Class: Ask::Agent::Session

Inherits:
Object
  • Object
show all
Includes:
Test::SessionOverride
Defined in:
lib/ask/agent/session.rb

Constant Summary collapse

RECENTLY_COMPLETED_MAX =

Max ids remembered as "recently completed" to guard against late loop registrations resurrecting ghost pending calls.

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Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Test::SessionOverride

#called_tool?, #stub_text, #stub_tool_call, #test_mode

Constructor Details

#initialize(model:, tools: [], max_turns: 25, max_tool_retries: 3, compactor: nil, hooks: {}, state: nil, persistence: nil, id: nil, system_prompt: nil, parallel_tools: true, reflector: nil, telemetry: true, meta_agent: nil, agent_dir: nil, evaluator: nil, audit_log: nil, skills_disclosure: true, approval: nil, tool_call_repair: nil, checkpoints: false, todos: false, plan_mode: false, memory: nil, memory_learning: false, offload_large_outputs: false, artifacts: false, artifact_uploader: nil, **chat_options) ⇒ Session

Returns a new instance of Session.



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# File 'lib/ask/agent/session.rb', line 24

def initialize(model:, tools: [], max_turns: 25, max_tool_retries: 3,
               compactor: nil, hooks: {}, state: nil, persistence: nil,
               id: nil, system_prompt: nil, parallel_tools: true,
               reflector: nil, telemetry: true, meta_agent: nil,
               agent_dir: nil, evaluator: nil, audit_log: nil,
               skills_disclosure: true, approval: nil,
               tool_call_repair: nil, checkpoints: false,
               todos: false, plan_mode: false, memory: nil,
               memory_learning: false, offload_large_outputs: false,
               artifacts: false, artifact_uploader: nil,
               **chat_options)
  @id = id || SecureRandom.uuid
  @agent_dir = agent_dir
  @max_turns = max_turns
  @max_tool_retries = max_tool_retries
  @parallel_tools = parallel_tools
  @skills_disclosure = skills_disclosure
  @event_handlers = { all: [] }
  @running = false
  @deleted = false
  @abort_requested = false
  @pending_tools = {}
  @recently_completed = []
  @pending_mutex = Mutex.new
  @followup_pending = false
  @turn_count = 0
  # Concurrency-safe steering: turn id bumped at every
  # TurnStart; steers arriving mid-turn are queued and dispatched at
  # the next turn boundary.
  @turn_id = 0
  @queued_steers = []
  @steer_mutex = Mutex.new
  on(Events::TurnStart) { @turn_id += 1 }
  @created_at = Time.now
  @_no_tools_instructed = false

  @total_input_tokens = 0
  @total_output_tokens = 0
  @total_cost = 0.0

  @telemetry = telemetry.is_a?(Telemetry) ? telemetry : Telemetry.new(enabled: !!telemetry)

  # Task list (todo_write tool) — built before resolve_tools so the
  # tool can be injected with a reference to it.
  @todos_enabled = !!todos
  @todo_list = TodoList.new if @todos_enabled
  @todo_list&.subscribe { |entries| emit(Events::TodoUpdated.new(todos: entries)) }
  # Durable memory (memory_write / memory_search tools). An instance
  # with its own namespace and state adapter; nil disables memory.
  @memory = memory
  # Learning: extract durable facts from the transcript when the
  # session ends (requires memory).
  if memory_learning && !@memory
    raise ArgumentError, "memory_learning: requires a memory: instance"
  end
  @memory_learning = !!memory_learning

  # Large-output offloading: tool results above a size threshold are
  # stored in a ToolOutputStore (state adapter when present, else
  # in-process) and the transcript keeps a preview + reference.
  @offload_threshold = case offload_large_outputs
  when true then 4000
  when Integer then offload_large_outputs
  else nil
  end
  @output_store = if @offload_threshold
    ToolOutputStore.new(state: state || persistence || Ask::State::Memory.new)
  end

  # Tool deliverables (artifacts): metadata[:artifact] on tool results
  # is collected into the store — inline content for small text,
  # external URIs for large binaries (uploader lifts content to a URI
  # when provided).
  @artifact_store = if artifacts
    ArtifactStore.new(
      state: state || persistence || Ask::State::Memory.new,
      uploader: artifact_uploader
    )
  end

