umbraco-extensibility SKILL.md skillA
umbraco-extensibility from mattbrailsford/umbraco-devkit is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add mattbrailsford/umbraco-devkit/umbraco-extensibility@git:20261017.8be9de3Pins git:20261017.8be9de3 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- mattbrailsford/umbraco-devkit
- Path
plugins/umbraco-devkit/skills/umbraco-extensibility/SKILL.md- Versions recorded
- 5
- Latest version
- git:20261017.8be9de3, committed Oct 17, 2026
- First version recorded
- Oct 15, 2026
- Size
- 9,940 bytes
- Repository stars
- 3
- License
- MIT
Umbraco's extension mechanisms (Composers, collection builders, notification handlers, attribute discovery) and a catalogue of backend CMS extension points: property value converters, Management API endpoints, content finders, health checks, search indexing, package migrations, background jobs, and more. Use when making a feature extensible or choosing which extension point fits. Not for property editor UI, dashboards, sections or trees, which the official Backoffice Skills plugin covers.
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
# Extending Umbraco, not just building on top of it
## *🎯 Why: Design for Change*
Packages get extended by code you'll never see. Reuse Umbraco's own extension mechanisms so
the extension surface stays stable while the implementation changes; don't invent your own
DI/config/plugin system. For package conventions beyond extension points, see
`umbraco-package-conventions`.
## Composers — your package's DI entry point
A `Composer` (`IComposer`) registers a package into Umbraco's startup, auto-discovered via
assembly scanning. Keep one per package (or per logical concern in a large package). Keep it
thin: it wires things up, no logic.
```csharp
public class MyPackageComposer : IComposer
{
public void Compose(IUmbracoBuilder builder)
{
builder.Services.AddSingleton<IMyPackageService, MyPackageService>();
builder.MyPackageThings().Add<DefaultThing>();
}
}
```
## Collection builders — how you make *your own* extension points
If other packages (or your own future features) need to plug in, expose a collection builder,
not a raw list or config flag. Umbraco uses the same mechanism for content finders, editors,
and notification handlers:
```csharp
…Read the whole file at its exact version.
How to install
mdr add mattbrailsford/umbraco-devkit/umbraco-extensibility@sha256:e84f854e5e750ed0The line at the top of this page pins the label git:20261017.8be9de3, 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_qba4e4sifiyfv5gb)
1 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 5 versions of this file, between Oct 15, 2026 and Oct 17, 2026, more than one a day.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261017.8be9de3 latest | 2026-10-17 | 8be9de3 | 9,940 B | A | view · diff |
| git:20261017.5c556f0 | 2026-10-17 | 5c556f0 | 9,936 B | A | view · diff |
| git:20261017.405da48 | 2026-10-17 | 405da48 | 9,964 B | A | view · diff |
| git:20261016.a78a902 | 2026-10-16 | a78a902 | 9,991 B | A | view · diff |
| git:20261015.539424f | 2026-10-15 | 539424f | 10,515 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 (9940 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
mattbrailsford/umbraco-devkit · 3 stars · license MIT · pushed 2026-10-19 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_qba4e4sifiyfv5gb GET https://markdownregistry.com/api/v1/resolve?ref=mattbrailsford/umbraco-devkit/umbraco-extensibility GET https://markdownregistry.com/api/v1/blob/e84f854e5e750ed0f6df6a51e7451afcb106cb223954716e97fe24ca43abb75e
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.