321 lines
9.7 KiB
Ruby
321 lines
9.7 KiB
Ruby
# frozen_string_literal: true
|
|
|
|
require "json_rpc_handler"
|
|
require_relative "instrumentation"
|
|
require_relative "methods"
|
|
require_relative "server/capabilities"
|
|
|
|
module MCP
|
|
class Server
|
|
DEFAULT_VERSION = "0.1.0"
|
|
|
|
class RequestHandlerError < StandardError
|
|
attr_reader :error_type
|
|
attr_reader :original_error
|
|
|
|
def initialize(message, request, error_type: :internal_error, original_error: nil)
|
|
super(message)
|
|
@request = request
|
|
@error_type = error_type
|
|
@original_error = original_error
|
|
end
|
|
end
|
|
|
|
include Instrumentation
|
|
|
|
attr_writer :capabilities
|
|
attr_accessor :name, :version, :tools, :prompts, :resources, :server_context, :configuration, :transport
|
|
|
|
def initialize(
|
|
name: "model_context_protocol",
|
|
version: DEFAULT_VERSION,
|
|
tools: [],
|
|
prompts: [],
|
|
resources: [],
|
|
resource_templates: [],
|
|
server_context: nil,
|
|
configuration: nil,
|
|
capabilities: nil,
|
|
transport: nil
|
|
)
|
|
@name = name
|
|
@version = version
|
|
@tools = tools.to_h { |t| [t.name_value, t] }
|
|
@prompts = prompts.to_h { |p| [p.name_value, p] }
|
|
@resources = resources
|
|
@resource_templates = resource_templates
|
|
@resource_index = index_resources_by_uri(resources)
|
|
@server_context = server_context
|
|
@configuration = MCP.configuration.merge(configuration)
|
|
@capabilities = Capabilities.new(capabilities)
|
|
@capabilities.support_tools if tools.any?
|
|
@capabilities.support_prompts if prompts.any?
|
|
@capabilities.support_resources if resources.any? || resource_templates.any?
|
|
|
|
@handlers = {
|
|
Methods::RESOURCES_LIST => method(:list_resources),
|
|
Methods::RESOURCES_READ => method(:read_resource_no_content),
|
|
Methods::RESOURCES_TEMPLATES_LIST => method(:list_resource_templates),
|
|
Methods::TOOLS_LIST => method(:list_tools),
|
|
Methods::TOOLS_CALL => method(:call_tool),
|
|
Methods::PROMPTS_LIST => method(:list_prompts),
|
|
Methods::PROMPTS_GET => method(:get_prompt),
|
|
Methods::INITIALIZE => method(:init),
|
|
Methods::PING => ->(_) { {} },
|
|
|
|
# No op handlers for currently unsupported methods
|
|
Methods::RESOURCES_SUBSCRIBE => ->(_) {},
|
|
Methods::RESOURCES_UNSUBSCRIBE => ->(_) {},
|
|
Methods::COMPLETION_COMPLETE => ->(_) {},
|
|
Methods::LOGGING_SET_LEVEL => ->(_) {},
|
|
}
|
|
@transport = transport
|
|
end
|
|
|
|
def capabilities
|
|
@capabilities.to_h
|
|
end
|
|
|
|
def handle(request)
|
|
JsonRpcHandler.handle(request) do |method|
|
|
handle_request(request, method)
|
|
end
|
|
end
|
|
|
|
def handle_json(request)
|
|
JsonRpcHandler.handle_json(request) do |method|
|
|
handle_request(request, method)
|
|
end
|
|
end
|
|
|
|
def define_tool(name: nil, description: nil, input_schema: nil, annotations: nil, &block)
|
|
tool = Tool.define(name:, description:, input_schema:, annotations:, &block)
|
|
@tools[tool.name_value] = tool
|
|
end
|
|
|
|
def define_prompt(name: nil, description: nil, arguments: [], &block)
|
|
prompt = Prompt.define(name:, description:, arguments:, &block)
|
|
@prompts[prompt.name_value] = prompt
|
|
end
|
|
|
|
