API Versioning

What it does

When your agent uses it

• Mentions API version
• Breaking change
• Backward compatibility

Example prompts

• “API version”
• “versioning”
• “Asp.Versioning”
• “/api-versioning”

Workflow steps

4 steps, taken from the first numbered list in SKILL.md.

1. 1Version from day one — Adding versioning later is painful. Start with a version in the URL even if you only have v1.
2. 2URL segment versioning is the default — /api/v1/orders is the most discoverable and cache-friendly strategy.
3. 3Never break existing versions — Add a new version for breaking changes. Deprecate the old version with a timeline.
4. 4Version the API, not individual endpoints — All endpoints in a version group share the same version number.

What it can do on your machine

Read from SKILL.md and the folder at commit 2330089. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  No scripts in the folder and no shell commands in SKILL.md (its code samples are csharp).

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

API Versioning loads about 1.2k tokens when it runs. Until then it costs about 105 tokens; SKILL.md has 154 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~105

When it runs · the whole SKILL.md, loaded when a task matches

~1.2k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from codewithmukesh/dotnet-claude-kit at commit 2330089, republished under its MIT licence (© codewithmukesh). 154 words, ~1,172 tokens.

name

api-versioning

description

API versioning strategies for ASP.NET Core. Covers Asp.Versioning library, URL segment, header, and query string strategies, version deprecation, and OpenAPI integration. Load this skill when adding versioning to an API, evolving an API with breaking changes, or when the user mentions "API version", "versioning", "v1/v2", "Asp.Versioning", "deprecation", "breaking change", or "backward compatibility".

// Program.cs
builder.Services.AddApiVersioning(options =>
{
    options.DefaultApiVersion = new ApiVersion(1, 0);
    options.AssumeDefaultVersionWhenUnspecified = true;
    options.ReportApiVersions = true;
    options.ApiVersionReader = new UrlSegmentApiVersionReader();
})
.AddApiExplorer(options =>
{
    options.GroupNameFormat = "'v'VVV";
    options.SubstituteApiVersionInUrl = true;
});

var v1 = app.NewApiVersionSet()
    .HasApiVersion(new ApiVersion(1, 0))
    .Build();

var v2 = app.NewApiVersionSet()
    .HasApiVersion(new ApiVersion(2, 0))
    .Build();

app.MapGroup("/api/v{version:apiVersion}/orders")
    .WithApiVersionSet(v1)
    .WithTags("Orders")
    .MapOrderEndpointsV1();

app.MapGroup("/api/v{version:apiVersion}/orders")
    .WithApiVersionSet(v2)
    .WithTags("Orders")
    .MapOrderEndpointsV2();

options.ApiVersionReader = new HeaderApiVersionReader("X-Api-Version");

// Client sends: X-Api-Version: 2.0

var v1 = app.NewApiVersionSet()
    .HasDeprecatedApiVersion(new ApiVersion(1, 0))
    .HasApiVersion(new ApiVersion(2, 0))
    .Build();

// Response headers will include: api-deprecated-versions: 1.0

public static class OrderEndpointsV1
{
    public static RouteGroupBuilder MapOrderEndpointsV1(this RouteGroupBuilder group)
    {
        group.MapGet("/{id:guid}", GetOrderV1);
        group.MapPost("/", CreateOrderV1);
        return group;
    }

    private static async Task<Results<Ok<OrderResponseV1>, NotFound>> GetOrderV1(
        Guid id, ISender sender, CancellationToken ct)
    {
        // V1 response shape
        var result = await sender.Send(new GetOrder.Query(id), ct);
        return result.IsSuccess
            ? TypedResults.Ok(result.Value.ToV1())
            : TypedResults.NotFound();
    }
}

public static class OrderEndpointsV2
{
    public static RouteGroupBuilder MapOrderEndpointsV2(this RouteGroupBuilder group)
    {
        group.MapGet("/{id:guid}", GetOrderV2);
        group.MapPost("/", CreateOrderV2);
        return group;
    }

    private static async Task<Results<Ok<OrderResponseV2>, NotFound>> GetOrderV2(
        Guid id, ISender sender, CancellationToken ct)
    {
        // V2 response shape — includes new fields
        var result = await sender.Send(new GetOrder.Query(id), ct);
        return result.IsSuccess
            ? TypedResults.Ok(result.Value.ToV2())
            : TypedResults.NotFound();
    }
}

// BAD — inconsistent versioning within a group
app.MapGet("/api/v1/orders", ListOrdersV1);
app.MapGet("/api/v2/orders/{id}", GetOrderV2); // V2 only for this endpoint?

// GOOD — version the entire group
app.MapGroup("/api/v1/orders").MapOrderEndpointsV1();
app.MapGroup("/api/v2/orders").MapOrderEndpointsV2();

// BAD for REST APIs — version hidden in query string, not cache-friendly
GET /api/orders?api-version=2.0

// GOOD — version in URL, discoverable and cacheable
GET /api/v2/orders

© codewithmukesh, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in skills/api-versioning of codewithmukesh/dotnet-claude-kit.

Open the folder on GitHubat commit 2330089

Used in 1 other repository

We found 4 copies of this SKILL.md (exact, near-identical or edited) in other folders, from 1 other GitHub owner. This page covers the copy in codewithmukesh/dotnet-claude-kit, which our catalogue first saw on October 7, 2026.

• Resgrid/Core.forge/skills/api-versioning.agents/skills/api-versioning+2 more