monochrome

monochrome is a skill for Claude Code, Codex from vaneenige/monochrome-ui. It costs 97 tokens per session (2,380 once invoked), scanned A, original, MIT.

A set of instructions for using monochrome, a small UI library that makes HTML controls such as dialogs, menus, tabs, and tooltips interactive and accessible. It explains the required HTML attributes and identifiers.

In plain words
What is it for?
Use it when building or fixing interactive HTML components, especially dialogs, menus, accordions, popovers, tabs, and tooltips.
Why use it?
It reduces the need to write separate event handling and accessibility wiring for these controls. It also helps keep the markup connected correctly so assistive technologies can understand it.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions AGENTS.md.

Good fit Use it when building or fixing interactive HTML components, especially dialogs, menus, accordions, popovers, tabs, and tooltips.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/vaneenige/monochrome-ui/monochrome
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 vaneenige/monochrome-ui --skill monochrome
Clone the repo
git clone --depth 1 https://github.com/vaneenige/monochrome-ui

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 monochrome

README.md
[![agentmods](https://agentmods.dev/badge/skills/vaneenige/monochrome-ui/monochrome/github.svg)](https://agentmods.dev/skills/vaneenige/monochrome-ui/monochrome)
Your own site
<a href="https://agentmods.dev/skills/vaneenige/monochrome-ui/monochrome"><img src="https://agentmods.dev/badge/skills/vaneenige/monochrome-ui/monochrome/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.

agentmods 80×15 button for monochrome

Your own site · 80×15
<a href="https://agentmods.dev/skills/vaneenige/monochrome-ui/monochrome"><img src="https://agentmods.dev/badge/skills/vaneenige/monochrome-ui/monochrome.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 97 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,380 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00097 $0.02380
Opus 5.5 $0.00039 $0.00952
Sonnet 5.5 $0.00019 $0.00476
Haiku 4.5 $0.00010 $0.00238

Measured 8d ago against content hash 610edc862d25, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

monochrome 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.

skills/monochrome/SKILL.md · 178 lines

How it starts

The opening of the file, as written. The whole thing — 178 lines — stays where its author put it; the contents beside it link to each section on GitHub.

monochrome

monochrome makes correctly marked-up HTML interactive. Import it once; every component on the page works, including markup added later (framework renders, innerHTML, streamed or generated HTML). There is no init call, no state object, and no event wiring. The DOM is the state: the core reads and writes ARIA attributes.

Components: Accordion, Collapsible, Dialog, Menu, Menubar, Popover, Tabs, Tooltip. Optional: Router.

The spec for the installed version is in node_modules/monochrome/spec/, one file per component plus choosing, conventions, styling, and router; spec/<topic>.md below means that folder. Without the package installed, npx monochrome docs <topic> prints the same pages.

Hard rules

  1. Ids wire everything. mct:<kind>:<id> is a trigger, mcc:<kind>:<id> its content, mcr:<kind>:<id> a root. Every id is unique on the page.
  2. Link both ways. Trigger aria-controls names the content id; content aria-labelledby names the trigger id (a dialog names its title). Accordion panels are role="region"; collapsible content links back only as a role="region". Tooltip triggers use aria-describedby. One id per attribute.
  3. Triggers are <button type="button">. Only tooltip triggers may be any focusable element.
  4. Never write JS to open, close, select, or toggle. No showModal(), no popovertarget, no useState for open state, no handler that flips hidden or aria-*. The core does it. Handlers for what an item does (onClick on a menu item) are fine.
  5. State lives in ARIA. Author the initial values (aria-expanded="false" plus hidden, aria-selected, aria-checked), then let the core own them. Disable with aria-disabled="true", never disabled (the parts' disabled prop renders aria-disabled for you).
  6. monochrome ships no CSS; style with attribute selectors: [aria-expanded="true"], [aria-selected="true"], [aria-checked="true"], [data-mc-highlighted], :popover-open, dialog[open]. Menus, popovers, and tooltips need the Required CSS from their spec's Styling section, copied as it is: it places them at their trigger from the variables and the [data-mc-y] / [data-mc-x] side the core writes. Don't write placement of your own. Pick a side and alignment with data-mc-side (top, right, bottom, left) and data-mc-align (start, center, end) on the content.
  7. One import family. import "monochrome" (or the CDN script) for plain pages; in apps, the component files add writes (each imports its own monochrome/<component> module). Never both: listeners would register twice. When React or Vue only renders HTML on the server (a static site, no client bundle of the component files), their imports never reach the browser: load the core once from the script every page runs, and drop the core import (and "use client") from the component files (spec/conventions.md, Server rendering).
  8. Deliberate behaviour is not a bug. Each spec ends with Design choices: tabs select on Enter, not on focus; arrows skip disabled items; tooltips have no delay and never show on touch; menus open on press. Don't add code to change them.

Read the full file on GitHub · 178 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.

  1. 8d ago First seen · 178 lines · 97 tokens per session scan A 610edc862d25

Subscribe to this mod's changes

monochrome is a skill published in the GitHub repository vaneenige/monochrome-ui (133 stars, last pushed 8d ago), licensed MIT. It adds 97 tokens to every session and 2,380 once invoked, about $0.0004 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.

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