  # Plan mode — research phase gated to read-only tools until a human
  # approves the model's plan (submitted via the exit_plan_mode tool).
  @plan_mode = plan_mode.is_a?(Hash) ? true : !!plan_mode
  @plan_mode_read_only_tools = if plan_mode.is_a?(Hash) && plan_mode[:read_only_tools]
    Array(plan_mode[:read_only_tools]).map(&:to_s)
  else
    %w[read glob grep web_search]
  end
  @plan_queue = ApprovalQueue.new(
    on_approve: ->(action) { approve_plan(action) },
    on_reject: ->(action) { reject_plan(action) },
    # Same race closure as the tool approval queue: register the
    # pending call at submit time so plan approvals land even when
    # the executor is still in flight.
    on_submit: ->(action) {
      register_pending_tool(action.tool_call_id, {
        tool_name: action.tool_name,
        message: action.message || "Plan awaiting approval",
        status: "pending",
        tool_call_id: action.tool_call_id,
        action_id: action.id
      })
    }
  ) if @plan_mode

  @tools = resolve_tools(tools)
  @chat = build_chat(model, system_prompt, @tools, **chat_options)
  @loop = Loop.new(max_turns: max_turns)
  @tool_executor = ToolExecutor.new(
    max_retries: max_tool_retries,
    parallel: parallel_tools,
    output_offload_threshold: @offload_threshold,
    output_store: @output_store,
    artifact_store: @artifact_store
  )
  @compactor = compactor ? build_compactor(compactor) : nil
  @hooks = Hooks.new(hooks)
  @audit_log = build_audit_log(audit_log)
  @approval_queue = build_approval(approval)
  @tool_call_repair = tool_call_repair

  # Plan gate runs before user hooks and the approval policy: in plan
  # mode, non-read-only tools are blocked outright (never queued).
  if @plan_mode
    @hooks = Hooks.new(
      before_tool: [method(:plan_mode_gate)] + Array(@hooks.instance_variable_get(:@before_tool)),
      after_tool: @hooks.instance_variable_get(:@after_tool)
    )
  end

  @system_context = build_system_context(system_prompt)
  apply_system_context

  @state = state || persistence
  if checkpoints && !@state
    raise ArgumentError, "checkpoints: requires a state: adapter"
  end
  @checkpoints = !!checkpoints
  @checkpoint_store = CheckpointStore.new(@state) if @checkpoints

  reflector_opts = reflector.is_a?(Hash) ? reflector : {}
  @reflector = if reflector
    Reflector.new(
      model: @chat,
      max_reflections: reflector_opts[:max_reflections] || 1
    )
  end

  @meta_agent_config = meta_agent
  @meta_agent_results = nil

  @compactor&.chat = @chat

  # Parse evaluator configuration
  @evaluator = nil
  @evaluator_config = {}

  if evaluator
    eval_model = if evaluator.is_a?(Hash)
                   @evaluator_config = evaluator
                   evaluator[:model] || Ask::Agent.configuration.default_evaluator_model || model_id_from(@chat)
                 else
                   Ask::Agent.configuration.default_evaluator_model || model_id_from(@chat)
                 end

    @evaluator = Evaluator.new(model: eval_model)
  end
end

Instance Attribute Details

#approval_queue ⇒ Ask::Agent::ApprovalQueue? (readonly)

The approval queue backing this session, or nil when the session was created without approval support. Use it to inspect pending actions and approve/reject them.

Returns:



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# File 'lib/ask/agent/session.rb', line 198

def approval_queue
  @approval_queue
end

#artifact_store ⇒ Ask::Agent::ArtifactStore? (readonly)

Returns store for tool deliverables (only when the artifacts: option is enabled).

Returns:



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# File 'lib/ask/agent/session.rb', line 213

def artifact_store
  @artifact_store
end

#chat ⇒ Object (readonly)

Returns the value of attribute chat.



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# File 'lib/ask/agent/session.rb', line 13

def chat
  @chat
end

#created_at ⇒ Object (readonly)

Returns the value of attribute created_at.



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# File 'lib/ask/agent/session.rb', line 13

def created_at
  @created_at
end

#id ⇒ Object (readonly)

Returns the value of attribute id.



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# File 'lib/ask/agent/session.rb', line 13

def id
  @id
end

#memory ⇒ Ask::Agent::Memory? (readonly)

Returns durable memory (only when passed via the memory: option).

Returns:



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# File 'lib/ask/agent/session.rb', line 207

def memory
  @memory
end

#messages ⇒ Object (readonly)

Returns the value of attribute messages.



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# File 'lib/ask/agent/session.rb', line 13

def messages
  @messages
end

#meta_agent_results ⇒ Object (readonly)

Returns the value of attribute meta_agent_results.



