CrestApps.AgentSkills

Shared AI agent skills and MCP tooling for .NET applications and Orchard Core based projects. The repository contains three projects plus a GitHub Copilot CLI plugin marketplace:

Quick Start

Generic MCP Skill Engine

dotnet add package CrestApps.AgentSkills.Mcp

builder.Services.AddMcpServer(mcp =>
{
    mcp.AddAgentSkills();
});

• Works with any .agents/skills directory (or a custom path).
• Use this when you need a framework-agnostic MCP skill engine.

Orchard Core Local AI Authoring

dotnet add package CrestApps.AgentSkills.OrchardCore
dotnet build

After the first build after install, the solution root will contain:

.agents/
  skills/
    orchardcore/
      orchardcore.content-types/
        SKILL.md
        references/
      orchardcore.modules/
        SKILL.md
        references/
      orchardcore.recipes/
        SKILL.md
      ...

• Files are copied on the first build after install/update, before compilation starts (BeforeTargets="PrepareForBuild;CompileDesignTime").
• In Visual Studio, a design-time build fires automatically after package install, so the folder appears immediately.
• dotnet restore alone does not trigger the copy — this is a fundamental NuGet/MSBuild limitation.
• No runtime dependency — purely for development and AI tooling guidance.
• Files are refreshed when the package is updated.

Orchard Core MCP Server Hosting

dotnet add package CrestApps.AgentSkills.Mcp.OrchardCore

builder.Services.AddMcpServer(mcp =>
{
    mcp.AddOrchardCoreSkills();
});

• Loads skills at runtime via OrchardCore FileSystemStore.
• IMcpResourceFileStore, IMcpPromptProvider, and IMcpResourceProvider registered as singletons — no repeated file reads.
• No file copying to solution.

Full Orchard Core Experience

Install both Orchard Core packages to get local AI authoring and MCP server support.

Orchard Core Copilot CLI Plugin

If you want Orchard Core skills in GitHub Copilot CLI without copying files into your repository, install the crestapps-orchardcore plugin from this repository's marketplace:

copilot plugin marketplace add CrestApps/CrestApps.AgentSkills
copilot plugin install crestapps-orchardcore@crestapps-agentskills

• Uses the Orchard Core skills from this repository as a Copilot CLI plugin
• Avoids managing .agents/skills inside your solution
• Best option when you want plugin-based installation instead of NuGet-managed or manually copied skill files

Copilot CLI Plugin Marketplace

This repository now includes GitHub Copilot CLI marketplace manifests at .github/plugin/marketplace.json and .claude-plugin/marketplace.json, plus a plugin at plugins/crestapps-orchardcore.

Install the Orchard Core plugin from the marketplace

copilot plugin marketplace add CrestApps/CrestApps.AgentSkills
copilot plugin install crestapps-orchardcore@crestapps-agentskills

You can browse the marketplace entries after adding it:

copilot plugin marketplace browse crestapps-agentskills

You can confirm it loaded successfully with:

copilot plugin list

In an interactive Copilot CLI session you can also run:

/skills list

The plugin loads the bundled Orchard Core skills from plugins/crestapps-orchardcore/skills, so users do not need to clone this repository into their own project or copy files into .agents/skills just to use the skills.

How Copilot CLI discovers this plugin

Copilot CLI does not automatically scan GitHub for plugins in arbitrary repositories. Users must tell Copilot CLI where the plugin or marketplace lives.

There are two supported ways:

1. Add the repository as a marketplace:

copilot plugin marketplace add CrestApps/CrestApps.AgentSkills
copilot plugin install crestapps-orchardcore@crestapps-agentskills

When users run copilot plugin marketplace add CrestApps/CrestApps.AgentSkills, Copilot CLI looks for a marketplace manifest in .github/plugin/marketplace.json or .claude-plugin/marketplace.json. That is why both files are now included in this repository.

