docs: Clarify translation compilation is handled by CI/CD

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

.gitea/workflows/release.yml

@@ -18,7 +18,7 @@ jobs:
         uses: shivammathur/setup-php@v2
         with:
           php-version: '8.3'
-          extensions: mbstring, xml, zip, intl, gettext
+          extensions: mbstring, xml, zip, intl, gettext, redis, apcu
           tools: composer:v2
 
       - name: Get version from tag

.gitignore

@@ -4,3 +4,6 @@ wp-plugins
 wp-core
 vendor/
 releases/*
+
+# Marketing texts (not for distribution)
+MARKETING.md

CHANGELOG.md

@@ -5,6 +5,105 @@ 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).
 
+## [0.4.7] - 2026-02-03
+
+### Added
+
+- Database query duration distribution panel in Grafana Runtime dashboard
+- `wordpress_db_query_duration_seconds` metric now listed in Help tab
+- Documentation for enabling `SAVEQUERIES` constant for query timing
+
+### Changed
+
+- Updated README with instructions for enabling database query timing
+- Grafana Runtime dashboard now includes bucket distribution chart for DB queries
+
+## [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
+
+- Sub-tabs navigation within Metrics tab (Endpoint, Selection, Runtime, Advanced)
+- Option to disable early mode in admin settings (Metrics → Advanced)
+- Support for `WP_PROMETHEUS_DISABLE_EARLY_MODE` environment variable
+- Early mode status display in settings
+
+### Fixed
+
+- Early mode setting now saves correctly (moved into form with proper settings group)
+
+### Changed
+
+- Reorganized Metrics tab into logical sub-sections for better usability
+- Early mode can now be disabled for users who need the `wp_prometheus_collect_metrics` hook
+- Updated translations with sub-tab and early mode strings (English and German)
+
+## [0.4.1] - 2026-02-02
+
+### Fixed
+
+- Fixed memory exhaustion when wp-fedistream (Twig-based) plugin is active
+- Added early metrics endpoint handler that intercepts `/metrics` requests before full WordPress initialization
+- Removed content filters (`the_content`, `the_excerpt`, `get_the_excerpt`, `the_title`) during metrics collection to prevent recursion
+- Skip third-party extensibility hooks during early metrics mode to avoid conflicts
+- Changed `template_redirect` hook to `parse_request` for earlier request interception
+
 ## [0.4.0] - 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
 
@@ -78,11 +79,7 @@ Text domain: `wp-prometheus`
 - `en_US` - English (United States) [base language - .pot template]
 - `de_CH` - German (Switzerland, formal)
 
-To compile translations to .mo files for production:
+Translation compilation (.po → .mo) is handled automatically by CI/CD pipeline during release builds. No local compilation needed.
-
-```bash
-for po in languages/*.po; do msgfmt -o "${po%.po}.mo" "$po"; done
-```
 
 ### Create releases
 
@@ -291,6 +288,150 @@ add_action( 'wp_prometheus_collect_metrics', function( $collector ) {
 
