feat: Add dashboard extension hook for third-party plugins (v0.4.6)

Add wp_prometheus_register_dashboards action hook allowing third-party
plugins to register their own Grafana dashboard templates.

- DashboardProvider: registration system with file/JSON support
- Security: path traversal protection, JSON validation
- Admin UI: "Extension" badge and plugin attribution
- Isolated mode support for dashboard registration hook

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -5,6 +5,63 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.4.6] - 2026-02-03
+
+### Added
+
+- Dashboard extension hook `wp_prometheus_register_dashboards` for third-party plugins
+- Third-party plugins can now register their own Grafana dashboard templates
+- Support for file-based and inline JSON dashboard registration
+- "Extension" badge for third-party dashboards in admin UI
+- Plugin attribution display for third-party dashboards
+- Security: Path traversal protection for registered dashboard files
+- Isolated mode support for dashboard registration hook
+
+### Changed
+
+- DashboardProvider now supports both built-in and third-party registered dashboards
+- Dashboard cards show source (built-in vs extension) with visual distinction
+
+## [0.4.5] - 2026-02-02
+
+### Fixed
+
+- Settings now persist correctly across Metrics sub-tabs
+- Auth token no longer gets cleared when saving from Selection sub-tab
+- Enabled metrics no longer get cleared when saving from Endpoint sub-tab
+- Isolated mode setting no longer gets cleared when saving from other sub-tabs
+
+### Changed
+
+- Split Metrics settings into separate WordPress option groups per sub-tab
+- Each sub-tab now uses its own settings group to prevent cross-tab overwrites
+
+## [0.4.4] - 2026-02-02
+
+### Added
+
+- Safe mode for metrics collection (default):
+  - Removes problematic content filters early
+  - Allows third-party plugins to register `wp_prometheus_collect_metrics` hooks
+  - Wraps custom hooks in output buffering and try-catch for protection
+- Isolated mode option for maximum compatibility:
+  - Outputs metrics before other plugins fully load
+  - Use only if Safe mode causes issues
+- `WP_PROMETHEUS_ISOLATED_MODE` environment variable support
+- Mode comparison table in admin settings
+
+### Changed
+
+- Replaced "early mode" with two clear modes: Safe (default) and Isolated
+- Custom metrics hooks now fire by default with protection against recursion
+- Filter removal now also includes `the_content_feed` and `comment_text`
+- Updated admin UI with clearer explanations of each mode
+
+### Fixed
+
+- Third-party plugins can now add custom metrics without memory issues
+- Twig-based plugins (like wp-fedistream) no longer cause recursion
+
 ## [0.4.3] - 2026-02-02
 
 ### Added

CLAUDE.md

@@ -23,6 +23,7 @@ This plugin provides a Prometheus `/metrics` endpoint and an extensible way to a
 - Grafana dashboard templates for easy visualization
 - Dedicated plugin settings under 'Settings/Metrics' menu
 - Extensible by other plugins using `wp_prometheus_collect_metrics` action hook
+- Dashboard extension hook `wp_prometheus_register_dashboards` for third-party Grafana dashboards
 - License management integration
 
 ### Key Fact: 100% AI-Generated
@@ -33,7 +34,7 @@ This project is proudly **"vibe-coded"** using Claude.AI - the entire codebase w
 
 **Note for AI Assistants:** Clean this section after the specific features are done or new releases are made. Effective changes are tracked in `CHANGELOG.md`. Do not add completed versions here - document them in the Session History section at the end of this file.
 
-*No planned features at this time.*
+*No pending roadmap items.*
 
 ## Technical Stack
 
@@ -291,6 +292,76 @@ add_action( 'wp_prometheus_collect_metrics', function( $collector ) {
 
 ## Session History
 
+### 2026-02-03 - Dashboard Extension Hook (v0.4.6)
+
+- Added `wp_prometheus_register_dashboards` action hook for third-party plugins
+- Third-party plugins can now register their own Grafana dashboard templates
+- Implementation in `DashboardProvider.php`:
+  - `register_dashboard(slug, args)` method for registrations
+  - Supports file-based dashboards (absolute path to JSON) or inline JSON content
+  - Security: Path traversal protection (files must be under `WP_CONTENT_DIR`)
+  - `fire_registration_hook()` with output buffering and exception handling
+  - Respects isolated mode setting (skips third-party hooks when enabled)
+  - `is_third_party()` and `get_plugin_name()` helper methods
+- Updated admin UI in Settings.php:
+  - "Extension" badge displayed on third-party dashboard cards
+  - Plugin attribution shown below third-party dashboards
+  - Visual distinction with blue border for third-party cards
+- **Key Learning**: Extension hook design pattern
+  - Fire hook lazily on first `get_available()` call, not in constructor
+  - Use `$hook_fired` flag to prevent double-firing
+  - Wrap hook execution in try-catch to isolate failures
+  - Validate registrations thoroughly before accepting them
+- **Key Learning**: Security for file-based registrations
+  - Require absolute paths (`path_is_absolute()`)
+  - Validate files exist and are readable
+  - Use `realpath()` to resolve symlinks and prevent traversal
+  - Restrict to `WP_CONTENT_DIR` (not just plugin directories)
+
+### 2026-02-02 - Settings Persistence Fix (v0.4.5)
+
+- Fixed critical bug where settings would get cleared when saving from different Metrics sub-tabs
+- Root cause: All settings were registered under single `wp_prometheus_metrics_settings` group
+  - When saving from "Endpoint" sub-tab, only auth token was in POST data
+  - WordPress Settings API would process all registered settings in the group
+  - Missing fields (enabled_metrics, isolated_mode) would receive null/undefined
+  - Sanitize callbacks returned empty values, overwriting existing settings
+- Solution: Split into separate settings groups per sub-tab:
+  - `wp_prometheus_endpoint_settings` for auth token
+  - `wp_prometheus_selection_settings` for enabled metrics
+  - `wp_prometheus_advanced_settings` for isolated mode
+- **Key Learning**: WordPress Settings API and multiple forms
+  - When multiple forms share the same settings group, saving one form can clear settings from another
+  - Each form with `settings_fields()` should use a unique option group
+  - `register_setting()` group name must match `settings_fields()` group name
+
+### 2026-02-02 - Safe Mode & Custom Hooks Fix (v0.4.4)
+
+- Redesigned metrics collection to support both plugin compatibility AND custom metrics:
+  - **Safe Mode (default)**: Removes content filters early but lets WordPress load normally
+  - **Isolated Mode**: Legacy early mode that skips custom hooks entirely
+- Implementation:
+  - `WP_PROMETHEUS_METRICS_REQUEST` constant set for any /metrics request
+  - Content filters removed via `plugins_loaded` hook at priority 0
+  - Collector fires `wp_prometheus_collect_metrics` with protection (output buffering, try-catch)
+  - `wp_prometheus_isolated_mode` option replaces `wp_prometheus_disable_early_mode`
+  - `WP_PROMETHEUS_ISOLATED_MODE` environment variable for containerized deployments
+- Collector now wraps custom hooks in `fire_custom_metrics_hook()` method:
+  - Removes content filters again before hook (in case re-added)
+  - Uses output buffering to discard accidental output
+  - Catches exceptions to prevent breaking metrics output
+  - Logs errors when WP_DEBUG is enabled
+- Updated admin UI with mode comparison table
+- **Key Learning**: Hybrid approach for plugin compatibility
+  - The memory issue comes from content filter recursion, not just plugin loading
+  - Removing filters early (before any plugin can trigger them) prevents recursion
+  - Plugins still load and can register their `wp_prometheus_collect_metrics` hooks
+  - Hooks fire after filters are removed, in a protected context
+- **Key Learning**: Defense in depth for custom hooks
+  - Remove filters again right before hook fires (plugins may re-add them)
+  - Output buffering catches any echo/print from misbehaving plugins
+  - Try-catch prevents one broken plugin from breaking metrics entirely
+
 ### 2026-02-02 - Sub-tabs & Early Mode Fix (v0.4.3)
 
