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+# Ad Code Manager
+
+WordPress plugin for easy ad code management.
+
+## Project Knowledge
+
+| Property | Value |
+|----------|-------|
+| **Main file** | `ad-code-manager.php` |
+| **Text domain** | `ad-code-manager` |
+| **Namespace** | `Automattic\AdCodeManager` |
+| **Source directory** | `src/` |
+| **Version** | 0.8.0 |
+| **Requires PHP** | 7.4+ |
+| **Requires WP** | 6.4+ |
+
+### Directory Structure
+
+```
+ad-code-manager/
+├── src/                    # Main plugin classes (PSR-4)
+│   ├── Providers/          # Ad provider implementations (DoubleClick, Google AdSense)
+│   └── UI/                 # Admin UI components (autocomplete, contextual help)
+├── tests/
+│   ├── Unit/               # Unit tests (Brain Monkey)
+│   └── Integration/        # Integration tests (wp-env)
+├── languages/              # Translation files
+├── .github/workflows/      # CI: cs-lint, integration, unit, deploy
+└── .phpcs.xml.dist         # PHPCS configuration
+```
+
+### Key Classes
+
+- `Ad_Code_Manager` — Main plugin class
+- `Acm_Widget` — WordPress widget for ad display
+- `Acm_Wp_List_Table` — Admin list table for managing ad codes
+- `Acm_Provider` — Base class for ad providers
+- `Providers/` — Concrete providers: DoubleClick, Google AdSense variants
+
+### Dependencies
+
+- `automattic/vipwpcs` — WordPress VIP coding standards
+- `yoast/wp-test-utils` — Test utilities (Brain Monkey, WP integration)
+
+## Commands
+
+```bash
+composer cs                # Check code standards (PHPCS)
+composer cs-fix            # Auto-fix code standard violations
+composer lint              # PHP syntax lint
+composer test:unit         # Run unit tests
+composer test:integration  # Run integration tests (requires wp-env: npx wp-env start)
+composer test:integration-ms  # Run multisite integration tests
+composer coverage          # Run tests with HTML coverage report
+```
+
+## Conventions
+
+Follow the standards documented in `~/code/plugin-standards/` for full details. Key points:
+
+- **Commits**: Use the `/commit` skill. Favour explaining "why" over "what".
+- **PRs**: Use the `/pr` skill. Squash and merge by default.
+- **Branch naming**: `feature/description`, `fix/description` from `develop`.
+- **Testing**: Write integration tests for WordPress-dependent behaviour, unit tests for isolated logic. Use `Yoast\WPTestUtils\WPIntegration\TestCase` for integration, `Yoast\WPTestUtils\BrainMonkey\YoastTestCase` for unit. Test files named `*Test.php`, one logical concept per test, Arrange-Act-Assert pattern.
+- **Code style**: WordPress coding standards via PHPCS. Tabs for indentation. PHPDoc on all public methods.
+- **i18n**: All user-facing strings must use the `ad-code-manager` text domain.
+
+## Architectural Decisions
+
+- **Provider pattern**: Ad networks are abstracted behind the `Acm_Provider` base class. New ad networks should be added as new provider classes in `src/Providers/`, not by modifying the core plugin.
+- **PSR-4 autoloading**: Classes in `src/` use PSR-4 under the `Automattic\AdCodeManager` namespace.
+- **WordPress.org deployment**: Has a deploy workflow for WordPress.org SVN. Do not manually modify SVN assets.
+
+## Common Pitfalls
+
+- Do not edit WordPress core files or bundled dependencies in `vendor/`.
+- Do not add ad provider logic directly to the main plugin class — create a new provider in `src/Providers/`.
+- Run `composer cs` before committing. CI will reject code standard violations.
+- Integration tests require `npx wp-env start` running first. If tests fail with connection errors, check that wp-env is up.
+- The widget class extends `WP_Widget` directly — do not refactor this to a block without explicit agreement, as it would be a breaking change for existing users.