# `Snodo.Tool.GenServer`
[🔗](https://github.com/joshrotenberg/snodo/blob/v0.4.1/lib/snodo/tool/gen_server.ex#L1)

Generates MCP tools for explicitly declared GenServer calls and casts.

Import `genserver_call/2` and `genserver_cast/2` into a `Snodo.Server` module.
Each declaration generates an ordinary `Snodo.Tool` module and registers it
through the server DSL. The target is a fixed, registered module name; MCP
clients cannot choose a process, message, or Elixir term.

    defmodule CounterServer do
      use Snodo.Server, name: "counter", version: "1.0.0"
      import Snodo.Tool.GenServer

      genserver_call "counter_get",
        target: Counter,
        input_schema: %{"type" => "object", "additionalProperties" => false},
        message: :get,
        encode_reply: fn count -> %{"value" => count} end
    end

`:message` may be a fixed term or a one-argument function receiving the
validated string-keyed input map. Calls require `:encode_reply`, a one-argument
function that returns a JSON object. `:timeout` defaults to 5,000 milliseconds
and must be a positive integer. Failed validation, message construction,
unavailable targets, timeouts, and non-JSON replies become tool error results.

Input schemas may use the assertions enforced by
`Snodo.Schema.Validator.Basic` and the annotations `title`, `description`,
`default`, and `x-mcp-header`. Unsupported keywords fail compilation so a
declaration cannot advertise a constraint that this adapter ignores.

A cast result means only that `GenServer.cast/2` accepted the message for
sending. An absent target is reported as a tool error, but the target can
stop after the availability check. A successful cast does not establish
that the target received or processed it.

# `genserver_call`
*macro* 

Defines and registers a tool that sends a bounded `GenServer.call/3`.

# `genserver_cast`
*macro* 

Defines and registers a tool that sends `GenServer.cast/2`.

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