 ## Session History
 
+### 2026-02-03 - Database Query Timing Documentation (v0.4.7)
+
+- Added database query duration distribution panel to Grafana Runtime dashboard
+- Added `wordpress_db_query_duration_seconds` metric to Help tab metrics reference
+- Added documentation in README explaining how to enable `SAVEQUERIES` for query timing
+- Updated translation files (.pot and .po) with new strings
+- **Key Learning**: WordPress `SAVEQUERIES` constant
+  - Enables `$wpdb->queries` array with query strings, timing, and call stacks
+  - Required for `wordpress_db_query_duration_seconds` histogram metric
+  - Has performance overhead - recommended for development, use cautiously in production
+  - Without it, only query counts are available (not timing data)
+
+### 2026-02-03 - Dashboard Extension Hook (v0.4.6)
+
+- Added `wp_prometheus_register_dashboards` action hook for third-party plugins
+- Third-party plugins can now register their own Grafana dashboard templates
+- Implementation in `DashboardProvider.php`:
+  - `register_dashboard(slug, args)` method for registrations
+  - Supports file-based dashboards (absolute path to JSON) or inline JSON content
+  - Security: Path traversal protection (files must be under `WP_CONTENT_DIR`)
+  - `fire_registration_hook()` with output buffering and exception handling
+  - Respects isolated mode setting (skips third-party hooks when enabled)
+  - `is_third_party()` and `get_plugin_name()` helper methods
+- Updated admin UI in Settings.php:
+  - "Extension" badge displayed on third-party dashboard cards
+  - Plugin attribution shown below third-party dashboards
+  - Visual distinction with blue border for third-party cards
+- **Key Learning**: Extension hook design pattern
+  - Fire hook lazily on first `get_available()` call, not in constructor
+  - Use `$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:
+  - **Endpoint**: Authentication token configuration
+  - **Selection**: Enable/disable individual metrics
+  - **Runtime**: Reset runtime metrics data
+  - **Advanced**: Early mode toggle and status
+- Fixed early mode setting not being saved (was outside form element)
+- Added CSS styling for horizontal sub-tab navigation
+- **Key Learning**: WordPress Settings API form structure
+  - 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)
+
+- Added option to disable early mode for users who need extensibility
+- Implementation:
+  - Added `wp_prometheus_disable_early_mode` WordPress option
+  - Added `WP_PROMETHEUS_DISABLE_EARLY_MODE` environment variable support
+  - Option check in `wp_prometheus_early_metrics_check()` before early interception
+  - Environment variable accepts `1`, `true`, `yes`, `on` (case-insensitive)
+- Admin UI in Metrics tab:
+  - "Early Mode" section with description of functionality
+  - Checkbox to disable early metrics interception
+  - Environment override notice when env var is set
+  - Current status indicator showing early mode state
+- **Key Learning**: Balancing compatibility vs extensibility
+  - Early mode fixes memory issues but disables `wp_prometheus_collect_metrics` hook
+  - Users with custom metrics need the hook, so early mode must be optional
+  - Default remains enabled (safe) with explicit opt-out for advanced users
+
+### 2026-02-02 - Plugin Compatibility Fix (v0.4.1)
+
+- Fixed memory exhaustion (1GB limit) when wp-fedistream (Twig-based) plugin is active
+- Root cause: Infinite recursion through WordPress hook system when content filters trigger Twig rendering
+- Solution: Early metrics endpoint interception before full WordPress initialization
+- Implementation changes:
+  - Added `wp_prometheus_early_metrics_check()` in bootstrap file (wp-prometheus.php)
+  - Checks REQUEST_URI for `/metrics` pattern before `plugins_loaded` fires
+  - Defines `WP_PROMETHEUS_EARLY_METRICS` constant to signal early mode
+  - Removes content filters (`the_content`, `the_excerpt`, `get_the_excerpt`, `the_title`)
+  - Collector skips `wp_prometheus_collect_metrics` action in early mode
+  - Changed MetricsEndpoint from `template_redirect` to `parse_request` hook
+- **Key Learning**: WordPress plugin loading order and hook timing
+  - Plugins load alphabetically, so wp-fedistream ('f') loads before wp-prometheus ('p')
+  - `template_redirect` fires too late - after themes and Twig initialize
+  - `parse_request` fires earlier but still after plugin files load
+  - Earliest interception point: top-level code in plugin bootstrap file
+- **Key Learning**: Content filter recursion in WordPress
+  - `get_the_excerpt()` internally triggers `apply_filters('the_content', ...)`
+  - This creates unexpected recursion vectors when Twig templates process content
+  - Solution: Remove all content-related filters before metrics collection
+- **Key Learning**: Isolating metrics collection from WordPress template system
+  - Use `remove_all_filters()` to clear problematic filter chains
+  - Skip extensibility hooks (`do_action`) when in isolated early mode
+  - Exit immediately after output to prevent further WordPress processing
+
 ### 2026-02-02 - Persistent Storage (v0.4.0)
 
 - Added persistent storage support for metrics:

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
@@ -92,6 +98,21 @@ scrape_configs:
 
 **Note:** Runtime metrics aggregate data across requests. Enable only the metrics you need to minimize performance impact.
 
+#### Enabling Database Query Timing
+
+The `wordpress_db_query_duration_seconds` histogram requires WordPress's `SAVEQUERIES` constant to be enabled. Add this to your `wp-config.php`:
+
+```php
+define( 'SAVEQUERIES', true );
+```
+
+**Important considerations:**
+
+- `SAVEQUERIES` has a performance overhead as it logs all queries with timing and call stacks
+- Recommended for development/staging environments, use with caution in production
+- Without `SAVEQUERIES`, only query counts (`wordpress_db_queries_total`) are available
+- The histogram shows total query time per request, grouped by endpoint
+
 ### Cron Metrics (v0.2.0+)
 
 | Metric | Type | Labels | Description |
@@ -154,6 +175,51 @@ $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