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# File 'lib/ask/agent/session.rb', line 20

def meta_agent_results
  @meta_agent_results
end

#output_store ⇒ Ask::Agent::ToolOutputStore? (readonly)

Returns store for offloaded large tool outputs (only when large-output offloading is enabled).

Returns:



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# File 'lib/ask/agent/session.rb', line 210

def output_store
  @output_store
end

#plan_queue ⇒ Ask::Agent::ApprovalQueue? (readonly)

Returns queue carrying plan approvals (only when plan mode is enabled).

Returns:



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# File 'lib/ask/agent/session.rb', line 201

def plan_queue
  @plan_queue
end

#skills_registry ⇒ Ask::Skills::Registry? (readonly)

Returns auto-discovered skills registry.

Returns:

  • (Ask::Skills::Registry, nil) —

    auto-discovered skills registry



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# File 'lib/ask/agent/session.rb', line 22

def skills_registry
  @skills_registry
end

#todo_list ⇒ Ask::Agent::TodoList? (readonly)

Returns session task list (only when todos are enabled).

Returns:



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# File 'lib/ask/agent/session.rb', line 204

def todo_list
  @todo_list
end

#tool_calls_made ⇒ Object (readonly)

Returns the value of attribute tool_calls_made.



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# File 'lib/ask/agent/session.rb', line 14

def tool_calls_made
  @tool_calls_made
end

#tools ⇒ Object (readonly)

Returns the value of attribute tools.



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# File 'lib/ask/agent/session.rb', line 13

def tools
  @tools
end

#total_cost ⇒ Object (readonly)

Returns the value of attribute total_cost.



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# File 'lib/ask/agent/session.rb', line 14

def total_cost
  @total_cost
end

#total_input_tokens ⇒ Object (readonly)

Returns the value of attribute total_input_tokens.



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# File 'lib/ask/agent/session.rb', line 14

def total_input_tokens
  @total_input_tokens
end

#total_output_tokens ⇒ Object (readonly)

Returns the value of attribute total_output_tokens.



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# File 'lib/ask/agent/session.rb', line 14

def total_output_tokens
  @total_output_tokens
end

#turn_count ⇒ Object (readonly)

Returns the value of attribute turn_count.



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# File 'lib/ask/agent/session.rb', line 13

def turn_count
  @turn_count
end

#turn_id ⇒ Integer (readonly)

Returns id of the turn currently running (or the last completed turn when idle).

Returns:

  • (Integer) —

    id of the turn currently running (or the last completed turn when idle)



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# File 'lib/ask/agent/session.rb', line 667

def turn_id
  @turn_id
end

Class Method Details

.deep_symbolize_keys(obj) ⇒ Object

Recursively convert string keys to symbol keys in hashes. Needed when loading session data that was serialized through JSON.



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# File 'lib/ask/agent/session.rb', line 1130

def self.deep_symbolize_keys(obj)
  case obj
  when Hash
    obj.each_with_object({}) { |(k, v), h| h[k.to_sym] = deep_symbolize_keys(v) }
  when Array
    obj.map { |e| deep_symbolize_keys(e) }
  else
    obj
  end
end

.deserialize_content(content) ⇒ Object

Rebuild message content from a persisted value: block hashes are reconstructed via Ask::Content.from_h (deep_symbolize_keys may have symbol keys — from_h normalizes).



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# File 'lib/ask/agent/session.rb', line 1042

def self.deserialize_content(content)
  content.is_a?(Array) ? content.map { |block| Ask::Content.from_h(block) } : content
end

.load(id, adapter:) ⇒ Object 



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# File 'lib/ask/agent/session.rb', line 430

def self.load(id, adapter:)
  data = adapter.get(id)
  return nil unless data

  data = deep_symbolize_keys(data)

  session = new(
    id: data[:id],
    model: data.dig(:metadata, :model),
    # Restore saved user tools by class name. Tools that cannot be
    # restored — renamed/removed classes (NameError) or constructors
    # with required args (ArgumentError) — are skipped with a warning
    # instead of failing the whole load; resolve_tools re-adds the
    # framework-injected load_skill tool with a proper registry.
    tools: data.dig(:metadata, :tools).to_a.filter_map do |name|
      begin
        name.constantize.new
      rescue NameError, ArgumentError => e
        warn "[ask-agent] Session.load skipped tool '#{name}': #{e.class}: #{e.message}"
        nil
      end
    end,
    state: adapter,
    # Checkpointing is restored automatically when the session has
    # checkpoints in the store; todos likewise when the snapshot has
    # a task list.
    checkpoints: !adapter.get("#{id}#{CheckpointStore::HEAD_KEY}").nil?,
    todos: !data[:todos].nil?
  )

