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core intermediate

Demand Tracker Agent

A Jido agent that tracks listing demand with boost/cool/decay actions. Demonstrates Directives — the agent's mechanism for requesting side effects like emitting domain events (Emit) and scheduling future signals (Schedule).

directives emit schedule signals state

Related guides and notebooks

Guide
Your first agent
Define typed state and run your first command.
Livebook
Your first agent
Run the companion notebook in Livebook
Concept
Actions
Understand action contracts, validation, and composition.
Next
Build your first workflow
Chain actions into a multi-step workflow.
Livebook
Build your first workflow
Run the companion notebook in Livebook
Explanation

What this example teaches

Interactive Demo

Run the agent and inspect state

Source Code

Read the production implementation

demand_tracker_agent.ex boost_action.ex cool_action.ex decay_action.ex toggle_auto_decay_action.ex demand_tracker_agent_live.ex
lib/agent_jido/demos/demand/actions/decay_action.ex 57 lines 
defmodule AgentJido.Demos.Demand.DecayAction do
  @moduledoc """
  Decays demand toward zero by a fixed amount.
  Emits a domain event when demand changes.
  """
  use Jido.Action,
    name: "decay",
    description: "Decays demand toward zero",
    schema: []

  alias Jido.Agent.Directive
  alias Jido.Signal

  @decay_amount 2

  @impl true
  def run(_params, context) do
    current_demand = Map.get(context.state, :demand, 50)
    listing_id = Map.get(context.state, :listing_id, "demo-listing")
    ticks = Map.get(context.state, :ticks, 0)
    now = DateTime.utc_now()

    new_demand = max(current_demand - @decay_amount, 0)

    state = %{
      demand: new_demand,
      ticks: ticks + 1,
      last_updated_at: now
    }

    directives = []

    # Emit domain event if demand changed
    directives =
      if current_demand != new_demand do
        emit_signal =
          Signal.new!(
            "listing.demand.changed",
            %{
              listing_id: listing_id,
              previous: current_demand,
              current: new_demand,
              delta: new_demand - current_demand,
              reason: :decay
            },
            source: "/demo/demand-tracker"
          )

        [Directive.emit(emit_signal) | directives]
      else
        directives
      end

    {:ok, state, directives}
  end
end