Template Comparison

This skill helps an agent compare 2+ dotnet new templates side by side so the user can pick the right one. It inspects each template's parameters and feature support and renders a comparison table.

When to Use

• User is deciding between similar templates (e.g., webapi vs webapp, blazor vs blazorwasm)
• User asks "which template should I use for X?"
• User wants to understand how two or more templates differ before creating a project

When Not to Use

• User wants to create a project — route to template-instantiation
• User wants to author or validate a custom template — route to template-authoring or template-validation
• User just needs to find or inspect a single template — route to template-discovery

Inputs

Workflow

Evidence contract: a side-by-side table is useful only when every option claim is grounded in the currently installed templates. Run each --help command sequentially, capture the same requested dimensions for each template, and label an unavailable option as Not exposed rather than guessing or borrowing a flag from another template.

Decision contract: optimize the comparison for the user's stated decision, not table size. Cover every requested dimension, omit unrelated option rows, give a scenario-specific reason, and include one safe --dry-run command for the recommended starting point when it would make the recommendation actionable.

Step 1: Inspect each template

Run dotnet new <template> --help for each template being compared to collect its parameters (names, types, defaults, choices) and supported frameworks:

dotnet new webapi --help
dotnet new webapp --help

If a template is not installed, search for its provider and report the missing prerequisite. Install it only when the user asked you to modify the environment or approved the install.

Run --help calls sequentially. The template engine uses a global mutex, so running several dotnet new <template> --help commands concurrently can fail with a transient "mutex"/"persistence" error and empty output. Inspect templates one at a time; if a call fails, retry it once before moving on, and still produce the comparison from whatever parameter knowledge you have rather than ending with no answer.

Step 2: Build the comparison table

Produce a side-by-side table covering:

• Parameters — name, type, default, choices
• Feature support — auth, AOT, Docker, controllers, interactivity
• Available frameworks — e.g., net8.0, net9.0, net10.0
• Classifications — categories the template advertises (Web, API, Blazor, etc.)

Use one row per requested decision dimension and cite the observed option name in the cell. Do not fill a requested row with general framework knowledge when it is specifically about what the template generates or exposes.

When the user asks about generated dependencies without allowing project creation, inspect the installed template package's source .csproj files. --help and --dry-run do not reveal package references. Do not create temporary projects merely to inspect them, and do not guess current package IDs or test-platform defaults.

Example shape:

Step 3: Recommend

End with a decisive Recommendation line — never leave the user with just a table. Format:

Recommendation: <template> — one sentence tying the choice to the user's stated scenario. (Pick the other if <condition>.)

Then link to template-instantiation to create it. A comparison that ends without naming a winner (or a clear "it depends on X") is incomplete — that indecision is what makes this skill tie with a plain answer.

Decision shortcuts for common pairs

Use these only for the recommendation, not as evidence of current parameter support. Still inspect with --help before filling the comparison table:

These constraints override the shorthand above:

• Choose mvc when the user explicitly anticipates a large application or shared controller logic, even if its first pages are CRUD-focused.
• Choose blazor with Server interactivity over webapp when rich interactive forms are central but useful HTML must arrive on the first response. Explain that the initial render is server-produced and that interactive components use the Blazor form/component model rather than Razor Pages PageModel.
• For offline support, choose blazorwasm and explain the PWA/service-worker requirement, cached-after-first-load behavior, and lack of a required live server for execution.
• For a durable queue processor, choose worker and tie the decision to Generic Host lifecycle, dependency injection, configuration, logging, graceful shutdown, and a real durable queue rather than an in-memory loop.

Validation

• Every template requested was inspected via dotnet new <template> --help
• The comparison covers parameters, feature support, frameworks, and classifications
• Differences relevant to the user's scenario are called out explicitly
• A recommendation (or clear trade-off) is provided
• Unsupported or absent options are labeled instead of guessed
• The final recommendation is a single decisive Recommendation: line

Common Pitfalls

More Info

• dotnet new templates — built-in template reference
• dotnet new — CLI reference