# `Lotus.MCP`
[🔗](https://github.com/elixir-lotus/lotus/blob/v1.3.0/lib/lotus/mcp.ex#L2)

An MCP server for Lotus, built on [Sake](https://hexdocs.pm/sake): it lets
an MCP client (Claude Code, Claude Desktop, an agent) explore your data
sources, run read-only queries, run saved queries and dashboards, and
save queries, charts and dashboards, as the person signed in to your app.

Compiled only when the host depends on `:sake`. Serve it on an endpoint of
its own, or mount it in your app's own Sake server:

    # router.ex
    sake_endpoint "/lotus/mcp", server: Lotus.MCP, auth: true

    # or
    defmodule MyApp.MCP do
      use Sake.Server, name: "my-app", version: "1.0.0"
      mount Lotus.MCP, prefix: "lotus"
    end

## Scopes

  * `lotus:read` — list data sources, schemas, tables and columns, saved
    queries and dashboards.
  * `lotus:query` — run read-only statements, saved queries and dashboards,
    and read a column's distinct values.
  * `lotus:write` — save and change queries, charts and dashboards.

Every statement runs read-only, whatever `config :lotus, read_only:` says,
and through Lotus's visibility rules and middleware with the person as the
actor; a statement that writes is not saved either. Nothing is deleted
through MCP. Nobody may use it until `config :lotus, :mcp, authorize:`
says who.

## Configuration

    config :lotus, :mcp,
      # Required: who may use Lotus over MCP. Takes the signed-in
      # principal, returns true to allow. Without it, nobody may.
      authorize: {MyApp.Reporting, :lotus_user?},
      # The :context and :scope Lotus gets for the signed-in principal
      # (default: the principal as both).
      actor: {MyApp.Reporting, :lotus_actor},
      # Only these data sources (default: all).
      data_sources: ["analytics"],
      # The most rows a tool returns at once (default: 500).
      max_rows: 500

See the MCP guide for authorization and connecting Claude Code.

---

*Consult [api-reference.md](api-reference.md) for complete listing*