vscode: Skill for Claude Code

.github/skills/ux-css-layout/SKILL.md

ux-css-layout is a skill for Claude Code, Codex from microsoft/vscode. It costs 52 tokens per session (3,886 once invoked), scanned A, original, MIT.

CSS guidance for organising VS Code styles, naming classes, building layouts, handling scrolling, and truncating overflowing text.

In plain words
What is it for?
Use it when writing or fixing CSS for workbench components, split views, grids, scrollable areas, responsive layouts, and text overflow.
Why use it?
It provides consistent layout and styling patterns for VS Code components, including responsive behaviour and ellipses for text that does not fit.

Skill for Claude CodeCodex ✓ vendor

Written for no agent in particular: nothing here depends on one.

This is microsoft/vscode's own configuration. It tells Claude Code and Codex how to work on vscode itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything vscode configures →

About the project

Visual Studio Code is a code editor that supports editing, navigating, understanding, debugging, and extending software projects. Developers use it for the edit-build-debug cycle, and the catalogue add-ons provide skills, instructions, and agents for working within the editor.

microsoft/vscode · 194,219 stars · on GitHub · code.visualstudio.com

Reuse

Borrowing it

Nothing to install: this file belongs to microsoft/vscode. 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/microsoft/vscode/main/.github/skills/ux-css-layout/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/microsoft/vscode

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 ux-css-layout

README.md
[![agentmods](https://agentmods.dev/badge/skills/microsoft/vscode/ux-css-layout/github.svg)](https://agentmods.dev/skills/microsoft/vscode/ux-css-layout)
Your own site
<a href="https://agentmods.dev/skills/microsoft/vscode/ux-css-layout"><img src="https://agentmods.dev/badge/skills/microsoft/vscode/ux-css-layout/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 ux-css-layout

Your own site · 80×15
<a href="https://agentmods.dev/skills/microsoft/vscode/ux-css-layout"><img src="https://agentmods.dev/badge/skills/microsoft/vscode/ux-css-layout.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,886 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. Third-party audits
  • Snyk pass 6 Sept 2026
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00052 $0.03886
Opus 5.5 $0.00021 $0.01554
Sonnet 5.5 $0.00010 $0.00777
Haiku 4.5 $0.00005 $0.00389

Measured 1mo ago against content hash ed8945a22484, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

ux-css-layout 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 1mo 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.

.github/skills/ux-css-layout/SKILL.md · 333 lines

How it starts

The opening of the file, as written. The whole thing — 333 lines — stays where its author put it; the contents beside it link to each section on GitHub.

This skill covers CSS file organization, naming, standard sizes, programmatic layout (SplitView, Grid, scrollable), responsive patterns, and text overflow handling.


1. File Organization

CSS files are co-located with their TypeScript components:

src/vs/base/browser/ui/button/
    button.ts
    button.css
src/vs/workbench/contrib/myFeature/browser/
    myFeature.ts
    media/
        myFeature.css

Import CSS directly in the TS file:

import './media/myFeature.css';
// or for base widgets:
import './button.css';

Workbench-level global styles live in src/vs/workbench/browser/media/.

2. Class Naming

  • monaco- prefix for all major components: .monaco-workbench, .monaco-split-view2, .monaco-scrollable-element
  • Modifier classes: .monaco-split-view2.vertical, .monaco-split-view2.horizontal
  • State classes: .visible, .focused, .active, .highlight
  • Feature-specific classes use kebab-case without prefix: .my-feature, .outline-pane, .welcome-view-content

3. Standard Sizes

Element Size
Part title height 35px
Title padding (horizontal) 8px
Title label inner padding 12px
Action area padding 5px
Action icon size 16px
Body font-size 13px (workbench), 11px (HTML body)
Line height 1.4em
Validation message font-size 12px (line-height: 17px)

For padding/margin/gap, border-radius, font-size/font-weight, codicon size and border width, prefer the design-system size tokens over raw px — see §10 Design-System Size Tokens. Canonical reference: .github/instructions/design-tokens.instructions.md (auto-injected for src/vs/**/*.css).

4. CSS Selector Quality

Anti-pattern (flagged) Correct pattern
ID selectors for styling (#my-widget) Class selectors (.my-widget)
Overly specific selectors Minimal specificity needed
Styles in the wrong file Co-located with the component
Missing min-width: 0 on flex children Prevents truncation issues
Forgetting pointer-events: none on hidden overlays Prevents click-through bugs

Read the full file on GitHub · 333 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. 1mo ago Changed · -56 lines ed8945a22484
  2. 1mo ago First seen · 389 lines · 52 tokens per session scan A fbff718595b1

Subscribe to this mod's changes

ux-css-layout is a skill published in the GitHub repository microsoft/vscode (194,219 stars, last pushed today), licensed MIT. It adds 52 tokens to every session and 3,886 once invoked, about $0.0002 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 2026-09-03.

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