Class: RubyLLM::MCP::Native::Client

Inherits:
Object
  • Object
show all
Defined in:
lib/ruby_llm/mcp/native/client.rb

Overview

Native MCP protocol client implementation This is the core protocol implementation that handles all MCP operations It's self-contained and could potentially be extracted as a separate gem

Constant Summary collapse

TOOL_CALL_CANCELLED_MESSAGE = 
"Tool call was cancelled by the client"

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name:, transport_type:, transport_config: {}, human_in_the_loop_callback: nil, roots_callback: nil, logging_enabled: false, logging_level: nil, elicitation_enabled: false, elicitation_callback: nil, progress_tracking_enabled: false, sampling_callback: nil, notification_callback: nil, extensions_capabilities: nil, protocol_version: nil, request_timeout: nil) ⇒ Client

rubocop:disable Metrics/ParameterLists



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# File 'lib/ruby_llm/mcp/native/client.rb', line 15

def initialize( # rubocop:disable Metrics/ParameterLists
  name:,
  transport_type:,
  transport_config: {},
  human_in_the_loop_callback: nil,
  roots_callback: nil,
  logging_enabled: false,
  logging_level: nil,
  elicitation_enabled: false,
  elicitation_callback: nil,
  progress_tracking_enabled: false,
  sampling_callback: nil,
  notification_callback: nil,
  extensions_capabilities: nil,
  protocol_version: nil,
  request_timeout: nil
)
  @name = name
  @transport_type = transport_type
  @config = transport_config.merge(request_timeout: request_timeout || MCP.config.request_timeout)
  @requested_protocol_version = protocol_version || MCP.config.protocol_version || Native::Protocol.latest_version
  @protocol_version = @requested_protocol_version
  @extensions_capabilities = extensions_capabilities || {}

  # Callbacks
  @human_in_the_loop_callback = human_in_the_loop_callback
  @roots_callback = roots_callback
  @logging_enabled = logging_enabled
  @logging_level = logging_level
  @elicitation_enabled = elicitation_enabled
  @elicitation_callback = elicitation_callback
  @progress_tracking_enabled = progress_tracking_enabled
  @sampling_callback = sampling_callback
  @notification_callback = notification_callback

  @transport = nil
  @capabilities = nil
  @task_registry = Native::TaskRegistry.new

  # Track in-flight server-initiated requests for cancellation
  @in_flight_requests = {}
  @in_flight_mutex = Mutex.new

  # Human-in-the-loop approvals are scoped per client lifecycle.
  @registry_owner_id = "native-client-#{SecureRandom.uuid}"
  @human_in_the_loop_registry = Handlers::HumanInTheLoopRegistry.for_owner(@registry_owner_id)
end

Instance Attribute Details

#capabilities ⇒ Object (readonly)

Returns the value of attribute capabilities.



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# File 'lib/ruby_llm/mcp/native/client.rb', line 12

def capabilities
  @capabilities
end

#config ⇒ Object (readonly)

Returns the value of attribute config.



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# File 'lib/ruby_llm/mcp/native/client.rb', line 12

def config
  @config
end

#elicitation_callback ⇒ Object (readonly)

Returns the value of attribute elicitation_callback.



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# File 'lib/ruby_llm/mcp/native/client.rb', line 12

def elicitation_callback
  @elicitation_callback
end

#human_in_the_loop_registry ⇒ Object (readonly)

Returns the value of attribute human_in_the_loop_registry.



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# File 'lib/ruby_llm/mcp/native/client.rb', line 12

def human_in_the_loop_registry
  @human_in_the_loop_registry
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/ruby_llm/mcp/native/client.rb', line 12

def name
  @name
end

#protocol_version ⇒ Object (readonly)

Returns the value of attribute protocol_version.



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# File 'lib/ruby_llm/mcp/native/client.rb', line 12

def protocol_version
  @protocol_version
end

#registry_owner_id ⇒ Object (readonly)

Returns the value of attribute registry_owner_id.



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# File 'lib/ruby_llm/mcp/native/client.rb', line 12

def registry_owner_id
  @registry_owner_id
end

#sampling_callback ⇒ Object (readonly)

Returns the value of attribute sampling_callback.



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# File 'lib/ruby_llm/mcp/native/client.rb', line 12

def sampling_callback
  @sampling_callback
end

#task_registry ⇒ Object (readonly)

Returns the value of attribute task_registry.



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# File 'lib/ruby_llm/mcp/native/client.rb', line 12

def task_registry
  @task_registry
end

#transport_type ⇒ Object (readonly)

Returns the value of attribute transport_type.



