Issho's tools over MCP, with Sake: a Sake.Server of the tools you give, Issho's (Issho.Tools.room/0) and the components' (Kotoba.Issho.tools/0, Hakushi.Issho.tools/0), for any MCP client. The same tools serve your app's own model without MCP (Issho.Tools).

defmodule MyApp.MCP do
  use Issho.MCP,
    name: "my-app",
    version: "1.0.0",
    tools: Issho.Tools.room() ++ Kotoba.Issho.tools() ++ Hakushi.Issho.tools()
end

# config/config.exs
config :issho, Issho.MCP, instance: MyApp.Issho

Serve it as your app serves MCP: over HTTP or stdio, with Sake's authorization, your own, or none, on its own endpoint or mounted in your own server (mount MyApp.MCP). Who a caller is in the rooms: Issho.MCP.Session.

Options: those of use Sake.Server (:name, :version, :instructions...), and :tools, a list of Issho.Tool modules.

The inbox

An agent that is not connected is not told anything: MCP has no way to reach it. What people said to it meanwhile waits in its inbox (Issho.Inbox): the inbox tool takes it, and the server's instructions, unless you give your own (then add instructions/0 to them), say to read it first. The server has the resource issho://inbox (Issho.MCP.Inbox), and the clients that subscribe to it hear when it changes: those connected. To wake one that is not, give the instance an :on_mention.

Issho tells the servers that answered a call on the node of the comment; in a cluster, name them all in the config: config :issho, Issho.MCP, servers: [MyApp.MCP]. A server that declares its own resources lists Issho.MCP.Inbox among them. Sake is an optional dependency of Issho: add {:sake, "~> 0.4"} to serve MCP, and start {Sake, ...} in your supervision tree, before the endpoint (Sake's streams and tasks run there): without it, a client that listens for changes (subscriptions/listen, as Claude Code does on connecting) fails with "Sake.Plug.Streams is not running". See the Agents guide.