diff --git a/.github/PR_VALIDATION_GUIDE.md b/.github/PR_VALIDATION_GUIDE.md
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+# PR Validation CI/CD Guide
+
+## What Was Implemented
+
+### 1. CI Workflow Changes (`.github/workflows/ci.yml`)
+
+Added a new `validate-pr` job that runs **only on pull requests** and validates:
+
+- ✅ **PR Title**: Must follow Conventional Commits format with minimum 10 characters
+- ✅ **PR Description**: Must contain at least 15 words
+- ✅ **Branch Name**: Must follow `feature/*`, `fix/*`, or `docs/*` pattern
+
+The `build` job now depends on `validate-pr`, so validation failures block the build.
+
+### 2. Documentation Updates (`CONTRIBUTING.md`)
+
+Added comprehensive sections covering:
+- Branch naming conventions with examples
+- PR title format requirements
+- PR description requirements with example
+
+---
+
+## Testing the Validation
+
+### ✅ Valid PR Example
+
+**Branch:** `feature/add-user-profile`
+
+**Title:** `feat: add user profile page with avatar upload`
+
+**Description:**
+```
+This PR implements a new user profile page where users can view and edit their information.
+
+Changes include:
+- New ProfilePage component with form validation
+- Avatar upload functionality using multipart/form-data
+- Integration with existing user API endpoints
+
+Tested manually with different user accounts. Closes #45
+```
+
+**Result:** ✅ All validations pass
+
+---
+
+### ❌ Invalid PR Examples
+
+#### Example 1: Bad Title
+**Branch:** `feature/profile-page`  
+**Title:** `update`  
+**Description:** Valid description with more than 15 words explaining the changes made...
+
+**Result:** ❌ Fails - Title doesn't follow convention
+
+---
+
+#### Example 2: Short Description
+**Branch:** `feature/profile-page`  
+**Title:** `feat: add user profile page`  
+**Description:** `Closes #45`
+
+**Result:** ❌ Fails - Description too short (only 2 words)
+
+---
+
+#### Example 3: Bad Branch Name
+**Branch:** `my-feature`  
+**Title:** `feat: add user profile page`  
+**Description:** Valid description with more than 15 words...
+
+**Result:** ❌ Fails - Branch name doesn't follow convention
+
+---
+
+## How to Test Locally
+
+You can test the validation logic locally before pushing:
+
+### Test PR Title
+```bash
+title="feat: add user authentication system"
+if echo "$title" | grep -qE '^(feat|fix|docs|style|refactor|perf|test|chore|ci|build|revert): .{10,}$'; then
+  echo "✅ Valid"
+else
+  echo "❌ Invalid"
+fi
+```
+
+### Test PR Description Word Count
+```bash
+description="This PR adds OAuth2 authentication support using Google as the provider."
+word_count=$(echo "$description" | wc -w)
+if [ "$word_count" -ge 15 ]; then
+  echo "✅ Valid ($word_count words)"
+else
+  echo "❌ Too short ($word_count words)"
+fi
+```
+
+### Test Branch Name
+```bash
+branch="feature/user-authentication"
+if echo "$branch" | grep -qE '^(feature|fix|docs)/[a-z0-9-]+$'; then
+  echo "✅ Valid"
+else
+  echo "❌ Invalid"
+fi
+```
+
+---
+
+## Validation Rules Summary
+
+| Check | Rule | Example |
+|-------|------|---------|
+| **Branch Name** | `feature/*`, `fix/*`, or `docs/*` | `feature/add-login` |
+| **PR Title** | `<type>: <description (10+ chars)>` | `feat: add OAuth login` |
+| **PR Description** | Minimum 15 words | See valid example above |
+
+---
+
+## CI Behavior
+
+- **On Push to main/develop**: Validation is skipped (only runs on PRs)
+- **On Pull Request**: Validation runs first, then build/lint/type-check
+- **If Validation Fails**: Build job is blocked, PR cannot be merged
+- **If Validation Passes**: Normal CI pipeline continues
+
+---
+
+## For Contributors
+
+Before opening a PR, ensure:
+
+1. ✅ Your branch follows the naming convention
+2. ✅ Your PR title is descriptive and follows the format
+3. ✅ Your PR description explains what, why, and how
+4. ✅ You've tested your changes locally
+
+This helps maintainers review faster and keeps the project history clean!
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 0db5929..8c10817 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -1,5 +1,71 @@
 # Contributing
 
+## Branch Naming Convention
+
+All feature branches must follow this naming pattern before opening a PR:
+
+- `feature/your-feature-name`
+- `fix/short-description`
+- `docs/what-you-documented`
+
+**Examples:**
+- ✅ `feature/user-authentication`
+- ✅ `fix/null-pointer-login`
+- ✅ `docs/update-api-reference`
+- ❌ `my-branch`
+- ❌ `update`
+
+**PRs submitted from branches that do not follow this convention will be rejected by CI.**
+
+---
+
+## Pull Request Title
+
+PR titles must follow the **Conventional Commits** format:
+
+```
+<type>: <short description (min 10 characters)>
+```
+
+**Allowed types:** `feat`, `fix`, `docs`, `style`, `refactor`, `perf`, `test`, `chore`, `ci`, `build`, `revert`
+
+**Examples:**
+- ✅ `feat: add OAuth2 login support`
+- ✅ `fix: resolve crash on empty cart checkout`
+- ✅ `docs: update installation steps for Windows`
+- ❌ `Closes #22`
+- ❌ `fix: x`
+- ❌ `updates`
+
+**The CI pipeline will automatically reject PRs that do not meet this format.**
+
+---
+
+## Pull Request Description
+
+Every PR must include a **meaningful description**. A bare issue reference like `Closes #22` is not acceptable as a full description.
+
+Your PR body should answer:
+- **What problem does this PR solve?**
+- **How did you solve it?**
+- **Any relevant context, screenshots, or testing notes?**
+
+**PRs with fewer than 15 words in the description will be rejected by CI.**
+
+**Example:**
+```markdown
+This PR adds OAuth2 authentication support using Google as the provider.
+
+Changes include:
+- New GoogleAuthController with callback handling
+- User creation/lookup on successful OAuth flow
+- JWT token generation after authentication
+
+Tested with multiple Google accounts. Closes #22
+```
+
+---
+
 ## Import Guidelines
 Rule: Always use relative imports.