diff --git a/.yarnrc.yml b/.yarnrc.yml
index 8a4e27b2611..21eb9091d6a 100644
--- a/.yarnrc.yml
+++ b/.yarnrc.yml
@@ -239,7 +239,7 @@ catalogs:
     react-native-windows: ^0.81.0
     react-test-renderer: 19.1.4
 
-dynamicPackageExtensions: ./scripts/dynamic.extensions.mjs
+dynamicPackageExtensions: ./scripts/dynamic.extensions.mts
 
 enableGlobalCache: false
 
diff --git a/package.json b/package.json
index 4f83e0cf82a..eec4e8ddfd9 100644
--- a/package.json
+++ b/package.json
@@ -16,17 +16,17 @@
   ],
   "scripts": {
     "build": "lage build-all",
-    "clean-all": "node ./scripts/src/preinstall/clean-all.js",
+    "clean-all": "node ./scripts/src/preinstall/clean-all.ts",
     "docs": "yarn workspace fluent-rn-website start",
     "bundle:repo": "lage bundle",
     "clean": "lage clean",
     "change": "node .github/scripts/change.mts",
     "changeset:version": "node .github/scripts/changeset-version-with-postbump.mts",
     "change:check": "node .github/scripts/change.mts --check",
-    "check-publishing": "node ./scripts/src/cli.mjs check-publishing",
+    "check-publishing": "node ./scripts/src/cli.ts check-publishing",
     "lint-fix": "cross-env FURN_FIX_MODE=true lage lint",
     "lint-package-fix": "cross-env FURN_FIX_MODE=true lage lint-package",
-    "preinstall": "node ./scripts/src/preinstall/use-yarn-please.js",
+    "preinstall": "node ./scripts/src/preinstall/use-yarn-please.ts",
     "format": "oxfmt",
     "format:check": "oxfmt --check",
     "lint-lockfile": "lint-lockfile",
diff --git a/scripts/dynamic.extensions.mjs b/scripts/dynamic.extensions.mts
similarity index 62%
rename from scripts/dynamic.extensions.mjs
rename to scripts/dynamic.extensions.mts
index f1635d5cbaa..c6c50ee7109 100644
--- a/scripts/dynamic.extensions.mjs
+++ b/scripts/dynamic.extensions.mts
@@ -1,23 +1,19 @@
-// @ts-check
-
 import fs from 'node:fs';
 import path from 'node:path';
-import { getToolVersion, hasJestConfig } from './src/preinstall/tool-versions.js';
+import { getToolVersion, hasJestConfig } from './src/preinstall/tool-versions.ts';
+import type { PackageManifest } from './src/utils/projectRoot.ts';
 
-/**
- * @typedef {() => boolean} ConditionalCheck
- */
+type ConditionalCheck = () => boolean;
 
 /**
  * Conditionally add a dependency to the given dependencies object if it is not already present
- * @param {string[]} depsToAdd
- * @param {import('./src/utils/projectRoot.ts').PackageManifest} manifest
- * @param {ConditionalCheck | boolean | undefined} condition
- * @returns {Record<string, string>}
  */
-function conditionallyAdd(depsToAdd, manifest, condition) {
-  /** @type {Record<string, string>} */
-  const newDeps = {};
+function conditionallyAdd(
+  depsToAdd: string[],
+  manifest: PackageManifest,
+  condition: ConditionalCheck | boolean | undefined,
+): Record<string, string> {
+  const newDeps: Record<string, string> = {};
   if (!condition || (typeof condition === 'function' ? condition() : condition)) {
     for (const dep of depsToAdd) {
       if (!manifest.dependencies?.[dep] && !manifest.devDependencies?.[dep]) {
@@ -36,29 +32,23 @@ function conditionallyAdd(depsToAdd, manifest, condition) {
 }
 
 /**
- * @param {import('./src/utils/projectRoot.ts').PackageManifest} manifest - The package manifest.
- * @returns {boolean} true if oxfmt should be added based on the manifest's prettier scripts
+ * Returns true if oxfmt should be added based on the manifest's prettier scripts.
  */
-function addOxfmt(manifest) {
+function addOxfmt(manifest: PackageManifest): boolean {
   return Boolean(manifest && manifest.scripts && (manifest.scripts.format || manifest.scripts['format:fix']));
 }
 
