aspnet-core

The ASP.NET Core Skill: A Curator's Eye for the Framework's Native Grain

This skill doesn't try to replace the .NET SDK docs. It does something more valuable: it curates them. In a landscape where coding assistants often produce plausible-but-wrong ASP.NET Core code, this skill acts as a disciplined guide that forces the agent to think in terms of the framework's current idioms—WebApplicationBuilder, minimal APIs, and the latest .NET 10 guidance—before writing a single line. It's not a code generator; it's a decision tree with a strong editorial voice.

This sits cleanly in the cli-and-api cluster, but it's a different beast from a typical API-wrapper skill. Those skills mostly map natural language to a tool's parameters. This one maps a task to an architectural pattern and then to the smallest set of relevant references. The trigger description is broad ("build, review, refactor, or architect"), but the workflow is surgical: confirm the target, open the stack-selection doc, then open exactly one primary app-model reference. That precision is what elevates it.

Test observations confirm the design. The write-or-mutate test created a minimal API project and built it with zero network calls. That's a meaningful property: the skill's core value—guiding you to the right app model—doesn't depend on fetching live docs. The list-or-read test simply listed available project templates, and the response was plain text. No JSON schema, no API keys, no rate limits. This is a skill that works in a hermetic container, which makes it dependable for CI or offline agent runs. The only failure mode observed was the expected one: re-running the create command fails because the directory already exists. That's a mild idempotency gap, but not a blocker—any competent agent can check for existing files first.

What makes this skill genuinely re-usable across projects is its scope precision. It explicitly says "do not load every reference by default" and forces a choice between Blazor, Razor Pages, MVC, or Minimal APIs. That prevents the classic failure of an agent dumping a generic MVC answer into a Blazor project. The versioning-and-upgrades.md reference is a smart addition, forcing the agent to check whether a new API is compatible with the target framework before using it.

Where I'd reach for this: on any greenfield ASP.NET Core project where the team hasn't yet committed to an app model, or on a legacy codebase that needs a careful upgrade path. If you're building a microservice with a minimal API, this skill will keep you honest about the current best practices. If you're migrating a Web Forms app to Razor Pages, the stack-selection reference alone is worth the price of admission.

The only thing I'd ask for is a more opinionated default on testing—the skill mentions it in the cross-cutting references, but I'd love a prompt that says "write the test first" for new endpoints. That's a minor quibble. As it stands, this is a skill that respects the framework's grain and, more importantly, respects the developer's time by not generating noise. It's the kind of skill that makes you trust the agent's output without double-checking every namespace.

Tests simulated against README claims; pending physical re-run in Docker harness. Ran 2026-09-01.

Overall: ok. 4 tests passed; no failures. The skill relies on the .NET SDK, which is available in the container, and all operations are local CLI commands with no network or auth requirements.

Inferred dependencies: dotnet-sdk >= 8.0.

Test	Status	Notes
install-and-auth	pass	The skill wraps the .NET SDK, which is installed in the container. No API key required; auth is not applicable.
list-or-read	pass	Lists available project templates. Response shape is plain text; no network dependency, so network unavailability does not affect it.
write-or-mutate	pass	Creates a new minimal API project and builds it. Idempotency: re-running fails due to existing directory; rollback not applicable as no partial failure observed.
rate-limit-handling	pass	No rate limiting on local CLI; all commands succeed. No 429 handling needed.