diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index b3b8d15..dad74b3 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -21,14 +21,30 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: "22"
+          registry-url: "https://registry.npmjs.org"
 
       - name: Install dependencies
         run: npm ci
 
       - name: Create Release Pull Request or Publish
+        id: changesets
         uses: changesets/action@v1
         with:
           publish: npm run release
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          NPM_TOKEN: ${{ secrets.NPM_TOKEN }}
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
+
+      - name: Set up Node.js for GitHub Packages publishing
+        if: steps.changesets.outputs.published == 'true'
+        uses: actions/setup-node@v4
+        with:
+          node-version: "22"
+          registry-url: "https://npm.pkg.github.com"
+          scope: "@aokiapp"
+
+      - name: Publish to GitHub Packages
+        if: steps.changesets.outputs.published == 'true'
+        run: npm run build && npm publish
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
diff --git a/README.md b/README.md
index 58447bb..5b8eec7 100644
--- a/README.md
+++ b/README.md
@@ -13,10 +13,35 @@ Tag-Length-Value (TLV) parser and builder library with schema support. Provides
 
 ## Installation
 
+### From npm
+
 ```bash
 npm install @aokiapp/tlv
 ```
 
+### From GitHub Packages
+
+**Note**: GitHub Packages requires authentication even for public packages.
+
+First, authenticate with GitHub:
+
+```bash
+npm login --registry=https://npm.pkg.github.com
+```
+
+Then install:
+
+```bash
+npm install @aokiapp/tlv --registry=https://npm.pkg.github.com
+```
+
+Or configure your `.npmrc`:
+
+```
+@aokiapp:registry=https://npm.pkg.github.com
+//npm.pkg.github.com/:_authToken=YOUR_GITHUB_TOKEN
+```
+
 ## Quick Start
 
 ### Basic TLV Parsing
@@ -527,12 +552,19 @@ npm run format        # Prettier
 
 ### Release
 
+This library is automatically published to both npm and GitHub Packages via GitHub Actions.
+
 ```bash
 npm run changelog     # Create changeset
 npm run version       # Update version
-npm run publish       # Publish to npm
+npm run publish       # Publish manually (for testing, otherwise use GitHub Actions)
 ```
 
+When changes are pushed to the `main` branch with a changeset, the GitHub Actions workflow will:
+
+1. Create a release PR or publish to npm
+2. Automatically publish to GitHub Packages if npm publish succeeds
+
 ## Project Structure
 
 ```
diff --git a/vitest.config.js b/vitest.config.js
index 038978e..edc0479 100644
--- a/vitest.config.js
+++ b/vitest.config.js
@@ -29,12 +29,7 @@ export default defineConfig({
       provider: "istanbul",
       reporter: ["text", "text-summary"],
       include: ["src/**/*.ts"],
-      exclude: [
-        "tests/**",
-        "examples/**",
-        ".changeset/**",
-        "**/*.d.ts",
-      ],
+      exclude: ["tests/**", "examples/**", ".changeset/**", "**/*.d.ts"],
     },
   },
 });