 /**
  * Check if Jest is already in the manifest or if a Jest script is defined.
- * @param {string} cwd - The current working directory.
- * @param {import('./src/utils/projectRoot.ts').PackageManifest} manifest - The package manifest.
- * @returns {boolean} - True if Jest should be added, false otherwise.
  */
-function addJest(cwd, manifest) {
+function addJest(cwd: string, manifest: PackageManifest): boolean {
   return Boolean(manifest.scripts?.test && hasJestConfig(cwd));
 }
 
 /**
  * Get the dynamic dependencies for the given package given the package root directory and its manifest.
- * @param {{cwd: string, manifest: import('./src/utils/projectRoot.ts').PackageManifest}} param0
- * @returns { { dependencies: Record<string, string> } }
  */
-export default function ({ cwd, manifest }) {
+export default function ({ cwd, manifest }: { cwd: string; manifest: PackageManifest }): { dependencies: Record<string, string> } {
   const enableLinting = Boolean(manifest.scripts && manifest.scripts.lint);
 
   return {
diff --git a/scripts/package.json b/scripts/package.json
index 5f939174fce..aecaac3c6d8 100644
--- a/scripts/package.json
+++ b/scripts/package.json
@@ -9,14 +9,14 @@
     "directory": "scripts"
   },
   "bin": {
-    "fluentui-scripts": "./src/cli.mjs"
+    "fluentui-scripts": "./src/cli.ts"
   },
   "type": "module",
-  "main": "./src/index.js",
+  "main": "./src/index.ts",
   "exports": {
     ".": {
-      "require": "./src/index.js",
-      "default": "./src/index.js"
+      "require": "./src/index.ts",
+      "default": "./src/index.ts"
     },
     "./babel-config": "./configs/jest/babel.config.cjs",
     "./jest-config": "./configs/jest/jest.config.cjs",
@@ -29,10 +29,10 @@
     "build": "tsgo",
     "build-core": "tsgo",
     "bundlesize": "bundlesize --debug",
-    "depcheck": "node ./src/cli.mjs depcheck",
-    "format": "node ./src/cli.mjs format",
-    "lint": "node ./src/cli.mjs lint",
-    "lint-package": "node ./src/cli.mjs lint-package"
+    "depcheck": "node ./src/cli.ts depcheck",
+    "format": "node ./src/cli.ts format",
+    "lint": "node ./src/cli.ts lint",
+    "lint-package": "node ./src/cli.ts lint-package"
   },
   "dependencies": {
     "@babel/core": "catalog:",
diff --git a/scripts/src/cli.mjs b/scripts/src/cli.ts
old mode 100755
new mode 100644
similarity index 79%
rename from scripts/src/cli.mjs
rename to scripts/src/cli.ts
index 8220c1e8462..788a380a2ae
--- a/scripts/src/cli.mjs
+++ b/scripts/src/cli.ts
@@ -1,14 +1,13 @@
 #!/usr/bin/env node
-// @ts-check
 
 import { Builtins, Cli } from 'clipanion';
 import { BuildCommand } from './tasks/build.ts';
-import { CleanCommand } from './tasks/clean.js';
-import { FormatCommand } from './tasks/format.js';
-import { LintCommand } from './tasks/lint.js';
+import { CleanCommand } from './tasks/clean.ts';
+import { FormatCommand } from './tasks/format.ts';
+import { LintCommand } from './tasks/lint.ts';
 import { LintPackageCommand } from './tasks/lintPackage.ts';
-import { JestCommand } from './tasks/jest.js';
-import { CheckPublishingCommand } from './tasks/checkPublishingTask.js';
+import { JestCommand } from './tasks/jest.ts';
+import { CheckPublishingCommand } from './tasks/checkPublishingTask.ts';
 import { DepcheckCommand } from './tasks/depcheck.ts';
 
