diff --git a/src/Abilities/AbilityRegistrar.php b/src/Abilities/AbilityRegistrar.php
index 439044a..0e84f0e 100644
--- a/src/Abilities/AbilityRegistrar.php
+++ b/src/Abilities/AbilityRegistrar.php
@@ -6,6 +6,7 @@ namespace LIT\MCP\Abilities;
 
 use LIT\MCP\Access;
 use LIT\MCP\Integrations\IntegrationRegistry;
+use LIT\MCP\Log;
 use LIT\MCP\Server\RequestContext;
 use Throwable;
 use WP_Error;
@@ -64,8 +65,7 @@ final class AbilityRegistrar
                 try {
                     return $ability->permission(is_array($input) ? $input : []);
                 } catch (Throwable $e) {
-                    $message = sprintf('[wp-lit-mcp] %s failed: %s', $ability->name(), $e);
-                    error_log($message); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+                    Log::failure($ability->name(), $e);
                     return Errors::internal();
                 }
             },
@@ -73,12 +73,10 @@ final class AbilityRegistrar
                 try {
                     return $ability->execute(is_array($input) ? $input : []);
                 } catch (WriteFailed $e) {
-                    $message = sprintf('[wp-lit-mcp] %s failed: %s', $ability->name(), $e);
-                    error_log($message); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+                    Log::failure($ability->name(), $e);
                     return $e->toError();
                 } catch (Throwable $e) {
-                    $message = sprintf('[wp-lit-mcp] %s failed: %s', $ability->name(), $e);
-                    error_log($message); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+                    Log::failure($ability->name(), $e);
                     return Errors::internal();
                 }
             },
diff --git a/src/Abilities/FollowUp.php b/src/Abilities/FollowUp.php
index 4c641bb..039f79b 100644
--- a/src/Abilities/FollowUp.php
+++ b/src/Abilities/FollowUp.php
@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace LIT\MCP\Abilities;
 
+use LIT\MCP\Log;
 use Throwable;
 
 /**
@@ -20,8 +21,7 @@ final class FollowUp
         try {
             return $step();
         } catch (Throwable $e) {
-            $message = sprintf('[wp-lit-mcp] %s failed: %s', $context, $e);
-            error_log($message); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+            Log::failure($context, $e);
             $warnings[] = $warning;
 
             return null;
diff --git a/src/ChangeLog/ChangeLog.php b/src/ChangeLog/ChangeLog.php
index ae0e712..574c2db 100644
--- a/src/ChangeLog/ChangeLog.php
+++ b/src/ChangeLog/ChangeLog.php
@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace LIT\MCP\ChangeLog;
 
 use LIT\MCP\Abilities\FollowUp;
+use LIT\MCP\Log;
 use LIT\MCP\Server\RequestContext;
 
 /**
@@ -57,8 +58,7 @@ class ChangeLog
         );
 
         if ($inserted === false) {
-            $message = sprintf('[wp-lit-mcp] change log insert failed for %s %s:%s', $ability, $objectType, $objectId);
-            error_log($message); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+            Log::line(sprintf('change log insert failed for %s %s:%s', $ability, $objectType, $objectId));
             return null;
         }
 
diff --git a/src/Integrations/Divi/Pages/DiviPageLoader.php b/src/Integrations/Divi/Pages/DiviPageLoader.php
index 1306dc6..08d06f1 100644
--- a/src/Integrations/Divi/Pages/DiviPageLoader.php
+++ b/src/Integrations/Divi/Pages/DiviPageLoader.php
@@ -10,6 +10,7 @@ use LIT\MCP\Integrations\Divi\BlockTree\NodeIndex;
 use LIT\MCP\Integrations\Divi\BlockTree\Parser;
 use LIT\MCP\Integrations\WordPress\PostGuard;
 use LIT\MCP\Integrations\WordPress\Schema\ContentSchema;
+use LIT\MCP\Log;
 use WP_Error;
 use WP_Post;
 
