diff --git a/packages/svelte/scripts/check-treeshakeability.js b/packages/svelte/scripts/check-treeshakeability.js
index 6297dd535e..7b9fb816be 100644
--- a/packages/svelte/scripts/check-treeshakeability.js
+++ b/packages/svelte/scripts/check-treeshakeability.js
@@ -5,6 +5,9 @@ import virtual from '@rollup/plugin-virtual';
 import { nodeResolve } from '@rollup/plugin-node-resolve';
 import { compile } from 'svelte/compiler';
 
+/**
+ * @param {string} entry
+ */
 async function bundle_code(entry) {
 	const bundle = await rollup({
 		input: '__entry__',
diff --git a/packages/svelte/scripts/process-messages/index.js b/packages/svelte/scripts/process-messages/index.js
index b8f9a8f4b5..032e1fd28a 100644
--- a/packages/svelte/scripts/process-messages/index.js
+++ b/packages/svelte/scripts/process-messages/index.js
@@ -54,11 +54,23 @@ for (const category of fs.readdirSync('messages')) {
 	}
 }
 
+/**
+ * @param {string} name
+ * @param {string} dest
+ */
 function transform(name, dest) {
 	const source = fs
 		.readFileSync(new URL(`./templates/${name}.js`, import.meta.url), 'utf-8')
 		.replace(/\r\n/g, '\n');
 
+	/**
+	 * @type {Array<{
+	 * 	type: string;
+	 * 	value: string;
+	 * 	start: number;
+	 * 	end: number
+	 * }>}
+	 */
 	const comments = [];
 
 	let ast = acorn.parse(source, {
@@ -135,6 +147,7 @@ function transform(name, dest) {
 
 	for (const code in category) {
 		const { messages } = category[code];
+		/** @type {string[]} */
 		const vars = [];
 
 		const group = messages.map((text, i) => {
@@ -225,7 +238,7 @@ function transform(name, dest) {
 			Block(node, context) {
 				if (!node.value.includes('PARAMETER')) return;
 
-				const value = node.value
+				const value = /** @type {string} */ (node.value)
 					.split('\n')
 					.map((line) => {
 						if (line === ' * MESSAGE') {
diff --git a/packages/svelte/tsconfig.json b/packages/svelte/tsconfig.json
index 8c27517244..062a5b1ece 100644
--- a/packages/svelte/tsconfig.json
+++ b/packages/svelte/tsconfig.json
@@ -31,10 +31,12 @@
 		}
 	},
 	"include": [
-		"./src",
+		"./*.js",
+		"./scripts/",
+		"./src/",
 		"./tests/*/test.ts",
 		"./tests/runtime-browser/test-ssr.ts",
 		"./tests/*/samples/*/_config.js"
 	],
-	"exclude": ["./src/compiler/optimizer"]
+	"exclude": ["./scripts/process-messages/templates/", "./src/compiler/optimizer/"]
 }