Modern DSL for defining MCP server primitives next to their handlers.

Use this module with ExMCP.Server.Handler:

defmodule MyServer do
  use ExMCP.Server.Handler
  use ExMCP.Server.DSL, name: "my-server", version: "1.0.0"

  tool "echo", "Echo back the input" do
    param :message, :string, required: true
    param :tags, {:array, :string}, default: []

    run fn %{message: message}, state ->
      {:ok, message, state}
    end
  end
end

Param types include :string, :integer, :number, :boolean, :object/:map, and {:array, item_type}. Bare :array is rejected at compile time.

Invalid declarations fail at compile time with file/line and fix hints (missing handlers, duplicate names, wrong instructions per kind, etc.).

Inside DSL modules, ToolResult is an alias for ExMCP.Server.DSL.Result. See the project DSL guide for full details.