 const cli = new Cli({
diff --git a/scripts/src/index.js b/scripts/src/index.ts
similarity index 78%
rename from scripts/src/index.js
rename to scripts/src/index.ts
index a4d81b66e68..5c342fe8014 100644
--- a/scripts/src/index.js
+++ b/scripts/src/index.ts
@@ -1,2 +1 @@
-// @ts-check
 export { isPnpmMode } from './utils/ispnpm.ts';
diff --git a/scripts/src/preinstall/clean-all.js b/scripts/src/preinstall/clean-all.ts
similarity index 82%
rename from scripts/src/preinstall/clean-all.js
rename to scripts/src/preinstall/clean-all.ts
index 90fe5dba7bd..1d3fd0e9cc9 100644
--- a/scripts/src/preinstall/clean-all.js
+++ b/scripts/src/preinstall/clean-all.ts
@@ -1,16 +1,10 @@
-// @ts-check
-
-const child_process = require('child_process');
-const fs = require('fs');
-const path = require('path');
-const os = require('os');
+import child_process from 'node:child_process';
+import fs from 'node:fs';
+import path from 'node:path';
+import os from 'node:os';
 // This script MUST NOT have any deps aside from Node built-ins, because it deletes all node_modules!
 
-/**
- * @param {string} question - The question to prompt the user with
- * @returns {Promise<string>}
- * */
-function prompt(question) {
+function prompt(question: string): Promise<string> {
   return new Promise((resolve) => {
     process.stdin.resume();
     process.stdout.write(question);
@@ -22,10 +16,7 @@ function prompt(question) {
   });
 }
 
-/**
- * @param {string} itemPath - The path to the item to check
- */
-function deleteIfSymlink(itemPath) {
+function deleteIfSymlink(itemPath: string): void {
   itemPath = path.resolve(itemPath);
   try {
     // Compare realpath since fs.statSync(itemPath).isSymbolicLink() doesn't work on Windows
@@ -40,10 +31,8 @@ function deleteIfSymlink(itemPath) {
 
 /**
  * Deletes symlinks in the specified node_modules directory.
- * @param {string} nodeModulesPath - The path to the node_modules directory
- * @returns {void}
  */
-function deleteNodeModulesSymlinks(nodeModulesPath) {
+function deleteNodeModulesSymlinks(nodeModulesPath: string): void {
   if (!fs.existsSync(nodeModulesPath)) {
     return;
   }
@@ -62,10 +51,8 @@ function deleteNodeModulesSymlinks(nodeModulesPath) {
 
 /**
  * Deletes symlinks in the specified parent folder.
- * @param {string} parentFolder - The path to the parent folder
- * @returns {void}
  */
-function deleteSymlinks(parentFolder) {
+function deleteSymlinks(parentFolder: string): void {
   const parentPath = path.join(process.cwd(), parentFolder);
   if (!fs.existsSync(parentPath)) {
     return;
diff --git a/scripts/src/preinstall/tool-versions.js b/scripts/src/preinstall/tool-versions.ts
similarity index 80%
rename from scripts/src/preinstall/tool-versions.js
rename to scripts/src/preinstall/tool-versions.ts
index f3cdedec8d3..c86fbd11cd0 100644
--- a/scripts/src/preinstall/tool-versions.js
+++ b/scripts/src/preinstall/tool-versions.ts
@@ -2,12 +2,12 @@ import fs from 'node:fs';
 import path from 'node:path';
 import { fileURLToPath } from 'node:url';
 
+import type { PackageManifest } from '../utils/projectRoot.ts';
+
 /**
  * Get the package.json manifest for a given folder.
- * @param {string} folder
- * @returns {import('../utils/projectRoot.ts').PackageManifest}
  */
-function getPackageManifest(folder) {
+function getPackageManifest(folder: string): PackageManifest {
   const manifestPath = path.join(folder, 'package.json');
   return JSON.parse(fs.readFileSync(manifestPath, 'utf-8'));
 }
@@ -17,8 +17,7 @@ const scriptFolder = path.join(path.dirname(fileURLToPath(import.meta.url)), '..
 const scriptManifest = getPackageManifest(scriptFolder);
 const rootManifest = getPackageManifest(path.dirname(scriptFolder));
 
-/** @type {Record<string, string>} */
-const devToolVersions = {
+const devToolVersions: Record<string, string> = {
   '@eslint/js': '^9.0.0',
   '@microsoft/eslint-plugin-sdl': '^1.1.0',
   '@react-native-community/cli': '^13.6.4',
@@ -58,27 +57,21 @@ const devToolVersions = {
   ...rootManifest.devDependencies,
 };
 
-/** @type {Record<string, string>} */
-const workspaceToolVersions = {
+const workspaceToolVersions: Record<string, string> = {
   '@fluentui-react-native/scripts': 'workspace:*',
 };
 