  data[:messages].each do |msg|
    session.chat.add_message(
      role: msg[:role].to_sym,
      content: deserialize_content(msg[:content]),
      tool_call_id: msg[:tool_call_id]
    )
  end
  session.instance_variable_get(:@todo_list)&.restore(data[:todos])
	
   session.instance_variable_set(:@messages, session.chat.messages.dup)
   session
end

.serialize_content(message) ⇒ Object

Persist content blocks as their to_h hashes so attachments survive save/load; plain messages stay strings.



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# File 'lib/ask/agent/session.rb', line 1035

def self.serialize_content(message)
  message.content_blocks ? message.content_blocks.map(&:to_h) : message.content.to_s
end

Instance Method Details

#abort ⇒ Object 



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# File 'lib/ask/agent/session.rb', line 481

def abort
  @abort_requested = true
end

#abort_requested? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ask/agent/session.rb', line 485

def abort_requested? = @abort_requested

#approve_plan(action) ⇒ Object 



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# File 'lib/ask/agent/session.rb', line 634

def approve_plan(action)
  @plan_mode = false
  plan = action.args[:plan] || action.args["plan"] || ""
  emit(Events::PlanApproved.new(plan: plan))
  complete_pending_tool(
    tool_call_id: action.tool_call_id,
    result: {
      tool_name: "exit_plan_mode",
      message: "Plan approved — execute it now.",
      status: "success",
      is_error: false
    }
  )
end

#artifacts ⇒ Array<Hash>

Returns artifact summaries for this session (id, filename, mime_type, size, uri), newest first.

Returns:

  • (Array<Hash>) —

    artifact summaries for this session (id, filename, mime_type, size, uri), newest first

Raises:

  • (RuntimeError) —

    when artifacts are not enabled



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# File 'lib/ask/agent/session.rb', line 569

def artifacts
  require_artifacts!
  @artifact_store.list(@id)
end

#checkpoint_history ⇒ Array<Integer>

Returns checkpoint seqs, oldest first.

Returns:

  • (Array<Integer>) —

    checkpoint seqs, oldest first

Raises:

  • (RuntimeError) —

    when checkpointing is not enabled



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# File 'lib/ask/agent/session.rb', line 491

def checkpoint_history
  require_checkpoints!
  @checkpoint_store.history(@id)
end

#complete_pending_tool(tool_call_id:, result:) ⇒ Boolean

Completes a pending (async) tool call from a background thread.

Adds the tool result to the conversation and, when the session is idle, runs a follow-up turn so the agent voices the answer. If a turn is running, the follow-up fires as soon as it ends.

Parameters:

  • tool_call_id (String) —

    the original tool call id

  • result (Hash) —

    tool result hash (is_error:, ...)

Returns:

  • (Boolean) —

    true if the completion was registered



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# File 'lib/ask/agent/session.rb', line 741

def complete_pending_tool(tool_call_id:, result:)
  follow_up = @pending_mutex.synchronize do
    pending = @pending_tools.delete(tool_call_id)
    return false unless pending

    # Remember the id briefly so a late loop registration (from a
    # completion that landed while the executor was in flight) cannot
    # resurrect it as a ghost pending call.
    @recently_completed << tool_call_id
    @recently_completed.shift if @recently_completed.size > RECENTLY_COMPLETED_MAX

    @chat.add_message(
      role: :tool,
      content: result[:message].to_s,
      tool_call_id: tool_call_id
    )
    if @running
      @followup_pending = true
      false
    else
      true
    end
  end
  emit(Events::ToolCompleted.new(name: result[:tool_name], id: tool_call_id, result: result))
  run_follow_up if follow_up
  true
end

#delete ⇒ Object 



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# File 'lib/ask/agent/session.rb', line 473

def delete
  @deleted = true
  @checkpoint_store&.delete(@id)
  @output_store&.delete(@id)
  @artifact_store&.delete(@id)
  @state&.delete(@id)
end

#deleted? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ask/agent/session.rb', line 424

def deleted? = @deleted

#drain_leftover_steers ⇒ Object

Move any queued steers left over from a previous run into the conversation (the session was idle, so they are dispatched now).



