Dotnet Local Tools skill

.NET Local Tools

When to Use This Skill

Use this skill when:

• Setting up consistent tooling across a development team
• Ensuring CI/CD pipelines use the same tool versions as local development
• Managing project-specific CLI tools (docfx, incrementalist, dotnet-ef, etc.)
• Avoiding global tool version conflicts between projects

What Are Local Tools?

Local tools are .NET CLI tools that are installed and versioned per-repository rather than globally. They're defined in .config/dotnet-tools.json and restored with dotnet tool restore.

Local vs Global Tools

Aspect	Global Tools	Local Tools
Installation	dotnet tool install -g	dotnet tool restore
Scope	Machine-wide	Per-repository
Version control	Manual	In .config/dotnet-tools.json
CI/CD	Must install each tool	Single restore command
Conflicts	Can have version conflicts	Isolated per project

---

Setting Up Local Tools

Initialize the Manifest

# Create .config/dotnet-tools.json
dotnet new tool-manifest

This creates:

.config/
└── dotnet-tools.json

Install Tools Locally

# Install a tool locally
dotnet tool install docfx

# Install specific version
dotnet tool install docfx --version 2.78.3

# Install from a specific source
dotnet tool install MyTool --add-source https://mycompany.pkgs.visualstudio.com/_packaging/feed/nuget/v3/index.json

Restore Tools

# Restore all tools from manifest
dotnet tool restore

---

dotnet-tools.json Format

{
  "version": 1,
  "isRoot": true,
  "tools": {
    "docfx": {
      "version": "2.78.3",
      "commands": [
        "docfx"
      ],
      "rollForward": false
    },
    "dotnet-ef": {
      "version": "9.0.0",
      "commands": [
        "dotnet-ef"
      ],
      "rollForward": false
    },
    "incrementalist.cmd": {
      "version": "1.2.0",
      "commands": [
        "incrementalist"
      ],
      "rollForward": false
    },
    "dotnet-reportgenerator-globaltool": {
      "version": "5.4.1",
      "commands": [
        "reportgenerator"
      ],
      "rollForward": false
    }
  }
}

Fields

Field	Description
version	Manifest schema version (always 1)
isRoot	Marks this as the root manifest (prevents searching parent directories)
tools	Dictionary of tool configurations
tools.<name>.version	Exact version to install
tools.<name>.commands	CLI commands the tool provides
tools.<name>.rollForward	Allow newer versions (usually false for reproducibility)

---

Common Tools

Documentation

# DocFX - API documentation generator
dotnet tool install docfx

"docfx": {
  "version": "2.78.3",
  "commands": ["docfx"],
  "rollForward": false
}

Usage:

dotnet docfx docfx.json
dotnet docfx serve _site

Entity Framework Core

# EF Core CLI for migrations
dotnet tool install dotnet-ef

"dotnet-ef": {
  "version": "9.0.0",
  "commands": ["dotnet-ef"],
  "rollForward": false
}

Usage:

dotnet ef migrations add InitialCreate
dotnet ef database update

Code Coverage

# ReportGenerator for coverage reports
dotnet tool install dotnet-reportgenerator-globaltool

"dotnet-reportgenerator-globaltool": {
  "version": "5.4.1",
  "commands": ["reportgenerator"],
  "rollForward": false
}

Usage:

dotnet reportgenerator -reports:coverage.cobertura.xml -targetdir:coveragereport -reporttypes:Html

Incremental Builds

# Incrementalist - build only changed projects
dotnet tool install incrementalist.cmd

"incrementalist.cmd": {
  "version": "1.2.0",
  "commands": ["incrementalist"],
  "rollForward": false
}

Usage:

# Get projects affected by changes since main branch
incrementalist --branch main

Code Formatting

# CSharpier - opinionated C# formatter
dotnet tool install csharpier

"csharpier": {
  "version": "0.30.3",
  "commands": ["dotnet-csharpier"],
  "rollForward": false
}

Usage:

dotnet csharpier .
dotnet csharpier --check .  # CI mode - fails if changes needed

