Multiple client instances

[hubertpompecki]

It seems it's not possible to start more than one instance of a given client, trying to follow the docs results in an error, here's a minimum example:

Mix.install([{:anubis_mcp, "~> 0.13.1"}])

defmodule Test.MCPClient do
  use Anubis.Client,
    name: "Test",
    version: "1.0.0",
    protocol_version: "2025-03-26",
    capabilities: [:roots, :sampling]
end

defmodule Test.Application do
  def start() do
    children = [
      Supervisor.child_spec(
        {Test.MCPClient, name: :some_id_1, transport: {:stdio, command: "command", args: ["1"]}},
        id: :some_id_1
      ),
      Supervisor.child_spec(
        {Test.MCPClient, name: :some_id_2, transport: {:stdio, command: "command", args: ["2"]}},
        id: :some_id_2
      )
    ]

    opts = [strategy: :one_for_all, name: Astro.Supervisor]
    Supervisor.start_link(children, opts)
  end
end

Test.Application.start()

Gives:

** (EXIT from #PID<0.94.0>) shutdown: failed to start child: :some_id_2
    ** (EXIT) shutdown: failed to start child: Anubis.Client.Base
        ** (EXIT) already started: #PID<0.205.0>

In my use case I'm trying to use a dynamic supervisor and start connections to an MCP server on behalf of many different end users (therefore passing different credentials) but here I'm using stdio for a minimal example as per docs.

Thank you for your great work on this lib.

[hubertpompecki]

I think it's an issue with documentation, here is a working version of the script above:

Mix.install([{:anubis_mcp, "~> 0.13.1"}])

defmodule Test.MCPClient do
  use Anubis.Client,
    name: "Test",
    version: "1.0.0",
    protocol_version: "2025-03-26",
    capabilities: [:roots, :sampling]
end

defmodule Test.Application do
  def start() do
    children = [
      Supervisor.child_spec(
        {Test.MCPClient, client_name: :some_id_1, transport: {:stdio, command: "command", args: ["1"]}},
        id: :some_id_1
      ),
      Supervisor.child_spec(
        {Test.MCPClient, client_name: :some_id_2, transport: {:stdio, command: "command", args: ["2"]}},
        id: :some_id_2
      )
    ]

    opts = [strategy: :one_for_all, name: Astro.Supervisor]
    Supervisor.start_link(children, opts)
  end
end

Test.Application.start()

In particular, it is client_name: :some_id_1 rather than name: :some_id_1.

A specific instance of a client can then be used with:

Anubis.Client.Base.list_tools(:some_id_1)
Anubis.Client.Base.list_tools(:some_id_2)

[zoedsoupe]

thanks for the issue! im tracking all documentation issues, the library evolved so quickly and the documentation pages were writing based on old RFC/implementation plans