@@ -9,6 +9,61 @@
     margin-top: 20px;
 }
 
+/* Sub-tabs navigation */
+.wp-prometheus-subtabs {
+    margin-top: 15px;
+}
+
+.wp-prometheus-subtab-nav {
+    display: flex;
+    margin: 0;
+    padding: 0;
+    list-style: none;
+    border-bottom: 1px solid #c3c4c7;
+}
+
+.wp-prometheus-subtab-item {
+    margin: 0;
+    padding: 0;
+}
+
+.wp-prometheus-subtab-item a {
+    display: block;
+    padding: 8px 16px;
+    text-decoration: none;
+    color: #50575e;
+    border: 1px solid transparent;
+    border-bottom: none;
+    margin-bottom: -1px;
+    background: transparent;
+    font-size: 13px;
+    font-weight: 400;
+}
+
+.wp-prometheus-subtab-item a:hover {
+    color: #2271b1;
+    background: #f6f7f7;
+}
+
+.wp-prometheus-subtab-item.active a {
+    color: #1d2327;
+    background: #fff;
+    border-color: #c3c4c7;
+    border-bottom-color: #fff;
+    font-weight: 600;
+}
+
+.wp-prometheus-subtab-content {
+    background: #fff;
+    border: 1px solid #c3c4c7;
+    border-top: none;
+    padding: 20px;
+}
+
+.wp-prometheus-subtab-content h3:first-child {
+    margin-top: 0;
+}
+
 /* License status box */
 .wp-prometheus-license-status {
     margin: 15px 0;
@@ -161,6 +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;

assets/dashboards/wordpress-runtime.json

@@ -946,6 +946,95 @@
       ],
       "title": "Average Query Duration (Overall)",
       "type": "stat"
+    },
+    {
+      "datasource": {
+        "type": "prometheus",
+        "uid": "${DS_PROMETHEUS}"
+      },
+      "fieldConfig": {
+        "defaults": {
+          "color": {
+            "mode": "palette-classic"
+          },
+          "custom": {
+            "axisBorderShow": false,
+            "axisCenteredZero": false,
+            "axisColorMode": "text",
+            "axisLabel": "",
+            "axisPlacement": "auto",
+            "fillOpacity": 80,
+            "gradientMode": "none",
+            "hideFrom": {
+              "legend": false,
+              "tooltip": false,
+              "viz": false
+            },
+            "lineWidth": 1,
+            "scaleDistribution": {
+              "type": "linear"
+            },
+            "thresholdsStyle": {
+              "mode": "off"
+            }
+          },
+          "mappings": [],
+          "thresholds": {
+            "mode": "absolute",
+            "steps": [
+              {
+                "color": "green",
+                "value": null
+              }
+            ]
+          }
+        },
+        "overrides": []
+      },
+      "gridPos": {
+        "h": 8,
+        "w": 24,
+        "x": 0,
+        "y": 39
+      },
+      "id": 15,
+      "options": {
+        "barRadius": 0,
+        "barWidth": 0.97,
+        "fullHighlight": false,
+        "groupWidth": 0.7,
+        "legend": {
+          "calcs": [],
+          "displayMode": "list",
+          "placement": "bottom",
+          "showLegend": true
+        },
+        "orientation": "horizontal",
+        "showValue": "auto",
+        "stacking": "none",
+        "tooltip": {
+          "mode": "single",
+          "sort": "none"
+        },
+        "xTickLabelRotation": 0,
+        "xTickLabelSpacing": 0
+      },
+      "targets": [
+        {
+          "datasource": {
+            "type": "prometheus",
+            "uid": "${DS_PROMETHEUS}"
+          },
+          "editorMode": "code",
+          "expr": "sum(wordpress_db_query_duration_seconds_bucket) by (le)",
+          "format": "table",
+          "instant": true,
+          "legendFormat": "{{le}}",
+          "refId": "A"
+        }
+      ],
+      "title": "Query Duration Distribution (Buckets)",
+      "type": "barchart"
     }
   ],
   "refresh": "30s",

languages/wp-prometheus-de_CH.po

@@ -3,7 +3,7 @@
 # This file is distributed under the GPL v2 or later.
 msgid ""
 msgstr ""
-"Project-Id-Version: WP Prometheus 0.4.0\n"
+"Project-Id-Version: WP Prometheus 0.4.2\n"
 "Report-Msgid-Bugs-To: https://src.bundespruefstelle.ch/magdev/wp-prometheus/issues\n"
 "POT-Creation-Date: 2026-02-02T00:00:00+00:00\n"
 "PO-Revision-Date: 2026-02-02T00:00:00+00:00\n"
@@ -317,6 +317,10 @@ msgstr "HTTP-Anfragedauer-Verteilung"
 msgid "Database queries by endpoint"
 msgstr "Datenbank-Abfragen nach Endpunkt"
 
