build-napplet SKILL.md skillB
build-napplet from brenorb/freedom-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add brenorb/freedom-skills/build-napplet@v0.1.0Pins v0.1.0 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- B, 16 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- brenorb/freedom-skills
- Path
skills/build-napplet/SKILL.md- Versions recorded
- 1
- Latest version
- v0.1.0, committed Jul 30, 2026
- Size
- 24,783 bytes
- Repository stars
- 20
- License
- none declared
Use when writing a napplet (sandboxed Nostr iframe app) - Vite setup, the NIP-5A manifest plugin, runtime-injected window.napplet, the @napplet/sdk API for every current package-implemented NAP domain, OUTBOX-first event access, relay as explicit escape hatch, optional NAP-KEYS shortcuts/keybindings, post-injection optional-domain fallback checks, and the single-file artifact rule. Pairs with design-napplet (plan first), port-nostr-app (for migrations), and test-napplet (verify before publish).
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
# Building a Napplet
Implements a `design-napplet` spec. A napplet is a single self-contained `/index.html` the shell loads into a `sandbox="allow-scripts"` iframe (no `allow-same-origin`); all host access is proxied over postMessage per NIP-5D. The napplet never holds keys. Protocol truth: NIP-5D (<https://github.com/nostr-protocol/nips/pull/2303>) + NAPs (<https://github.com/napplet/naps>). Never invent wire surface; flag gaps.
## Sandbox Authority Contract
Treat this as a pre-code gate. If the implementation plan needs any direct
browser network, browser persistence, or external runtime asset, rewrite the
plan before coding.
- Never call `fetch`, `XMLHttpRequest`, `WebSocket`, `localStorage`,
`sessionStorage`, IndexedDB, `document.cookie`, `window.nostr`, or any relay
pool/signing API from napplet code.
- Never load runtime bytes through external `<script src>`, `<link href>`,
`<img src>`, `<audio src>`, `<video src>`, CSS `url(https://...)`, dynamic
`import("https://...")`, or side files that the opaque-origin `srcdoc`
iframe must fetch.
- ROMs, WASM companions, images, avatars, media, fonts, JSON, and other bytes
…Read the whole file at its exact version.
How to install
mdr add brenorb/freedom-skills/build-napplet@sha256:d88c244b28b16950The line at the top of this page pins the label v0.1.0, 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_isb2se5hnfcrgsd2)
2 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 1 version of this file, committed on Jul 30, 2026.
Audit of the latest version
- fail: No script tag (matched: <script)
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (24783 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
Starting a new one? Use a template for SKILL.md on mdpantry, which passes every one of these checks and says what to change in it.
Source
brenorb/freedom-skills · 20 stars · license none declared · pushed 2026-11-05 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_isb2se5hnfcrgsd2 GET https://markdownregistry.com/api/v1/resolve?ref=brenorb/freedom-skills/build-napplet GET https://markdownregistry.com/api/v1/blob/d88c244b28b16950ef184a3f1de0be1faa8d36ea359d91504a718adbe9f2a402
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.