Code Analysis

# JB dotnet-inspect (requires license)
dotnet tool install jb

"jb": {
  "version": "2024.3.4",
  "commands": ["jb"],
  "rollForward": false
}

---

CI/CD Integration

GitHub Actions

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Setup .NET
        uses: actions/setup-dotnet@v4
        with:
          global-json-file: global.json

      - name: Restore tools
        run: dotnet tool restore

      - name: Build
        run: dotnet build

      - name: Test with coverage
        run: dotnet test --collect:"XPlat Code Coverage"

      - name: Generate coverage report
        run: dotnet reportgenerator -reports:**/coverage.cobertura.xml -targetdir:coveragereport

      - name: Build documentation
        run: dotnet docfx docs/docfx.json

Azure Pipelines

steps:
  - task: UseDotNet@2
    inputs:
      useGlobalJson: true

  - script: dotnet tool restore
    displayName: 'Restore .NET tools'

  - script: dotnet build -c Release
    displayName: 'Build'

  - script: dotnet test -c Release --collect:"XPlat Code Coverage"
    displayName: 'Test'

  - script: dotnet reportgenerator -reports:**/coverage.cobertura.xml -targetdir:$(Build.ArtifactStagingDirectory)/coverage
    displayName: 'Generate coverage report'

---

Managing Tool Versions

Update a Tool

# Update to latest version
dotnet tool update docfx

# Update to specific version
dotnet tool update docfx --version 2.79.0

List Installed Tools

# List local tools
dotnet tool list

# List with outdated check
dotnet tool list --outdated

Remove a Tool

dotnet tool uninstall docfx

---

Best Practices

1. Always Set isRoot: true

Prevents MSBuild from searching parent directories for tool manifests:

{
  "version": 1,
  "isRoot": true,
  ...
}

2. Pin Exact Versions

Use "rollForward": false for reproducible builds:

"docfx": {
  "version": "2.78.3",
  "rollForward": false
}

3. Restore in CI Before Use

Always run dotnet tool restore before using any local tool:

- run: dotnet tool restore
- run: dotnet docfx docs/docfx.json

4. Document Tool Requirements

Add a comment or section in README:

## Development Setup

1. Restore tools: `dotnet tool restore`
2. Build: `dotnet build`
3. Test: `dotnet test`

5. Use Dependabot for Updates

# .github/dependabot.yml
version: 2
updates:
  - package-ecosystem: "nuget"
    directory: "/"
    schedule:
      interval: "weekly"
    # Includes local tools in .config/dotnet-tools.json

---

Troubleshooting

Tool Not Found After Restore

Ensure you're running from the repository root:

# Wrong - running from subdirectory
cd src/MyApp
dotnet docfx  # Error: tool not found

# Correct - run from solution root
cd ../..
dotnet docfx docs/docfx.json

Version Conflicts

If you see version conflicts, check for:

1. Global tool with different version: dotnet tool list -g
2. Multiple tool manifests: Look for .config/dotnet-tools.json in parent directories

Clearing Tool Cache

# Clear NuGet tool cache
dotnet nuget locals all --clear

# Re-restore tools
dotnet tool restore

---

Example: Complete Development Setup

{
  "version": 1,
  "isRoot": true,
  "tools": {
    "docfx": {
      "version": "2.78.3",
      "commands": ["docfx"],
      "rollForward": false
    },
    "dotnet-ef": {
      "version": "9.0.0",
      "commands": ["dotnet-ef"],
      "rollForward": false
    },
    "dotnet-reportgenerator-globaltool": {
      "version": "5.4.1",
      "commands": ["reportgenerator"],
      "rollForward": false
    },
    "csharpier": {
      "version": "0.30.3",
      "commands": ["dotnet-csharpier"],
      "rollForward": false
    },
    "incrementalist.cmd": {
      "version": "1.2.0",
      "commands": ["incrementalist"],
      "rollForward": false
    }
  }
}

Development workflow:

# Initial setup
dotnet tool restore

# Format code before commit
dotnet csharpier .

# Run tests with coverage
dotnet test --collect:"XPlat Code Coverage"
dotnet reportgenerator -reports:**/coverage.cobertura.xml -targetdir:coverage

# Build documentation
dotnet docfx docs/docfx.json

# Check which projects changed (for large repos)
incrementalist --branch main