-/**
- *
- * @param {string} packageName
- * @returns {string | null}
- */
-export function getToolVersion(packageName) {
+export function getToolVersion(packageName: string): string | null {
   return devToolVersions[packageName] ?? workspaceToolVersions[packageName] ?? null;
 }
 
 const CONFIG_EXTENSIONS = ['.js', '.cjs', '.mjs', '.ts', '.cts', '.mts'];
 
 /**
- * @param {string} cwd - The current working directory.
- * @returns {boolean} - True if a Jest config file exists in the cwd, false otherwise.
+ * @param cwd the current working directory.
+ * @returns true if a Jest config file exists in the cwd, false otherwise.
  */
-export function hasJestConfig(cwd) {
+export function hasJestConfig(cwd: string): boolean {
   for (const ext of CONFIG_EXTENSIONS) {
     if (fs.existsSync(path.join(cwd, `jest.config${ext}`))) {
       return true;
diff --git a/scripts/src/preinstall/use-yarn-please.js b/scripts/src/preinstall/use-yarn-please.ts
similarity index 100%
rename from scripts/src/preinstall/use-yarn-please.js
rename to scripts/src/preinstall/use-yarn-please.ts
diff --git a/scripts/src/tasks/build.ts b/scripts/src/tasks/build.ts
index 7579032b75c..b3dcc73ce73 100644
--- a/scripts/src/tasks/build.ts
+++ b/scripts/src/tasks/build.ts
@@ -1,7 +1,5 @@
-// @ts-check
-
 import { Command } from 'clipanion';
-import { runYarn } from '../utils/runScript.js';
+import { runYarn } from '../utils/runScript.ts';
 import { getProjectRoot } from '../utils/projectRoot.ts';
 import { getResolvedConfig } from '../utils/buildConfig.ts';
 
diff --git a/scripts/src/tasks/checkPublishingTask.js b/scripts/src/tasks/checkPublishingTask.ts
similarity index 78%
rename from scripts/src/tasks/checkPublishingTask.js
rename to scripts/src/tasks/checkPublishingTask.ts
index 21be1cba732..54fe94c7a4c 100644
--- a/scripts/src/tasks/checkPublishingTask.js
+++ b/scripts/src/tasks/checkPublishingTask.ts
@@ -1,28 +1,21 @@
-// @ts-check
-
 import { Command } from 'clipanion';
 import { getPackageInfos, findGitRoot } from 'workspace-tools';
 
-import { checkDependencies } from '../utils/checkDependencies.js';
+import { checkDependencies } from '../utils/checkDependencies.ts';
 
-/**
- * @typedef {'dependencies' | 'devDependencies' | 'peerDependencies'} DependencyType
- * @typedef {{ dependencyTypes?: DependencyType[] }} CheckPublishingOptions
- */
+type DependencyType = 'dependencies' | 'devDependencies' | 'peerDependencies';
 
 export class CheckPublishingCommand extends Command {
-  /** @override */
-  static paths = [['check-publishing']];
+  static override paths = [['check-publishing']];
 
-  /** @override */
-  static usage = Command.Usage({
+  static override usage = Command.Usage({
     description: 'Check the matrix of packages for publishing errors',
     details: 'This command checks for published packages that have a dependency on a private package.',
     examples: [['Check for publishing errors', '$0 check-publishing']],
   });
 
   async execute() {
-    const dependencyTypes = ['dependencies'];
+    const dependencyTypes: DependencyType[] = ['dependencies'];
     const packageInfos = getPackageInfos(findGitRoot(process.cwd()));
     console.info('Starting scan for publishing errors');
     try {
diff --git a/scripts/src/tasks/clean.js b/scripts/src/tasks/clean.ts
similarity index 77%
rename from scripts/src/tasks/clean.js
rename to scripts/src/tasks/clean.ts
index 0e3a8789c2a..8bbe1f947fe 100644
--- a/scripts/src/tasks/clean.js
+++ b/scripts/src/tasks/clean.ts
@@ -1,15 +1,11 @@
-// @ts-check
-
 import { Command } from 'clipanion';
 import fs from 'node:fs';
 import path from 'node:path';
 
 export class CleanCommand extends Command {
-  /** @override */
-  static paths = [['clean']];
+  static override paths = [['clean']];
 