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# File 'lib/ask/agent/session.rb', line 592

def drain_leftover_steers
  while (message = drain_one_steer) != ""
    @chat.add_message(role: :user, content: message)
  end
end

#drain_one_steer ⇒ Object

Pop the next queued steer (called by the loop at each turn boundary); returns "" when nothing is queued.



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# File 'lib/ask/agent/session.rb', line 586

def drain_one_steer
  @steer_mutex.synchronize { @queued_steers.shift }.to_s
end

#emit(event) ⇒ Object 



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# File 'lib/ask/agent/session.rb', line 417

def emit(event)
  @event_handlers[:all].each { |h| h.call(event) }
  handlers = @event_handlers[event.class]
  handlers&.each { |h| h.call(event) }
end

#extract_memories ⇒ Object

Extract durable facts from this session's transcript into memory (memory_learning: true). Best-effort — extraction never breaks the session; failures are swallowed.



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# File 'lib/ask/agent/session.rb', line 601

def extract_memories
  extractor = MemoryExtractor.new(model: model_id_from(@chat), memory: @memory)
  extractor.extract(transcript: @chat.messages, session_id: @id)
rescue StandardError
  nil
end

#fetch_artifact(id) ⇒ Hash?

Returns the full record (content or uri).

Parameters:

  • id (String) —

    artifact id

Returns:

  • (Hash, nil) —

    the full record (content or uri)

Raises:

  • (RuntimeError) —

    when artifacts are not enabled



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# File 'lib/ask/agent/session.rb', line 577

def fetch_artifact(id)
  require_artifacts!
  @artifact_store.fetch(@id, id)
end

#fork(at_seq: nil, at_turn: nil) ⇒ Ask::Agent::Session

Fork the session at a checkpoint: a new session (new id, same model and tools) whose history is everything up to that point, backed by its own checkpoint chain. Continue the branch with run.

Parameters:

  • at_seq (Integer, nil) (defaults to: nil) —

    checkpoint to fork from (xor +at_turn:)

  • at_turn (Integer, nil) (defaults to: nil) —

    fork at the last checkpoint whose turn count equals at_turn (xor +at_seq:)

Returns:

Raises:

  • (ArgumentError) —

    when the checkpoint does not exist

  • (RuntimeError) —

    when checkpointing is not enabled



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# File 'lib/ask/agent/session.rb', line 542

def fork(at_seq: nil, at_turn: nil)
  require_checkpoints!

  seq = resolve_checkpoint_seq(at_seq, at_turn)
  data = load_checkpoint(seq: seq)
  raise ArgumentError, "no checkpoint #{seq}" unless data

  forked_id = @checkpoint_store.fork(@id, at_seq: seq)
  forked = self.class.new(
    id: forked_id,
    model: data[:metadata][:model],
    tools: @tools,
    state: @state,
    checkpoints: true,
    todos: @todos_enabled,
    plan_mode: @plan_mode
  )
  restore_into(forked, data)
  emit(Events::SessionForked.new(session_id: @id, forked_id: forked_id, seq: seq))
  forked
end

#inject_memories(message) ⇒ Object

Retrieve memories relevant to the incoming message and inject them as a system message, so a new session starts with what earlier sessions learned.



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# File 'lib/ask/agent/session.rb', line 611

def inject_memories(message)
  hits = @memory.search(message.to_s, limit: 5)
  return if hits.empty?

  @chat.add_message(
    role: :system,
    content: "Relevant memories from previous sessions:\n" + hits.map { |e| "- #{e.content}" }.join("\n")
  )
end

#load_checkpoint(seq: nil) ⇒ Hash?

Load a checkpoint's snapshot.

Parameters:

  • seq (Integer, nil) (defaults to: nil) —

    checkpoint seq; defaults to the head

Returns:

  • (Hash, nil) —

    the snapshot with symbol keys

Raises:

  • (RuntimeError) —

    when checkpointing is not enabled



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# File 'lib/ask/agent/session.rb', line 501

def load_checkpoint(seq: nil)
  require_checkpoints!
  data = @checkpoint_store.load(@id, seq: seq)
  data && self.class.deep_symbolize_keys(data)
end

#on(type, &block) ⇒ Object 



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# File 'lib/ask/agent/session.rb', line 411

def on(type, &block)
  @event_handlers[type] ||= []
  @event_handlers[type] << block
  self
end

#on_event(&block) ⇒ Object 



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# File 'lib/ask/agent/session.rb', line 406

def on_event(&block)
  @event_handlers[:all] << block
  self
end

#pending_tools? ⇒ Boolean

Returns true while at least one async tool is running.

