if Code.ensure_loaded?(Plug.Conn) do
  defmodule Extools do
    @moduledoc """
    MCP server exposing live Elixir runtime introspection tools to AI agents.

    ## Dual mode

    **Phoenix** — add one line to your endpoint (dev only):

        # lib/my_app_web/endpoint.ex
        if Mix.env() == :dev do
          plug Extools
        end

    The MCP endpoint is served at `http://localhost:4000/extools/mcp`.
    Requests to any other path pass through untouched.

    **Non-Phoenix** — configure a port and the application starts a
    standalone Bandit server (requires `{:bandit, "~> 1.0"}` in deps):

        # config/dev.exs
        config :extools, port: 4040

    The MCP endpoint is served at `http://localhost:4040/extools/mcp`.
    """

    @behaviour Plug

    alias Hermes.Server.Transport.StreamableHTTP.Plug, as: MCPPlug

    @mcp_path "/extools/mcp"

    @impl Plug
    def init(opts) do
      MCPPlug.init(Keyword.merge([server: Extools.MCPServer], opts))
    end

    @impl Plug
    def call(%Plug.Conn{request_path: path} = conn, mcp_opts) do
      if path == @mcp_path or String.starts_with?(path, @mcp_path <> "/") do
        MCPPlug.call(conn, mcp_opts)
      else
        conn
      end
    end
  end
else
  defmodule Extools do
    @moduledoc """
    Stub module — `Plug` is not available in this project.

    To use the Extools HTTP endpoint, add a Plug-providing dependency:

      * Phoenix apps already have one (via `phoenix`).
      * Non-Phoenix apps: add `{:bandit, "~> 1.0", only: :dev}` and set
        `config :extools, port: 4040`.
    """
  end
end