Route a Discord reaction as a signal

A reaction is the lowest-friction hand-raise a community produces and the easiest to miss. The @hogsend/plugin-discord connector turns a MESSAGE_REACTION_ADD dispatch into a discord.reaction_added event, carrying the emoji name in its properties. A trigger.where filters enrollment to a single emoji at the enrollment guard, so only the reaction you care about ever creates journey state — and the run flags a scalars-only lead.flagged event the notify task or Discord channel destination turns into an operator touch.

The reaction's event properties

discord.reaction_added carries the emoji name, channel, message, and guild ids in eventProperties, set by the connector's transform:

eventProperties: {
  source: "discord",
  channelId,
  guildId,
  messageId,
  emoji: d.emoji?.name ?? null, // "👍", a custom emoji name, or null
}

trigger.where reads those properties at enrollment, so only the reactions you choose ever create journey state:

trigger: {
  event: Events.DISCORD_REACTION_ADDED, // "discord.reaction_added"
  where: (b) => b.prop("emoji").eq("👍"),
}

A 👍 enters; a 😂 never does — no wasted journey state and no in-run emoji branching.

The journey

// src/journeys/route-a-reaction-as-a-signal.ts
import { contacts } from "@hogsend/db";
import { days, defineJourney, getDb, hours } from "@hogsend/engine";
import { eq } from "drizzle-orm";
import { Events } from "./constants/index.js";

export const routeReactionSignal = defineJourney({
  meta: {
    id: "route-a-reaction-as-a-signal",
    name: "Human-in-the-loop — reaction signal",
    enabled: true,
    // Only a 👍 reaction enters. The connector puts the emoji name in
    // eventProperties.emoji; trigger.where filters on it at enrollment.
    trigger: {
      event: Events.DISCORD_REACTION_ADDED,
      where: (b) => b.prop("emoji").eq("👍"),
    },
    entryLimit: "once_per_period",
    entryPeriod: days(1),
    suppress: hours(12),
  },

  run: async (user, ctx) => {
    const db = getDb();
    const contact = await db.query.contacts.findFirst({
      where: eq(contacts.id, user.id),
    });

    // The reaction is the hand-raise. Flag it with a scalars-only event the
    // notify task (or the Discord alerts destination) turns into an operator
    // touch — identity is resolved server-side, never carried in properties.
    await ctx.trigger({
      event: Events.LEAD_FLAGGED, // "lead.flagged"
      userId: user.id,
      properties: {
        reason: "discord-reaction",
        emoji: "👍",
        linked: Boolean(contact?.email),
        flaggedAt: new Date().toISOString(),
      },
    });
  },
});

The filter runs before any state exists: a non-matching emoji is skipped with no journeyStates row created. Matching the emoji inside the run instead would burn an enrollment on every reaction in the server.

Why a scalars-only flag

Event properties travel the ingest pipeline and fan out to destinations, so lead.flagged carries reason, the emoji, and a linked flag — never the member's email or name. Whoever picks up the flag resolves identity from the authoritative contacts row:

• a notify-lead Hatchet task can email an operator past the lead's own preferences — see Lead alerts;
• the Discord alerts destination can post the hand-raise to a channel — see Discord engagement alerts.

The reaction always carries a discord_id (via userId discord:<snowflake>), so the flag fires whether or not the member has linked an email. The run records the linked state, so the follow-up can branch: email a linked member, or post to the channel for a Discord-only one.

Add the events

// src/journeys/constants/index.ts
export const Events = {
  DISCORD_REACTION_ADDED: "discord.reaction_added",
  LEAD_FLAGGED: "lead.flagged",
} as const;

discord.reaction_added is emitted by the connector; lead.flagged is your own cross-journey event. Register the journey by adding routeReactionSignal to your journeys array, as in Lifecycle journeys.

Related: Lead alerts is the operator follow-up, Discord engagement alerts pages a channel on the same flag, and the Journeys guide documents trigger.where and ctx.trigger.