build-an-agent-skill SKILL.md skillA
build-an-agent-skill from nirholas/three.ws is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add nirholas/three.ws/build-an-agent-skill@git:20261024.d553a25Pins git:20261024.d553a25 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- nirholas/three.ws
- Path
.agents/skills/build-an-agent-skill/SKILL.md- Versions recorded
- 2
- Latest version
- git:20261024.d553a25, committed Oct 24, 2026
- First version recorded
- Sep 20, 2026
- Size
- 9,816 bytes
- Repository stars
- 269
- License
- Apache-2.0
Write a real three.ws agent skill bundle (manifest.json + SKILL.md + tools.json + handlers.js) that gives a 3D agent a new capability, then install it on an agent and test it. Use when you or the user want to build, write, author, or code a custom skill, capability, tool, or ability for a three.ws agent or an <agent-3d> embed ("give my agent a new skill", "make my agent able to check the weather", "write a custom tool for my avatar", "add a gesture skill"). Covers the four-file bundle layout…
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
# Build a three.ws agent skill A three.ws skill is a directory served from any URL. The agent runtime fetches it, injects its instructions into the system prompt, exposes its tools to the LLM, and runs its handlers in a Web Worker sandbox. Because a skill is just files behind a URL, the same bundle installs into every agent without copying code. Do not confuse this with the Claude skill you are reading: that one teaches an external model how to use three.ws. This one teaches a three.ws agent a new capability. ## The four files | File | Required | Purpose | | --- | --- | --- | | `manifest.json` | yes | Identity, version, what it provides, config defaults | | `SKILL.md` | yes | Instructions injected into the agent's system prompt | | `tools.json` | yes, if it exposes tools | JSON Schema tool definitions the LLM can call | | `handlers.js` | no | ES module implementing each tool | A bundle with no `handlers.js` is valid and always trusted: it is a declarative skill that only shapes behavior (an accent, a house style, a refusal policy). Assets (`clips/`, `morphs/`, `prompts/`, `assets/`) sit beside those files and are resolved against `ctx.skillBaseURI`. …
Read the whole file at its exact version.
How to install
mdr add nirholas/three.ws/build-an-agent-skill@sha256:2569dc89a057d08aThe line at the top of this page pins the label git:20261024.d553a25, 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_evth2z5f7wct4te4)
4 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 2 versions of this file, between Sep 20, 2026 and Oct 24, 2026, about one every 34 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261024.d553a25 latest | 2026-10-24 | d553a25 | 9,816 B | A | view · diff |
| git:20260920.ad744e2 | 2026-09-20 | ad744e2 | 9,809 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 (9816 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
nirholas/three.ws · 269 stars · license Apache-2.0 · pushed 2026-11-06 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_evth2z5f7wct4te4 GET https://markdownregistry.com/api/v1/resolve?ref=nirholas/three.ws/build-an-agent-skill GET https://markdownregistry.com/api/v1/blob/2569dc89a057d08a4c4f932efbb57503b02e2cd28a419d51d440d3802031e7a7
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.