocable	true

yt-ab

A/B test a YouTube video's title (and optionally thumbnail) using YouTube Studio's native Test and Compare feature. Generates candidate titles from the video's transcript, then drives Studio in your logged-in Chrome to kick off the test.

Cadence — read this before answering ANY question about timing

The user may ask "should I test every hour / 4 hours / half-day?" before we start. Here is the right answer (sourced from YouTube Help, TubeBuddy guides, Descript guides — verified April 2026):

Native YT Test and Compare (titles + thumbnails — what THIS skill does):

• Concurrent A/B serving — YouTube distributes impressions across up to 3 variants simultaneously. There is no cadence to pick.
• Test runs up to 2 weeks, then YT picks the winner.
• Winner is decided by watch time, not CTR. This is counterintuitive — most "boost CTR" advice points at the wrong metric. Surface this to the user.
• Up to 3 variants per test (titles, thumbnails, or combinations of both).
• Can start immediately after publish. Concurrent serving handles launch-day algorithm skew internally because all variants are exposed during the same impression burst.
• A test result of "inconclusive" means view counts were too low for a decisive call. Higher views = more decisive.

Manual sequential rotation (only relevant for things YT doesn't natively test, like descriptions — NOT what this skill does):

• Industry standard: 24 hours per variant, switching at midnight Pacific (matches YT Analytics' day boundary).
• Wait 2-3 weeks after publish before starting a manual rotation — early data is biased by YT's new-video promotion bump.
• Hourly / 4-hourly / half-day rotation is measurably worse experimental design (confounds time-of-day with variant effect).

TL;DR for the user: "Native YT Test and Compare doesn't take a cadence — it serves all 3 variants concurrently and picks a winner in ~2 weeks based on watch time. So 'every hour vs 4 hours vs half-day' doesn't apply for titles or thumbnails. We'll just kick off the test and let YT run it."

When this fires

• /yt-ab <url> (explicit)
• "A/B test this title"
• "Test some title variants for [video]"
• "Set up Test and Compare for [video]"
• "What's a better title for this?"

Args

• $1 — YouTube video URL OR bare 11-char ID (required).
• --transcript <path> — optional explicit transcript file path. Defaults to fetching via scripts/generate-transcript.sh.

Steps

1. Resolve the video ID

Same regex as /yt-launch. Verify the video is on the user's channel (Enterprise Vibe Code, UCyxYcJWs5WstpM2h8KjabUw) — go run . video <id> will surface its presence in data/videos.json.

2. Get the transcript

Try in order:

1. If --transcript <path> provided, read that file.
2. Else: bash scripts/generate-transcript.sh <id> from the repo root. The script wraps the youtube-transcript-api CLI (installed via pipx install youtube-transcript-api).
3. If the script reports the package isn't installed, surface the install command and offer to fall back to step 4.
4. Last resort: read the video's existing description field from data/videos.json and warn the user that candidates will be lower-quality without the full transcript.

The transcript is cognition input — not stored on disk by this skill.

3. Show baseline numbers

cd /Users/mikelady/dev/youtube_analytics
go run . video <id>

Read its current title, view count, retention, traffic-source mix. Use these to inform candidate generation (e.g., if SUBSCRIBER traffic is dominant, your test is testing on viewers who already know the channel — calibrate the angle accordingly).

4. Generate candidate titles (cognition — your judgment)

You have THREE grounding inputs. Read all three before drafting:

(a) Transcript — what the video actually says. Don't lie.

(b) Channel voice (what's worked HERE):

go run . titles --top 10 --by retention --type long-form

Mike's channel tone: technical, candid about cost ($200/mo Claude), not-clickbait. Avoid all-caps shouting, em-dash overuse, and AI-slop tells like "REVEALED" / "INSANE".

(c) Peer-niche signal (what's working ACROSS the AI-coding niche right now):

jq -r '.fetched_at, (.channels | to_entries[] | "=== \(.key) (\(.value.angle))===", (.value.videos[] | "  \(.view_count) views: \(.title)"))' data/peer-videos.json

Updated weekly by fetch-peers. Each peer has a one-line angle (Fireship's hyper-tight news, t3dotgg's opinion-led POV, indydevdan's narrative outcome promise, etc). Use the contrast between Mike's voice and peer angles to pick distinct hook archetypes. Do NOT mimic peer voices wholesale — they're inspiration for angle (outcome-led, surprise-led, identity-led), not for word-for-word style. Mike's voice still wins.

Produce 3 alternative candidates. (The native test fits 3 variants total: the original as control plus 2 of your alternatives. Generating 3 gives the user a real choice of which 2 to run.) Constraints:

• ≤60 characters each (browse-page truncation sweet spot for desktop + mobile).
• Distinct angles — don't generate near-duplicates. Cover three of these archetypes (which to pick depends on the video; surface your choice to the user):
  • Outcome-led: what the viewer GETS by watching ("Stop AI Slop: Enterprise Rigor for Vibe Coding")
  • Surprise-led: hook that interrupts pattern-matching ("Why I Went to Cal Poly to Trash 'Vibe Coding'")
  • Identity-led: speaks to the viewer's self-image ("Senior Devs: Your New Job Is Yield Management")
  • Provocative imperative (t3dotgg-style): a clear directive that challenges a default ("Delete Your CLAUDE.md")
  • News-reaction (Fireship-style): subject + dramatic verb ("Anthropic Killed Tool Calling")
  • Concrete-deliverable (AI-Jason-style): "Build X with Y" promise, framework name forward
• Cite content from the transcript — title should be honest to what's actually in the video.

Show the original + 3 alternatives to the user with the angle you picked for each AND a one-liner about why. Then use AskUserQuestion (multiSelect: true) to have them pick which 2 alternatives go into the test alongside the original — the native dialog fits only 3 total. Let them swap wording too. Iterate until they say go.

