summarize

A command-line tool that summarizes web pages, local files, PDFs, and YouTube links, with an option to extract available video transcripts.

In plain words
What is it for?
Use it to summarize articles and files, or extract and summarize content from YouTube videos.
Why use it?
It saves time when you need the main points of long content or a best-effort transcript without reading or watching everything.

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/z80dev/lemon/summarize
Any agent
npx skills add z80dev/lemon --skill summarize
Clone the repo
git clone --depth 1 https://github.com/z80dev/lemon

Made for: Claude Code, Codex.

Per session 32 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 623 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 97% copy Near-identical to another mod 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 $0.00032 $0.00623
Opus 5 $0.00016 $0.00311
Sonnet 5 $0.00006 $0.00125
Haiku 4.5 $0.00003 $0.00062

Measured 2d ago against content hash fa20c0d02e38, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

summarize 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 2d 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.

Origin

This is a copy

97% identical to summarize — 22 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

apps/lemon_skills/priv/builtin_skills/summarize/SKILL.md · 88 lines

What it actually says

Summarize

Fast CLI to summarize URLs, local files, and YouTube links.

When to use (trigger phrases)

Use this skill immediately when the user asks any of:

  • “use summarize.sh”
  • “what’s this link/video about?”
  • “summarize this URL/article”
  • “transcribe this YouTube/video” (best-effort transcript extraction; no yt-dlp needed)

Quick start

summarize "https://example.com" --model google/gemini-3-flash-preview
summarize "/path/to/file.pdf" --model google/gemini-3-flash-preview
summarize "https://youtu.be/dQw4w9WgXcQ" --youtube auto

YouTube: summary vs transcript

Best-effort transcript (URLs only):

summarize "https://youtu.be/dQw4w9WgXcQ" --youtube auto --extract-only

If the user asked for a transcript but it’s huge, return a tight summary first, then ask which section/time range to expand.

Model + keys

Set the API key for your chosen provider:

  • OpenAI: OPENAI_API_KEY
  • Anthropic: ANTHROPIC_API_KEY
  • xAI: XAI_API_KEY
  • Google: GEMINI_API_KEY (aliases: GOOGLE_GENERATIVE_AI_API_KEY, GOOGLE_API_KEY)

Default model is google/gemini-3-flash-preview if none is set.

Useful flags

  • --length short|medium|long|xl|xxl|<chars>
  • --max-output-tokens <count>
  • --extract-only (URLs only)
  • --json (machine readable)
  • --firecrawl auto|off|always (fallback extraction)
  • --youtube auto (Apify fallback if APIFY_API_TOKEN set)

Config

Optional config file: ~/.summarize/config.json

{ "model": "openai/gpt-5.2" }

Optional services:

  • FIRECRAWL_API_KEY for blocked sites
  • APIFY_API_TOKEN for YouTube fallback
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. 2d ago First seen · 88 lines · 32 tokens per session scan A fa20c0d02e38

Subscribe to this mod's changes

summarize is a skill published in the GitHub repository z80dev/lemon (129 stars, last pushed 2d ago), licensed MIT. It adds 32 tokens to every session and 623 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 97% identical to summarize, differing in 22 lines, and is treated as a copy.

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