Agent skill

Sandbox HTML

Select elements out of HTML and convert a page to markdown in a Code node or CodeAct action, with cheerio and turndown running on the host

AGPL-3.0Auto-check passedDocuments & Office

Install Sandbox HTML

skills CLI

$ npx skills add nodetool-ai/nodetool --skill sandbox-html -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install nodetool-ai/nodetool sandbox-html --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/nodetool-ai/nodetool.git skills-src && mkdir -p .claude/skills && cp -r skills-src/packages/sandbox-packs/sandbox-html .claude/skills/sandbox-html && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "sandbox-html" agent skill from https://github.com/nodetool-ai/nodetool/tree/main/packages/sandbox-packs/sandbox-html into .claude/skills/sandbox-html/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "sandbox-html", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/nodetool-ai/nodetool/tree/main/packages/sandbox-packs/sandbox-html

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add nodetool-ai/nodetool --skill sandbox-html -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install nodetool-ai/nodetool sandbox-html --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/nodetool-ai/nodetool.git skills-src && mkdir -p .agents/skills && cp -r skills-src/packages/sandbox-packs/sandbox-html .agents/skills/sandbox-html && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "sandbox-html" agent skill from https://github.com/nodetool-ai/nodetool/tree/main/packages/sandbox-packs/sandbox-html into .agents/skills/sandbox-html/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "sandbox-html", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add nodetool-ai/nodetool --skill sandbox-html -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install nodetool-ai/nodetool sandbox-html --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/nodetool-ai/nodetool.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/packages/sandbox-packs/sandbox-html .cursor/skills/sandbox-html && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "sandbox-html" agent skill from https://github.com/nodetool-ai/nodetool/tree/main/packages/sandbox-packs/sandbox-html into .cursor/skills/sandbox-html/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "sandbox-html", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/nodetool-ai/nodetool.git --path packages/sandbox-packs/sandbox-html

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add nodetool-ai/nodetool --skill sandbox-html -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install nodetool-ai/nodetool sandbox-html --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/nodetool-ai/nodetool.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/packages/sandbox-packs/sandbox-html .gemini/skills/sandbox-html && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "sandbox-html" agent skill from https://github.com/nodetool-ai/nodetool/tree/main/packages/sandbox-packs/sandbox-html into .gemini/skills/sandbox-html/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "sandbox-html", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install nodetool-ai/nodetool sandbox-html

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add nodetool-ai/nodetool --skill sandbox-html -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/nodetool-ai/nodetool.git skills-src && mkdir -p .github/skills && cp -r skills-src/packages/sandbox-packs/sandbox-html .github/skills/sandbox-html && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "sandbox-html" agent skill from https://github.com/nodetool-ai/nodetool/tree/main/packages/sandbox-packs/sandbox-html into .github/skills/sandbox-html/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "sandbox-html", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add nodetool-ai/nodetool --skill sandbox-html -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install nodetool-ai/nodetool sandbox-html --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/nodetool-ai/nodetool.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/packages/sandbox-packs/sandbox-html .opencode/skills/sandbox-html && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "sandbox-html" agent skill from https://github.com/nodetool-ai/nodetool/tree/main/packages/sandbox-packs/sandbox-html into .opencode/skills/sandbox-html/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "sandbox-html", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: sandbox-html
GitHub stars: 560
Token cost: ~839 tokens
SKILL.md length: 268 words
Files: 2
Skills in repo: 127
Repo updated: Oct 9, 2026
First seen: Oct 7, 2026
Licence: AGPL-3.0

At a glance

Select elements out of HTML and convert a page to markdown in a Code node or CodeAct action, with cheerio and turndown running on the host

Documents & Office work in your project
SKILL.md covers select — CSS selection, toMarkdown — a whole page, toText — a whole page as plain… and extractLinks / extractImages /…, plus 4 more sections
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Sandbox HTML is an agent skill from nodetool-ai/nodetool. Select elements out of HTML and convert a page to markdown in a Code node or CodeAct action, with cheerio and turndown running on the host

Its SKILL.md is about 840 tokens, which your agent loads only when the skill is triggered. The skill folder holds 1 other file (for example `package.json`).