+#: src/Admin/Settings.php
+msgid "Database query duration distribution (requires SAVEQUERIES)"
+msgstr "Datenbank-Abfragedauer-Verteilung (erfordert SAVEQUERIES)"
+
 #: src/Admin/Settings.php
 msgid "Scheduled cron events by hook"
 msgstr "Geplante Cron-Ereignisse nach Hook"
@@ -879,3 +883,117 @@ msgstr "APCu funktioniert. Speicher: %s belegt."
 #: src/Metrics/StorageFactory.php
 msgid "APCu fetch operation returned unexpected value."
 msgstr "APCu-Abrufoperation hat unerwarteten Wert zurueckgegeben."
+
+#: src/Admin/Settings.php
+msgid "Early Mode"
+msgstr "Fruehzeitiger Modus"
+
+#: src/Admin/Settings.php
+msgid "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."
+msgstr "Der fruehzeitige Modus faengt /metrics-Anfragen vor der vollstaendigen WordPress-Initialisierung ab. Dies verhindert Speichererschoepfungsprobleme, die durch einige Plugins verursacht werden (z.B. Twig-basierte Themes/Plugins), deaktiviert jedoch den wp_prometheus_collect_metrics-Hook fuer benutzerdefinierte Metriken."
+
+#: src/Admin/Settings.php
+msgid "Early mode is configured via WP_PROMETHEUS_DISABLE_EARLY_MODE environment variable. Admin settings will be ignored."
+msgstr "Der fruehzeitige Modus ist ueber die Umgebungsvariable WP_PROMETHEUS_DISABLE_EARLY_MODE konfiguriert. Admin-Einstellungen werden ignoriert."
+
+#: src/Admin/Settings.php
+msgid "Disable Early Mode"
+msgstr "Fruehzeitigen Modus deaktivieren"
+
+#: src/Admin/Settings.php
+msgid "Disable early metrics interception"
+msgstr "Fruehzeitige Metriken-Abfangung deaktivieren"
+
+#: src/Admin/Settings.php
+msgid "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."
+msgstr "Wenn deaktiviert, werden Metriken ueber das normale WordPress-Template-Laden erfasst. Dies aktiviert den wp_prometheus_collect_metrics-Hook fuer benutzerdefinierte Metriken, kann jedoch Probleme mit einigen Plugins verursachen."
+
+#: src/Admin/Settings.php
+msgid "Early mode is active (this request was served via early interception)"
+msgstr "Fruehzeitiger Modus ist aktiv (diese Anfrage wurde ueber fruehzeitige Abfangung verarbeitet)"
+
+#: src/Admin/Settings.php
+msgid "Early mode is disabled"
+msgstr "Fruehzeitiger Modus ist deaktiviert"
+
+#: src/Admin/Settings.php
+msgid "Early mode is enabled (active for /metrics requests)"
+msgstr "Fruehzeitiger Modus ist aktiviert (aktiv fuer /metrics-Anfragen)"
+
+#: src/Admin/Settings.php
+msgid "Clear all accumulated runtime metric data (HTTP requests, database queries). This is useful for testing or starting fresh."
+msgstr "Alle gesammelten Laufzeit-Metrikdaten loeschen (HTTP-Anfragen, Datenbank-Abfragen). Dies ist nuetzlich zum Testen oder fuer einen Neuanfang."
+
+#: src/Admin/Settings.php
+msgid "Endpoint"
+msgstr "Endpunkt"
+
+#: src/Admin/Settings.php
+msgid "Selection"
+msgstr "Auswahl"
+
+#: src/Admin/Settings.php
+msgid "Runtime"
+msgstr "Laufzeit"
+
+#: src/Admin/Settings.php
+msgid "Advanced"
+msgstr "Erweitert"
+
+#: src/Admin/Settings.php
+msgid "Runtime Metrics Management"
+msgstr "Laufzeit-Metriken Verwaltung"
+
+#: src/Admin/Settings.php
+msgid "Runtime metrics track HTTP requests and database queries across requests. Use this section to manage accumulated data."
+msgstr "Laufzeit-Metriken erfassen HTTP-Anfragen und Datenbank-Abfragen ueber mehrere Anfragen hinweg. Verwenden Sie diesen Bereich zur Verwaltung der gesammelten Daten."
+
+#: 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