-  /** @override */
-  static usage = Command.Usage({
+  static override usage = Command.Usage({
     description: 'Cleans the current package',
     details: 'This command removes all build artifacts from the current package.',
     examples: [['Clean the current package', '$0 clean']],
@@ -22,9 +18,8 @@ export class CleanCommand extends Command {
 
 /**
  * Cleans the specified folder by removing certain directories and files.
- * @param {string} [cwd=process.cwd()] - The target directory to clean.
  */
-export function cleanFolder(cwd = process.cwd()) {
+export function cleanFolder(cwd: string = process.cwd()): number {
   const options = { force: true, maxRetries: 3, recursive: true };
   [
     'lib',
diff --git a/scripts/src/tasks/depcheck.ts b/scripts/src/tasks/depcheck.ts
index 2a4f08a71dd..eaeda5f150a 100644
--- a/scripts/src/tasks/depcheck.ts
+++ b/scripts/src/tasks/depcheck.ts
@@ -1,12 +1,10 @@
-// @ts-check
-
 import { Command, Option } from 'clipanion';
 import depcheck from 'depcheck';
 import type { ProjectRoot } from '../utils/projectRoot.ts';
 import { getProjectRoot } from '../utils/projectRoot.ts';
-import getInjectedDeps from '../../dynamic.extensions.mjs';
+import getInjectedDeps from '../../dynamic.extensions.mts';
 import { getReporter } from '../utils/getReporter.ts';
-import { getToolVersion } from '../preinstall/tool-versions.js';
+import { getToolVersion } from '../preinstall/tool-versions.ts';
 import micromatch from 'micromatch';
 import { isFixMode } from '../utils/env.ts';
 
diff --git a/scripts/src/tasks/format.js b/scripts/src/tasks/format.ts
similarity index 77%
rename from scripts/src/tasks/format.js
rename to scripts/src/tasks/format.ts
index 341377edd51..8878eeaec20 100644
--- a/scripts/src/tasks/format.js
+++ b/scripts/src/tasks/format.ts
@@ -1,15 +1,11 @@
-// @ts-check
-
 import { Command, Option } from 'clipanion';
-import { runScript } from '../utils/runScript.js';
+import { runScript } from '../utils/runScript.ts';
 import { isFixMode } from '../utils/env.ts';
 
 export class FormatCommand extends Command {
-  /** @override */
-  static paths = [['format']];
+  static override paths = [['format']];
 
-  /** @override */
-  static usage = Command.Usage({
+  static override usage = Command.Usage({
     description: 'Formats the current package',
     details: 'This command formats the current package using oxfmt.',
     examples: [['Format the current package', '$0 format']],
diff --git a/scripts/src/tasks/jest.js b/scripts/src/tasks/jest.ts
similarity index 73%
rename from scripts/src/tasks/jest.js
rename to scripts/src/tasks/jest.ts
index 97c8d33c43c..bbffcfbd255 100644
--- a/scripts/src/tasks/jest.js
+++ b/scripts/src/tasks/jest.ts
@@ -1,14 +1,11 @@
-// @ts-check
 import { Command, Option } from 'clipanion';
-import { runScript } from '../utils/runScript.js';
-import { hasJestConfig } from '../preinstall/tool-versions.js';
+import { runScript } from '../utils/runScript.ts';
+import { hasJestConfig } from '../preinstall/tool-versions.ts';
 
 export class JestCommand extends Command {
-  /** @override */
-  static paths = [['jest']];
+  static override paths = [['jest']];
 
-  /** @override */
-  static usage = Command.Usage({
+  static override usage = Command.Usage({
     description: 'Tests the current package using jest',
     details: 'This command tests the current package.',
     examples: [['Test the current package', '$0 jest']],
diff --git a/scripts/src/tasks/lint.js b/scripts/src/tasks/lint.ts
similarity index 91%
rename from scripts/src/tasks/lint.js
rename to scripts/src/tasks/lint.ts
index ed41dc97596..fdcf9716a93 100644
--- a/scripts/src/tasks/lint.js
+++ b/scripts/src/tasks/lint.ts
@@ -1,5 +1,3 @@
-// @ts-check
-
 import fs from 'node:fs';
 import path from 'node:path';
 import { fileURLToPath } from 'node:url';
@@ -7,11 +5,9 @@ import { Command, Option } from 'clipanion';
 import { isFixMode } from '../utils/env.ts';
 
 export class LintCommand extends Command {
-  /** @override */
-  static paths = [['lint']];
+  static override paths = [['lint']];
 