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# File 'lib/ruby_llm/mcp/native/client.rb', line 12

def transport_type
  @transport_type
end

Instance Method Details

#alive? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ruby_llm/mcp/native/client.rb', line 141

def alive?
  !!@transport&.alive?
end

#cancel_in_flight_request(request_id) ⇒ Symbol

Cancel an in-flight server-initiated request

Parameters:

  • request_id (String) —

    The ID of the request to cancel

Returns:

  • (Symbol) —

    cancellation outcome :cancelled, :already_cancelled, :already_completed, :not_found, :not_cancellable, :failed



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# File 'lib/ruby_llm/mcp/native/client.rb', line 453

def cancel_in_flight_request(request_id)
  operation = nil
  @in_flight_mutex.synchronize do
    operation = @in_flight_requests[request_id.to_s]
  end

  unless operation
    RubyLLM::MCP.logger.debug("Request #{request_id} was not found for cancellation")
    return :not_found
  end

  unless operation.respond_to?(:cancel)
    RubyLLM::MCP.logger.warn("Request #{request_id} cannot be cancelled or was already completed")
    return :not_cancellable
  end

  outcome = normalize_cancellation_outcome(operation.cancel)
  if %i[cancelled already_cancelled already_completed].include?(outcome)
    unregister_in_flight_request(request_id)
  end

  outcome
end

#cancelled_notification(reason:, request_id:) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 336

def cancelled_notification(reason:, request_id:)
  body = Native::Messages::Notifications.cancelled(request_id: request_id, reason: reason)
  request(body, wait_for_response: false)
end

#client_capabilities ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 379

def client_capabilities
  capabilities_hash = {}

  if @roots_callback&.call&.any?
    capabilities_hash[:roots] = {
      listChanged: true
    }
  end

  if MCP.config.sampling.enabled?
    sampling_capabilities = {}
    sampling_capabilities[:tools] = {} if MCP.config.sampling.tools
    sampling_capabilities[:context] = {} if MCP.config.sampling.context
    capabilities_hash[:sampling] = sampling_capabilities
  end

  if @elicitation_enabled
    elicitation_capabilities = {}
    elicitation_capabilities[:form] = {} if MCP.config.elicitation.form
    elicitation_capabilities[:url] = {} if MCP.config.elicitation.url
    capabilities_hash[:elicitation] = elicitation_capabilities unless elicitation_capabilities.empty?
  end

  if MCP.config.respond_to?(:tasks) && MCP.config.tasks.enabled?
    capabilities_hash[:tasks] = {
      list: {},
      cancel: {}
    }
  end

  if @extensions_capabilities.any? && Native::Protocol.extensions_supported?(@protocol_version)
    capabilities_hash[:extensions] = @extensions_capabilities
  end

  capabilities_hash
end

#completion_prompt(name:, argument:, value:, context: nil) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 265

def completion_prompt(name:, argument:, value:, context: nil)
  body = Native::Messages::Requests.completion_prompt(name: name, argument: argument, value: value,
                                                      context: context, tracking_progress: tracking_progress?)
  request(body)
end

#completion_resource(uri:, argument:, value:, context: nil) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 259

def completion_resource(uri:, argument:, value:, context: nil)
  body = Native::Messages::Requests.completion_resource(uri: uri, argument: argument, value: value,
                                                        context: context, tracking_progress: tracking_progress?)
  request(body)
end

#elicitation_response(id:, elicitation:) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 373

def elicitation_response(id:, elicitation:)
  body = Native::Messages::Responses.elicitation(id: id, action: elicitation[:action],
                                                 content: elicitation[:content])
  request(body, wait_for_response: false)
end

#error_response(id:, message:, code: Native::JsonRpc::ErrorCodes::SERVER_ERROR, data: nil) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 368

def error_response(id:, message:, code: Native::JsonRpc::ErrorCodes::SERVER_ERROR, data: nil)
  body = Native::Messages::Responses.error(id: id, message: message, code: code, data: data)
  request(body, wait_for_response: false)
end

#execute_prompt(name:, arguments:) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 253

def execute_prompt(name:, arguments:)
  body = Native::Messages::Requests.prompt_call(name: name, arguments: arguments,
                                                tracking_progress: tracking_progress?)
  request(body)
end

#execute_tool(name:, parameters:) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 190

def execute_tool(name:, parameters:)
  if @human_in_the_loop_callback
    approved = evaluate_tool_approval(name: name, parameters: parameters)
    return create_cancelled_result unless approved
  end

  body = Native::Messages::Requests.tool_call(name: name, parameters: parameters,
                                              tracking_progress: tracking_progress?)
  request(body)
end

#initialize_notification ⇒ Object

Notifications



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# File 'lib/ruby_llm/mcp/native/client.rb', line 331

def initialize_notification
  body = Native::Messages::Notifications.initialized
  request(body, wait_for_response: false)
end

#initialize_request ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 170

def initialize_request
  body = Native::Messages::Requests.initialize(
    protocol_version: protocol_version,
    capabilities: client_capabilities
  )
  request(body)
end