Returns:

  • (Boolean) —

    true while at least one async tool is running



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# File 'lib/ask/agent/session.rb', line 728

def pending_tools?
  @pending_mutex.synchronize { !@pending_tools.empty? }
end

#plan_mode? ⇒ Boolean

Returns whether the session is in plan mode (research phase; non-read-only tools are blocked until the plan is approved).

Returns:

  • (Boolean) —

    whether the session is in plan mode (research phase; non-read-only tools are blocked until the plan is approved)



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# File 'lib/ask/agent/session.rb', line 623

def plan_mode? = @plan_mode

#plan_mode_gate(tool_call, _context) ⇒ Object

Before-tool gate active while in plan mode: only read-only tools (and exit_plan_mode itself) run until a human approves the plan.



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# File 'lib/ask/agent/session.rb', line 627

def plan_mode_gate(tool_call, _context)
  return { action: :proceed } unless @plan_mode
  return { action: :proceed } if @plan_mode_read_only_tools.include?(tool_call.name) || tool_call.name == "exit_plan_mode"

  { action: :block, reason: "Plan mode: only read-only tools until the plan is approved" }
end

#queued_steers ⇒ Integer

Returns steers queued and not yet dispatched.

Returns:

  • (Integer) —

    steers queued and not yet dispatched



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# File 'lib/ask/agent/session.rb', line 701

def queued_steers
  @steer_mutex.synchronize { @queued_steers.size }
end

#reflection_count ⇒ Object 



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# File 'lib/ask/agent/session.rb', line 16

def reflection_count
  @reflector&.reflection_count || 0
end

#register_pending_tool(tool_call_id, result) ⇒ Object

Registers a pending tool call (called by the loop when a tool returned Ask::Result.pending, or at approval-queue submit time). The background work completes later via #complete_pending_tool.

A call can be resolved (approved/rejected) while the executor is still in flight; when the loop then registers the same call, the registration is skipped so no ghost pending entry is left behind.



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# File 'lib/ask/agent/session.rb', line 714

def register_pending_tool(tool_call_id, result)
  @pending_mutex.synchronize do
    return if @recently_completed.include?(tool_call_id)
    if (action_id = result[:action_id]) && @approval_queue
      action = @approval_queue[action_id]
      return if action && action.status != :pending
    end
    @pending_tools[tool_call_id] = result
  end
  emit(Events::ToolPending.new(name: result[:tool_name], id: tool_call_id))
  nil
end

#reject_plan(action) ⇒ Object 



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# File 'lib/ask/agent/session.rb', line 649

def reject_plan(action)
  plan = action.args[:plan] || action.args["plan"] || ""
  emit(Events::PlanRejected.new(plan: plan))
  complete_pending_tool(
    tool_call_id: action.tool_call_id,
    result: {
      tool_name: "exit_plan_mode",
      message: "Plan rejected by the user — revise your plan and resubmit.",
      status: "rejected",
      is_error: false
    }
  )
end

#reset_messages! ⇒ Object 



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# File 'lib/ask/agent/session.rb', line 800

def reset_messages!
  @chat.reset_messages!
  @messages = []
end

#rollback!(seq: nil, turn: nil) ⇒ self

Rewind the session to an earlier checkpoint: messages and turn count are restored from the snapshot, and the store's head moves back. Later checkpoints are kept, so the session can roll forward again.

Parameters:

  • seq (Integer, nil) (defaults to: nil) —

    checkpoint seq (xor +turn:)

  • turn (Integer, nil) (defaults to: nil) —

    roll back to the last checkpoint whose turn count equals turn (xor +seq:)

Returns:

  • (self)

Raises:

  • (ArgumentError) —

    when the checkpoint does not exist

  • (RuntimeError) —

    when checkpointing is not enabled or the session is running



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# File 'lib/ask/agent/session.rb', line 518

def rollback!(seq: nil, turn: nil)
  require_checkpoints!
  raise "cannot roll back a running session" if @running

  seq = resolve_checkpoint_seq(seq, turn)
  data = load_checkpoint(seq: seq)
  raise ArgumentError, "no checkpoint #{seq}" unless data

  @checkpoint_store.rollback(@id, seq)
  restore_from_snapshot(data)
  emit(Events::SessionRolledBack.new(session_id: @id, seq: seq, turn_count: @turn_count))
  self
end