-  /** @override */
-  static usage = Command.Usage({
+  static override usage = Command.Usage({
     description: 'Lints the current package',
     details: 'This command lints the current package using oxlint.',
     examples: [['Lint the current package', '$0 lint']],
diff --git a/scripts/src/tasks/lintPackage.ts b/scripts/src/tasks/lintPackage.ts
index 36880e06c07..2221277e82e 100644
--- a/scripts/src/tasks/lintPackage.ts
+++ b/scripts/src/tasks/lintPackage.ts
@@ -478,7 +478,7 @@ export class LintPackageCommand extends Command {
   }
 
   private getFluentScriptsText(command: string) {
-    return this.isScripts ? `node ./src/cli.mjs ${command}` : `fluentui-scripts ${command}`;
+    return this.isScripts ? `node ./src/cli.ts ${command}` : `fluentui-scripts ${command}`;
   }
 }
 
diff --git a/scripts/src/tasks/runAlignDeps.ts b/scripts/src/tasks/runAlignDeps.ts
index 624f29d816d..ab476e01c85 100644
--- a/scripts/src/tasks/runAlignDeps.ts
+++ b/scripts/src/tasks/runAlignDeps.ts
@@ -1,6 +1,6 @@
 import { scriptsDir } from '../utils/ispnpm.ts';
 import { spawn } from 'node:child_process';
-import { yarnVerb } from '../utils/runScript.js';
+import { yarnVerb } from '../utils/runScript.ts';
 import path from 'node:path';
 
 export async function runAlignDeps(targetDir: string, fixMode: boolean): Promise<number> {
diff --git a/scripts/src/utils/checkDependencies.js b/scripts/src/utils/checkDependencies.ts
similarity index 82%
rename from scripts/src/utils/checkDependencies.js
rename to scripts/src/utils/checkDependencies.ts
index e9593f70163..afd57daee1e 100644
--- a/scripts/src/utils/checkDependencies.js
+++ b/scripts/src/utils/checkDependencies.ts
@@ -1,5 +1,3 @@
-// @ts-check
-
 /**
  * Quick and dirty script to ensure we have got our nested peerDependencies correct
  *
@@ -11,7 +9,17 @@ import { readFileSync, writeFileSync } from 'node:fs';
 
 import { findGitRoot, getPackageInfos } from 'workspace-tools';
 
-export function checkDependencies() {
+type PackageJson = {
+  'rnx-kit'?: { kitType?: string };
+  peerDependencies?: Record<string, string>;
+  peerDependenciesMeta?: Record<string, { optional: boolean }>;
+};
+
+type PackageInfoWithJson = ReturnType<typeof getPackageInfos>[string] & {
+  pkgJson: PackageJson;
+};
+
+export function checkDependencies(): void {
   let requireRescan = true;
   let everWrote = false;
 
@@ -21,7 +29,7 @@ export function checkDependencies() {
   while (requireRescan) {
     requireRescan = false;
 
-    const infos = getPackageInfos(findGitRoot(process.cwd()));
+    const infos = getPackageInfos(findGitRoot(process.cwd())) as Record<string, PackageInfoWithJson>;
 
     // getPackageInfos unfortunately doesn't provide peerDependenciesMeta, so we need to parse the whole package.json
     for (const pkgName in infos) {
@@ -34,10 +42,8 @@ export function checkDependencies() {
 
       const deps = { ...infos[pkgName].dependencies, ...infos[pkgName].peerDependencies };
 
-      /** @type {{ name: string, version: string }[]} */
-      const missingPeerDeps = [];
-      /** @type {string[]} */
-      const missingPeerDepsMeta = [];
+      const missingPeerDeps: { name: string; version: string }[] = [];
+      const missingPeerDepsMeta: string[] = [];
 
       for (const dep in deps) {
         if (infos[dep]) {
@@ -69,7 +75,7 @@ export function checkDependencies() {
           infos[pkgName].pkgJson.peerDependencies = {};
         }
         for (const missingDep of missingPeerDeps) {
-          infos[pkgName].pkgJson.peerDependencies[missingDep.name] = missingDep.version;
+          infos[pkgName].pkgJson.peerDependencies![missingDep.name] = missingDep.version;
         }
         requireWriteFile = true;
       }
@@ -80,7 +86,7 @@ export function checkDependencies() {
         }
 