 - Split Metrics tab into sub-tabs for better organization:
@@ -304,6 +375,10 @@ add_action( 'wp_prometheus_collect_metrics', function( $collector ) {
   - Settings must be inside `<form action="options.php">` with `settings_fields()` call
   - Each sub-tab needs its own form wrapper for proper saving
   - Sub-tabs use URL query parameter (`subtab`) within the main tab
+- **Key Learning**: WordPress plugin versioning requires TWO updates
+  - Plugin header comment `Version: x.x.x` (line ~6) - used by WordPress admin
+  - PHP constant `WP_PROMETHEUS_VERSION` (line ~133) - used internally
+  - CI/CD checks both must match the git tag, causing release failures if mismatched
 
 ### 2026-02-02 - Early Mode Toggle (v0.4.2)
 

README.md

@@ -6,7 +6,13 @@ A WordPress plugin that provides a Prometheus-compatible `/metrics` endpoint wit
 
 - Prometheus-compatible authenticated `/metrics` endpoint
 - Default WordPress metrics (users, posts, comments, plugins)
+- Runtime metrics (HTTP requests, database queries)
+- Cron job and transient cache metrics
+- WooCommerce integration (products, orders, revenue)
+- Custom metric builder with admin UI
+- Grafana dashboard templates with download
 - Extensible by other plugins using hooks
+- Dashboard extension hook for third-party Grafana dashboards
 - Settings page under Settings > Metrics
 - Bearer token authentication
 - License management integration
@@ -154,6 +160,51 @@ $histogram = $collector->register_histogram( $name, $help, $labels, $buckets );
 $histogram->observe( $value, $labelValues );
 ```
 
+## Extending with Custom Dashboards (v0.4.6+)
+
+Add your own Grafana dashboard templates using the `wp_prometheus_register_dashboards` action:
+
+```php
+add_action( 'wp_prometheus_register_dashboards', function( $provider ) {
+    // File-based dashboard
+    $provider->register_dashboard( 'my-plugin-dashboard', array(
+        'title'       => __( 'My Plugin Metrics', 'my-plugin' ),
+        'description' => __( 'Dashboard for my custom metrics', 'my-plugin' ),
+        'icon'        => 'dashicons-chart-bar',
+        'file'        => MY_PLUGIN_PATH . 'assets/dashboards/my-dashboard.json',
+        'plugin'      => 'My Plugin Name',
+    ) );
+
+    // OR inline JSON dashboard
+    $provider->register_dashboard( 'dynamic-dashboard', array(
+        'title'       => __( 'Dynamic Dashboard', 'my-plugin' ),
+        'description' => __( 'Dynamically generated dashboard', 'my-plugin' ),
+        'icon'        => 'dashicons-admin-generic',
+        'json'        => json_encode( $dashboard_array ),
+        'plugin'      => 'My Plugin Name',
+    ) );
+} );
+```
+
+### Registration Parameters
+
+| Parameter | Required | Description |
+| --------- | -------- | ----------- |
+| `title` | Yes | Dashboard title displayed in admin |
+| `description` | No | Description shown below the title |
+| `icon` | No | Dashicon class (default: `dashicons-chart-line`) |
+| `file` | Yes* | Absolute path to JSON file |
+| `json` | Yes* | Inline JSON content |
+| `plugin` | No | Plugin name for attribution |
+
+*Either `file` or `json` is required, but not both.
+
+### Security Notes
+
+- File paths must be absolute and within `wp-content/`
+- Inline JSON is validated during registration
+- Third-party dashboards are marked with an "Extension" badge in the admin UI
+
 ## Development
 
 ### Build for Release

assets/css/admin.css

@@ -16,7 +16,7 @@
 
 .wp-prometheus-subtab-nav {
     display: flex;
-    margin: 0 0 20px 0;
+    margin: 0;
     padding: 0;
     list-style: none;
     border-bottom: 1px solid #c3c4c7;
@@ -216,6 +216,32 @@
     font-size: 13px;
 }
 
+/* Third-party dashboard card styling */
+.wp-prometheus-dashboard-card.third-party {
+    position: relative;
+    border-color: #2271b1;
+}
+
+.wp-prometheus-dashboard-card .dashboard-badge {
+    position: absolute;
+    top: -8px;
+    right: -8px;
+    background: #2271b1;
+    color: #fff;
+    font-size: 10px;
+    font-weight: 600;
+    padding: 3px 8px;
+    border-radius: 10px;
+    text-transform: uppercase;
+    letter-spacing: 0.5px;
+}
+
+.wp-prometheus-dashboard-card .dashboard-plugin {
+    color: #646970;
+    margin: -5px 0 15px 0;
+    font-style: italic;
+}
+
 /* Import options panel */
 #import-options {
     border-radius: 4px;

languages/wp-prometheus-de_CH.po

@@ -947,3 +947,49 @@ msgstr "Laufzeit-Metriken erfassen HTTP-Anfragen und Datenbank-Abfragen ueber me
 #: src/Admin/Settings.php
 msgid "Reset Data"
 msgstr "Daten zuruecksetzen"
+
+#: src/Admin/Settings.php
+msgid "Extension"
+msgstr "Erweiterung"
+
+#. translators: %s: Plugin name
+#: src/Admin/Settings.php
+msgid "Provided by: %s"
+msgstr "Bereitgestellt von: %s"
+
+#: src/Admin/Settings.php
+msgid "No dashboards available."
+msgstr "Keine Dashboards verfuegbar."
+
+#: src/Admin/Settings.php
+msgid "Pre-built dashboards for visualizing your WordPress metrics in Grafana."
+msgstr "Vorgefertigte Dashboards zur Visualisierung Ihrer WordPress-Metriken in Grafana."
+
+#: src/Admin/Settings.php
+msgid "Installation Instructions"
+msgstr "Installationsanleitung"
+
+#: src/Admin/Settings.php
+msgid "Download the JSON file for your desired dashboard."
+msgstr "Laden Sie die JSON-Datei fuer das gewuenschte Dashboard herunter."
+
+#: src/Admin/Settings.php
+msgid "In Grafana, go to Dashboards → Import."
+msgstr "Gehen Sie in Grafana zu Dashboards → Import."
+
+#: src/Admin/Settings.php
+msgid "Upload the JSON file or paste its contents."
+msgstr "Laden Sie die JSON-Datei hoch oder fuegen Sie den Inhalt ein."
+
+#: src/Admin/Settings.php
+msgid "Select your Prometheus data source when prompted."
+msgstr "Waehlen Sie Ihre Prometheus-Datenquelle, wenn Sie dazu aufgefordert werden."
+
+#: src/Admin/Settings.php
+msgid "Click Import to create the dashboard."
+msgstr "Klicken Sie auf Import, um das Dashboard zu erstellen."
+
+#. translators: %s: Metrics URL
