diff --git a/packages/core/scripts/check-routes.mjs b/packages/core/scripts/check-routes.mts
similarity index 74%
rename from packages/core/scripts/check-routes.mjs
rename to packages/core/scripts/check-routes.mts
index 1cb08866ba7a..b15899ed5ed8 100644
--- a/packages/core/scripts/check-routes.mjs
+++ b/packages/core/scripts/check-routes.mts
@@ -1,7 +1,7 @@
 import { Routes } from 'discord-api-types/v10';
 import { glob, readFile } from 'node:fs/promises';
 
-const usedRoutes = new Set();
+const usedRoutes = new Set<string>();
 
 const ignoredRoutes = new Set([
 	// Deprecated
@@ -13,12 +13,14 @@ const ignoredRoutes = new Set([
 	'nitroStickerPacks',
 ]);
 
-for await (const file of glob('src/api/*.ts')) {
-	const content = await readFile(file, 'utf-8');
+const cwd = new URL('../src/api/', import.meta.url);
+
+for await (const file of glob('**/*.ts', { cwd })) {
+	const content = await readFile(new URL(file, cwd), 'utf-8');
 
 	const routes = content.matchAll(/Routes\.([\w\d_]+)/g);
 	for (const route of routes) {
-		usedRoutes.add(route[1]);
+		usedRoutes.add(route[1]!);
 	}
 }
 
diff --git a/packages/core/scripts/find-returns-not-return-type.mts b/packages/core/scripts/find-returns-not-return-type.mts
new file mode 100644
index 000000000000..71e11042b175
--- /dev/null
+++ b/packages/core/scripts/find-returns-not-return-type.mts
@@ -0,0 +1,28 @@
+import { glob, readFile } from 'node:fs/promises';
+
+const cwd = new URL('../src/api/', import.meta.url);
+const results: string[] = [];
+
+for await (const file of glob('**/*.ts', { cwd })) {
+	const content = await readFile(new URL(file, cwd), { encoding: 'utf-8' });
+
+	const matches = content.matchAll(/as Promise<(?<returnType>\w+)>/g);
+
+	for (const match of matches) {
+		const returnType = match.groups!.returnType!;
+
+		if (!returnType.startsWith('REST') || !returnType.includes('Result')) {
+			results.push(`in file core/src/api/${file}: ${returnType}`);
+		}
+	}
+}
+
+if (results.length > 0) {
+	console.warn('Found return types that are not REST return types:');
+
+	for (const result of results) {
+		console.warn(`  - ${result}`);
+	}
+} else {
+	console.log('No return types that are not REST return types found');
+}
diff --git a/packages/core/src/api/channel.ts b/packages/core/src/api/channel.ts
index 89f38d9403d8..ca062a70e860 100644
--- a/packages/core/src/api/channel.ts
+++ b/packages/core/src/api/channel.ts
@@ -3,7 +3,6 @@
 import { makeURLSearchParams, type RawFile, type RequestData, type REST } from '@discordjs/rest';
 import {
 	Routes,
-	type APIThreadChannel,
 	type RESTDeleteAPIChannelResult,
 	type RESTGetAPIChannelInvitesResult,
 	type RESTGetAPIChannelMessageReactionUsersQuery,
@@ -566,7 +565,7 @@ export class ChannelsAPI {
 			body,
 			reason,
 			signal,
-		}) as Promise<APIThreadChannel>;
+		}) as Promise<RESTPostAPIChannelThreadsResult>;
 	}
 
 	/**