diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..1ed453a
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,10 @@
+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+
+[*.{js,json,yml}]
+charset = utf-8
+indent_style = space
+indent_size = 2
diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..af3ad12
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,4 @@
+/.yarn/**            linguist-vendored
+/.yarn/releases/*    binary
+/.yarn/plugins/**/*  binary
+/.pnp.*              binary linguist-generated
diff --git a/.github/workflows/pull_request_code_quality.yml b/.github/workflows/pull_request_code_quality.yml
index 461742b..5402d03 100644
--- a/.github/workflows/pull_request_code_quality.yml
+++ b/.github/workflows/pull_request_code_quality.yml
@@ -1,4 +1,4 @@
-name: Code quality
+name: Code Quality
 
 on:
   push:
@@ -10,9 +10,26 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
+
+      - name: Setup Node.js 20.x
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20.x
+          registry-url: "https://registry.npmjs.org"
+
+      - name: Enable Corepack
+        run: corepack enable
+
+      - name: Install yarn
+        run: yarn install
+
       - name: Setup Biome
         uses: biomejs/setup-biome@v2
         with:
           version: latest
+
       - name: Run Biome
         run: biome ci .
+
+      - name: Run TypeScript Check
+        run: npx tsc --noEmit
diff --git a/.gitignore b/.gitignore
index c6bba59..76e449e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -128,3 +128,5 @@ dist
 .yarn/build-state.yml
 .yarn/install-state.gz
 .pnp.*
+
+.dump
diff --git a/src/index.ts b/src/index.ts
new file mode 100644
index 0000000..e29e78d
--- /dev/null
+++ b/src/index.ts
@@ -0,0 +1,3 @@
+export const add = (a: number, b: number) => {
+  return a + b
+}