feat(discord): add safety features to reaction triggers

- Only trigger on reaction ADD (not remove)
- Add rate limiting: 30s cooldown per user per message (configurable)
- Add emoji filtering: reactionTriggerEmojis array to limit which emojis trigger
- Update documentation with new options

docs/channels/discord.md

@@ -341,10 +341,18 @@ Use `guilds.<id>.reactionTrigger` to invoke an agent turn when a user reacts to
 - `all`: trigger agent on reactions to any message.
 - `allowlist`: trigger agent for reactions from `guilds.<id>.users` only.
 
+Additional options:
+- `guilds.<id>.reactionTriggerEmojis`: array of emojis that trigger (e.g., `["🤖", "👀"]`). Omit to allow all emojis.
+- `guilds.<id>.reactionTriggerCooldownMs`: cooldown between triggers per user per message. Default: 30000 (30 seconds). Set to 0 to disable.
+
 When triggered, the agent receives a synthetic message containing:
 - The reactor's user tag and the emoji they used
 - The content of the reacted-to message (if available)
-- Action type (added or removed)
+
+Notes:
+- Only reaction **adds** trigger the agent (removes do not)
+- Rate limiting prevents spam from rapid reactions
+- Uses the guild's `users` allowlist when mode is `allowlist`
 
 This is useful for interactive workflows where reactions serve as commands (e.g., 👀 to request analysis, 🤖 to trigger a response).
 

src/config/types.discord.ts

@@ -53,6 +53,10 @@ export type DiscordGuildEntry = {
   reactionNotifications?: DiscordReactionNotificationMode;
   /** Reaction trigger mode: invoke agent turn on reaction (off|own|all|allowlist). Default: off. */
   reactionTrigger?: DiscordReactionTriggerMode;
+  /** Only trigger on specific emojis (e.g., ["🤖", "👀"]). Empty/omitted = all emojis. */
+  reactionTriggerEmojis?: string[];
+  /** Cooldown in ms between reaction triggers per user per message. Default: 30000 (30s). */
+  reactionTriggerCooldownMs?: number;
   users?: Array<string | number>;
   channels?: Record<string, DiscordGuildChannelConfig>;
 };

src/config/zod-schema.providers-core.ts

@@ -208,6 +208,10 @@ export const DiscordGuildSchema = z
     reactionNotifications: z.enum(["off", "own", "all", "allowlist"]).optional(),
     /** Reaction trigger mode: invoke agent turn on reaction (off|own|all|allowlist). Default: off. */
     reactionTrigger: z.enum(["off", "own", "all", "allowlist"]).optional(),
+    /** Only trigger on specific emojis (e.g., ["🤖", "👀"]). Empty/omitted = all emojis. */
+    reactionTriggerEmojis: z.array(z.string()).optional(),
+    /** Cooldown in ms between reaction triggers per user per message. Default: 30000 (30s). */
+    reactionTriggerCooldownMs: z.number().int().min(0).optional(),
     users: z.array(z.union([z.string(), z.number()])).optional(),
     channels: z.record(z.string(), DiscordGuildChannelSchema.optional()).optional(),
   })

src/discord/monitor/allow-list.ts

@@ -24,6 +24,10 @@ export type DiscordGuildEntryResolved = {
   reactionNotifications?: "off" | "own" | "all" | "allowlist";
   /** Reaction trigger mode: invoke agent turn on reaction (off|own|all|allowlist). Default: off. */
   reactionTrigger?: "off" | "own" | "all" | "allowlist";
+  /** Only trigger on specific emojis. Empty/omitted = all emojis. */
+  reactionTriggerEmojis?: string[];
+  /** Cooldown in ms between reaction triggers per user per message. Default: 30000 (30s). */
+  reactionTriggerCooldownMs?: number;
   users?: Array<string | number>;
   channels?: Record<
     string,

src/discord/monitor/listeners.ts

@@ -28,6 +28,39 @@ type LoadedConfig = ReturnType<typeof import("../../config/config.js").loadConfi
 type RuntimeEnv = import("../../runtime.js").RuntimeEnv;
 type Logger = ReturnType<typeof import("../../logging/subsystem.js").createSubsystemLogger>;
 