@@ -2,7 +2,7 @@
 # This file is distributed under the GPL v2 or later.
 msgid ""
 msgstr ""
-"Project-Id-Version: WP Prometheus 0.4.0\n"
+"Project-Id-Version: WP Prometheus 0.4.2\n"
 "Report-Msgid-Bugs-To: https://src.bundespruefstelle.ch/magdev/wp-prometheus/issues\n"
 "POT-Creation-Date: 2026-02-02T00:00:00+00:00\n"
 "MIME-Version: 1.0\n"
@@ -314,6 +314,10 @@ msgstr ""
 msgid "Database queries by endpoint"
 msgstr ""
 
+#: src/Admin/Settings.php
+msgid "Database query duration distribution (requires SAVEQUERIES)"
+msgstr ""
+
 #: src/Admin/Settings.php
 msgid "Scheduled cron events by hook"
 msgstr ""
@@ -876,3 +880,117 @@ msgstr ""
 #: src/Metrics/StorageFactory.php
 msgid "APCu fetch operation returned unexpected value."
 msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Early Mode"
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "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."
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Early mode is configured via WP_PROMETHEUS_DISABLE_EARLY_MODE environment variable. Admin settings will be ignored."
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Disable Early Mode"
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Disable early metrics interception"
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "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."
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Early mode is active (this request was served via early interception)"
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Early mode is disabled"
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Early mode is enabled (active for /metrics requests)"
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Clear all accumulated runtime metric data (HTTP requests, database queries). This is useful for testing or starting fresh."
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Endpoint"
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Selection"
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Runtime"
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Advanced"
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Runtime Metrics Management"
+msgstr ""
+
+#: src/Admin/Settings.php
+msgid "Runtime metrics track HTTP requests and database queries across requests. Use this section to manage accumulated data."
+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

@@ -107,17 +107,25 @@ 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 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,
+		) );
+
 		// Auth token section.
 		add_settings_section(
 			'wp_prometheus_auth_section',
@@ -394,32 +402,261 @@ class Settings {
 		<?php
 	}
 
+	/**
+	 * Get metrics sub-tabs.
+	 *
+	 * @return array
+	 */
+	private function get_metrics_subtabs(): array {
+		return array(
+			'endpoint'  => __( 'Endpoint', 'wp-prometheus' ),
+			'selection' => __( 'Selection', 'wp-prometheus' ),
+			'runtime'   => __( 'Runtime', 'wp-prometheus' ),
+			'advanced'  => __( 'Advanced', 'wp-prometheus' ),
+		);
+	}
+
+	/**
+	 * Get current metrics sub-tab.
+	 *
+	 * @return string
+	 */
+	private function get_current_metrics_subtab(): string {
+		$subtab  = isset( $_GET['subtab'] ) ? sanitize_key( $_GET['subtab'] ) : 'endpoint';
+		$subtabs = $this->get_metrics_subtabs();
+		return array_key_exists( $subtab, $subtabs ) ? $subtab : 'endpoint';
+	}
+
 	/**
 	 * Render metrics tab content.
 	 *
 	 * @return void
 	 */
 	private function render_metrics_tab(): void {
+		$subtabs         = $this->get_metrics_subtabs();
+		$current_subtab  = $this->get_current_metrics_subtab();
+		?>
+		<div class="wp-prometheus-subtabs">
+			<ul class="wp-prometheus-subtab-nav">
+				<?php foreach ( $subtabs as $subtab_id => $subtab_name ) : ?>
+					<?php
+					$subtab_url = add_query_arg(
+						array(
+							'page'   => 'wp-prometheus',
+							'tab'    => 'metrics',
+							'subtab' => $subtab_id,
+						),
+						admin_url( 'options-general.php' )
+					);
+					$active_class = ( $current_subtab === $subtab_id ) ? ' active' : '';
+					?>
+					<li class="wp-prometheus-subtab-item<?php echo esc_attr( $active_class ); ?>">
+						<a href="<?php echo esc_url( $subtab_url ); ?>"><?php echo esc_html( $subtab_name ); ?></a>
+					</li>
+				<?php endforeach; ?>
+			</ul>
+
+			<div class="wp-prometheus-subtab-content">
+				<?php
+				switch ( $current_subtab ) {
+					case 'endpoint':
+						$this->render_metrics_endpoint_subtab();
+						break;
+					case 'selection':
+						$this->render_metrics_selection_subtab();
+						break;
+					case 'runtime':
+						$this->render_metrics_runtime_subtab();
+						break;
+					case 'advanced':
+						$this->render_metrics_advanced_subtab();
+						break;
+				}
+				?>
+			</div>
+		</div>
+		<?php
+	}
+
+	/**
+	 * Render metrics endpoint sub-tab.
+	 *
+	 * @return void
+	 */
+	private function render_metrics_endpoint_subtab(): void {
 		?>
 		<form method="post" action="options.php">
-			<?php
+			<?php settings_fields( 'wp_prometheus_endpoint_settings' ); ?>
-			settings_fields( 'wp_prometheus_metrics_settings' );
+
-			do_settings_sections( 'wp-prometheus-metrics' );
+			<h3><?php esc_html_e( 'Authentication', 'wp-prometheus' ); ?></h3>
-			submit_button();
+			<p class="description"><?php esc_html_e( 'Configure authentication for the /metrics endpoint.', 'wp-prometheus' ); ?></p>
-			?>
+
+			<table class="form-table" role="presentation">
+				<tr>
+					<th scope="row">
+						<label for="wp_prometheus_auth_token"><?php esc_html_e( 'Auth Token', 'wp-prometheus' ); ?></label>
+					</th>
+					<td>
+						<?php $this->render_auth_token_field(); ?>
+					</td>
+				</tr>
+			</table>
+
+			<?php submit_button(); ?>
 		</form>
+		<?php
+	}
 
