diff --git a/src/api/routes/messages.ts b/src/api/routes/messages.ts
index 241c093..3e70e18 100644
--- a/src/api/routes/messages.ts
+++ b/src/api/routes/messages.ts
@@ -2,12 +2,22 @@ import { Router, type Request } from 'express';
 import { messageService } from '../../discord/services/index.js';
 import { SendMessageSchema, EditMessageSchema, GetMessagesSchema } from '../../types/api.types.js';
 
+/** Route params for message endpoints (merged from parent router) */
+interface MessageParams {
+    channelId?: string;
+    messageId?: string;
+    emoji?: string;
+}
+
 const router = Router({ mergeParams: true });
 
-// Helper to get merged params
+/**
+ * Helper to get merged params with type safety.
+ * Express mergeParams merges parent route params, so channelId comes from the parent router.
+ */
 function getParams(req: Request): { channelId: string; messageId?: string; emoji?: string } {
-    // eslint-disable-next-line @typescript-eslint/no-explicit-any
-    const params = req.params as any;
+    // Params are merged from parent router via mergeParams: true
+    const params = req.params as MessageParams;
     return { channelId: params.channelId ?? '', messageId: params.messageId, emoji: params.emoji };
 }
 
diff --git a/src/discord/events/index.ts b/src/discord/events/index.ts
index 17ec196..adff331 100644
--- a/src/discord/events/index.ts
+++ b/src/discord/events/index.ts
@@ -1,4 +1,5 @@
 import type { Server as SocketIOServer } from 'socket.io';
+import type { User, GuildScheduledEvent } from 'discord.js';
 import { discordClient } from '../client.js';
 import {
     serializeMessage,
@@ -267,7 +268,8 @@ export function registerDiscordEvents(): void {
 
     discordClient.on('userUpdate', (oldUser, newUser) => {
         // oldUser may be partial, so we only serialize if not partial
-        const oldSerialized = oldUser.partial ? null : serializeUser(oldUser as any);
+        // Type assertion is safe here because we've checked partial === false
+        const oldSerialized = oldUser.partial ? null : serializeUser(oldUser as User);
         broadcastEvent({
             event: 'userUpdate',
             guildId: null,
@@ -605,25 +607,40 @@ export function registerDiscordEvents(): void {
 
     discordClient.on('guildScheduledEventUpdate', (oldEvent, newEvent) => {
         // oldEvent may be partial
+        // Type assertions are safe here because we've checked partial === false
         const oldSerialized = oldEvent && !oldEvent.partial
-            ? serializeScheduledEvent(oldEvent as any)
+            ? serializeScheduledEvent(oldEvent as GuildScheduledEvent)
             : null;
         broadcastEvent({
             event: 'guildScheduledEventUpdate',
             guildId: newEvent.guildId,
             data: {
                 old: oldSerialized,
-                new: serializeScheduledEvent(newEvent as any),
+                new: serializeScheduledEvent(newEvent as GuildScheduledEvent),
             },
         });
     });
 
     discordClient.on('guildScheduledEventDelete', (event) => {
-        // event may be partial, but we still want to broadcast the deletion
+        // For partial events, only broadcast minimal deletion info
+        // Full serialization would fail as many properties are undefined
+        if (event.partial) {
+            broadcastEvent({
+                event: 'guildScheduledEventDelete',
+                guildId: event.guildId,
+                data: {
+                    id: event.id,
+                    guildId: event.guildId,
+                    partial: true,
+                },
+            });
+            return;
+        }
+
         broadcastEvent({
             event: 'guildScheduledEventDelete',
             guildId: event.guildId,
-            data: serializeScheduledEvent(event as any),
+            data: serializeScheduledEvent(event as GuildScheduledEvent),
         });
     });
 
diff --git a/src/index.ts b/src/index.ts
index 61c7724..73ccbab 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -2,6 +2,7 @@ import { loginDiscord, waitForReady, discordClient } from './discord/client.js';
 import { registerDiscordEvents } from './discord/events/index.js';
 import { createApiServer, startApiServer } from './api/server.js';
 import { pluginManager } from './plugins/manager.js';
+import { shutdownRateLimiter } from './api/middleware/rateLimit.js';
 import { config } from './config/index.js';
 
 async function main(): Promise<void> {
@@ -44,6 +45,9 @@ async function main(): Promise<void> {
 async function shutdown(): Promise<void> {
     console.log('\n🛑 Shutting down...');
 
