SwaggerMcp 1.1.1

SwaggerMcp

Expose your ASP.NET Core API as an MCP (Model Context Protocol) server. Tag controller actions with [McpTool] or minimal APIs with .WithMcpTool(...); SwaggerMcp discovers them, builds JSON Schema for inputs, and exposes a single POST /mcp endpoint that speaks the MCP Streamable HTTP transport. Tool calls are dispatched in-process through your real pipeline (filters, validation, authorization run as normal).

Full documentation (configuration, governance, observability, minimal APIs, limitations): repository README or your GitLab repo root README.md.

Install

<PackageReference Include="SwaggerMcp" Version="1.0.2" />

Quick Start

1. Register and map

// Program.cs
builder.Services.AddSwaggerMcp(options =>
{
    options.ServerName = "My API";
    options.ServerVersion = "1.0.0";
});

// After UseRouting(), UseAuthorization()
app.MapSwaggerMcp();  // GET and POST /mcp

2. Tag controller actions

[HttpGet("{id}")]
[McpTool("get_order", Description = "Retrieves a single order by ID.")]
public ActionResult<Order> GetOrder(int id) { ... }

[HttpPost]
[McpTool("create_order", Description = "Creates a new order.")]
public ActionResult<Order> CreateOrder([FromBody] CreateOrderRequest request) { ... }

3. Optional: minimal APIs

app.MapGet("/api/health", () => Results.Ok(new { status = "ok" }))
   .WithMcpTool("health_check", "Returns API health status.");

If you use both controllers and minimal APIs, add builder.Services.AddEndpointsApiExplorer(); and app.MapControllers(); so controller tools are discovered.

Point any MCP client (e.g. Claude Desktop) at your app’s /mcp URL.

Configuration (summary)

Governance: Use [McpTool(..., Roles = new[] { "Admin" }, Policy = "RequireEditor")] or .WithMcpTool(..., roles: ..., policy: ...) to restrict which tools appear in tools/list per user.

Metrics: Implement IMcpMetricsSink and register it after AddSwaggerMcp() to record tool invocations (name, status code, duration, success/failure).

Versioning

We follow Semantic Versioning. Breaking changes are documented in the repository (e.g. VERSIONING.md).