1. Install the plugin directly from the repository subdirectory:

copilot plugin install CrestApps/CrestApps.AgentSkills:plugins/crestapps-orchardcore

That direct install works because the marketplace manifest in .github/plugin/marketplace.json includes the crestapps-orchardcore plugin entry and points it at plugins/crestapps-orchardcore.

Publish the marketplace so others can use it

There is no separate approval-based central marketplace submission process described in the current Copilot CLI docs. A public repository becomes a marketplace when it contains .github/plugin/marketplace.json or .claude-plugin/marketplace.json and the referenced plugin content.

To publish this plugin and marketplace:

1. Commit and push the plugin files, plugin README, and both marketplace manifests to the default branch of the public CrestApps/CrestApps.AgentSkills repository.
2. Verify the marketplace manifests point to plugins/crestapps-orchardcore and the plugin entry points its skills path at plugins/crestapps-orchardcore/skills.
3. From a clean machine or user profile, run copilot plugin marketplace add CrestApps/CrestApps.AgentSkills.
4. Optionally confirm discovery with copilot plugin marketplace browse crestapps-agentskills.
5. Install the plugin with copilot plugin install crestapps-orchardcore@crestapps-agentskills.
6. Verify installation with copilot plugin list and confirm the skills appear with /skills list in a new Copilot CLI session.
7. Optionally verify the direct install path also works with copilot plugin install CrestApps/CrestApps.AgentSkills:plugins/crestapps-orchardcore.
8. Optionally tag a release in GitHub so users have a clear published milestone to reference.
9. Share the marketplace add/install commands and the direct install command in release notes, documentation, and examples so users can discover it easily.

Manual folder download fallback

If you do not want to use the Copilot CLI plugin system, you can still download only the Orchard Core skill files under src/CrestApps.AgentSkills/orchardcore into .agents/skills/orchardcore with a small PowerShell script:

$owner = "CrestApps"
$repo = "CrestApps.AgentSkills"
$branch = "main"
$sourceRoot = "src/CrestApps.AgentSkills/orchardcore/"
$targetRoot = ".agents\skills\orchardcore"

$tree = Invoke-RestMethod -Uri "https://api.github.com/repos/$owner/$repo/git/trees/$branch?recursive=1"
$files = $tree.tree | Where-Object { $_.type -eq "blob" -and $_.path.StartsWith($sourceRoot) }

foreach ($file in $files) {
    $relativePath = $file.path.Substring($sourceRoot.Length)
    $destinationPath = Join-Path $targetRoot $relativePath
    $destinationDirectory = Split-Path $destinationPath -Parent

    New-Item -ItemType Directory -Force -Path $destinationDirectory | Out-Null
    Invoke-WebRequest -Uri "https://raw.githubusercontent.com/$owner/$repo/$branch/$($file.path)" -OutFile $destinationPath
}

That script downloads only the files inside src/CrestApps.AgentSkills/orchardcore and recreates the same directory structure under .agents/skills/orchardcore.

Skill Format (agentskills.io specification)

Each skill is defined in a single SKILL.md file inside a skill directory under src/CrestApps.AgentSkills/orchardcore/. The file must contain YAML front-matter with at least name and description fields:

---
name: orchardcore.example
description: A description of what this skill does and when to use it.
---

# Skill Title

Skill content goes here (guidelines, code templates, examples, etc.)

Requirements

• The SKILL.md file must start with --- and contain a closing --- delimiter
• The name field must match the directory name exactly
• The description field is required and should clearly explain the skill's purpose
• Additional reference material can be placed in a references/ subdirectory as .md files

