Discord: dedupe listener registration on reload

Closes #744

CHANGELOG.md

@@ -7,6 +7,7 @@
 - Memory: allow custom OpenAI-compatible embedding endpoints for memory search (remote baseUrl/apiKey/headers). (#819 — thanks @mukhtharcm)
 
 ### Fixes
+- Discord: avoid duplicate message/reaction listeners on monitor reloads. (#744 — thanks @thewilloftheshadow)
 - System events: include local timestamps when events are injected into prompts. (#245 — thanks @thewilloftheshadow)
 - Cron: accept `jobId` aliases for cron update/run/remove params in gateway validation. (#252 — thanks @thewilloftheshadow)
 - Models/Google: normalize Gemini 3 model ids to preview variants before runtime selection. (#795 — thanks @thewilloftheshadow)

src/discord/monitor.test.ts

@@ -7,6 +7,7 @@ import {
   isDiscordGroupAllowedByPolicy,
   normalizeDiscordAllowList,
   normalizeDiscordSlug,
+  registerDiscordListener,
   resolveDiscordChannelConfig,
   resolveDiscordGuildEntry,
   resolveDiscordReplyTarget,
@@ -34,6 +35,18 @@ const makeEntries = (
   return out;
 };
 
+describe("registerDiscordListener", () => {
+  class FakeListener {}
+
+  it("dedupes listeners by constructor", () => {
+    const listeners: object[] = [];
+
+    expect(registerDiscordListener(listeners, new FakeListener())).toBe(true);
+    expect(registerDiscordListener(listeners, new FakeListener())).toBe(false);
+    expect(listeners).toHaveLength(1);
+  });
+});
+
 describe("discord allowlist helpers", () => {
   it("normalizes slugs", () => {
     expect(normalizeDiscordSlug("Friends of Clawd")).toBe("friends-of-clawd");

src/discord/monitor.ts

@@ -175,6 +175,17 @@ function logSlowDiscordListener(params: {
   }
 }
 
+export function registerDiscordListener(
+  listeners: Array<object>,
+  listener: object,
+) {
+  if (listeners.some((existing) => existing.constructor === listener.constructor)) {
+    return false;
+  }
+  listeners.push(listener);
+  return true;
+}
+
 async function resolveDiscordThreadStarter(params: {
   channel: DiscordThreadChannel;
   client: Client;
@@ -602,8 +613,12 @@ export async function monitorDiscordProvider(opts: MonitorDiscordOpts = {}) {
     guildEntries,
   });
 
-  client.listeners.push(new DiscordMessageListener(messageHandler, logger));
-  client.listeners.push(
+  registerDiscordListener(
+    client.listeners,
+    new DiscordMessageListener(messageHandler, logger),
+  );
+  registerDiscordListener(
+    client.listeners,
     new DiscordReactionListener({
       cfg,
       accountId: account.accountId,
@@ -613,7 +628,8 @@ export async function monitorDiscordProvider(opts: MonitorDiscordOpts = {}) {
       logger,
     }),
   );
-  client.listeners.push(
+  registerDiscordListener(
+    client.listeners,
     new DiscordReactionRemoveListener({
       cfg,
       accountId: account.accountId,