+    // Clean up rate limiter intervals
+    shutdownRateLimiter();
+
     // Unload plugins gracefully
     if (pluginManager.count > 0) {
         console.log('🔌 Unloading plugins...');
diff --git a/src/plugins/manager.ts b/src/plugins/manager.ts
index 746804e..2766e1b 100644
--- a/src/plugins/manager.ts
+++ b/src/plugins/manager.ts
@@ -214,7 +214,9 @@ export class PluginManager {
                         normalizedArgs = args.map(wrapHandler);
                     }
 
-                    pluginSubRouter!.use(...normalizedArgs as Parameters<typeof pluginSubRouter.use>);
+                    // pluginSubRouter is guaranteed non-null here since we just created it
+                    const router = pluginSubRouter as Router;
+                    router.use(...normalizedArgs as Parameters<typeof router.use>);
                 },
             };
 
diff --git a/src/plugins/sdk.ts b/src/plugins/sdk.ts
index ebb237f..2571cb1 100644
--- a/src/plugins/sdk.ts
+++ b/src/plugins/sdk.ts
@@ -167,6 +167,11 @@ export function createEventHelpers(eventBus: PluginEventBus) {
     };
 }
 
+/**
+ * Type for the event helpers object returned by createEventHelpers
+ */
+export type EventHelpers = ReturnType<typeof createEventHelpers>;
+
 /**
  * Plugin definition options for definePlugin helper
  */
diff --git a/src/types/events.types.ts b/src/types/events.types.ts
index c07a629..90f8d7b 100644
--- a/src/types/events.types.ts
+++ b/src/types/events.types.ts
@@ -563,7 +563,14 @@ export interface GuildScheduledEventUpdateEvent {
 export interface GuildScheduledEventDeleteEvent {
     event: 'guildScheduledEventDelete';
     guildId: string;
-    data: SerializedScheduledEvent;
+    data: SerializedScheduledEvent | {
+        /** Event ID (always available even for partial events) */
+        id: string;
+        /** Guild ID (always available even for partial events) */
+        guildId: string;
+        /** Indicates this is a partial event with limited data */
+        partial: true;
+    };
 }
 
 export interface GuildScheduledEventUserAddEvent {
diff --git a/src/types/plugin.types.ts b/src/types/plugin.types.ts
index 06132fb..cf2b335 100644
--- a/src/types/plugin.types.ts
+++ b/src/types/plugin.types.ts
@@ -9,7 +9,7 @@ import type {
     SocketData,
 } from './events.types.js';
 import type { PluginEventBus, EventSubscription } from '../plugins/event-bus.js';
-import type { PluginRouter, PluginLogger } from '../plugins/sdk.js';
+import type { PluginRouter, PluginLogger, EventHelpers } from '../plugins/sdk.js';
 
 /**
  * The context passed to plugins on load.
@@ -92,13 +92,7 @@ export interface HoloPlugin {
      * ```
      */
     events?: (
-        helpers: {
-            onDiscord: <T = unknown>(event: string, handler: (data: T) => void | Promise<void>) => EventSubscription;
-            onCustom: <T = Record<string, unknown>>(event: string, handler: (data: T) => void | Promise<void>) => EventSubscription;
-            emit: <T extends Record<string, unknown>>(event: string, data: T) => void;
-            onPluginLoaded: (handler: (data: { name: string; version: string }) => void) => EventSubscription;
-            onPluginUnloaded: (handler: (data: { name: string }) => void) => EventSubscription;
-        },
+        helpers: EventHelpers,
         ctx: PluginContext
     ) => EventSubscription[];