Class: LLM::MCP

Inherits:
Object
  • Object
show all
Includes:
RPC
Defined in:
lib/llm/mcp.rb,
lib/llm/mcp/rpc.rb,
lib/llm/mcp/pipe.rb,
lib/llm/mcp/error.rb,
lib/llm/mcp/command.rb

Overview

The LLM::MCP class provides access to servers that implement the Model Context Protocol. MCP defines a standard way for clients and servers to exchange capabilities such as tools, prompts, resources, and other structured interactions.

In llm.rb, LLM::MCP currently supports stdio servers and focuses on discovering tools that can be used through LLM::Context and LLM::Agent.

Defined Under Namespace

Modules: RPC, Transport Classes: Command, Error, Pipe

Constant Summary collapse

TimeoutError = 
Class.new(Error)

Instance Method Summary collapse

Methods included from RPC

#call

Constructor Details

#initialize(llm = nil, stdio:, timeout: 30) ⇒ LLM::MCP

Returns A new MCP instance.

Parameters:

  • llm (LLM::Provider, nil) (defaults to: nil) —

    The provider to use for MCP transports that need one

  • stdio (Hash) —

    The configuration for the stdio transport

  • timeout (Integer) (defaults to: 30) —

    The maximum amount of time to wait when reading from an MCP process

Options Hash (stdio:):

  • :argv (Array<String>) —

    The command to run for the MCP process

  • :env (Hash) —

    The environment variables to set for the MCP process

  • :cwd (String, nil) —

    The working directory for the MCP process



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# File 'lib/llm/mcp.rb', line 34

def initialize(llm = nil, stdio:, timeout: 30)
  @llm = llm
  @command = Command.new(**stdio)
  @monitor = Monitor.new
  @transport = Transport::Stdio.new(command:)
  @timeout = timeout
end

Instance Method Details

#call_tool(name, arguments = {}) ⇒ Object

Calls a tool by name with the given arguments

Parameters:

  • name (String) —

    The name of the tool to call

  • arguments (Hash) (defaults to: {}) —

    The arguments to pass to the tool

Returns:

  • (Object) —

    The result of the tool call



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# File 'lib/llm/mcp.rb', line 78

def call_tool(name, arguments = {})
  lock do
    res = call(transport, "tools/call", {name:, arguments:})
    adapt_tool_result(res)
  end
end

#start ⇒ void

This method returns an undefined value.

Starts the MCP process.



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# File 'lib/llm/mcp.rb', line 45

def start
  lock do
    transport.start
    call(transport, "initialize", {clientInfo: {name: "llm.rb", version: LLM::VERSION}})
    call(transport, "notifications/initialized")
  end
end

#stop ⇒ void

This method returns an undefined value.

Stops the MCP process.



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# File 'lib/llm/mcp.rb', line 56

def stop
  lock do
    transport.stop
    nil
  end
end

#tools ⇒ Array<Class<LLM::Tool>>

Returns the tools provided by the MCP process.

Returns:



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# File 'lib/llm/mcp.rb', line 66

def tools
  lock do
    res = call(transport, "tools/list")
    res["tools"].map { LLM::Tool.mcp(self, _1) }
  end
end