#run(message, tools: nil, reset: true, attachments: nil) ⇒ Object 



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# File 'lib/ask/agent/session.rb', line 215

def run(message, tools: nil, reset: true, attachments: nil)
  raise "Session deleted" if @deleted
  raise "Session already running" if @running

  @running = true
  @abort_requested = false
  Ask::Agent.current_session = self
  if reset
    @turn_count = 0
    @loop.reset!
  end

  emit(Events::SessionStart.new)

  active_tools = @tools

  # Retrieve relevant memories from previous sessions into context.
  inject_memories(message) if reset && @memory

  if active_tools.empty? && !@_no_tools_instructed
    @chat.add_message(role: :system, content: "You have no tools available. Do not claim you can look up information or use tools of any kind. Just respond based on your existing knowledge.")
    @_no_tools_instructed = true
  end

  # Leftover queued steers from a previous run become user messages
  # before this run starts.
  drain_leftover_steers

  begin
    @tool_executor.telemetry = @telemetry

     response = @loop.run_turn(
       chat: @chat,
       message: message,
       attachments: attachments,
       tools: active_tools,
       tool_executor: @tool_executor,
       compactor: @compactor,
       hooks: @hooks,
       event_emitter: self,
       session_id: @id,
      tool_call_repair: @tool_call_repair,
      steer_source: method(:drain_one_steer),
       persist: @state ? method(:persist!) : nil
     )

    @total_input_tokens += @loop.last_input_tokens.to_i
    @total_output_tokens += @loop.last_output_tokens.to_i
    @total_cost += @loop.last_cost.to_f
  rescue MaxTurnsExceeded => e
    emit(Events::MaxTurnsExceeded.new(max_turns: @max_turns))
    @telemetry.log(:max_turns_exceeded, session_id: @id, max_turns: @max_turns)
    response = last_content
  rescue LoopDetected => e
    emit(Events::LoopDetected.new(tool_name: e.message, repeated_count: 3))
    @telemetry.log(:loop_detected, session_id: @id, tool_name: e.message, repeated_count: 3)
    response = last_content
  rescue Ask::ContextLengthExceeded
    if @compactor && !@compactor.overflow_recovered?
      @compactor.recover_from_overflow
      retry
    end
    response = "I'm sorry, the conversation has grown too long. Please start a new session."
  rescue StandardError => e
    emit(Events::Error.new(error: e.message, recoverable: true))
    raise
  ensure
    @running = false
    Ask::Agent.current_session = nil if Ask::Agent.current_session.equal?(self)
    persist! if @state
    # Learn from this session: extract durable facts into memory.
    # Only on the initial run (not follow-ups); best-effort, never
    # raises.
    extract_memories if reset && @memory_learning
    # A pending tool completed while this run was busy: voice the
    # result now that the turn is over (one follow-up per completion).
    follow_up = @pending_mutex.synchronize do
      take = @followup_pending
      @followup_pending = false
      take
    end
    run_follow_up if follow_up
  end

  @tool_calls_made = @tool_executor.total_executions

  # Independent evaluator step (generator/evaluator separation).
  # Runs BEFORE self-reflection so the evaluator gets a fresh, unbiased look
  # at the generator's output using a separate model and isolated context.
  @skip_reflector = false

  if @evaluator && !@abort_requested
    goal = @evaluator_config[:goal] || message

    eval_result = @evaluator.evaluate(
      goal: goal.to_s,
      response: response,
      event_emitter: self
    )

    @telemetry.log(:evaluation_end, session_id: @id,
                   decision: eval_result.decision,
                   feedback: eval_result.feedback,
                   scores: eval_result.scores)

    case eval_result.decision
    when :revise
      @chat.add_message(
        role: :system,
        content: "An independent evaluator has requested revisions:\n\n#{eval_result.feedback}"
      )

      response = @loop.run_turn(
        chat: @chat,
        message: "",
        tools: active_tools,
        tool_executor: @tool_executor,
        compactor: @compactor,
        hooks: @hooks,
        event_emitter: self,
        session_id: @id,
        tool_call_repair: @tool_call_repair
      )

      @total_input_tokens += @loop.last_input_tokens.to_i
      @total_output_tokens += @loop.last_output_tokens.to_i
      @total_cost += @loop.last_cost.to_f