+#: src/Admin/Settings.php
+msgid "Make sure your Prometheus instance is configured to scrape %s with the correct authentication token."
+msgstr "Stellen Sie sicher, dass Ihre Prometheus-Instanz so konfiguriert ist, dass sie %s mit dem richtigen Authentifizierungs-Token abruft."

languages/wp-prometheus.pot

@@ -944,3 +944,49 @@ msgstr ""
 #: src/Admin/Settings.php
 msgid "Reset Data"
 msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Extension"
+msgstr ""
+
+#. translators: %s: Plugin name
+#: src/Admin/Settings.php
+msgid "Provided by: %s"
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "No dashboards available."
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Pre-built dashboards for visualizing your WordPress metrics in Grafana."
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Installation Instructions"
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Download the JSON file for your desired dashboard."
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "In Grafana, go to Dashboards → Import."
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Upload the JSON file or paste its contents."
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Select your Prometheus data source when prompted."
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Click Import to create the dashboard."
+msgstr ""
+
+#. translators: %s: Metrics URL
+#: src/Admin/Settings.php
+msgid "Make sure your Prometheus instance is configured to scrape %s with the correct authentication token."
+msgstr ""

src/Admin/DashboardProvider.php

@@ -16,22 +16,37 @@ if ( ! defined( 'ABSPATH' ) ) {
  * DashboardProvider class.
  *
  * Provides Grafana dashboard templates for download.
+ * Supports both built-in dashboards and third-party registrations.
  */
 class DashboardProvider {
 
 	/**
-	 * Dashboard directory path.
+	 * Dashboard directory path for built-in dashboards.
 	 *
 	 * @var string
 	 */
 	private string $dashboard_dir;
 
 	/**
-	 * Available dashboard definitions.
+	 * Built-in dashboard definitions.
 	 *
 	 * @var array
 	 */
-	private array $dashboards = array();
+	private array $builtin_dashboards = array();
+
+	/**
+	 * Third-party registered dashboard definitions.
+	 *
+	 * @var array
+	 */
+	private array $registered_dashboards = array();
+
+	/**
+	 * Whether the registration hook has been fired.
+	 *
+	 * @var bool
+	 */
+	private bool $hook_fired = false;
 
 	/**
 	 * Constructor.
@@ -39,43 +54,241 @@ class DashboardProvider {
 	public function __construct() {
 		$this->dashboard_dir = WP_PROMETHEUS_PATH . 'assets/dashboards/';
 
-		$this->dashboards = array(
+		$this->builtin_dashboards = array(
 			'wordpress-overview'    => array(
 				'title'       => __( 'WordPress Overview', 'wp-prometheus' ),
 				'description' => __( 'General WordPress metrics including users, posts, comments, and plugins.', 'wp-prometheus' ),
 				'file'        => 'wordpress-overview.json',
 				'icon'        => 'dashicons-wordpress',
+				'source'      => 'builtin',
 			),
 			'wordpress-runtime'     => array(
 				'title'       => __( 'Runtime Performance', 'wp-prometheus' ),
 				'description' => __( 'HTTP request metrics, database query performance, and response times.', 'wp-prometheus' ),
 				'file'        => 'wordpress-runtime.json',
 				'icon'        => 'dashicons-performance',
+				'source'      => 'builtin',
 			),
 			'wordpress-woocommerce' => array(
 				'title'       => __( 'WooCommerce Store', 'wp-prometheus' ),
 				'description' => __( 'WooCommerce metrics including products, orders, revenue, and customers.', 'wp-prometheus' ),
 				'file'        => 'wordpress-woocommerce.json',
 				'icon'        => 'dashicons-cart',
+				'source'      => 'builtin',
 			),
 		);
 	}
 
+	/**
+	 * Register a third-party dashboard.
+	 *
+	 * @param string $slug Dashboard slug (unique identifier).
+	 * @param array  $args Dashboard configuration {
+	 *     @type string $title       Dashboard title (required).
+	 *     @type string $description Dashboard description.
+	 *     @type string $icon        Dashicon class (e.g., 'dashicons-chart-bar').
+	 *     @type string $file        Absolute path to JSON file (mutually exclusive with 'json').
+	 *     @type string $json        Inline JSON content (mutually exclusive with 'file').
+	 *     @type string $plugin      Plugin name for attribution.
+	 * }
+	 * @return bool True if registered successfully, false otherwise.
+	 */
+	public function register_dashboard( string $slug, array $args ): bool {
+		// Sanitize slug - must be valid identifier.
+		$slug = sanitize_key( $slug );
+
+		if ( empty( $slug ) ) {
+			if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+				// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+				error_log( 'WP Prometheus: Dashboard registration failed - invalid slug' );
+			}
+			return false;
+		}
+
+		// Check for duplicate slugs (built-in takes precedence).
+		if ( isset( $this->builtin_dashboards[ $slug ] ) ) {
+			if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+				// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+				error_log( "WP Prometheus: Dashboard slug '$slug' conflicts with built-in dashboard" );
+			}
+			return false;
+		}
+
+		// Check for duplicate slugs in already registered dashboards.
+		if ( isset( $this->registered_dashboards[ $slug ] ) ) {
+			if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+				// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+				error_log( "WP Prometheus: Dashboard slug '$slug' already registered" );
+			}
+			return false;
+		}
+
+		// Validate required fields.
+		if ( empty( $args['title'] ) ) {
+			if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+				// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+				error_log( "WP Prometheus: Dashboard '$slug' missing required 'title'" );
+			}
+			return false;
+		}
+
+		// Must have either 'file' or 'json', not both.
