Your first flow

Say it to your agent:

Watch helpdesk tickets on vx.helpdesk.tickets. Priority arrives in French — map critique→P1, haute→P2, otherwise P3 — and post P1/P2 alerts to Slack with the requester’s email, lowercased.

What lands (flows/helpdesk_ticket_alerts.vjs):

# flow: helpdesk_ticket_alerts
source "vx.helpdesk.tickets"

# French priority label -> severity code. The business expert edits this table.
SEVERITY_CODES = {"critique": "P1", "haute": "P2"}
ALERT_LEVELS = ["P1", "P2"]

code = SEVERITY_CODES[priority] ?? "P3"
email = lower(requester?.email)

if code in ALERT_LEVELS:
    emit "vx.slack.out", {text: f"[{code}] {subject} — {email}"}
end

Three things to notice:

• The business lives in UPPERCASE literals. SEVERITY_CODES and ALERT_LEVELS appear in the panel as editable tables — a domain expert corrects "haute" to "P1" without reading a line of code, and the flow restarts itself (ADR-0005). Adding a new row — "bloquante" → "P1" — is the same gesture: the panel inserts it span-exact, no agent needed (changing the flow’s logic is the one that’s a sentence to the agent).
• The language is pure. No I/O, no clock, no network in a flow — input event in, emits out. That is what makes replay, time-travel and canary structurally safe later.
• Delivery is at-least-once, persisted. The event was on JetStream before the flow saw it; the emit is acknowledged before the input is.

Feed it an event:

curl -X POST localhost:8787/ingest/helpdesk.tickets \
  -d '{"priority":"critique","subject":"SAP down","requester":{"email":"[email protected]"}}'

then watch it in the panel — the event, its emit, and the editable surface, side by side. More recipes, each validated live: the cookbook.