def notify_tools_list_changed
|
|
return unless @transport
|
|
|
|
@transport.send_notification(Methods::NOTIFICATIONS_TOOLS_LIST_CHANGED)
|
|
rescue => e
|
|
report_exception(e, { notification: "tools_list_changed" })
|
|
end
|
|
|
|
def notify_prompts_list_changed
|
|
return unless @transport
|
|
|
|
@transport.send_notification(Methods::NOTIFICATIONS_PROMPTS_LIST_CHANGED)
|
|
rescue => e
|
|
report_exception(e, { notification: "prompts_list_changed" })
|
|
end
|
|
|
|
def notify_resources_list_changed
|
|
return unless @transport
|
|
|
|
@transport.send_notification(Methods::NOTIFICATIONS_RESOURCES_LIST_CHANGED)
|
|
rescue => e
|
|
report_exception(e, { notification: "resources_list_changed" })
|
|
end
|
|
|
|
def resources_list_handler(&block)
|
|
@capabilities.support_resources
|
|
@handlers[Methods::RESOURCES_LIST] = block
|
|
end
|
|
|
|
def resources_read_handler(&block)
|
|
@handlers[Methods::RESOURCES_READ] = block
|
|
end
|
|
|
|
def resources_templates_list_handler(&block)
|
|
@capabilities.support_resources
|
|
@handlers[Methods::RESOURCES_TEMPLATES_LIST] = block
|
|
end
|
|
|
|
def tools_list_handler(&block)
|
|
@capabilities.support_tools
|
|
@handlers[Methods::TOOLS_LIST] = block
|
|
end
|
|
|
|
def tools_call_handler(&block)
|
|
@handlers[Methods::TOOLS_CALL] = block
|
|
end
|
|
|
|
def prompts_list_handler(&block)
|
|
@capabilities.support_prompts
|
|
@handlers[Methods::PROMPTS_LIST] = block
|
|
end
|
|
|
|
def prompts_get_handler(&block)
|
|
@handlers[Methods::PROMPTS_GET] = block
|
|
end
|
|
|
|
private
|
|
|
|
def handle_request(request, method)
|
|
handler = @handlers[method]
|
|
unless handler
|
|
instrument_call("unsupported_method") {}
|
|
return
|
|
end
|
|
|
|
Methods.ensure_capability!(method, capabilities)
|
|
|
|
->(params) {
|
|
instrument_call(method) do
|
|
case method
|
|
when Methods::TOOLS_LIST
|
|
{ tools: @handlers[Methods::TOOLS_LIST].call(params) }
|
|
when Methods::PROMPTS_LIST
|
|
{ prompts: @handlers[Methods::PROMPTS_LIST].call(params) }
|
|
when Methods::RESOURCES_LIST
|
|
{ resources: @handlers[Methods::RESOURCES_LIST].call(params) }
|
|
when Methods::RESOURCES_READ
|
|
{ contents: @handlers[Methods::RESOURCES_READ].call(params) }
|
|
when Methods::RESOURCES_TEMPLATES_LIST
|
|
{ resourceTemplates: @handlers[Methods::RESOURCES_TEMPLATES_LIST].call(params) }
|
|
else
|
|
@handlers[method].call(params)
|
|
end
|
|
rescue => e
|
|
report_exception(e, { request: request })
|
|
if e.is_a?(RequestHandlerError)
|
|
add_instrumentation_data(error: e.error_type)
|
|
raise e
|
|
end
|
|
|
|
add_instrumentation_data(error: :internal_error)
|
|
raise RequestHandlerError.new("Internal error handling #{method} request", request, original_error: e)
|
|
end
|
|
}
|
|
end
|
|
|
|
def server_info
|
|
@server_info ||= {
|
|
name:,
|
|
version:,
|
|
}
|
|
end
|
|
|
|
def init(request)
|
|
{
|
|
protocolVersion: configuration.protocol_version,
|
|
capabilities: capabilities,
|
|
serverInfo: server_info,
|
|
}
|
|
end
|
|
|
|
def list_tools(request)
|
|
@tools.map { |_, tool| tool.to_h }
|
|
end
|
|
|
|
def call_tool(request)
|
|
tool_name = request[:name]
|
|
tool = tools[tool_name]
|
|
unless tool
|
|