+		$has_file = ! empty( $args['file'] );
+		$has_json = ! empty( $args['json'] );
+
+		if ( ! $has_file && ! $has_json ) {
+			if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+				// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+				error_log( "WP Prometheus: Dashboard '$slug' must have 'file' or 'json'" );
+			}
+			return false;
+		}
+
+		if ( $has_file && $has_json ) {
+			if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+				// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+				error_log( "WP Prometheus: Dashboard '$slug' cannot have both 'file' and 'json'" );
+			}
+			return false;
+		}
+
+		// Validate file path if provided.
+		if ( $has_file ) {
+			$file_path = $args['file'];
+
+			// Must be absolute path.
+			if ( ! path_is_absolute( $file_path ) ) {
+				if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+					// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+					error_log( "WP Prometheus: Dashboard '$slug' file path must be absolute" );
+				}
+				return false;
+			}
+
+			// File must exist and be readable.
+			if ( ! file_exists( $file_path ) || ! is_readable( $file_path ) ) {
+				if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+					// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+					error_log( "WP Prometheus: Dashboard '$slug' file not found: $file_path" );
+				}
+				return false;
+			}
+
+			// Security: Prevent path traversal - file must be under wp-content.
+			$real_path      = realpath( $file_path );
+			$wp_content_dir = realpath( WP_CONTENT_DIR );
+
+			if ( false === $real_path || false === $wp_content_dir ||
+				strpos( $real_path, $wp_content_dir ) !== 0 ) {
+				if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+					// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+					error_log( "WP Prometheus: Dashboard '$slug' file outside wp-content" );
+				}
+				return false;
+			}
+		}
+
+		// Validate JSON if provided inline.
+		if ( $has_json ) {
+			$decoded = json_decode( $args['json'], true );
+			if ( null === $decoded && json_last_error() !== JSON_ERROR_NONE ) {
+				if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+					// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+					error_log( "WP Prometheus: Dashboard '$slug' has invalid JSON" );
+				}
+				return false;
+			}
+		}
+
+		// Build dashboard entry.
+		$this->registered_dashboards[ $slug ] = array(
+			'title'       => sanitize_text_field( $args['title'] ),
+			'description' => sanitize_text_field( $args['description'] ?? '' ),
+			'icon'        => sanitize_html_class( $args['icon'] ?? 'dashicons-chart-line' ),
+			'file'        => $has_file ? $file_path : null,
+			'json'        => $has_json ? $args['json'] : null,
+			'plugin'      => sanitize_text_field( $args['plugin'] ?? '' ),
+			'source'      => 'third-party',
+		);
+
+		return true;
+	}
+
+	/**
+	 * Fire the dashboard registration hook with protection.
+	 *
+	 * @return void
+	 */
+	private function fire_registration_hook(): void {
+		if ( $this->hook_fired ) {
+			return;
+		}
+
+		$this->hook_fired = true;
+
+		// Check for isolated mode - skip third-party hooks.
+		$isolated_mode = defined( 'WP_PROMETHEUS_ISOLATED_MODE' ) && WP_PROMETHEUS_ISOLATED_MODE;
+
+		// Also check option for admin-side isolated mode.
+		if ( ! $isolated_mode ) {
+			$isolated_mode = (bool) get_option( 'wp_prometheus_isolated_mode', false );
+		}
+
+		if ( $isolated_mode ) {
+			return;
+		}
+
+		// Use output buffering to capture any accidental output.
+		ob_start();
+
+		try {
+			/**
+			 * Fires to allow third-party plugins to register dashboards.
+			 *
+			 * @since 0.4.6
+			 *
+			 * @param DashboardProvider $provider The dashboard provider instance.
+			 */
+			do_action( 'wp_prometheus_register_dashboards', $this );
+		} catch ( \Throwable $e ) {
+			if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+				// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+				error_log( 'WP Prometheus: Error in dashboard registration hook: ' . $e->getMessage() );
+			}
+		}
+
+		// Discard any output from plugins.
+		ob_end_clean();
+	}
+
 	/**
 	 * Get list of available dashboards.
 	 *
 	 * @return array
 	 */
 	public function get_available(): array {
+		// Fire registration hook first (only once).
+		$this->fire_registration_hook();
+
 		$available = array();
 
-		foreach ( $this->dashboards as $slug => $dashboard ) {
+		// Add built-in dashboards (check file exists).
+		foreach ( $this->builtin_dashboards as $slug => $dashboard ) {
 			$file_path = $this->dashboard_dir . $dashboard['file'];
 			if ( file_exists( $file_path ) ) {
 				$available[ $slug ] = $dashboard;
 			}
 		}
 
+		// Add registered third-party dashboards.
+		foreach ( $this->registered_dashboards as $slug => $dashboard ) {
+			// Already validated during registration, but double-check.
+			if ( ! empty( $dashboard['json'] ) ||
+				( ! empty( $dashboard['file'] ) && file_exists( $dashboard['file'] ) ) ) {
+				$available[ $slug ] = $dashboard;
+			}
+		}
+
 		return $available;
 	}
 
@@ -86,35 +299,70 @@ class DashboardProvider {
 	 * @return string|null JSON content or null if not found.
 	 */
 	public function get_dashboard( string $slug ): ?string {
-		// Validate slug to prevent directory traversal.
+		// Fire registration hook first.
+		$this->fire_registration_hook();
+
+		// Validate slug.
 		$slug = sanitize_file_name( $slug );
 
-		if ( ! isset( $this->dashboards[ $slug ] ) ) {
+		// Check built-in dashboards first.
-			return null;
+		if ( isset( $this->builtin_dashboards[ $slug ] ) ) {
+			$dashboard = $this->builtin_dashboards[ $slug ];
+			$file_path = $this->dashboard_dir . $dashboard['file'];
+
+			// Security: Ensure file is within dashboard directory.
+			$real_path = realpath( $file_path );
+			$real_dir  = realpath( $this->dashboard_dir );
+
+			if ( false === $real_path || false === $real_dir ||