+// Rate limiting for reaction triggers: Map<"messageId:userId", lastTriggerTimestamp>
+const reactionTriggerCooldowns = new Map<string, number>();
+const DEFAULT_REACTION_TRIGGER_COOLDOWN_MS = 30_000; // 30 seconds
+
+function checkReactionTriggerCooldown(params: {
+  messageId: string;
+  userId: string;
+  cooldownMs?: number;
+}): boolean {
+  const { messageId, userId, cooldownMs = DEFAULT_REACTION_TRIGGER_COOLDOWN_MS } = params;
+  if (cooldownMs <= 0) return true; // No cooldown
+
+  const key = `${messageId}:${userId}`;
+  const now = Date.now();
+  const lastTrigger = reactionTriggerCooldowns.get(key);
+
+  if (lastTrigger && now - lastTrigger < cooldownMs) {
+    return false; // Still in cooldown
+  }
+
+  reactionTriggerCooldowns.set(key, now);
+
+  // Cleanup old entries periodically (keep map from growing unbounded)
+  if (reactionTriggerCooldowns.size > 1000) {
+    const cutoff = now - cooldownMs * 2;
+    for (const [k, v] of reactionTriggerCooldowns) {
+      if (v < cutoff) reactionTriggerCooldowns.delete(k);
+    }
+  }
+
+  return true; // Allowed
+}
+
 export type DiscordMessageEvent = Parameters<MessageCreateListener["handle"]>[0];
 
 export type DiscordMessageHandler = (data: DiscordMessageEvent, client: Client) => Promise<void>;
@@ -242,16 +275,38 @@ async function handleDiscordReactionEvent(params: {
     const message = await data.message.fetch().catch(() => null);
     const messageAuthorId = message?.author?.id ?? undefined;
 
-    // Check if we should trigger an agent turn
-    const shouldTrigger = shouldTriggerDiscordReaction({
-      mode: reactionTriggerMode,
-      botId: botUserId,
-      messageAuthorId,
-      userId: user.id,
-      userName: user.username,
-      userTag: formatDiscordUserTag(user),
-      allowlist: guildInfo?.users,
-    });
+    const emojiLabel = formatDiscordReactionEmoji(data.emoji);
+
+    // Check if we should trigger an agent turn (only on "added", not "removed")
+    let shouldTrigger = false;
+    if (action === "added") {
+      shouldTrigger = shouldTriggerDiscordReaction({
+        mode: reactionTriggerMode,
+        botId: botUserId,
+        messageAuthorId,
+        userId: user.id,
+        userName: user.username,
+        userTag: formatDiscordUserTag(user),
+        allowlist: guildInfo?.users,
+      });
+
+      // Check emoji filter if configured
+      if (shouldTrigger && guildInfo?.reactionTriggerEmojis?.length) {
+        const allowedEmojis = guildInfo.reactionTriggerEmojis;
+        shouldTrigger = allowedEmojis.includes(emojiLabel);
+      }
+
+      // Check rate limit
+      if (shouldTrigger) {
+        const cooldownMs =
+          guildInfo?.reactionTriggerCooldownMs ?? DEFAULT_REACTION_TRIGGER_COOLDOWN_MS;
+        shouldTrigger = checkReactionTriggerCooldown({
+          messageId: data.message_id,
+          userId: user.id,
+          cooldownMs,
+        });
+      }
+    }
 
     // Check if we should notify via system event (only if not triggering)
     const shouldNotify =
@@ -267,8 +322,6 @@ async function handleDiscordReactionEvent(params: {
       });
 
     if (!shouldTrigger && !shouldNotify) return;
-
-    const emojiLabel = formatDiscordReactionEmoji(data.emoji);
     const actorLabel = formatDiscordUserTag(user);
     const guildSlug =
       guildInfo?.slug || (data.guild?.name ? normalizeDiscordSlug(data.guild.name) : data.guild_id);