/template-instantiation

name: template-instantiation
description: >
  Creates .NET projects from templates with validated parameters, smart defaults,
  Central Package Management adaptation, and latest NuGet version resolution.
  USE FOR: creating new dotnet projects, scaffolding solutions with multiple projects,
  installing or uninstalling template packages, creating projects that respect
  Directory.Packages.props (CPM), composing multi-project solutions (API + tests + library),
  getting latest NuGet package versions in newly created projects.
  DO NOT USE FOR: finding templates (use template-discovery), producing a detailed
  side-by-side comparison of templates (use template-comparison), authoring custom
  templates (use template-authoring), deciding
  cross-parameter defaults such as which framework to pair with native AOT or whether to
  keep HTTPS when auth is enabled (use template-smart-defaults), modifying existing
  projects or adding NuGet packages to existing projects.
license: MIT

Template Instantiation

This skill creates .NET projects from templates using `dotnet new` CLI commands, with guidance for parameter validation, Central Package Management adaptation, and multi-project composition.

> **Match the workspace, then stop.** The highest-value move is aligning the new project with the repo it lands in: detect **CPM** (`Directory.Packages.props`) and the **target framework** used by neighbouring `.csproj` files, and mirror both. **Treat the discovered target framework as an explicit choice** — pass it as `--framework` so `template-smart-defaults` won't override it; deviate only when it's incompatible with a requested feature (then flag the conflict). Do this in as few steps as possible — a `--dry-run`, the create, and one `dotnet build` to confirm is usually enough. Extra exploratory turns add cost without improving the result.

When to Use

• User asks to create a new .NET project, app, or service
• User needs a solution with multiple projects (API + tests + library)
• User wants to create a project that respects existing `Directory.Packages.props`
• User needs to install or manage template packages

When Not to Use

• User is searching for templates — route to `template-discovery` skill; for a detailed side-by-side comparison — route to `template-comparison` skill
• User wants to author a custom template — route to `template-authoring` skill
• User wants to add packages to an existing project — use `dotnet add package` directly

Inputs

| Input | Required | Description | |-------|----------|-------------| | Template name or intent | Yes | Template short name (e.g., `webapi`) or natural-language description | | Project name | Yes | Name for the created project | | Output path | Recommended | Directory where the project should be created | | Parameters | No | Template-specific parameters (e.g., `--framework`, `--auth`, `--aot`) |

Workflow

Step 1: Resolve template and parameters

If the user provides a natural-language description, map it to a template short name (see the keyword table in the `template-discovery` skill). If they provide a template name, proceed directly.

Use `dotnet new <template> --help` to review available parameters, defaults, and types for any parameters the user did not specify.

When a parameter the user chose implies a value for an unset *related* parameter, **invoke the `template-smart-defaults` skill** to resolve the gap before assembling the command line — e.g., native AOT implies a recent AOT-capable target framework, a non-`None` `--auth` choice means HTTPS must stay enabled (don't add `--no-https`), and `--use-controllers` excludes the minimal-API option. Smart defaults only fill gaps; never let them override a value the user set explicitly. The workspace framework discovered in Step 2 counts as such an explicit value — pass it to smart-defaults as the chosen `--framework` so it isn't treated as an unset gap; deviate only if it is incompatible with the requested feature/template (then surface the conflict to the user).

Step 2: Analyze the workspace

Check the existing solution structure before creating:

• Is Central Package Management (CPM) enabled? Look for `Directory.Packages.props`
• What target frameworks are in use? Check existing `.csproj` files
• Is there a `global.json` pinning the SDK?

This ensures the new project is consistent with the workspace.

Step 3: Preview the creation

Use `dotnet new <template> --dry-run` to show the user what files would be created. Confirm before proceeding.

dotnet new webapi --name MyApi --framework net10.0 --dry-run

Step 4: Create the project

Use `dotnet new` with the template name and all parameters:

dotnet new webapi --name MyApi --output ./src/MyApi --framework net10.0 --auth Individual

Common parameter combinations

| Template | Parameters | Example | |----------|-----------|---------| | `webapi` | `--auth` (None, Individual, SingleOrg, Windows), `--aot` (native AOT) | `dotnet new webapi -n MyApi --auth Individual --aot` | | `webapi` | `--use-controllers` (use controllers vs minimal APIs) | `dotnet new webapi -n MyApi --use-controllers` | | `blazor` | `--interactivity` (None, Server, WebAssembly, Auto), `--auth` | `dotnet new blazor -n MyApp --interactivity Server` | | `grpc` | `--aot` (native AOT) | `dotnet new grpc -n MyService --aot` | | `worker` | `--aot` (native AOT) | `dotnet new worker -n MyWorker --aot` |

Note: Use `dotnet new <template> --help` to see all available parameters for any template.

After creation, adapt the project to Central Package Management and refresh stale versions:

1. **Detect CPM** — walk up the directory tree from the new project looking for a `Directory.Packages.props`. 2. **Strip inline versions** — if found, for each `<PackageReference Include="X" Version="Y" />` the template generated, remove the `Version` attribute from the `.csproj` (leaving `<PackageReference Include="X" />`). 3. **Centralize the version**