The immutable runtime for swarm intelligence

# A durable agent: the consistency boundary.
# Pure decide / evolve over an event stream — no I/O, no clock.
agent Account:
  snapshot every 100 events
  state { account_id, balance: 0, status: "new" }

  # decide: current state + command -> events (+ optional reply)
  decide OpenAccount(cmd) when status is "new":
    emit  AccountOpened(account_id: cmd.account_id)
    reply "opened"

  decide Withdraw(amount) when amount > balance:
    reject "insufficient_funds"

  # evolve: fold an event back into state. Runs on every replay, forever.
  evolve AccountOpened(e):
    account_id = e.account_id
    status     = "open"

# An AI agent. Its event stream IS the run record;
# replay never re-calls the model.
ai_agent Triage:
  model:          fast
  prompt:         "You are a support triage assistant."
  tools:          [ LookupCustomer ]
  max_iterations: 4

# Dispatch a run, then await the answer.
run    = dispatch Triage.StartRun(query: "double charged")
answer = await(run)

# A durable job: a worker is just an event-sourced agent.
# Retries, scheduling and backoff come from the runtime — not your code.
worker EmailReceipt:
  queue        "mailers"
  max_attempts 20          # retry with capped backoff, then dead-letter

  perform(job):
    charge = load(job.charge_id)
    send_receipt(charge.email, charge.amount)   # a failure here just retries

# Enqueue now, or schedule for later. Survives a restart either way.
enqueue EmailReceipt(charge_id: "ch_42")
enqueue EmailReceipt(charge_id: "ch_99") schedule_in: minutes(30)

# Route commands to agents, then start the application.
router App:
  validate every command

  identify Account by account_id, prefix "account-"
  dispatch [ OpenAccount, Deposit, Withdraw ] -> Account

# Strong consistency blocks until the durable handlers ack.
start App
dispatch Deposit(account_id: "A", amount: 50) with consistency: strong