         for (const missingMeta of missingPeerDepsMeta) {
-          infos[pkgName].pkgJson.peerDependenciesMeta[missingMeta] = {
+          infos[pkgName].pkgJson.peerDependenciesMeta![missingMeta] = {
             optional: true,
           };
         }
diff --git a/scripts/src/utils/resolvePaths.js b/scripts/src/utils/resolvePaths.ts
similarity index 72%
rename from scripts/src/utils/resolvePaths.js
rename to scripts/src/utils/resolvePaths.ts
index a6f9f18a842..41c9fd7566c 100644
--- a/scripts/src/utils/resolvePaths.js
+++ b/scripts/src/utils/resolvePaths.ts
@@ -4,11 +4,9 @@ import path from 'node:path';
 
 /**
  * Find all node_modules directories up to the project root
- * @returns {string[]} - An array of paths to node_modules directories found in the project root.
  */
-export function nodeModulesToRoot() {
-  /** @type {string[]} */
-  const results = [];
+export function nodeModulesToRoot(): string[] {
+  const results: string[] = [];
   findUp.sync((directory) => {
     const nodeModulesPath = path.join(directory, 'node_modules');
     if (fs.existsSync(nodeModulesPath)) {
diff --git a/scripts/src/utils/runScript.js b/scripts/src/utils/runScript.ts
similarity index 71%
rename from scripts/src/utils/runScript.js
rename to scripts/src/utils/runScript.ts
index 49e5dae321e..50d60fdb907 100644
--- a/scripts/src/utils/runScript.js
+++ b/scripts/src/utils/runScript.ts
@@ -1,33 +1,23 @@
-// @ts-check
-
 import { spawn } from 'node:child_process';
 import { getProjectRoot } from './projectRoot.ts';
 import os from 'node:os';
 
 export const yarnVerb = os.platform() === 'win32' ? 'yarn.cmd' : 'yarn';
 
-/** @type {Record<string, string>} */
-const cmdToModule = {
+const cmdToModule: Record<string, string> = {
   tsc: 'typescript',
 };
 
 /**
  * Get the path to a bin entrypoint for a js package.
- * @param {string} command
- * @returns {string | undefined}
  */
-function getBinPath(command) {
+function getBinPath(command: string): string | undefined {
   const wdRoot = getProjectRoot(process.cwd());
   const cmdModule = cmdToModule[command] ?? command;
   return wdRoot.openModule(cmdModule).getBinPath(command);
 }
 
-/**
- * @param {string} command
- * @param {...string} args
- * @returns {Promise<number>}
- */
-export async function runScript(command, ...args) {
+export async function runScript(command: string, ...args: string[]): Promise<number> {
   const binPath = getBinPath(command);
   const verb = binPath ? process.execPath : yarnVerb;
   const spawnArgs = binPath ? [binPath, ...args] : ['exec', command, ...args];
@@ -43,12 +33,7 @@ export async function runScript(command, ...args) {
   });
 }
 
-/**
- * @param {string} command
- * @param {...string} args
- * @returns {Promise<number>}
- */
-export async function runYarn(command, ...args) {
+export async function runYarn(command: string, ...args: string[]): Promise<number> {
   const verb = yarnVerb;
   const spawnArgs = [command, ...args];
   return new Promise((resolve) => {
diff --git a/scripts/tsconfig.json b/scripts/tsconfig.json
index b9983f0655d..07998cf34bf 100644
--- a/scripts/tsconfig.json
+++ b/scripts/tsconfig.json
@@ -1,8 +1,6 @@
 {
   "extends": "@rnx-kit/tsconfig/tsconfig.node.json",
   "compilerOptions": {
-    "allowJs": true,
-    "checkJs": true,
     "noEmit": true,
     "allowSyntheticDefaultImports": true,
     "target": "es2022"
diff --git a/yarn.lock b/yarn.lock
index d58e8f824e7..404af1a744e 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -4878,7 +4878,7 @@ __metadata:
     workspace-tools: "npm:^0.26.3"
     zx: "npm:^8.2.4"
   bin:
-    fluentui-scripts: ./src/cli.mjs
+    fluentui-scripts: ./src/cli.ts
   languageName: unknown
   linkType: soft