+				strpos( $real_path, $real_dir ) !== 0 ) {
+				return null;
+			}
+
+			if ( ! file_exists( $file_path ) || ! is_readable( $file_path ) ) {
+				return null;
+			}
+
+			// phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents
+			$content = file_get_contents( $file_path );
+
+			return false === $content ? null : $content;
 		}
 
-		$file_path = $this->dashboard_dir . $this->dashboards[ $slug ]['file'];
+		// Check registered dashboards.
+		if ( isset( $this->registered_dashboards[ $slug ] ) ) {
+			$dashboard = $this->registered_dashboards[ $slug ];
 
-		// Security: Ensure file is within dashboard directory.
+			// Inline JSON.
-		$real_path = realpath( $file_path );
+			if ( ! empty( $dashboard['json'] ) ) {
-		$real_dir  = realpath( $this->dashboard_dir );
+				return $dashboard['json'];
+			}
 
-		if ( false === $real_path || false === $real_dir || strpos( $real_path, $real_dir ) !== 0 ) {
+			// File-based.
-			return null;
+			if ( ! empty( $dashboard['file'] ) ) {
+				$file_path = $dashboard['file'];
+
+				// Security: Re-verify file is under wp-content.
+				$real_path      = realpath( $file_path );
+				$wp_content_dir = realpath( WP_CONTENT_DIR );
+
+				if ( false === $real_path || false === $wp_content_dir ||
+					strpos( $real_path, $wp_content_dir ) !== 0 ) {
+					return null;
+				}
+
+				if ( ! file_exists( $file_path ) || ! is_readable( $file_path ) ) {
+					return null;
+				}
+
+				// phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents
+				$content = file_get_contents( $file_path );
+
+				return false === $content ? null : $content;
+			}
 		}
 
-		if ( ! file_exists( $file_path ) || ! is_readable( $file_path ) ) {
+		return null;
-			return null;
-		}
-
-		// phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents
-		$content = file_get_contents( $file_path );
-
-		if ( false === $content ) {
-			return null;
-		}
-
-		return $content;
 	}
 
 	/**
@@ -124,13 +372,20 @@ class DashboardProvider {
 	 * @return array|null Dashboard metadata or null if not found.
 	 */
 	public function get_metadata( string $slug ): ?array {
+		// Fire registration hook first.
+		$this->fire_registration_hook();
+
 		$slug = sanitize_file_name( $slug );
 
-		if ( ! isset( $this->dashboards[ $slug ] ) ) {
+		if ( isset( $this->builtin_dashboards[ $slug ] ) ) {
-			return null;
+			return $this->builtin_dashboards[ $slug ];
 		}
 
-		return $this->dashboards[ $slug ];
+		if ( isset( $this->registered_dashboards[ $slug ] ) ) {
+			return $this->registered_dashboards[ $slug ];
+		}
+
+		return null;
 	}
 
 	/**
@@ -140,12 +395,61 @@ class DashboardProvider {
 	 * @return string|null Filename or null if not found.
 	 */
 	public function get_filename( string $slug ): ?string {
+		// Fire registration hook first.
+		$this->fire_registration_hook();
+
 		$slug = sanitize_file_name( $slug );
 
-		if ( ! isset( $this->dashboards[ $slug ] ) ) {
+		// Built-in dashboards have predefined filenames.
-			return null;
+		if ( isset( $this->builtin_dashboards[ $slug ] ) ) {
+			return $this->builtin_dashboards[ $slug ]['file'];
 		}
 
-		return $this->dashboards[ $slug ]['file'];
+		// Registered dashboards - use file basename or generate from slug.
+		if ( isset( $this->registered_dashboards[ $slug ] ) ) {
+			$dashboard = $this->registered_dashboards[ $slug ];
+
+			if ( ! empty( $dashboard['file'] ) ) {
+				return basename( $dashboard['file'] );
+			}
+
+			// Generate filename from slug for inline JSON.
+			return $slug . '.json';
+		}
+
+		return null;
+	}
+
+	/**
+	 * Check if a dashboard is from a third-party plugin.
+	 *
+	 * @param string $slug Dashboard slug.
+	 * @return bool True if third-party, false if built-in or not found.
+	 */
+	public function is_third_party( string $slug ): bool {
+		$this->fire_registration_hook();
+
+		$slug = sanitize_file_name( $slug );
+
+		return isset( $this->registered_dashboards[ $slug ] );
+	}
+
+	/**
+	 * Get the plugin name for a third-party dashboard.
+	 *
+	 * @param string $slug Dashboard slug.
+	 * @return string|null Plugin name or null if not found/built-in.
+	 */
+	public function get_plugin_name( string $slug ): ?string {
+		$this->fire_registration_hook();
+
+		$slug = sanitize_file_name( $slug );
+
+		if ( isset( $this->registered_dashboards[ $slug ] ) ) {
+			$plugin = $this->registered_dashboards[ $slug ]['plugin'];
+			return ! empty( $plugin ) ? $plugin : null;
+		}
+
+		return null;
 	}
 }

src/Admin/Settings.php

@@ -107,18 +107,20 @@ class Settings {
 	 * @return void
 	 */
 	public function register_settings(): void {
-		// Register settings for metrics tab.
+		// Register settings for endpoint sub-tab.
-		register_setting( 'wp_prometheus_metrics_settings', 'wp_prometheus_auth_token', array(
+		register_setting( 'wp_prometheus_endpoint_settings', 'wp_prometheus_auth_token', array(
 			'type'              => 'string',
 			'sanitize_callback' => 'sanitize_text_field',
 		) );
 
-		register_setting( 'wp_prometheus_metrics_settings', 'wp_prometheus_enabled_metrics', array(
+		// Register settings for selection sub-tab.
+		register_setting( 'wp_prometheus_selection_settings', 'wp_prometheus_enabled_metrics', array(
 			'type'              => 'array',
 			'sanitize_callback' => array( $this, 'sanitize_metrics' ),
 		) );
 
-		register_setting( 'wp_prometheus_metrics_settings', 'wp_prometheus_disable_early_mode', array(
+		// Register settings for advanced sub-tab.
+		register_setting( 'wp_prometheus_advanced_settings', 'wp_prometheus_isolated_mode', array(
 			'type'              => 'boolean',
 			'sanitize_callback' => 'rest_sanitize_boolean',
 			'default'           => false,
@@ -484,7 +486,7 @@ class Settings {
 	private function render_metrics_endpoint_subtab(): void {
 		?>
 		<form method="post" action="options.php">
-			<?php settings_fields( 'wp_prometheus_metrics_settings' ); ?>
+			<?php settings_fields( 'wp_prometheus_endpoint_settings' ); ?>
 