-		<hr style="margin: 30px 0;">
+	/**
+	 * Render metrics selection sub-tab.
+	 *
+	 * @return void
+	 */
+	private function render_metrics_selection_subtab(): void {
+		?>
+		<form method="post" action="options.php">
+			<?php settings_fields( 'wp_prometheus_selection_settings' ); ?>
 
-		<h3><?php esc_html_e( 'Reset Runtime Metrics', 'wp-prometheus' ); ?></h3>
+			<h3><?php esc_html_e( 'Enabled Metrics', 'wp-prometheus' ); ?></h3>
-		<p class="description"><?php esc_html_e( 'Clear all accumulated runtime metric data (HTTP requests, database queries). This is useful for testing or starting fresh.', 'wp-prometheus' ); ?></p>
+			<p class="description"><?php esc_html_e( 'Select which metrics to expose on the /metrics endpoint.', 'wp-prometheus' ); ?></p>
-		<p>
+
-			<button type="button" id="wp-prometheus-reset-runtime" class="button button-secondary">
+			<table class="form-table" role="presentation">
-				<?php esc_html_e( 'Reset Runtime Metrics', 'wp-prometheus' ); ?>
+				<tr>
-			</button>
+					<th scope="row"><?php esc_html_e( 'Select Metrics', 'wp-prometheus' ); ?></th>
-			<span id="wp-prometheus-reset-spinner" class="spinner" style="float: none;"></span>
+					<td>
-		</p>
+						<?php $this->render_enabled_metrics_field(); ?>
-		<div id="wp-prometheus-reset-message" style="display: none; margin-top: 10px;"></div>
+					</td>
+				</tr>
+			</table>
+
+			<?php submit_button(); ?>
+		</form>
+		<?php
+	}
+
+	/**
+	 * Render metrics runtime sub-tab.
+	 *
+	 * @return void
+	 */
+	private function render_metrics_runtime_subtab(): void {
+		?>
+		<h3><?php esc_html_e( 'Runtime Metrics Management', 'wp-prometheus' ); ?></h3>
+		<p class="description"><?php esc_html_e( 'Runtime metrics track HTTP requests and database queries across requests. Use this section to manage accumulated data.', 'wp-prometheus' ); ?></p>
+
+		<table class="form-table" role="presentation">
+			<tr>
+				<th scope="row"><?php esc_html_e( 'Reset Data', 'wp-prometheus' ); ?></th>
+				<td>
+					<p class="description" style="margin-bottom: 10px;">
+						<?php esc_html_e( 'Clear all accumulated runtime metric data (HTTP requests, database queries). This is useful for testing or starting fresh.', 'wp-prometheus' ); ?>
+					</p>
+					<button type="button" id="wp-prometheus-reset-runtime" class="button button-secondary">
+						<?php esc_html_e( 'Reset Runtime Metrics', 'wp-prometheus' ); ?>
+					</button>
+					<span id="wp-prometheus-reset-spinner" class="spinner" style="float: none;"></span>
+					<div id="wp-prometheus-reset-message" style="display: none; margin-top: 10px;"></div>
+				</td>
+			</tr>
+		</table>
+		<?php
+	}
+
+	/**
+	 * Render metrics advanced sub-tab.
+	 *
+	 * @return void
+	 */
+	private function render_metrics_advanced_subtab(): void {
+		$isolated_mode = get_option( 'wp_prometheus_isolated_mode', false );
+		$env_override  = false !== getenv( 'WP_PROMETHEUS_ISOLATED_MODE' );
+		$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_advanced_settings' ); ?>
+
+			<h3><?php esc_html_e( 'Metrics Collection Mode', 'wp-prometheus' ); ?></h3>
+
+			<div class="notice notice-info inline" style="padding: 12px; margin: 15px 0;">
+				<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-warning inline" style="padding: 12px; margin: 15px 0;">
+					<strong><?php esc_html_e( 'Environment Override Active', 'wp-prometheus' ); ?></strong>
+					<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( 'Isolated Mode', 'wp-prometheus' ); ?></th>
+					<td>
+						<label>
+							<input type="checkbox" name="wp_prometheus_isolated_mode" value="1"
+								<?php checked( $isolated_mode ); ?>
+								<?php disabled( $env_override ); ?>>
+							<?php esc_html_e( 'Enable isolated mode', 'wp-prometheus' ); ?>
+						</label>
+						<p class="description">
+							<?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 ( $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( 'Safe mode active - custom hooks enabled with filter protection', 'wp-prometheus' ); ?>
+						<?php elseif ( $isolated_mode ) : ?>
+							<span class="dashicons dashicons-lock" style="color: orange;"></span>
+							<?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( '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
 	}
 
