aster-ui-demo

aster-ui-demo is a skill for Claude Code, Codex from Zfinix/aster. It costs 87 tokens per session (567 once invoked), scanned A, original, Apache-2.0.

A workflow for showing a real user-interface change in the actual application rather than in a throwaway mockup. It serves the application, checks it in a browser, and opens the running result for the user.

In plain words
What is it for?
Use it to build a UI change in the real frontend, click through it in a browser harness, check responsive layout, and run the real test suites.
Why use it?
A static mockup cannot show whether a change works with real data, matches the surrounding product, or holds up at narrow screen sizes. This workflow checks those things before the user sees the result.

Skill for Claude CodeCodex

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

Good fit Use it to build a UI change in the real frontend, click through it in a browser harness, check responsive layout, and run the real test suites.

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

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 aster-ui-demo

README.md
[![agentmods](https://agentmods.dev/badge/skills/zfinix/aster/aster-ui-demo.svg)](https://agentmods.dev/skills/zfinix/aster/aster-ui-demo)
Your own site
<a href="https://agentmods.dev/skills/zfinix/aster/aster-ui-demo"><img src="https://agentmods.dev/badge/skills/zfinix/aster/aster-ui-demo.svg" alt="Measured on agentmods" height="20"></a>
Per session 87 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 567 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
  • 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 $0.00087 $0.00567
Opus 5 $0.00044 $0.00283
Sonnet 5 $0.00017 $0.00113
Haiku 4.5 $0.00009 $0.00057

Measured yesterday against content hash 607e9d142ffc, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

aster-ui-demo 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 yesterday.

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/aster-ui-demo/SKILL.md · 45 lines

What it actually says

Demo UI work in the real surface

Never build a standalone HTML mockup to show a UI idea. Users judge UI by clicking the real product, and a mockup cannot answer the only questions that matter: does it work, does it match the surrounding design, does it survive real data.

The workflow

  1. Build it for real. Implement the change in the actual frontend source, even when the user only asked to "see it first". For this repo that means editors/vscode/webview/ (shared webview used by both the VS Code panel and the browser harness) or desktop/ for Tauri surfaces.
  2. Serve it in the browser harness. From editors/vscode/, run bun run dev:web (builds the webview, then runs out/devhost/main.js, a real browser-runnable host with a stubbed vscode API). Background it and note the port (default 4327).
  3. Click through it yourself first. Use browser automation to exercise the feature before the user sees it: open the panel, trigger the feature, resize narrow (300px) to check layout. Fix what breaks.
  4. Open it for the user. Use open_preview on the harness URL so they can click through the running app. State plainly that it is the real surface, running in a browser host.
  5. Run the real checks before calling it done: bun run test (vitest) in editors/vscode/, and make check or scoped cargo test -p aster-cli for Rust changes.

Reporting

Reference real files with line numbers, describe behavior the user can trigger by clicking, and note anything the browser harness cannot reproduce (native menus, real extension API calls) so the user knows what still needs testing in the actual editor.

Why not mockups

A mockup gets one reaction ("looks fine") and then the work is thrown away. The real build gets the same reaction plus every real bug found before the feature ships. The mockup path only wastes the turn it saves.

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. yesterday First seen · 45 lines · 87 tokens per session scan A 607e9d142ffc

Subscribe to this mod's changes

aster-ui-demo is a skill published in the GitHub repository Zfinix/aster (46 stars, last pushed yesterday), licensed Apache-2.0. It adds 87 tokens to every session and 567 once invoked, about $0.0004 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 2026-09-06.

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