 			<h3><?php esc_html_e( 'Authentication', 'wp-prometheus' ); ?></h3>
 			<p class="description"><?php esc_html_e( 'Configure authentication for the /metrics endpoint.', 'wp-prometheus' ); ?></p>
@@ -513,7 +515,7 @@ class Settings {
 	private function render_metrics_selection_subtab(): void {
 		?>
 		<form method="post" action="options.php">
-			<?php settings_fields( 'wp_prometheus_metrics_settings' ); ?>
+			<?php settings_fields( 'wp_prometheus_selection_settings' ); ?>
 
 			<h3><?php esc_html_e( 'Enabled Metrics', 'wp-prometheus' ); ?></h3>
 			<p class="description"><?php esc_html_e( 'Select which metrics to expose on the /metrics endpoint.', 'wp-prometheus' ); ?></p>
@@ -566,57 +568,93 @@ class Settings {
 	 * @return void
 	 */
 	private function render_metrics_advanced_subtab(): void {
-		$disabled     = get_option( 'wp_prometheus_disable_early_mode', false );
+		$isolated_mode = get_option( 'wp_prometheus_isolated_mode', false );
-		$env_override = false !== getenv( 'WP_PROMETHEUS_DISABLE_EARLY_MODE' );
+		$env_override  = false !== getenv( 'WP_PROMETHEUS_ISOLATED_MODE' );
-		$early_active = defined( 'WP_PROMETHEUS_EARLY_METRICS' ) && WP_PROMETHEUS_EARLY_METRICS;
+		$is_metrics_request = defined( 'WP_PROMETHEUS_METRICS_REQUEST' ) && WP_PROMETHEUS_METRICS_REQUEST;
+		$is_isolated   = defined( 'WP_PROMETHEUS_ISOLATED_MODE' ) && WP_PROMETHEUS_ISOLATED_MODE;
 		?>
 		<form method="post" action="options.php">
-			<?php settings_fields( 'wp_prometheus_metrics_settings' ); ?>
+			<?php settings_fields( 'wp_prometheus_advanced_settings' ); ?>
 
-			<h3><?php esc_html_e( 'Early Mode', 'wp-prometheus' ); ?></h3>
+			<h3><?php esc_html_e( 'Metrics Collection Mode', 'wp-prometheus' ); ?></h3>
-			<p class="description">
+
-				<?php esc_html_e( 'Early mode intercepts /metrics requests before full WordPress initialization. This prevents memory exhaustion issues caused by some plugins (e.g., Twig-based themes/plugins) but disables the wp_prometheus_collect_metrics hook for custom metrics.', 'wp-prometheus' ); ?>
+			<div class="notice notice-info inline" style="padding: 12px; margin: 15px 0;">
-			</p>
+				<p><strong><?php esc_html_e( 'Safe Mode (Default)', 'wp-prometheus' ); ?></strong></p>
+				<p><?php esc_html_e( 'Content filters are removed early to prevent memory issues with Twig-based plugins, but WordPress loads normally. Third-party plugins can add custom metrics via the wp_prometheus_collect_metrics hook.', 'wp-prometheus' ); ?></p>
+			</div>
 
 			<?php if ( $env_override ) : ?>
-				<div class="notice notice-info inline" style="padding: 12px; margin: 15px 0;">
+				<div class="notice notice-warning inline" style="padding: 12px; margin: 15px 0;">
 					<strong><?php esc_html_e( 'Environment Override Active', 'wp-prometheus' ); ?></strong>
-					<p><?php esc_html_e( 'Early mode is configured via WP_PROMETHEUS_DISABLE_EARLY_MODE environment variable. Admin settings will be ignored.', 'wp-prometheus' ); ?></p>
+					<p><?php esc_html_e( 'Mode is configured via WP_PROMETHEUS_ISOLATED_MODE environment variable. Admin settings will be ignored.', 'wp-prometheus' ); ?></p>
 				</div>
 			<?php endif; ?>
 
 			<table class="form-table" role="presentation">
 				<tr>
-					<th scope="row"><?php esc_html_e( 'Disable Early Mode', 'wp-prometheus' ); ?></th>
+					<th scope="row"><?php esc_html_e( 'Isolated Mode', 'wp-prometheus' ); ?></th>
 					<td>
 						<label>
-							<input type="checkbox" name="wp_prometheus_disable_early_mode" value="1"
+							<input type="checkbox" name="wp_prometheus_isolated_mode" value="1"
-								<?php checked( $disabled ); ?>
+								<?php checked( $isolated_mode ); ?>
 								<?php disabled( $env_override ); ?>>
-							<?php esc_html_e( 'Disable early metrics interception', 'wp-prometheus' ); ?>
+							<?php esc_html_e( 'Enable isolated mode', 'wp-prometheus' ); ?>
 						</label>
 						<p class="description">
-							<?php esc_html_e( 'When disabled, metrics are collected through normal WordPress template loading. This enables the wp_prometheus_collect_metrics hook for custom metrics but may cause issues with some plugins.', 'wp-prometheus' ); ?>
+							<?php esc_html_e( 'Isolated mode outputs metrics immediately before other plugins fully load. This provides maximum isolation but disables the wp_prometheus_collect_metrics hook. Use this only if you experience issues with Safe Mode.', 'wp-prometheus' ); ?>
 						</p>
 					</td>
 				</tr>
 				<tr>
 					<th scope="row"><?php esc_html_e( 'Current Status', 'wp-prometheus' ); ?></th>
 					<td>
-						<?php if ( $early_active ) : ?>
+						<?php if ( $is_isolated ) : ?>
+							<span class="dashicons dashicons-lock" style="color: orange;"></span>
+							<?php esc_html_e( 'Isolated mode active - custom hooks are disabled', 'wp-prometheus' ); ?>
+						<?php elseif ( $is_metrics_request ) : ?>
 							<span class="dashicons dashicons-yes-alt" style="color: green;"></span>
-							<?php esc_html_e( 'Early mode is active (this request was served via early interception)', 'wp-prometheus' ); ?>
+							<?php esc_html_e( 'Safe mode active - custom hooks enabled with filter protection', 'wp-prometheus' ); ?>
-						<?php elseif ( $disabled || $env_override ) : ?>
+						<?php elseif ( $isolated_mode ) : ?>
-							<span class="dashicons dashicons-dismiss" style="color: gray;"></span>
+							<span class="dashicons dashicons-lock" style="color: orange;"></span>
-							<?php esc_html_e( 'Early mode is disabled', 'wp-prometheus' ); ?>
+							<?php esc_html_e( 'Isolated mode enabled (active for /metrics requests)', 'wp-prometheus' ); ?>
 						<?php else : ?>
 							<span class="dashicons dashicons-yes-alt" style="color: green;"></span>
-							<?php esc_html_e( 'Early mode is enabled (active for /metrics requests)', 'wp-prometheus' ); ?>
+							<?php esc_html_e( 'Safe mode enabled (default) - custom hooks with filter protection', 'wp-prometheus' ); ?>