@@ -51,8 +52,7 @@ class DiviPageLoader
         try {
             $document = $this->parser->parse($content);
         } catch (MalformedMarkup $e) {
-            $message = sprintf('[wp-lit-mcp] divi parse of post %d failed: %s', $post->ID, $e->getMessage());
-            error_log($message); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+            Log::failure(sprintf('divi parse of post %d', $post->ID), $e->getMessage());
 
             return Errors::unsupported(
                 sprintf(
diff --git a/src/Integrations/Divi/Pages/DiviReplaceTextAbility.php b/src/Integrations/Divi/Pages/DiviReplaceTextAbility.php
index fdfd2b9..e37b66f 100644
--- a/src/Integrations/Divi/Pages/DiviReplaceTextAbility.php
+++ b/src/Integrations/Divi/Pages/DiviReplaceTextAbility.php
@@ -15,6 +15,7 @@ use LIT\MCP\Integrations\Divi\BlockTree\Serializer;
 use LIT\MCP\Integrations\Divi\Compose\TextReplacer;
 use LIT\MCP\Integrations\WordPress\PostGuard;
 use LIT\MCP\Integrations\WordPress\Schema\ContentSchema;
+use LIT\MCP\Log;
 use Throwable;
 use WP_Error;
 
@@ -484,8 +485,7 @@ final class DiviReplaceTextAbility implements Ability
 
     private static function log(int $postId, Throwable $e): void
     {
-        $message = sprintf('[wp-lit-mcp] lit/divi-replace-text on post %d failed: %s', $postId, $e);
-        error_log($message); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+        Log::failure(sprintf('lit/divi-replace-text on post %d', $postId), $e);
     }
 
     private function db(): \wpdb
diff --git a/src/Integrations/Divi/Pages/DynamicContentMap.php b/src/Integrations/Divi/Pages/DynamicContentMap.php
index aaea737..369aa72 100644
--- a/src/Integrations/Divi/Pages/DynamicContentMap.php
+++ b/src/Integrations/Divi/Pages/DynamicContentMap.php
@@ -7,6 +7,7 @@ namespace LIT\MCP\Integrations\Divi\Pages;
 use Closure;
 use LIT\MCP\Integrations\Divi\Compose\Placeholders;
 use LIT\MCP\Integrations\Divi\Compose\VariableRef;
+use LIT\MCP\Log;
 use Throwable;
 
 /**
@@ -43,12 +44,7 @@ class DynamicContentMap
         try {
             $options = $this->registry !== null ? ($this->registry)($postId) : self::divi($postId);
         } catch (Throwable $e) {
-            $message = sprintf(
-                '[wp-lit-mcp] divi dynamic content options of post %d failed: %s',
-                $postId,
-                $e->getMessage()
-            );
-            error_log($message); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+            Log::failure(sprintf('divi dynamic content options of post %d', $postId), $e->getMessage());
 
             return null;
         }
diff --git a/src/Integrations/Media/MediaImporter.php b/src/Integrations/Media/MediaImporter.php
index 08b49a3..fc0838a 100644
--- a/src/Integrations/Media/MediaImporter.php
+++ b/src/Integrations/Media/MediaImporter.php
@@ -7,6 +7,7 @@ namespace LIT\MCP\Integrations\Media;
 use LIT\MCP\Abilities\Errors;
 use LIT\MCP\Abilities\WriteFailed;
 use LIT\MCP\Limits;
+use LIT\MCP\Log;
 use Throwable;
 use WP_Error;
 
@@ -197,8 +198,7 @@ class MediaImporter
         );
         if ($attachmentId instanceof WP_Error) {
             // WordPress' message can contain server paths: only for the log, not for the client.
-            $message = sprintf('[wp-lit-mcp] media sideload failed: %s', $attachmentId->get_error_message());
-            error_log($message); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+            Log::failure('media sideload', $attachmentId->get_error_message());
 
             return Errors::writeFailed(
                 'WordPress hat die Datei nicht übernommen (z. B. Upload-Verzeichnis nicht beschreibbar).'
diff --git a/src/Integrations/Media/MediaUsageFinder.php b/src/Integrations/Media/MediaUsageFinder.php
index ec10818..9340092 100644
--- a/src/Integrations/Media/MediaUsageFinder.php
+++ b/src/Integrations/Media/MediaUsageFinder.php
@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace LIT\MCP\Integrations\Media;
 
 use Closure;
+use LIT\MCP\Log;
 
 /**
  * Finds where an attachment is used (spec §6.3). Deliberately errs on the side of "used":
@@ -165,8 +166,7 @@ class MediaUsageFinder
         }
 
