add-youtube-transcript

add-youtube-transcript is a skill for Claude Code, Codex from sliamh11/Deus. It costs 37 tokens per session (581 once invoked), scanned B, original, MIT.

An installer that adds YouTube caption and subtitle extraction to an AI coding agent through an MCP server. MCP is a standard way to connect an agent to an external tool.

In plain words
What is it for?
Use it when the agent needs to fetch captions or subtitles from a YouTube video.
Why use it?
It removes the manual work of installing the transcript server, adding its configuration, preserving existing servers, and checking that it starts.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/sliamh11/deus/add-youtube-transcript
Any agent
npx skills add sliamh11/Deus --skill add-youtube-transcript
Clone the repo
git clone --depth 1 https://github.com/sliamh11/Deus

Made for: Claude Code, Codex.

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.

agentmods badge for add-youtube-transcript

README.md
[![agentmods](https://agentmods.dev/badge/skills/sliamh11/deus/add-youtube-transcript.svg)](https://agentmods.dev/skills/sliamh11/deus/add-youtube-transcript)
Your own site
<a href="https://agentmods.dev/skills/sliamh11/deus/add-youtube-transcript"><img src="https://agentmods.dev/badge/skills/sliamh11/deus/add-youtube-transcript.svg" alt="Measured on agentmods" height="20"></a>
Per session 37 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 581 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5 $0.00037 $0.00581
Opus 5 $0.00018 $0.00291
Sonnet 5 $0.00007 $0.00116
Haiku 4.5 $0.00004 $0.00058

Measured 5d ago against content hash 0d50586a0bc9, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

add-youtube-transcript scanned grade B with 1 finding 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 5d ago.

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.

Reads MCP configurationmediumAgent snooping

mcp.json carries server URLs and auth tokens; reading it lets a mod discover and abuse other integrations.

cat .mcp.json 2>/dev/null
.claude/skills/add-youtube-transcript/SKILL.md · 90 lines

What it actually says

Add YouTube Transcript

This skill adds YouTube transcript extraction capability to Deus via an MCP server. Once installed, the agent can fetch captions and subtitles from any YouTube video using the get_transcript tool.

Phase 1: Pre-flight

Check if already configured

Check if .mcp.json already has a youtube-transcript entry:

cat .mcp.json 2>/dev/null

If youtube-transcript is already present, inform the user it's already installed and skip to Phase 3 (Verify).

Phase 2: Install and Configure

Install the MCP server package

npm install --save-dev @kimtaeyoon83/mcp-server-youtube-transcript

Configure MCP

Read the current .mcp.json and add the youtube-transcript server entry. The final .mcp.json should include:

{
  "mcpServers": {
    "youtube-transcript": {
      "command": "npx",
      "args": ["-y", "@kimtaeyoon83/mcp-server-youtube-transcript"]
    }
  }
}

If .mcp.json already has other servers configured, merge the new entry — do not overwrite existing servers.

Build

npm run build

Phase 3: Verify

Test the MCP server starts

npx @kimtaeyoon83/mcp-server-youtube-transcript --help 2>&1 || echo "Server binary accessible"

Tell the user:

YouTube transcript extraction is now available. The agent can fetch captions from any YouTube video.

Usage: Ask the agent to get a transcript from a YouTube URL, or use the get_transcript tool directly with a video URL or ID.

Supported options:

  • url — YouTube video URL or video ID
  • lang — Language code (default: "en", e.g., "ko", "he", "es")

Removal

To remove YouTube transcript support:

  1. Remove the MCP server entry from .mcp.json:

    # Edit .mcp.json and remove the "youtube-transcript" key from mcpServers
    
  2. Uninstall the package:

    npm uninstall @kimtaeyoon83/mcp-server-youtube-transcript
    
  3. Rebuild:

    npm run build
    
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.

  1. 5d ago First seen · 90 lines · 37 tokens per session scan B 0d50586a0bc9

Subscribe to this mod's changes

add-youtube-transcript is a skill published in the GitHub repository sliamh11/Deus (51 stars, last pushed yesterday), licensed MIT. It adds 37 tokens to every session and 581 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it B with 1 finding (reads mcp configuration). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.