 						<?php endif; ?>
 					</td>
 				</tr>
 			</table>
 
+			<hr style="margin: 20px 0;">
+
+			<h4><?php esc_html_e( 'Mode Comparison', 'wp-prometheus' ); ?></h4>
+			<table class="widefat striped" style="max-width: 700px;">
+				<thead>
+					<tr>
+						<th><?php esc_html_e( 'Feature', 'wp-prometheus' ); ?></th>
+						<th><?php esc_html_e( 'Safe Mode', 'wp-prometheus' ); ?></th>
+						<th><?php esc_html_e( 'Isolated Mode', 'wp-prometheus' ); ?></th>
+					</tr>
+				</thead>
+				<tbody>
+					<tr>
+						<td><?php esc_html_e( 'Custom metrics hook', 'wp-prometheus' ); ?></td>
+						<td><span class="dashicons dashicons-yes" style="color: green;"></span></td>
+						<td><span class="dashicons dashicons-no" style="color: red;"></span></td>
+					</tr>
+					<tr>
+						<td><?php esc_html_e( 'Plugin compatibility', 'wp-prometheus' ); ?></td>
+						<td><?php esc_html_e( 'High', 'wp-prometheus' ); ?></td>
+						<td><?php esc_html_e( 'Maximum', 'wp-prometheus' ); ?></td>
+					</tr>
+					<tr>
+						<td><?php esc_html_e( 'Memory usage', 'wp-prometheus' ); ?></td>
+						<td><?php esc_html_e( 'Normal', 'wp-prometheus' ); ?></td>
+						<td><?php esc_html_e( 'Minimal', 'wp-prometheus' ); ?></td>
+					</tr>
+				</tbody>
+			</table>
+
 			<?php submit_button(); ?>
 		</form>
 		<?php
@@ -1176,20 +1214,45 @@ class Settings {
 			<h2><?php esc_html_e( 'Grafana Dashboard Templates', 'wp-prometheus' ); ?></h2>
 			<p class="description"><?php esc_html_e( 'Pre-built dashboards for visualizing your WordPress metrics in Grafana.', 'wp-prometheus' ); ?></p>
 
-			<div class="wp-prometheus-dashboard-grid">
+			<?php if ( empty( $dashboards ) ) : ?>
-				<?php foreach ( $dashboards as $slug => $dashboard ) : ?>
+				<p class="description"><?php esc_html_e( 'No dashboards available.', 'wp-prometheus' ); ?></p>
-					<div class="wp-prometheus-dashboard-card">
+			<?php else : ?>
-						<div class="dashboard-icon">
+				<div class="wp-prometheus-dashboard-grid">
-							<span class="dashicons <?php echo esc_attr( $dashboard['icon'] ); ?>"></span>
+					<?php
+					foreach ( $dashboards as $slug => $dashboard ) :
+						$is_third_party = $this->dashboard_provider->is_third_party( $slug );
+						$plugin_name    = $this->dashboard_provider->get_plugin_name( $slug );
+						$card_class     = 'wp-prometheus-dashboard-card' . ( $is_third_party ? ' third-party' : '' );
+						?>
+						<div class="<?php echo esc_attr( $card_class ); ?>">
+							<?php if ( $is_third_party ) : ?>
+								<span class="dashboard-badge"><?php esc_html_e( 'Extension', 'wp-prometheus' ); ?></span>
+							<?php endif; ?>
+							<div class="dashboard-icon">
+								<span class="dashicons <?php echo esc_attr( $dashboard['icon'] ); ?>"></span>
+							</div>
+							<h3><?php echo esc_html( $dashboard['title'] ); ?></h3>
+							<p><?php echo esc_html( $dashboard['description'] ); ?></p>
+							<?php if ( $is_third_party && $plugin_name ) : ?>
+								<p class="dashboard-plugin">
+									<small>
+										<?php
+										printf(
+											/* translators: %s: Plugin name */
+											esc_html__( 'Provided by: %s', 'wp-prometheus' ),
+											esc_html( $plugin_name )
+										);
+										?>
+									</small>
+								</p>
+							<?php endif; ?>
+							<button type="button" class="button button-primary download-dashboard" data-slug="<?php echo esc_attr( $slug ); ?>">
+								<?php esc_html_e( 'Download', 'wp-prometheus' ); ?>
+							</button>
 						</div>
-						<h3><?php echo esc_html( $dashboard['title'] ); ?></h3>
+					<?php endforeach; ?>
-						<p><?php echo esc_html( $dashboard['description'] ); ?></p>
+				</div>
-						<button type="button" class="button button-primary download-dashboard" data-slug="<?php echo esc_attr( $slug ); ?>">
+			<?php endif; ?>
-							<?php esc_html_e( 'Download', 'wp-prometheus' ); ?>
-						</button>
-					</div>
-				<?php endforeach; ?>
-			</div>
 
 			<hr style="margin: 30px 0;">
 

src/Metrics/Collector.php

@@ -121,14 +121,62 @@ class Collector {
         /**
          * Fires after default metrics are collected.
          *
-         * Skip in early metrics mode to avoid triggering third-party hooks
+         * In isolated mode, skip custom hooks to avoid any potential issues.
-         * that may cause recursion issues (e.g., Twig-based plugins).
+         * In safe mode (default), fire hooks with protection against recursion.
          *
          * @param Collector $collector The metrics collector instance.
          */
-        if ( ! defined( 'WP_PROMETHEUS_EARLY_METRICS' ) || ! WP_PROMETHEUS_EARLY_METRICS ) {
+        if ( defined( 'WP_PROMETHEUS_ISOLATED_MODE' ) && WP_PROMETHEUS_ISOLATED_MODE ) {
-            do_action( 'wp_prometheus_collect_metrics', $this );
+            // Isolated mode: skip all third-party hooks for maximum safety.
+            return;
         }
+
+        // Safe mode: fire custom hooks with protection.
+        $this->fire_custom_metrics_hook();
+    }
+
+    /**
+     * Fire custom metrics hook with protection against recursion.
+     *
+     * Removes potentially problematic filters, uses output buffering,
+     * and catches any errors from third-party plugins.
+     *
+     * @return void
+     */
+    private function fire_custom_metrics_hook(): void {
+        // Remove content filters again (in case any plugin re-added them).
+        if ( function_exists( 'wp_prometheus_remove_content_filters' ) ) {
+            wp_prometheus_remove_content_filters();
+        } else {
+            // Fallback if function doesn't exist.
+            remove_all_filters( 'the_content' );
+            remove_all_filters( 'the_excerpt' );
+            remove_all_filters( 'get_the_excerpt' );
+            remove_all_filters( 'the_title' );
+        }
+
+        // Use output buffering to prevent any accidental output from plugins.