add_instrumentation_data(error: :tool_not_found)
|
|
raise RequestHandlerError.new("Tool not found #{tool_name}", request, error_type: :tool_not_found)
|
|
end
|
|
|
|
arguments = request[:arguments]
|
|
add_instrumentation_data(tool_name:)
|
|
|
|
if tool.input_schema&.missing_required_arguments?(arguments)
|
|
add_instrumentation_data(error: :missing_required_arguments)
|
|
raise RequestHandlerError.new(
|
|
"Missing required arguments: #{tool.input_schema.missing_required_arguments(arguments).join(", ")}",
|
|
request,
|
|
error_type: :missing_required_arguments,
|
|
)
|
|
end
|
|
|
|
if configuration.validate_tool_call_arguments && tool.input_schema
|
|
begin
|
|
tool.input_schema.validate_arguments(arguments)
|
|
rescue Tool::InputSchema::ValidationError => e
|
|
add_instrumentation_data(error: :invalid_schema)
|
|
raise RequestHandlerError.new(e.message, request, error_type: :invalid_schema)
|
|
end
|
|
end
|
|
|
|
begin
|
|
call_params = tool_call_parameters(tool)
|
|
|
|
if call_params.include?(:server_context)
|
|
tool.call(**arguments.transform_keys(&:to_sym), server_context:).to_h
|
|
else
|
|
tool.call(**arguments.transform_keys(&:to_sym)).to_h
|
|
end
|
|
rescue => e
|
|
raise RequestHandlerError.new("Internal error calling tool #{tool_name}", request, original_error: e)
|
|
end
|
|
end
|
|
|
|
def list_prompts(request)
|
|
@prompts.map { |_, prompt| prompt.to_h }
|
|
end
|
|
|
|
def get_prompt(request)
|
|
prompt_name = request[:name]
|
|
prompt = @prompts[prompt_name]
|
|
unless prompt
|
|
add_instrumentation_data(error: :prompt_not_found)
|
|
raise RequestHandlerError.new("Prompt not found #{prompt_name}", request, error_type: :prompt_not_found)
|
|
end
|
|
|
|
add_instrumentation_data(prompt_name:)
|
|
|
|
prompt_args = request[:arguments]
|
|
prompt.validate_arguments!(prompt_args)
|
|
|
|
prompt.template(prompt_args, server_context:).to_h
|
|
end
|
|
|
|
def list_resources(request)
|
|
@resources.map(&:to_h)
|
|
end
|
|
|
|
# Server implementation should set `resources_read_handler` to override no-op default
|
|
def read_resource_no_content(request)
|
|
add_instrumentation_data(resource_uri: request[:uri])
|
|
[]
|
|
end
|
|
|
|
def list_resource_templates(request)
|
|
@resource_templates.map(&:to_h)
|
|
end
|
|
|
|
def report_exception(exception, server_context = {})
|
|
configuration.exception_reporter.call(exception, server_context)
|
|
end
|
|
|
|
def index_resources_by_uri(resources)
|
|
resources.each_with_object({}) do |resource, hash|
|
|
hash[resource.uri] = resource
|
|
end
|
|
end
|
|
|
|
def tool_call_parameters(tool)
|
|
method_def = tool_call_method_def(tool)
|
|
method_def.parameters.flatten
|
|
end
|
|
|
|
def tool_call_method_def(tool)
|
|
method = tool.method(:call)
|
|
|
|
if defined?(T::Utils) && T::Utils.respond_to?(:signature_for_method)
|
|
sorbet_typed_method_definition = T::Utils.signature_for_method(method)&.method
|
|
|
|
# Return the Sorbet typed method definition if it exists, otherwise fallback to original method
|
|
# definition if Sorbet is defined but not used by this tool.
|
|
sorbet_typed_method_definition || method
|
|
else
|
|
method
|
|
end
|
|
end
|
|
end
|
|
end
|