What is yt-video-info CLAUDE.md?

A set of Claude Code instructions for a TypeScript MCP server that retrieves YouTube video details and transcripts by reading YouTube pages, without API keys.

Use it when building, running, testing, or changing video metadata and transcript retrieval.

It gives the coding agent the project's commands, structure, and implementation details so it can modify the server correctly.

How Limecooler/yt-video-info configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to Limecooler/yt-video-info. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/Limecooler/yt-video-info/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/Limecooler/yt-video-info

Made for: Claude Code.

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/instructions/limecooler/yt-video-info/claude-md/github.svg)](https://agentmods.dev/instructions/limecooler/yt-video-info/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/limecooler/yt-video-info/claude-md"><img src="https://agentmods.dev/badge/instructions/limecooler/yt-video-info/claude-md/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/instructions/limecooler/yt-video-info/claude-md"><img src="https://agentmods.dev/badge/instructions/limecooler/yt-video-info/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 1,406 This file is loaded in full into every session.

When invoked 1,406 The same file — it is already loaded in full.

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	$0.01406	$0.01406
Opus 5	$0.00703	$0.00703
Sonnet 5	$0.00281	$0.00281
Haiku 4.5	$0.00141	$0.00141

Measured 8d ago against content hash ed3587935623, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

yt-video-info CLAUDE.md 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 8d 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.

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.

CLAUDE.md · 164 lines

How it starts

The opening of the file, as written. The whole thing — 164 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Project Overview

A lightweight MCP (Model Context Protocol) server that retrieves YouTube video information and transcripts using web scraping (no API keys required).

Common Commands

npm install - Install dependencies
npm run build - Build TypeScript to JavaScript
npm run dev - Run in development mode with auto-reload
npm start - Run the MCP server
npx tsx src/index.ts - Run directly without building

Architecture

Core Components

MCP Server (src/index.ts)
- Implements a single tool: get_video_info
- Handles MCP protocol communication via stdio
- Returns video metadata and transcripts
- Uses Zod for runtime validation of tool arguments
Scraper Module (src/scraper.ts)
- Extracts video data from YouTube's web interface
- Parses ytInitialPlayerResponse from HTML
- Attempts to fetch transcripts in multiple formats (json3, srv3, vtt)
- Implements retry logic with exponential backoff
- Caches results for improved performance
Types (src/types.ts)
- TypeScript interfaces for video metadata, transcripts, and errors
- Custom error types with specific error codes
- Enhanced error codes: INVALID_ID, NOT_FOUND, PRIVATE, AGE_RESTRICTED, REGION_BLOCKED, NO_TRANSCRIPT, PARSE_ERROR, NETWORK_ERROR, RATE_LIMITED, TIMEOUT
Validation (src/validation.ts)
- Zod schemas for runtime type validation
- Validates video IDs, API responses, and transcript formats
- Provides clear error messages for invalid inputs
Utils (src/utils.ts)
- Retry logic with exponential backoff and jitter
- Helper functions for error handling
- Sleep utility for delays
Cache (src/cache.ts)
- In-memory LRU cache with TTL support
- Separate caches for video info (1 hour) and transcripts (2 hours)
- Automatic cleanup of expired entries
Logger (src/logger.ts)
- Debug logging to stderr (doesn't interfere with MCP)
- Controlled by MCP_DEBUG or DEBUG environment variables
- Log levels: debug, info, warn, error

Read the full file on GitHub · 164 lines

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.

8d ago First seen · 164 lines · 1,406 tokens per session scan A ed3587935623

Subscribe to this mod's changes

yt-video-info CLAUDE.md is an instructions file published in the GitHub repository Limecooler/yt-video-info (1 stars, last pushed 1y ago), licensed MIT. It adds 1,406 tokens to every session, about $0.0070 per session on Opus 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 2026-08-31.

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yt-video-info: Instructions file for Claude Code