      # Skip reflector — we already iterated based on evaluator feedback
      @skip_reflector = true
    when :block
      emit(Events::EvaluationBlocked.new(
        feedback: eval_result.feedback,
        scores: eval_result.scores,
        evidence: eval_result.evidence
      ))
      response = "This response was blocked by the evaluator: #{eval_result.feedback}"
    when :accept
      # Fall through to reflector for backward compatibility
    end
  end

  if @reflector && !@skip_reflector && @reflector.reflect?(@tool_calls_made) && !@abort_requested
    eval_result = @reflector.evaluate(response: response, event_emitter: self)
    @telemetry.log(:reflection_end, session_id: @id, decision: eval_result[:decision], feedback: eval_result[:feedback])

    if eval_result[:decision] == :improve && !@abort_requested
      @chat.add_message(
        role: :system,
        content: "Improve your last response: #{eval_result[:feedback]}"
      )

      response = @loop.run_turn(
        chat: @chat,
        message: "",
        tools: active_tools,
        tool_executor: @tool_executor,
        compactor: @compactor,
        hooks: @hooks,
        event_emitter: self,
        session_id: @id,
        tool_call_repair: @tool_call_repair
      )

      @total_input_tokens += @loop.last_input_tokens.to_i
      @total_output_tokens += @loop.last_output_tokens.to_i
      @total_cost += @loop.last_cost.to_f
    end
  end

  if @meta_agent_config
    @telemetry.increment_session_count!
    try_auto_meta_agent
  end

  # Capture messages before emitting SessionEnd so event handlers
  # can access agent.messages during the callback
  @messages = @chat.messages.dup

  emit(Events::SessionEnd.new(
    result: response,
    turn_count: @turn_count,
    tool_calls_made: @tool_calls_made,
    input_tokens: @total_input_tokens,
    output_tokens: @total_output_tokens,
    cost: @total_cost
  ))

  response
end

#run_follow_up ⇒ Object

A follow-up turn driven by an async completion: runs the loop with the tool message already in the conversation, preserving turn state.



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# File 'lib/ask/agent/session.rb', line 771

def run_follow_up
  run("", reset: false)
rescue => e
  emit(Events::Error.new(error: e.message, recoverable: false))
  raise
end

#running? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ask/agent/session.rb', line 423

def running? = @running

#save ⇒ Object 



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# File 'lib/ask/agent/session.rb', line 426

def save
  persist! if @state
end

#skill(name) ⇒ Object

Load a skill by name or file path. Injects the skill's full instructions into the conversation as a system message.

Parameters:

  • name (String) —

    skill name (e.g. "rails.db_debug") or path to a .md file

Raises:

  • (Ask::Skills::Error) —

    if the skill is not found



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# File 'lib/ask/agent/session.rb', line 783

def skill(name)
  if @skills_registry && (s = @skills_registry[name])
    @chat.add_message(
      role: :system,
      content: "## Skill: #{s.name}\n\n#{s.description}\n\n---\n\n#{s.instructions}"
    )
  elsif File.exist?(name.to_s)
    content = File.read(name.to_s)
    @chat.add_message(
      role: :system,
      content: "## Skill: #{name}\n\n---\n\n#{content}"
    )
  else
    raise Ask::Skills::Error, "Skill not found: #{name.inspect}"
  end
end

#steer(message, expected_turn_id: nil, attachments: nil) ⇒ Hash

Inject a message into the session safely, from any thread (web, CLI, another agent):

  • :stale — the caller's expected_turn_id does not match the current turn id (the caller was looking at an older state).
  • :queued — a turn is running; the message is held and dispatched as the next user message at the next turn boundary.
  • :steered — the session is idle; the message is added to the conversation and processed by the next run.

Parameters:

  • message (String)
  • expected_turn_id (Integer, nil) (defaults to: nil) —

    the turn id the caller believes is current; nil skips the check

  • attachments (Array<Ask::Attachment>, nil) (defaults to: nil) —

    files to attach (applied when the session is idle; queued steers keep the message text only — the loop resolves queued messages as text)

Returns:

  • (Hash) —

    :stale|:queued|:steered, turn_id: Integer



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# File 'lib/ask/agent/session.rb', line 686

def steer(message, expected_turn_id: nil, attachments: nil)
  @steer_mutex.synchronize do
    if expected_turn_id && expected_turn_id != @turn_id
      return { status: :stale, turn_id: @turn_id }
    end
    if @running
      @queued_steers << message.to_s
      return { status: :queued, turn_id: @turn_id }
    end
  end
  @chat.add_message(role: :user, content: message.to_s, attachments: attachments)
  { status: :steered, turn_id: @turn_id }
end