firefox-extension SKILL.md skillA
firefox-extension from codeatcode/oss-ai-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add codeatcode/oss-ai-skills/firefox-extension@v2.0.0Pins v2.0.0 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- codeatcode/oss-ai-skills
- Path
extend/firefox-extension/SKILL.md- Versions recorded
- 5
- Latest version
- v2.0.0, committed Oct 28, 2026
- First version recorded
- Mar 9, 2026
- Size
- 7,114 bytes
- Repository stars
- 28
- License
- GPL-3.0
Use when developing Firefox WebExtensions - Manifest V2/V3 configuration, WebExtension APIs, content security policy, web-ext CLI, cross-browser support with the polyfill, AMO submission, or debugging extensions.
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
> **Objective:** Use this skill to reduce CSP-violation rejections, manifest-schema breakages, AMO-review failures, and cross-browser compat bugs by enforcing manifest-version discipline, CSP-safe patterns, and web-ext-verification rules below. # Firefox WebExtension Development ## Core Rules (do X because Y) - **Use `browser` namespace because** it is Promise-based natively in Firefox, avoiding callback boilerplate. - **Pin `manifest_version: 3` for new extensions because** MV2 is sunsetting and AMO warns on new MV2 submissions. - **Always include `browser_specific_settings.gecko.id` because** AMO rejects extensions without a unique ID. - **Set `strict_min_version: "109.0"` for MV3 because** service workers and the `action` API require Firefox 109+. - **Use `web-ext run --profile-create-new` for testing because** stale profile state causes false positives. See `references/apis.md` for the complete WebExtension API namespace list (51 APIs) and usage patterns. ## Manifest V3 Rules See `references/manifest-v3.md` for the full MV3 manifest schema reference. ### MV2 vs MV3 Migration Rules …
Read the whole file at its exact version.
How to install
mdr add codeatcode/oss-ai-skills/firefox-extension@sha256:384909d496153f64The line at the top of this page pins the label v2.0.0, 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_voeivsbngylqkais)
4 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 5 versions of this file, between Mar 9, 2026 and Oct 28, 2026, about one every 58 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| v2.0.0 latest | 2026-10-28 | 83beb90 | 7,114 B | A | view · diff |
| v2.0.0 | 2026-10-01 | 268819e | 13,188 B | A | view · diff |
| v2.0.0 | 2026-09-23 | f8bf298 | 8,885 B | A | view · diff |
| v1.0.0 | 2026-04-20 | e5744c4 | 20,740 B | A | view · diff |
| v1.0.0 | 2026-03-09 | 46f73cd | 20,748 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 (7114 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
codeatcode/oss-ai-skills · 28 stars · license GPL-3.0 · pushed 2026-10-28 · branch master
API
GET https://markdownregistry.com/api/v1/artifacts/art_voeivsbngylqkais GET https://markdownregistry.com/api/v1/resolve?ref=codeatcode/oss-ai-skills/firefox-extension GET https://markdownregistry.com/api/v1/blob/384909d496153f64afc859e8d4ed96288df2ff70a2aaa91f6c2aeb1cefe36635
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.