It sits in Documents & Office. The repository describes itself as: Agent-first Creative Workspace. The licence is AGPL-3.0.

When your agent uses it

Documents & Office work in your project

Example prompts

“/sandbox-html”

What it can do on your machine

Read from SKILL.md and the folder at commit 58765d3. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md (its code samples are javascript).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Sandbox HTML loads about 839 tokens when it runs. Until then it costs about 38 tokens; SKILL.md has 268 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~38
When it runs · the whole SKILL.md, loaded when a task matches: ~839

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from nodetool-ai/nodetool at commit 58765d3, republished under its AGPL-3.0 licence (© nodetool-ai). 268 words, ~839 tokens.

Download SKILL.mdSave it as .claude/skills/sandbox-html/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.

name: sandbox-html
description: Select elements out of HTML and convert a page to markdown in a Code node or CodeAct action, with cheerio and turndown running on the host

HTML in the sandbox

Specifier: @nodetool-ai/sandbox-html. Import it at the top of the body.

cheerio imports 25 Node builtins and turndown wants a DOM, so neither compiles into the guest. This pack is a host module: the import resolves to a generated facade over NodeTool's own implementation. Both exports are async.

select — CSS selection

import { select } from "@nodetool-ai/sandbox-html";

const hrefs = await select(inputs.html, "a[href]", { attr: "href", limit: 500 });
const titles = await select(inputs.html, "h2");   // trimmed text of each match
return { hrefs, titles };

Returns trimmed text per match, or the named attribute when attr is set. limit defaults to 100 and is clamped to 1000 — the cap is in the host implementation, so raising it in the call does nothing.

toMarkdown — a whole page

import { toMarkdown } from "@nodetool-ai/sandbox-html";

const markdown = await toMarkdown(inputs.html);
return { markdown };

The usual first step before summarizing or indexing a fetched page. Pass { turndown: {...} } to override turndown's own options.

toText — a whole page as plain text

import { toText } from "@nodetool-ai/sandbox-html";

const text = await toText(inputs.html);
return { text };

Strips <script>/<style> and every tag, then collapses whitespace.

extractLinks / extractImages / extractAudio / extractVideos

import {
  extractLinks,
  extractImages,
  extractAudio,
  extractVideos
} from "@nodetool-ai/sandbox-html";

const links = await extractLinks(inputs.html, inputs.baseUrl);
// [{ href, text, type: "internal" | "external" }, ...]

const images = await extractImages(inputs.html, inputs.baseUrl); // string[] of resolved URLs
const audio = await extractAudio(inputs.html, inputs.baseUrl);
const videos = await extractVideos(inputs.html, inputs.baseUrl);

baseUrl is optional. When set, relative src/href values resolve against it and extractLinks classifies same-origin links as internal. Each extractor returns at most 1000 items.

extractMetadata — title, description, keywords

import { extractMetadata } from "@nodetool-ai/sandbox-html";

const { title, description, keywords } = await extractMetadata(inputs.html);

Any field the page doesn't set comes back null.

extractReadableText — strip chrome, keep the article

import { extractReadableText } from "@nodetool-ai/sandbox-html";

const article = await extractReadableText(inputs.html);

Removes script/style/nav/aside/footer/header, then returns the text of the first match among article, main, [id*=content], [class*=content], or body. A page with none of those returns "No main content found".

Getting a page's base URL

No import needed — new URL(pageUrl).origin gives the base URL to pass into the extractors above.

Gotchas

Every export is async.
5 MB of HTML per call. Larger input is refused by name.
A selector that matches nothing returns [], never null. An invalid selector throws with cheerio's own message.
Extractors cap at 1000 items. Anything past that is silently dropped.

