CrestApps.Core MCP - Prompt Templates

Add MCP Support

Use CrestApps MCP client support to consume remote servers. Use the server support to expose CrestApps tools, prompts, and catalog-managed resources through an MCP C# SDK server.

AddMcpClient() registers the CrestApps client services with SSE and StdIO transport providers. AddMcpServer(...) registers CrestApps prompt and resource services, but an HTTP server also needs the MCP SDK server, its transport, and an endpoint mapping.

HTTP MCP Server

The following combines the CrestApps server services with the pinned MCP SDK HTTP transport. WithCrestAppsHandlers() supplies the CrestApps tool, prompt, and resource protocol handlers.

builder.Services.AddCrestAppsCore(crestApps => crestApps
    .AddAISuite(ai => ai
        .AddMcpServer(mcpServer => mcpServer
            .AddYesSqlStores())
    )
);

_ = builder.Services.AddMcpServer(options =>
{
    options.ServerInfo = new()
    {
        Name = "My MCP Server",
        Version = "1.0",
    };
})
.WithHttpTransport()
.WithCrestAppsHandlers();

var app = builder.Build();

app.MapMcp("mcp");

AddMcpServer(...) in the first registration is the CrestApps builder call. builder.Services.AddMcpServer() and app.MapMcp(...) are MCP SDK calls. Use both for an HTTP server. The server endpoint above is /mcp; apply authorization or other host middleware before exposing it publicly.

Client Registration

builder.Services.AddCrestAppsCore(crestApps => crestApps
    .AddAISuite(ai => ai
        .AddMcpClient(mcpClient => mcpClient
            .AddYesSqlStores())
    )
);

Use SSE transport for a remote HTTP MCP server. The default client registration also includes StdIO transport for a local process. Register only the connection and store features that the host needs.

Custom Resource Types

AddCoreAIMcpResourceType<THandler>() registers the type in McpOptions, registers the handler as scoped, and makes the handler available both through IEnumerable<IMcpResourceTypeHandler> and as a keyed service. The resource's Source selects that keyed handler at read time.

For raw service registration, add the CrestApps server services before the resource type:

builder.Services
    .AddCoreAIMcpServer()
    .AddCoreAIMcpResourceType<MyDatabaseResourceHandler>("database");

MyDatabaseResourceHandler must implement IMcpResourceTypeHandler. A catalog-managed resource needs a URI in its Resource property and a Source value of database. URI templates are listed as MCP resource templates; fixed URIs are listed as resources.