diff --git a/Makefile b/Makefile
index 07f36723..1fc5334d 100644
--- a/Makefile
+++ b/Makefile
@@ -30,8 +30,15 @@ psalm-baseline: vendor
 	vendor/bin/psalm --update-baseline --set-baseline=baseline.xml
 
 .PHONY: phpunit
-phpunit: vendor                                                                 ## run phpunit tests
-	XDEBUG_MODE=coverage vendor/bin/phpunit
+phpunit: vendor phpunit-unit phpunit-integration                              	## run phpunit tests
+
+.PHONY: phpunit-integration
+phpunit-integration: vendor                                                    	## run phpunit integration tests
+	vendor/bin/phpunit --testsuite=integration
+
+.PHONY: phpunit-unit
+phpunit-unit: vendor                                             				## run phpunit unit tests
+	XDEBUG_MODE=coverage vendor/bin/phpunit --testsuite=unit
 
 .PHONY: infection
 infection: vendor                                                               ## run infection
diff --git a/baseline.xml b/baseline.xml
index 2a1ccf71..e107ec3e 100644
--- a/baseline.xml
+++ b/baseline.xml
@@ -56,12 +56,16 @@
       <code><![CDATA[$projectionError->errorContext]]></code>
     </PossiblyNullPropertyFetch>
   </file>
-  <file src="src/Projection/Projectionist/DefaultProjectionist.php">
+  <file src="src/Projection/Projector/MetadataProjectorAccessor.php">
     <MixedMethodCall>
       <code><![CDATA[$method]]></code>
       <code><![CDATA[$method]]></code>
       <code><![CDATA[$method]]></code>
     </MixedMethodCall>
+    <MixedReturnTypeCoercion>
+      <code><![CDATA[$this->projector->$method(...)]]></code>
+      <code><![CDATA[Closure(Message):void]]></code>
+    </MixedReturnTypeCoercion>
   </file>
   <file src="src/Repository/DefaultRepository.php">
     <PropertyTypeCoercion>
diff --git a/docs/pages/getting_started.md b/docs/pages/getting_started.md
index ca32cfb0..9b8c53ea 100644
--- a/docs/pages/getting_started.md
+++ b/docs/pages/getting_started.md
@@ -281,6 +281,7 @@ use Doctrine\DBAL\DriverManager;
 use Patchlevel\EventSourcing\EventBus\DefaultEventBus;
 use Patchlevel\EventSourcing\Projection\Projection\Store\DoctrineStore;
 use Patchlevel\EventSourcing\Projection\Projectionist\DefaultProjectionist;
+use Patchlevel\EventSourcing\Projection\Projector\MetadataProjectorAccessorRepository;
 use Patchlevel\EventSourcing\Repository\DefaultRepositoryManager;
 use Patchlevel\EventSourcing\Serializer\DefaultEventSerializer;
 use Patchlevel\EventSourcing\Store\DoctrineDbalStore;
@@ -306,7 +307,7 @@ $eventStore = new DoctrineDbalStore(
 
 $hotelProjector = new HotelProjector($projectionConnection);
 
-$projectorRepository = new ProjectorRepository([
+$projectorRepository = new MetadataProjectorAccessorRepository([
     $hotelProjector,
 ]);
 
diff --git a/docs/pages/projection.md b/docs/pages/projection.md
index ecfe7916..a57b3246 100644
--- a/docs/pages/projection.md
+++ b/docs/pages/projection.md
@@ -469,6 +469,17 @@ $retryStrategy = new ClockBasedRetryStrategy(
 
     You can reactivate the projection manually or remove it and rebuild it from scratch.
 
+### Projector Accessor
+
+The projector accessor is responsible for providing the projectors to the projectionist.
+We provide a metadata projector accessor repository by default.
+
+```php
+use Patchlevel\EventSourcing\Projection\Projector\MetadataProjectorAccessorRepository;
+
+$projectorAccessorRepository = new MetadataProjectorAccessorRepository([$projector1, $projector2, $projector3]);
+```
+
 ### Projectionist
 