         $this->queryFailed = true;
-        $message = sprintf('[wp-lit-mcp] media usage query failed: %s', (string) $wpdb->last_error);
-        error_log($message); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+        Log::failure('media usage query', (string) $wpdb->last_error);
 
         return [];
     }
diff --git a/src/Log.php b/src/Log.php
new file mode 100644
index 0000000..9a79ed3
--- /dev/null
+++ b/src/Log.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace LIT\MCP;
+
+use Throwable;
+
+/**
+ * The plugin's one way into the PHP error log. Messages carry the "[wp-lit-mcp]" prefix; the
+ * log is for the site operator only and may contain details (paths, traces) that must never
+ * reach an MCP client.
+ */
+final class Log
+{
+    private const PREFIX = '[wp-lit-mcp] ';
+
+    /** Logs "[wp-lit-mcp] <context> failed: <detail>"; a Throwable is logged with its trace. */
+    public static function failure(string $context, Throwable|string $detail): void
+    {
+        self::line(sprintf('%s failed: %s', $context, (string) $detail));
+    }
+
+    /** Logs one free-form line with the plugin prefix. */
+    public static function line(string $message): void
+    {
+        error_log(self::PREFIX . $message); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+    }
+}
diff --git a/src/Server/ServerRegistrar.php b/src/Server/ServerRegistrar.php
index 7516852..5df84a2 100644
--- a/src/Server/ServerRegistrar.php
+++ b/src/Server/ServerRegistrar.php
@@ -7,6 +7,7 @@ namespace LIT\MCP\Server;
 use LIT\MCP\Abilities\ExposurePolicy;
 use LIT\MCP\Guides\InstructionsBuilder;
 use LIT\MCP\Integrations\IntegrationRegistry;
+use LIT\MCP\Log;
 use LIT\MCP\Plugin;
 use WP\MCP\Core\McpAdapter;
 use WP\MCP\Infrastructure\ErrorHandling\ErrorLogMcpErrorHandler;
@@ -131,8 +132,7 @@ final class ServerRegistrar
         $result = ($this->createAdapterServer)($args);
 
         if (is_wp_error($result)) {
-            $message = '[wp-lit-mcp] MCP server registration failed: ' . $result->get_error_message();
-            error_log($message); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+            Log::failure('MCP server registration', $result->get_error_message());
         }
     }
 
diff --git a/tests/Unit/LogTest.php b/tests/Unit/LogTest.php
new file mode 100644
index 0000000..d4bf86e
--- /dev/null
+++ b/tests/Unit/LogTest.php
@@ -0,0 +1,53 @@
+<?php
+
+declare(strict_types=1);
+
+namespace LIT\MCP\Tests\Unit;
+
+use LIT\MCP\Log;
+use RuntimeException;
+
+final class LogTest extends TestCase
+{
+    /** @return string What the callback wrote to the error log. */
+    private static function captured(callable $write): string
+    {
+        // error_log() is a PHP internal and cannot be stubbed; redirect it to a temp file instead.
+        $log = (string) tempnam(sys_get_temp_dir(), 'lit-mcp-log');
+        $previous = ini_set('error_log', $log);
+
+        try {
+            $write();
+        } finally {
+            ini_set('error_log', (string) $previous);
+        }
+
+        $content = (string) file_get_contents($log);
+        unlink($log);
+
+        return $content;
+    }
+
+    public function testFailureKeepsThePrefixedFormat(): void
+    {
+        $content = self::captured(static fn () => Log::failure('media usage query', 'Table gone'));
+
+        self::assertStringContainsString('[wp-lit-mcp] media usage query failed: Table gone', $content);
+    }
+
+    public function testFailureLogsAThrowableWithItsTrace(): void
+    {
+        $e = new RuntimeException('kaputt');
+        $content = self::captured(static fn () => Log::failure('lit/x', $e));
+
+        self::assertStringContainsString('[wp-lit-mcp] lit/x failed: RuntimeException: kaputt', $content);
+        self::assertStringContainsString('Stack trace', $content);
+    }
+
+    public function testLineOnlyAddsThePrefix(): void
+    {
+        $content = self::captured(static fn () => Log::line('change log insert failed for a b:1'));
+
+        self::assertStringContainsString('[wp-lit-mcp] change log insert failed for a b:1', $content);
+    }
+}