web-extension SKILL.md skillA
web-extension from firzus/agent-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add firzus/agent-skills/web-extension@git:20260728.2a6f6dcPins git:20260728.2a6f6dc in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- firzus/agent-skills
- Path
skills/web/web-extension/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260728.2a6f6dc, committed Jul 28, 2026
- Size
- 5,582 bytes
- Repository stars
- 4
- License
- MIT
Design, build, port, debug, test, or prepare browser extensions for Chromium, Firefox, and Safari using the WebExtensions model. Use when work involves manifest.json, Manifest V3, extension service workers or background scripts, content scripts, extension messaging, browser permissions, toolbar actions, options pages, sidebars, cross-browser extension compatibility, store-ready packages, Chrome Web Store, Firefox Add-ons, or Safari Web Extensions. Also use when migrating an existing extension…
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
# Web Extension Build extension behavior around explicit browser targets, execution contexts, permissions, and lifecycle constraints. Treat WebExtensions as a shared model with vendor-specific seams, not as one perfectly uniform platform. This skill covers WebExtensions and migrations to that model. Ordinary websites, browser automation, userscripts, bookmarklets, legacy Chrome Apps, and legacy Safari App Extensions remain outside its scope. ## Workflow 1. Discover the target before choosing architecture or syntax. Inspect the repo, then establish browsers and minimum versions, features, UI surfaces, host/data access, distribution channels, native companion needs, and existing tooling. Use [discovery and compatibility](./discovery-and-compatibility.md). 2. Create a compatibility matrix. For every required capability, classify it as common, syntax-different, API-different, or unavailable. Verify uncertain or version-sensitive support in current vendor documentation before coding. 3. Map execution contexts and message boundaries before implementation. Assign work to content scripts, background/event code, extension pages, page code, or …
Read the whole file at its exact version.
How to install
mdr add firzus/agent-skills/web-extension@sha256:256e54659cab1246The line at the top of this page pins the label git:20260728.2a6f6dc, 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_b7t5jvha7d7sdzxd)
3 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 1 version of this file, committed on Jul 28, 2026.
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 (5582 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
firzus/agent-skills · 4 stars · license MIT · pushed 2026-11-03 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_b7t5jvha7d7sdzxd GET https://markdownregistry.com/api/v1/resolve?ref=firzus/agent-skills/web-extension GET https://markdownregistry.com/api/v1/blob/256e54659cab1246c42e4ba1390338a108276ab14641f19b53c2cdcd53159bb6
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.