 Now we can create the projectionist and plug together the necessary services.
@@ -481,7 +492,7 @@ use Patchlevel\EventSourcing\Projection\Projectionist\DefaultProjectionist;
 $projectionist = new DefaultProjectionist(
     $eventStore,
     $projectionStore,
-    [$projector1, $projector2, $projector3],
+    $projectorAccessorRepository,
     $retryStrategy,
 );
 ```
diff --git a/src/Projection/Projectionist/DefaultProjectionist.php b/src/Projection/Projectionist/DefaultProjectionist.php
index 6e566fda..0f3e905c 100644
--- a/src/Projection/Projectionist/DefaultProjectionist.php
+++ b/src/Projection/Projectionist/DefaultProjectionist.php
@@ -5,17 +5,15 @@
 namespace Patchlevel\EventSourcing\Projection\Projectionist;
 
 use Closure;
-use Patchlevel\EventSourcing\Attribute\Subscribe;
 use Patchlevel\EventSourcing\EventBus\Message;
-use Patchlevel\EventSourcing\Metadata\Projector\AttributeProjectorMetadataFactory;
-use Patchlevel\EventSourcing\Metadata\Projector\ProjectorMetadata;
-use Patchlevel\EventSourcing\Metadata\Projector\ProjectorMetadataFactory;
 use Patchlevel\EventSourcing\Projection\Projection\Projection;
 use Patchlevel\EventSourcing\Projection\Projection\ProjectionCriteria;
 use Patchlevel\EventSourcing\Projection\Projection\ProjectionStatus;
 use Patchlevel\EventSourcing\Projection\Projection\RunMode;
 use Patchlevel\EventSourcing\Projection\Projection\Store\LockableProjectionStore;
 use Patchlevel\EventSourcing\Projection\Projection\Store\ProjectionStore;
+use Patchlevel\EventSourcing\Projection\Projector\ProjectorAccessor;
+use Patchlevel\EventSourcing\Projection\Projector\ProjectorAccessorRepository;
 use Patchlevel\EventSourcing\Projection\RetryStrategy\ClockBasedRetryStrategy;
 use Patchlevel\EventSourcing\Projection\RetryStrategy\RetryStrategy;
 use Patchlevel\EventSourcing\Store\Criteria;
@@ -23,24 +21,17 @@
 use Psr\Log\LoggerInterface;
 use Throwable;
 
-use function array_map;
-use function array_merge;
 use function count;
 use function in_array;
 use function sprintf;
 
 final class DefaultProjectionist implements Projectionist
 {
-    /** @var array<string, object>|null */
-    private array|null $projectorIndex = null;
-
-    /** @param iterable<object> $projectors */
     public function __construct(
         private readonly Store $messageStore,
         private readonly ProjectionStore $projectionStore,
-        private readonly iterable $projectors,
+        private readonly ProjectorAccessorRepository $projectorRepository,
         private readonly RetryStrategy $retryStrategy = new ClockBasedRetryStrategy(),
-        private readonly ProjectorMetadataFactory $metadataFactory = new AttributeProjectorMetadataFactory(),
         private readonly LoggerInterface|null $logger = null,
     ) {
     }
@@ -323,7 +314,7 @@ function (array $projections): void {
                         continue;
                     }
 
-                    $teardownMethod = $this->resolveTeardownMethod($projector);
+                    $teardownMethod = $projector->teardownMethod();
 
                     if (!$teardownMethod) {
                         $this->projectionStore->remove($projection);
@@ -402,7 +393,7 @@ function (array $projections): void {
                         continue;
                     }
 
-                    $teardownMethod = $this->resolveTeardownMethod($projector);
+                    $teardownMethod = $projector->teardownMethod();
 
                     if (!$teardownMethod) {
                         $this->projectionStore->remove($projection);
@@ -561,7 +552,7 @@ private function handleMessage(int $index, Message $message, Projection $project
             throw ProjectorNotFound::forProjectionId($projection->id());
         }
 
-        $subscribeMethods = $this->resolveSubscribeMethods($projector, $message);
+        $subscribeMethods = $projector->subscribeMethods($message->event()::class);
 
         if ($subscribeMethods === []) {
             $projection->changePosition($index);
@@ -611,19 +602,9 @@ private function handleMessage(int $index, Message $message, Projection $project
         );
     }
 
-    private function projector(string $projectionId): object|null
+    private function projector(string $projectionId): ProjectorAccessor|null
     {
-        if ($this->projectorIndex === null) {
-            $this->projectorIndex = [];
-
-            foreach ($this->projectors as $projector) {
-                $projectorId = $this->projectorMetadata($projector)->id;
-
-                $this->projectorIndex[$projectorId] = $projector;
-            }
-        }
-
-        return $this->projectorIndex[$projectionId] ?? null;
+        return $this->projectorRepository->get($projectionId);
     }
 
     private function handleOutdatedProjections(ProjectionistCriteria $criteria): void
@@ -764,7 +745,7 @@ function (array $projections): void {
                         throw ProjectorNotFound::forProjectionId($projection->id());
                     }
 
-                    $setupMethod = $this->resolveSetupMethod($projector);
+                    $setupMethod = $projector->setupMethod();
 
                     if (!$setupMethod) {
                         $projection->booting();
@@ -810,25 +791,25 @@ private function discoverNewProjections(): void
         $this->findForUpdate(
             new ProjectionCriteria(),
             function (array $projections): void {
-                foreach ($this->projectors as $projector) {