Repository Structure

.github/
├─ plugin/
│  └─ marketplace.json                         ← Copilot CLI marketplace manifest
│
plugins/
└─ crestapps-orchardcore/
   ├─ README.md
   └─ skills/                                  ← Generated Orchard Core bundle for plugin publishing

src/
├─ CrestApps.AgentSkills/                        ← Central skill content (single source of truth)
│  └─ orchardcore/                               ← Orchard Core specific skills
│     ├─ orchardcore.content-types/
│     │  ├─ SKILL.md                             ← Skill definition (front-matter + body)
│     │  └─ references/                          ← Optional reference/example files
│     ├─ orchardcore.modules/
│     ├─ orchardcore.recipes/
│     └─ ...
│
├─ CrestApps.AgentSkills.Mcp/                    ← Generic MCP engine
│  ├─ Extensions/                                ← MCP extension methods
│  ├─ Providers/                                 ← Prompt & resource providers
│  ├─ Services/                                  ← Skill file store + parsing
│  ├─ README.md
│  └─ CrestApps.AgentSkills.Mcp.csproj
│
├─ CrestApps.AgentSkills.OrchardCore/            ← Orchard Core dev package
│  ├─ buildTransitive/                           ← MSBuild .targets for solution-root copy
│  ├─ README.md
│  └─ CrestApps.AgentSkills.OrchardCore.csproj
│
└─ CrestApps.AgentSkills.Mcp.OrchardCore/        ← Orchard Core MCP runtime package
   ├─ Extensions/                                ← MCP extension methods
   ├─ Providers/                                 ← Prompt & resource providers
   ├─ Services/                                  ← IMcpResourceFileStore, McpSkillFileStore, SkillFrontMatterParser
   ├─ README.md
   └─ CrestApps.AgentSkills.Mcp.OrchardCore.csproj

The Orchard Core packages pack skill files from the central src/CrestApps.AgentSkills/orchardcore/ directory — the dev package packs them under skills/orchardcore/ (MSBuild copy only), while the MCP package packs them under contentFiles/any/any/.agents/skills/orchardcore/. The generic CrestApps.AgentSkills.Mcp package is skill-source agnostic and expects skills to be provided by your application.

Build & Test

Prerequisites

• .NET 10 SDK or later

Build

dotnet build -c Release -warnaserror /p:TreatWarningsAsErrors=true /p:RunAnalyzers=true /p:NuGetAudit=false

Run Tests

dotnet test -c Release --verbosity normal

Validate Skills Locally

You can verify all skill files are valid before submitting a PR:

Bash (Linux/macOS):

for dir in src/CrestApps.AgentSkills/orchardcore/*/; do
  name=$(basename "$dir")
  if [ ! -f "$dir/SKILL.md" ]; then echo "FAIL: $name missing SKILL.md"; continue; fi
  if ! head -1 "$dir/SKILL.md" | grep -q "^---$"; then echo "FAIL: $name bad front-matter"; continue; fi
  echo "OK: $name"
done

PowerShell (Windows):

Get-ChildItem -Path "src\CrestApps.AgentSkills\orchardcore" -Directory | ForEach-Object {
    $name = $_.Name
    $skillFile = Join-Path $_.FullName "SKILL.md"
    if (-not (Test-Path $skillFile)) {
        Write-Host "FAIL: $name missing SKILL.md" -ForegroundColor Red
    } else {
        $firstLine = Get-Content $skillFile -First 1
        if ($firstLine -ne "---") {
            Write-Host "FAIL: $name bad front-matter" -ForegroundColor Red
        } else {
            Write-Host "OK: $name" -ForegroundColor Green
        }
    }
}

Contributing

Contributions are welcome! Please review CONTRIBUTING.md for setup details and coding standards.

Submitting a New Skill PR

1. Open a New Skill Request issue (or confirm an existing one) to align on scope: https://github.com/CrestApps/CrestApps.AgentSkills/issues/new?template=skill_request.md.
2. Add a new directory under src/CrestApps.AgentSkills/orchardcore/<skill-name>/ with a SKILL.md that matches the agentskills.io specification.
3. Run the build and tests listed above, plus the local skill validation script.
4. Open a PR that links the issue (e.g., Fix #123), summarizes the skill, and includes any references or screenshots if applicable.

Warning:
This package will always overwrite files in the .agents/ folder in your solution root.
Any changes you make to files inside .agents/ that were generated by this package will be lost when you build after installing or updating this NuGet package.
Do not modify files added by this package inside .agents/. Treat them as read-only.

License

This project is licensed under the MIT License.