@@ -977,20 +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;">
 
@@ -1103,6 +1365,11 @@ class Settings {
 					<td><?php esc_html_e( 'Counter', 'wp-prometheus' ); ?></td>
 					<td><?php esc_html_e( 'Database queries by endpoint', 'wp-prometheus' ); ?></td>
 				</tr>
+				<tr>
+					<td><code>wordpress_db_query_duration_seconds</code></td>
+					<td><?php esc_html_e( 'Histogram', 'wp-prometheus' ); ?></td>
+					<td><?php esc_html_e( 'Database query duration distribution (requires SAVEQUERIES)', 'wp-prometheus' ); ?></td>
+				</tr>
 				<tr>
 					<td><code>wordpress_cron_events_total</code></td>
 					<td><?php esc_html_e( 'Gauge', 'wp-prometheus' ); ?></td>

src/Endpoint/MetricsEndpoint.php

@@ -45,7 +45,9 @@ class MetricsEndpoint {
      */
     private function init_hooks(): void {
         add_action( 'init', array( $this, 'register_endpoint' ) );
-        add_action( 'template_redirect', array( $this, 'handle_request' ) );
+        // Use parse_request instead of template_redirect to handle the request early,
+        // before themes and other plugins (like Twig-based ones) can interfere.
+        add_action( 'parse_request', array( $this, 'handle_request' ) );
     }
 
     /**
@@ -66,10 +68,13 @@ class MetricsEndpoint {
     /**
      * Handle the metrics endpoint request.
      *
+     * Called during parse_request to intercept before themes/plugins load.
+     *
+     * @param \WP $wp WordPress environment instance.
      * @return void
      */
-    public function handle_request(): void {
+    public function handle_request( \WP $wp ): void {
-        if ( ! get_query_var( 'wp_prometheus_metrics' ) ) {
+        if ( empty( $wp->query_vars['wp_prometheus_metrics'] ) ) {
             return;
         }
 

src/Metrics/Collector.php

@@ -121,9 +121,62 @@ class Collector {
         /**
          * Fires after default metrics are collected.
          *
+         * In isolated mode, skip custom hooks to avoid any potential issues.
+         * In safe mode (default), fire hooks with protection against recursion.
+         *
          * @param Collector $collector The metrics collector instance.
          */
-        do_action( 'wp_prometheus_collect_metrics', $this );
+        if ( defined( 'WP_PROMETHEUS_ISOLATED_MODE' ) && WP_PROMETHEUS_ISOLATED_MODE ) {
+            // 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: 0.4.0
+ * Version: 0.4.7
  * Requires at least: 6.4
  * Requires PHP: 8.3
  * Author: Marco Graetsch
@@ -21,12 +21,155 @@ if ( ! defined( 'ABSPATH' ) ) {
     exit;
 }
 
