Sake

Sake (酒) is MCP for Elixir and Phoenix: a server that speaks the modern, stateless 2026-07-28 protocol and the earlier handshake-and-session protocol on one endpoint, an OAuth 2.1 authorization server that makes your app's own login the identity provider, and a client for calling other MCP servers.

Quickstart

def deps do
  [{:sake, "~> 0.1"}, {:bandit, "~> 1.5"}]
end

defmodule MyApp.MCP.Echo do
  use Sake.Tool, name: "echo", description: "Returns the text it receives"
  arg :text, :string, required: true

  @impl true
  def execute(%{text: text}, _ctx), do: {:ok, text}
end

defmodule MyApp.MCP do
  use Sake.Server, name: "my-app", version: "1.0.0"
  tools [MyApp.MCP.Echo]
end

# In your supervision tree:
{Sake, secret_key_base: MyAppWeb.Endpoint.config(:secret_key_base)}

# In your Phoenix router:
import Sake.Router
scope "/" do
  sake_endpoint "/mcp", server: MyApp.MCP
end

claude mcp add --transport http my-app https://myapp.example.com/mcp

See guides/quickstart.md for turning on authorization in five steps, or mix dev in this repository for a complete, running example.

Features by era

The authorization flow, briefly

A client hits your endpoint, gets a 401, and discovers your app's authorize and token URLs from well-known metadata. Your existing login runs if the person is not signed in; a consent page shows what the client is asking for; approving issues an authorization code, which the client exchanges for an access and refresh token pair. Every later MCP request carries the access token as a bearer credential, scoped to that one endpoint's resource URL. See guides/authorization.md.

Guides

• Quickstart
• Tools
• Resources and prompts
• Authorization
• Multi-tenant endpoints
• The client
• Protocol versions
• Security

Status

0.1: the server (both eras, one endpoint), the authorization server (bearer, CIMD, dynamic registration, consent, token rotation), and the client. Next: client-side OAuth, a stdio transport, the device authorization grant, and tasks.

License

Sake is released under the MIT License. See LICENSE.