#ping ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 145

def ping
  body = Native::Messages::Requests.ping(tracking_progress: tracking_progress?)
  if alive?
    result = request(body)
  else
    transport.start

    result = request(body)
    @transport = nil
  end

  result.value == {}
rescue RubyLLM::MCP::Errors::TimeoutError, RubyLLM::MCP::Errors::TransportError
  false
end

#ping_response(id:) ⇒ Object

Responses



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# File 'lib/ruby_llm/mcp/native/client.rb', line 348

def ping_response(id:)
  body = Native::Messages::Responses.ping(id: id)
  request(body, wait_for_response: false)
end

#process_notification(result) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 161

def process_notification(result)
  notification = result.notification
  @notification_callback&.call(notification)
end

#process_request(result) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 166

def process_request(result)
  Native::ResponseHandler.new(self).execute(result)
end

#process_result(result) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 72

def process_result(result)
  if result.notification?
    process_notification(result)
    return nil
  end

  if result.request?
    process_request(result) if alive?
    return nil
  end

  if result.response?
    return result
  end

  nil
end

#prompt_list(cursor: nil) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 241

def prompt_list(cursor: nil)
  body = Native::Messages::Requests.prompt_list(cursor: cursor, tracking_progress: tracking_progress?)
  result = request(body)
  result.raise_error! if result.error?

  if result.next_cursor?
    result.value["prompts"] + prompt_list(cursor: result.next_cursor)
  else
    result.value["prompts"]
  end
end

#register_in_flight_request(request_id, cancellable_operation = nil) ⇒ Object

Register a server-initiated request that can be cancelled

Parameters:

  • request_id (String) —

    The ID of the request

  • cancellable_operation (CancellableOperation, nil) (defaults to: nil) —

    The operation that can be cancelled



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# File 'lib/ruby_llm/mcp/native/client.rb', line 435

def register_in_flight_request(request_id, cancellable_operation = nil)
  @in_flight_mutex.synchronize do
    @in_flight_requests[request_id.to_s] = cancellable_operation
  end
end

#request(body, **options) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 63

def request(body, **options)
  transport.request(body, **options)
rescue RubyLLM::MCP::Errors::TimeoutError => e
  if transport&.alive? && !e.request_id.nil?
    cancelled_notification(reason: "Request timed out", request_id: e.request_id)
  end
  raise e
end

#resource_list(cursor: nil) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 201

def resource_list(cursor: nil)
  body = Native::Messages::Requests.resource_list(cursor: cursor, tracking_progress: tracking_progress?)
  result = request(body)
  result.raise_error! if result.error?

  if result.next_cursor?
    result.value["resources"] + resource_list(cursor: result.next_cursor)
  else
    result.value["resources"]
  end
end

#resource_read(uri:) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 213

def resource_read(uri:)
  body = Native::Messages::Requests.resource_read(uri: uri, tracking_progress: tracking_progress?)
  request(body)
end

#resource_template_list(cursor: nil) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 218

def resource_template_list(cursor: nil)
  body = Native::Messages::Requests.resource_template_list(cursor: cursor,
                                                           tracking_progress: tracking_progress?)
  result = request(body)
  result.raise_error! if result.error?

  if result.next_cursor?
    result.value["resourceTemplates"] + resource_template_list(cursor: result.next_cursor)
  else
    result.value["resourceTemplates"]
  end
end

#resources_subscribe(uri:) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 231

def resources_subscribe(uri:)
  body = Native::Messages::Requests.resources_subscribe(uri: uri, tracking_progress: tracking_progress?)
  request(body, wait_for_response: false)
end

#resources_unsubscribe(uri:) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 236

def resources_unsubscribe(uri:)
  body = Native::Messages::Requests.resources_unsubscribe(uri: uri, tracking_progress: tracking_progress?)
  request(body, wait_for_response: false)
end

#restart! ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 135

def restart!
  @initialize_response = nil
  stop
  start
end

#result_response(id:, value:) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 358

def result_response(id:, value:)
  body = Native::Messages::Responses.result(id: id, value: value)
  request(body, wait_for_response: false)
end

#roots_list_change_notification ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 341

def roots_list_change_notification
  body = Native::Messages::Notifications.roots_list_changed
  request(body, wait_for_response: false)
end

#roots_list_response(id:) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 353

def roots_list_response(id:)
  body = Native::Messages::Responses.roots_list(id: id, roots_paths: roots_paths)
  request(body, wait_for_response: false)
end

