What is explainer-video-create?

A skill that creates a narrated MP4 video explaining how an existing software feature works. It investigates the code and project history first, then combines an animated presentation with a generated or recorded voice.

Use it to make a teaching video about code, architecture, state changes, rules, and failure paths, using Manim animation and ElevenLabs or local text-to-speech when available.

It keeps the explanation tied to evidence from the project instead of guessing about the feature's behavior.

explainer-video-create — Skill for Claude Code by yarlson/yarstack

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add yarlson/yarstack --skill explainer-video-create

Clone the repo

git clone --depth 1 https://github.com/yarlson/yarstack

Made for: Claude Code.

Or install yarstack, the plugin that ships this one along with the rest of its 46 skills, 1 agent.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/yarlson/yarstack/explainer-video-create/github.svg)](https://agentmods.dev/skills/yarlson/yarstack/explainer-video-create)

Your own site

<a href="https://agentmods.dev/skills/yarlson/yarstack/explainer-video-create"><img src="https://agentmods.dev/badge/skills/yarlson/yarstack/explainer-video-create/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/yarlson/yarstack/explainer-video-create"><img src="https://agentmods.dev/badge/skills/yarlson/yarstack/explainer-video-create.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 71 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 2,128 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00071	$0.02128
Opus 5.5	$0.00028	$0.00851
Sonnet 5.5	$0.00014	$0.00426
Haiku 4.5	$0.00007	$0.00213

Measured 7d ago against content hash 39cf6a95d8ca, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

explainer-video-create scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 7d ago.

The scan reads SKILL.md. This mod also ships 4 executable files (scripts/assemble.py, scripts/narrate.py, scripts/scenekit.py, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/yarstack/skills/explainer-video-create/SKILL.md · 92 lines

How it starts

The opening of the file, as written. The whole thing — 92 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Explainer Video Creation

Produce one narrated MP4 that teaches how a feature works. Every narrated claim must come from investigated evidence.

Workflow

1. Set the scope

Extract the project, feature, focus, audience, narration language, and output path from the request. Default to engineers who know the domain, English narration, a 3 to 5 minute length, and ~/Desktop/<feature>-explainer.mp4, or the scratch directory when ~/Desktop does not exist. Ask only when the feature or project cannot be identified.

2. Investigate the feature

Run system-investigate on the feature in read-only mode. Record a short fact sheet in the scratch directory:

each mechanism, state change, rule, and failure path the video will show, with a file:line reference;
one concrete example from repository history, such as a real commit, PR, or log line, when one exists;
facts that the evidence does not settle.

Narrate only facts from the sheet. Leave out inconclusive facts or present them as open questions.

3. Choose the voice

Select the first available provider:

elevenlabs: ELEVENLABS_API_KEY is in the environment, or in a .env file that the user named or that exists in the working directory or project root. Validate it with narrate.py --provider elevenlabs --language <ISO 639-1 code> --check-key, adding --env-file <path> when the key is in a file, before you write narration that depends on it. The check also fails when the script's model does not support the narration language.
say on macOS, or espeak when espeak-ng is installed.
silent, which only sets the timing.

The default voices speak English. For any other narration language, choose a voice for that language and pass it as --voice: an ElevenLabs voice ID, a voice from say -v '?', or a voice from espeak-ng --voices.

If no key is found, or the key fails validation, ask the user once. Offer three choices: give a key, use the best local voice, or make a silent video. Continue with the local voice only if the user agrees. Never print, log, or copy a key. ElevenLabs receives the narration text, so keep secrets, customer data, and internal hostnames out of the narration.

Read the full file on GitHub · 92 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

7d ago Changed 39cf6a95d8ca
9d ago Changed · +19 lines 88520cfbcf82
17d ago First seen · 73 lines · 71 tokens per session scan A 9aaf1fca0d8c

Subscribe to this mod's changes

explainer-video-create is a skill published in the GitHub repository yarlson/yarstack (3 stars, last pushed 6d ago), licensed MIT. It adds 71 tokens to every session and 2,128 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-10-08.

Code review Creative and media Learning and teaching agent-skills agent-workflows ai-coding coding-agents developer-tools

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explainer-video-create