Files

SKILL.md and 1 other file in packages/sandbox-packs/sandbox-html of nodetool-ai/nodetool.

SKILL.md
package.json

Open the folder on GitHubat commit 58765d3

Compare with similar skills

Sandbox HTML next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Sandbox HTML compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Sandbox HTML this skillnodetool-ai/nodetool	560	—	~839	Automated safety check: Pass	AGPL-3.0	today
Markdown Article FormatterJimLiu/baoyu-skills	26k	6 repos	~3.5k	Automated safety check: Pass	MIT	28 days ago
MarkitdownImCa0/just-laws	782	14 repos	~3.2k	Automated safety check: Notes	MIT	yesterday
Obsidian MarkdownAtmosphere/atmosphere	3.8k	20 repos	~1.3k	Automated safety check: Pass	Apache-2.0	today
DOCXrvdbreemen/OTGW-firmware	207	33 repos	~4.3k	Automated safety check: Pass	Proprietary	2 days ago
Gzh Designisjiamu/gzh-design-skill	3.9k	1 repos	~2.2k	Automated safety check: Pass	AGPL-3.0	6 days ago

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Questions about Sandbox HTML

What does Sandbox HTML do?

Select elements out of HTML and convert a page to markdown in a Code node or CodeAct action, with cheerio and turndown running on the host. Sandbox HTML is an agent skill from nodetool-ai/nodetool.

When should I use Sandbox HTML?

Sandbox HTML fits situations like: documents & Office work in your project.

How do I install Sandbox HTML in Claude Code?

Run `npx skills add nodetool-ai/nodetool --skill sandbox-html -a claude-code`. Or copy the skill folder (packages/sandbox-packs/sandbox-html in nodetool-ai/nodetool) into .claude/skills/sandbox-html in your project. Claude Code loads it when a task matches its description.

How do I install Sandbox HTML in Codex?

Run `npx skills add nodetool-ai/nodetool --skill sandbox-html -a codex`. Or copy the skill folder (packages/sandbox-packs/sandbox-html in nodetool-ai/nodetool) into .agents/skills/sandbox-html in your project. Codex loads it when a task matches its description.

Can I use Sandbox HTML in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add nodetool-ai/nodetool --skill sandbox-html -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/sandbox-html, .gemini/skills/sandbox-html, .github/skills/sandbox-html and .opencode/skills/sandbox-html in your project.

What does Sandbox HTML need to run?

SKILL.md names no scripts, command-line tools or credentials: Sandbox HTML is instructions for the agent only.

Does Sandbox HTML access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Sandbox HTML safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Sandbox HTML use?

Sandbox HTML is published under the AGPL-3.0 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Sandbox HTML use?

About 839 tokens (SKILL.md is roughly 3.4k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Sandbox HTML?

Skills that share tags, products or a category with Sandbox HTML: Markdown Article Formatter (JimLiu/baoyu-skills, 26k stars), Markitdown (ImCa0/just-laws, 782 stars), Obsidian Markdown (Atmosphere/atmosphere, 3.8k stars) and DOCX (rvdbreemen/OTGW-firmware, 207 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Sandbox HTML?

nodetool-ai (a GitHub organization) maintains it in nodetool-ai/nodetool, which has 560 GitHub stars. The repository holds 127 skills in this directory. The repository was last updated on October 9, 2026.

Source: nodetool-ai/nodetool on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Sandbox HTML

Facts

At a glance

What it does

When your agent uses it

Example prompts

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

HTML in the sandbox

select — CSS selection

toMarkdown — a whole page

toText — a whole page as plain text

extractLinks / extractImages / extractAudio / extractVideos

extractMetadata — title, description, keywords

extractReadableText — strip chrome, keep the article

Getting a page's base URL

Gotchas

Files

Compare with similar skills

Similar skills

More from nodetool-ai/nodetool

Related

Questions about Sandbox HTML