+/**
+ * Early metrics request detection.
+ *
+ * Detects /metrics requests early and removes problematic content filters
+ * to prevent recursion issues with Twig-based plugins. Unlike the previous
+ * "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.
+    $request_uri = isset( $_SERVER['REQUEST_URI'] ) ? sanitize_text_field( wp_unslash( $_SERVER['REQUEST_URI'] ) ) : '';
+    $path        = wp_parse_url( $request_uri, PHP_URL_PATH );
+
+    if ( ! preg_match( '#/metrics/?$#', $path ) ) {
+        return;
+    }
+
+    // Set flag to indicate we're handling a metrics request.
+    define( 'WP_PROMETHEUS_METRICS_REQUEST', true );
+
+    // 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 );
+    }
+
+    // Remove all content filters immediately to prevent recursion with Twig-based plugins.
+    // This is done for BOTH safe mode and isolated mode.
+    add_action( 'plugins_loaded', 'wp_prometheus_remove_content_filters', 0 );
+
+    // 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 ) ) {
+        return;
+    }
+
+    require_once $autoloader;
+
+    // Check license validity.
+    if ( ! \Magdev\WpPrometheus\License\Manager::is_license_valid() ) {
+        return; // Let normal flow handle unlicensed state.
+    }
+
+    // Authenticate.
+    $auth_token = get_option( 'wp_prometheus_auth_token', '' );
+    if ( empty( $auth_token ) ) {
+        status_header( 401 );
+        header( 'WWW-Authenticate: Bearer realm="WP Prometheus Metrics"' );
+        header( 'Content-Type: text/plain; charset=utf-8' );
+        echo 'Unauthorized';
+        exit;
+    }
+
+    // Check Bearer token.
+    $auth_header = '';
+    if ( isset( $_SERVER['HTTP_AUTHORIZATION'] ) ) {
+        $auth_header = sanitize_text_field( wp_unslash( $_SERVER['HTTP_AUTHORIZATION'] ) );
+    } elseif ( isset( $_SERVER['REDIRECT_HTTP_AUTHORIZATION'] ) ) {
+        $auth_header = sanitize_text_field( wp_unslash( $_SERVER['REDIRECT_HTTP_AUTHORIZATION'] ) );
+    }
+
+    $authenticated = false;
+    if ( ! empty( $auth_header ) && preg_match( '/Bearer\s+(.*)$/i', $auth_header, $matches ) ) {
+        $authenticated = hash_equals( $auth_token, $matches[1] );
+    }
+
+    // Check query parameter fallback.
+    // phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Auth token check.
+    if ( ! $authenticated && isset( $_GET['token'] ) ) {
+        $authenticated = hash_equals( $auth_token, sanitize_text_field( wp_unslash( $_GET['token'] ) ) );
+    }
+
+    if ( ! $authenticated ) {
+        status_header( 401 );
+        header( 'WWW-Authenticate: Bearer realm="WP Prometheus Metrics"' );
+        header( 'Content-Type: text/plain; charset=utf-8' );
+        echo 'Unauthorized';
+        exit;
+    }
+
+    // Set flag to indicate isolated mode - Collector will skip extensibility hooks.
+    define( 'WP_PROMETHEUS_ISOLATED_MODE', true );
+
+    // Output metrics and exit immediately.
+    $collector = new \Magdev\WpPrometheus\Metrics\Collector();
+
+    status_header( 200 );
+    header( 'Content-Type: text/plain; version=0.0.4; charset=utf-8' );
+    header( 'Cache-Control: no-cache, no-store, must-revalidate' );
+    header( 'Pragma: no-cache' );
+    header( 'Expires: 0' );
+
+    // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped -- Prometheus format.
+    echo $collector->render();
+    exit;
+}
+
+// Try early metrics handling before full plugin initialization.
+wp_prometheus_early_metrics_check();
+
 /**
  * Plugin version.
  *
  * @var string
  */
-define( 'WP_PROMETHEUS_VERSION', '0.4.0' );
+define( 'WP_PROMETHEUS_VERSION', '0.4.7' );
 
 /**
  * Plugin file path.