app-builder SKILL.md skillA
app-builder from vellum-ai/vellum-assistant is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add vellum-ai/vellum-assistant/app-builder@git:20260910.46a7109Pins git:20260910.46a7109 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- vellum-ai/vellum-assistant
- Path
assistant/src/config/bundled-skills/app-builder/SKILL.md- Versions recorded
- 7
- Latest version
- git:20260910.46a7109, committed Sep 10, 2026
- First version recorded
- Jul 16, 2026
- Size
- 28,533 bytes
- Repository stars
- 1,467
- License
- MIT
Build and edit small, personal visual tools and artifacts — dashboards, trackers, calculators, data visualizations, charts, simple landing pages, and slide decks the user wants for THEMSELVES. This is the right skill whenever the user asks to "visualize this," "make a chart," or "build an artifact" for their own use, or to edit an app they already built here. Do NOT reach for a ui_show dynamic_page to fake an artifact — build a real persistent app here. A one-off diagram, chart, or explainer…
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
You build small, personal visual tools — dashboards, trackers, calculators, data visualizations, simple landing pages, and slide decks. These are quick, single-user tools the user wants **for themselves**, not products they ship to other people.
Move fast: think, plan in one pass, pick a striking visual direction following the `frontend-design` skill (included with this load — see *Included Skill: Frontend Design* below), and build it immediately. Don't ask permission to be creative — pick the colors, the layout, the atmosphere, the micro-interactions. Every tool gets its own identity: a plant tracker feels earthy and green, a finance dashboard precise and navy. They should feel designed, not generated.
**Design quality is delegated to the `frontend-design` skill, and you MUST follow it completely.** That skill owns the aesthetics (typography, color, motion); this skill owns the technical infrastructure (sandbox, data, widgets, lifecycle). Its instructions load automatically with this skill — if they are missing (listed under *Suggested Included Skills (not loaded)*), call `skill_load("frontend-design")` before building anything. Building without them gives generic, templated…
…Read the whole file at its exact version.
How to install
mdr add vellum-ai/vellum-assistant/app-builder@sha256:9fff654b8f611331The line at the top of this page pins the label git:20260910.46a7109, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_mcrfrwayhm2qzg6u)
4 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 7 versions of this file, between Jul 16, 2026 and Sep 10, 2026, about one every 9 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260910.46a7109 latest | 2026-09-10 | 46a7109 | 28,533 B | A | view · diff |
| git:20260910.689abdd | 2026-09-10 | 689abdd | 28,008 B | A | view · diff |
| git:20260806.1365421 | 2026-08-06 | 1365421 | 26,360 B | A | view · diff |
| git:20260731.5daeba9 | 2026-07-31 | 5daeba9 | 26,356 B | A | view · diff |
| git:20260728.52ad633 | 2026-07-28 | 52ad633 | 26,098 B | A | view · diff |
| git:20260716.10b95db | 2026-07-16 | 10b95db | 25,908 B | A | view · diff |
| git:20260716.57b6a66 | 2026-07-16 | 57b6a66 | 25,760 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (28533 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
vellum-ai/vellum-assistant · 1,467 stars · license MIT · pushed 2026-10-29 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_mcrfrwayhm2qzg6u GET https://markdownregistry.com/api/v1/resolve?ref=vellum-ai/vellum-assistant/app-builder GET https://markdownregistry.com/api/v1/blob/9fff654b8f611331996267476a21d47a6eacd260ac2d800e92be92d5db373a5e
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.
More from vellum-ai/vellum-assistant
Every file in vellum-ai/vellum-assistant