+        ob_start();
+
+        try {
+            /**
+             * Fires after default metrics are collected.
+             *
+             * Third-party plugins can use this hook to add custom metrics.
+             *
+             * @param Collector $collector The metrics collector instance.
+             */
+            do_action( 'wp_prometheus_collect_metrics', $this );
+        } catch ( \Throwable $e ) {
+            // Log the error but don't let it break metrics output.
+            if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+                // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+                error_log( 'WP Prometheus: Error in custom metrics hook: ' . $e->getMessage() );
+            }
+        }
+
+        // Discard any output from plugins.
+        ob_end_clean();
     }
 
     /**

wp-prometheus.php

@@ -3,7 +3,7 @@
  * Plugin Name: WP Prometheus
  * Plugin URI: https://src.bundespruefstelle.ch/magdev/wp-prometheus
  * Description: Prometheus metrics endpoint for WordPress with extensible hooks for custom metrics.
- * Version: 0.4.3
+ * Version: 0.4.6
  * Requires at least: 6.4
  * Requires PHP: 8.3
  * Author: Marco Graetsch
@@ -22,11 +22,16 @@ if ( ! defined( 'ABSPATH' ) ) {
 }
 
 /**
- * Early metrics endpoint handler.
+ * Early metrics request detection.
  *
- * Intercepts /metrics requests before full WordPress initialization to avoid
+ * Detects /metrics requests early and removes problematic content filters
- * conflicts with other plugins that may cause issues during template loading.
+ * to prevent recursion issues with Twig-based plugins. Unlike the previous
- * This runs at plugin load time, before plugins_loaded hook.
+ * "early mode", this allows WordPress to continue loading so that third-party
+ * plugins can register their wp_prometheus_collect_metrics hooks.
+ *
+ * Two modes are available:
+ * - Safe mode (default): Removes filters early, lets WP load, fires custom hooks
+ * - Isolated mode: Outputs metrics immediately without custom hooks (legacy early mode)
  */
 function wp_prometheus_early_metrics_check(): void {
     // Only handle /metrics requests.
@@ -37,18 +42,58 @@ function wp_prometheus_early_metrics_check(): void {
         return;
     }
 
-    // Check if early mode is disabled via environment variable.
+    // Set flag to indicate we're handling a metrics request.
-    $env_disable = getenv( 'WP_PROMETHEUS_DISABLE_EARLY_MODE' );
+    define( 'WP_PROMETHEUS_METRICS_REQUEST', true );
-    if ( false !== $env_disable && in_array( strtolower( $env_disable ), array( '1', 'true', 'yes', 'on' ), true ) ) {
+
-        return;
+    // Check if isolated mode is enabled via environment variable.
+    $env_isolated = getenv( 'WP_PROMETHEUS_ISOLATED_MODE' );
+    $isolated_mode = false !== $env_isolated && in_array( strtolower( $env_isolated ), array( '1', 'true', 'yes', 'on' ), true );
+
+    // Check if isolated mode is enabled via option (legacy "early mode" setting).
+    if ( ! $isolated_mode && ! get_option( 'wp_prometheus_disable_early_mode', false ) ) {
+        // Check for legacy isolated mode option.
+        $isolated_mode = (bool) get_option( 'wp_prometheus_isolated_mode', false );
     }
 
-    // Check if early mode is disabled via option.
+    // Remove all content filters immediately to prevent recursion with Twig-based plugins.
-    // We can use get_option() here because WordPress core is already loaded.
+    // This is done for BOTH safe mode and isolated mode.
-    if ( get_option( 'wp_prometheus_disable_early_mode', false ) ) {
+    add_action( 'plugins_loaded', 'wp_prometheus_remove_content_filters', 0 );
-        return;
-    }
 
+    // Also remove filters now in case they were added by mu-plugins.
+    wp_prometheus_remove_content_filters();
+
+    // If isolated mode is enabled, handle metrics immediately without waiting for plugins.
+    if ( $isolated_mode ) {
+        wp_prometheus_isolated_metrics_handler();
+    }
+}
+
+/**
+ * Remove content filters that can cause recursion.
+ *
+ * Called early during metrics requests to prevent infinite loops
+ * with Twig-based plugins that hook into content filters.
+ *
+ * @return void
+ */
+function wp_prometheus_remove_content_filters(): void {
+    remove_all_filters( 'the_content' );
+    remove_all_filters( 'the_excerpt' );
+    remove_all_filters( 'get_the_excerpt' );
+    remove_all_filters( 'the_title' );
+    remove_all_filters( 'the_content_feed' );
+    remove_all_filters( 'comment_text' );
+}
+
+/**
+ * Handle metrics in isolated mode (no custom hooks).
+ *
+ * This is the legacy "early mode" that outputs metrics immediately
+ * without allowing third-party plugins to add custom metrics.
+ *
+ * @return void
+ */
+function wp_prometheus_isolated_metrics_handler(): void {
     // Check if autoloader exists.
     $autoloader = __DIR__ . '/vendor/autoload.php';
     if ( ! file_exists( $autoloader ) ) {
@@ -99,14 +144,8 @@ function wp_prometheus_early_metrics_check(): void {
         exit;
     }
 
-    // Set flag to indicate early metrics mode - Collector will skip extensibility hooks.
+    // Set flag to indicate isolated mode - Collector will skip extensibility hooks.
-    define( 'WP_PROMETHEUS_EARLY_METRICS', true );
+    define( 'WP_PROMETHEUS_ISOLATED_MODE', true );
-
-    // Remove all content filters to prevent recursion with Twig-based plugins.
-    remove_all_filters( 'the_content' );
-    remove_all_filters( 'the_excerpt' );
-    remove_all_filters( 'get_the_excerpt' );
-    remove_all_filters( 'the_title' );
 
     // Output metrics and exit immediately.
     $collector = new \Magdev\WpPrometheus\Metrics\Collector();
@@ -130,7 +169,7 @@ wp_prometheus_early_metrics_check();
  *
  * @var string
  */
-define( 'WP_PROMETHEUS_VERSION', '0.4.3' );
+define( 'WP_PROMETHEUS_VERSION', '0.4.6' );
 
 /**
  * Plugin file path.