If data/peer-videos.json is missing or stale (>14 days old): tell the user go run . fetch-peers would refresh peer-niche signal, then proceed with channel-voice-only grounding. Don't block on it.

5. Drive YouTube Studio's Test and Compare

This step uses mcp__claude-in-chrome against the user's already-logged-in Chrome. Before any browser tool, you MUST first load the chrome tools via ToolSearch (the MCP server's tools are deferred):

ToolSearch select:mcp__claude-in-chrome__tabs_context_mcp,mcp__claude-in-chrome__tabs_create_mcp,mcp__claude-in-chrome__navigate,mcp__claude-in-chrome__find,mcp__claude-in-chrome__click,mcp__claude-in-chrome__form_input,mcp__claude-in-chrome__get_page_text,mcp__claude-in-chrome__take_screenshot

Then:

1. Check current tabs with tabs_context_mcp (with createIfEmpty: true if no MCP tab group exists yet). Reuse if Studio is already open on this video.

2. Open Studio with tabs_create_mcp if needed, then navigate to https://studio.youtube.com/video/<id>/edit — the edit page is the right starting point. Test and Compare is NOT at top-level URLs like /abtesting or channel-level /test_and_compare (both 404). Don't waste turns trying.

3. Find the native A/B Testing button. It lives directly under the Title field on the edit page — labeled "A/B Testing" with a panel/screen icon. NOT to be confused with TubeBuddy's "A/B Testing" link (orange "tb" logo) which is the third-party rotation tool. They sit close together on the page. Use find with this query to disambiguate: A/B Testing button under the title field, not a link to tubebuddy. Available on brand-new videos (verified 2026-04-27 on a 10-hour-old video with 22 views — earlier assumptions about an impressions threshold were wrong).

4. Open the dialog and pick the test type. Click the button — a modal opens with three tabs: "Title only", "Thumbnail only", "Title and thumbnail". Default to "Title only" unless the user requested otherwise.

5. Fill the variant fields. The dialog shows three input fields:

   • Title 1 is pre-filled with the current title (the original) — don't touch it.
   • Title 2 = the user's first chosen alternative (required).
   • Title 3 = the user's second chosen alternative (optional but recommended — 3 variants > 2 for statistical power).

   The fields are contenteditable divs (NOT standard <input>/<textarea>), so form_input errors with Element type "DIV" is not a supported form input. Use left_click on the field's ref, then computer action type with the variant text. After all required fields are filled, the dialog footer flips from "2nd title is required" to a green checkmark + "Title test ready" — that's the gate to the Set test button.

6. Submit the test. Click "Set test" (footer of the dialog). The dialog closes and a toast appears: The test is ready and will start once you save your changes.

7. Save the video. Click "Save" in the top-right (it goes from disabled-grey to filled-dark when there are unsaved changes). A "Changes saved" toast confirms; both Save and Undo go back to disabled. The test is now LIVE.

8. Screenshot the post-save state for the experiment record. Don't fake success — if any step fails, surface clearly to the user.

6. Record the experiment

Write data/launch-experiments/<id>.yaml:

video_id: <id>
title: "<original title>"
published_at: <RFC3339 from videos.json>
test_kind: title
mode: native
variants:                          # exactly the 3 the test runs: original + the 2 the user chose
  - kind: original
    text: "<original title>"
  - kind: <angle of chosen alt 1>   # e.g. surprise-led
    text: "<chosen alternative 1>"
  - kind: <angle of chosen alt 2>   # e.g. identity-led
    text: "<chosen alternative 2>"
started_at: <RFC3339 UTC now>
estimated_end_at: <started_at + 14 days>
status: running
winner: ""
notes: "<e.g. which 3rd candidate was generated but not run, and why>"

The file is gitignored by default (per .gitignore's data/launch-experiments/ rule). The Sunday weekly review reads these and surfaces running tests in the report.

7. Commit (the experiment YAML is gitignored, so this only commits if other files changed)

If you modified anything tracked (e.g. the SKILL.md), commit + push. Otherwise just confirm to the user that the experiment is local-only.

8. Report to user

• ✓ Test running in YT Studio with 3 variants (1 original + 2 alternatives)
• ✓ YT will pick winner by watch time in ~2 weeks (mention this — counterintuitive!)
• ✓ Recorded to data/launch-experiments/<id>.yaml
• The Sunday weekly review will surface this experiment's status

What this skill does NOT do

• Doesn't auto-rotate titles via the Data API. That fights with the native test. Native test is the single source of truth.
• Doesn't generate or upload thumbnails. Image generation is out of scope. The skill describes thumbnail concepts in text if asked but the user makes/uploads images via Studio.
• Doesn't run description rotations. That's a different workflow (see cadence section above) and would need a separate skill.
• Doesn't grade the test. YT decides the winner. The Sunday review just reads the verdict YT delivers and updates the YAML.

Reference

• Cadence sources: YouTube Help: A/B test titles and thumbnails, TubeBuddy A/B Testing FAQs, Descript: How to A/B Test on YouTube (2026)
• Primitive Test: docs/primitive-test.md — generating candidates is cognition (in this prompt). Driving the browser is transport (Chrome-MCP). Recording the experiment is transport (file write). Grading is YT's job.
• Channel: Enterprise Vibe Code (UCyxYcJWs5WstpM2h8KjabUw).
• Setup: pipx install youtube-transcript-api once for transcript fetching.

This skill lives in the repo

Symlinked from ~/.claude/skills/yt-ab → /Users/mikelady/dev/youtube_analytics/skill/yt-ab. Edit in the repo; symlink picks up changes.