#roots_paths ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 416

def roots_paths
  @roots_callback&.call || []
end

#sampling_callback_enabled? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ruby_llm/mcp/native/client.rb', line 424

def sampling_callback_enabled?
  !@sampling_callback.nil?
end

#sampling_create_message_response(id:, model:, message:, **_options) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 363

def sampling_create_message_response(id:, model:, message:, **_options)
  body = Native::Messages::Responses.sampling_create_message(id: id, model: model, message: message)
  request(body, wait_for_response: false)
end

#set_elicitation_enabled(enabled:) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 325

def set_elicitation_enabled(enabled:)
  @elicitation_enabled = enabled
end

#set_logging(level:) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 271

def set_logging(level:)
  body = Native::Messages::Requests.logging_set_level(level: level, tracking_progress: tracking_progress?)
  request(body)
end

#set_progress_tracking(enabled:) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 321

def set_progress_tracking(enabled:)
  @progress_tracking_enabled = enabled
end

#start ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 90

def start
  return unless capabilities.nil?

  transport.start

  initialize_response = initialize_request
  initialize_response.raise_error! if initialize_response.error?

  # Extract and store the negotiated protocol version
  negotiated_version = initialize_response.value["protocolVersion"]

  if negotiated_version && !Native::Protocol.supported_version?(negotiated_version)
    raise Errors::UnsupportedProtocolVersion.new(
      message: <<~MESSAGE
        Unsupported protocol version, and could not negotiate a supported version: #{negotiated_version}.
        Supported versions: #{Native::Protocol.supported_versions.join(', ')}
      MESSAGE
    )
  end

  @protocol_version = negotiated_version if negotiated_version

  # Set the protocol version on the transport for subsequent requests
  if @transport.respond_to?(:set_protocol_version)
    @transport.set_protocol_version(@protocol_version)
  end

  @capabilities = RubyLLM::MCP::ServerCapabilities.new(initialize_response.value["capabilities"])
  initialize_notification

  if @logging_enabled && @logging_level
    set_logging(level: @logging_level)
  end
end

#stop ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 125

def stop
  @transport&.close
  @capabilities = nil
  @transport = nil
  @task_registry = Native::TaskRegistry.new
  @protocol_version = @requested_protocol_version || MCP.config.protocol_version || Native::Protocol.latest_version
  Handlers::HumanInTheLoopRegistry.release(@registry_owner_id)
  @human_in_the_loop_registry = Handlers::HumanInTheLoopRegistry.for_owner(@registry_owner_id)
end

#task_cancel(task_id:) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 308

def task_cancel(task_id:)
  body = Native::Messages::Requests.task_cancel(task_id: task_id, tracking_progress: tracking_progress?)
  result = request(body)
  result.raise_error! if result.error?

  task_registry.upsert(result.value)
  result
end

#task_get(task_id:) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 290

def task_get(task_id:)
  body = Native::Messages::Requests.task_get(task_id: task_id, tracking_progress: tracking_progress?)
  result = request(body)
  result.raise_error! if result.error?

  task_registry.upsert(result.value)
  result
end

#task_result(task_id:) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 299

def task_result(task_id:)
  body = Native::Messages::Requests.task_result(task_id: task_id, tracking_progress: tracking_progress?)
  result = request(body)
  result.raise_error! if result.error?

  task_registry.store_payload(task_id, result.value)
  result
end

#task_status_notification(task:) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 317

def task_status_notification(task:)
  task_registry.upsert(task)
end

#tasks_list(cursor: nil) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 276

def tasks_list(cursor: nil)
  body = Native::Messages::Requests.tasks_list(cursor: cursor, tracking_progress: tracking_progress?)
  result = request(body)
  result.raise_error! if result.error?

  task_registry.upsert_many(result.value["tasks"])

  if result.next_cursor?
    result.value["tasks"] + tasks_list(cursor: result.next_cursor)
  else
    result.value["tasks"] || []
  end
end

#tool_list(cursor: nil) ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 178

def tool_list(cursor: nil)
  body = Native::Messages::Requests.tool_list(cursor: cursor, tracking_progress: tracking_progress?)
  result = request(body)
  result.raise_error! if result.error?

  if result.next_cursor?
    result.value["tools"] + tool_list(cursor: result.next_cursor)
  else
    result.value["tools"]
  end
end

#tracking_progress? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ruby_llm/mcp/native/client.rb', line 420

def tracking_progress?
  @progress_tracking_enabled
end

#transport ⇒ Object 



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# File 'lib/ruby_llm/mcp/native/client.rb', line 428

def transport
  @transport ||= Native::Transport.new(@transport_type, self, config: @config)
end

#unregister_in_flight_request(request_id) ⇒ Object

Unregister a completed or cancelled request

Parameters:

  • request_id (String) —

    The ID of the request



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# File 'lib/ruby_llm/mcp/native/client.rb', line 443

def unregister_in_flight_request(request_id)
  @in_flight_mutex.synchronize do
    @in_flight_requests.delete(request_id.to_s)
  end
end