-                    $metadata = $this->projectorMetadata($projector);
-
+                foreach ($this->projectorRepository->all() as $projector) {
                     foreach ($projections as $projection) {
-                        if ($projection->id() === $metadata->id) {
+                        if ($projection->id() === $projector->id()) {
                             continue 2;
                         }
                     }
 
-                    $this->projectionStore->add(new Projection(
-                        $metadata->id,
-                        $metadata->group,
-                        $metadata->runMode,
-                    ));
+                    $this->projectionStore->add(
+                        new Projection(
+                            $projector->id(),
+                            $projector->group(),
+                            $projector->runMode(),
+                        ),
+                    );
 
                     $this->logger?->info(
                         sprintf(
                             'Projectionist: New Projector "%s" was found and added to the projection store.',
-                            $metadata->id,
+                            $projector->id(),
                         ),
                     );
                 }
@@ -836,52 +817,6 @@ function (array $projections): void {
         );
     }
 
-    private function resolveSetupMethod(object $projector): Closure|null
-    {
-        $metadata = $this->metadataFactory->metadata($projector::class);
-        $method = $metadata->setupMethod;
-
-        if ($method === null) {
-            return null;
-        }
-
-        return $projector->$method(...);
-    }
-
-    private function resolveTeardownMethod(object $projector): Closure|null
-    {
-        $metadata = $this->metadataFactory->metadata($projector::class);
-        $method = $metadata->teardownMethod;
-
-        if ($method === null) {
-            return null;
-        }
-
-        return $projector->$method(...);
-    }
-
-    /** @return iterable<Closure> */
-    private function resolveSubscribeMethods(object $projector, Message $message): iterable
-    {
-        $event = $message->event();
-        $metadata = $this->metadataFactory->metadata($projector::class);
-
-        $methods = array_merge(
-            $metadata->subscribeMethods[$event::class] ?? [],
-            $metadata->subscribeMethods[Subscribe::ALL] ?? [],
-        );
-
-        return array_map(
-            static fn (string $method) => $projector->$method(...),
-            $methods,
-        );
-    }
-
-    private function projectorMetadata(object $projector): ProjectorMetadata
-    {
-        return $this->metadataFactory->metadata($projector::class);
-    }
-
     private function latestIndex(): int
     {
         $stream = $this->messageStore->load(null, 1, null, true);
diff --git a/src/Projection/Projector/MetadataProjectorAccessor.php b/src/Projection/Projector/MetadataProjectorAccessor.php
new file mode 100644
index 00000000..543c406f
--- /dev/null
+++ b/src/Projection/Projector/MetadataProjectorAccessor.php
@@ -0,0 +1,89 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Projection\Projector;
+
+use Closure;
+use Patchlevel\EventSourcing\Attribute\Subscribe;
+use Patchlevel\EventSourcing\EventBus\Message;
+use Patchlevel\EventSourcing\Metadata\Projector\ProjectorMetadata;
+use Patchlevel\EventSourcing\Projection\Projection\RunMode;
+
+use function array_key_exists;
+use function array_map;
+use function array_merge;
+
+final class MetadataProjectorAccessor implements ProjectorAccessor
+{
+    /** @var array<class-string, list<Closure(Message):void>> */
+    private array $subscribeCache = [];
+
+    public function __construct(
+        private readonly object $projector,
+        private readonly ProjectorMetadata $metadata,
+    ) {
+    }
+
+    public function id(): string
+    {
+        return $this->metadata->id;
+    }
+
+    public function group(): string
+    {
+        return $this->metadata->group;
+    }
+
+    public function runMode(): RunMode
+    {
+        return $this->metadata->runMode;
+    }
+
+    public function setupMethod(): Closure|null
+    {
+        $method = $this->metadata->setupMethod;
+
+        if ($method === null) {
+            return null;
+        }
+
+        return $this->projector->$method(...);
+    }
+
+    public function teardownMethod(): Closure|null
+    {
+        $method = $this->metadata->teardownMethod;
+
+        if ($method === null) {
+            return null;
+        }
+
+        return $this->projector->$method(...);
+    }
+
+    /**
+     * @param class-string $eventClass
+     *
+     * @return list<Closure(Message):void>
+     */
+    public function subscribeMethods(string $eventClass): array
+    {
+        if (array_key_exists($eventClass, $this->subscribeCache)) {
+            return $this->subscribeCache[$eventClass];
+        }
+
+        $methods = array_merge(
+            $this->metadata->subscribeMethods[$eventClass] ?? [],
+            $this->metadata->subscribeMethods[Subscribe::ALL] ?? [],
+        );
+
+        $this->subscribeCache[$eventClass] = array_map(
+            /** @return Closure(Message):void */
+            fn (string $method) => $this->projector->$method(...),
+            $methods,
+        );
+
+        return $this->subscribeCache[$eventClass];
+    }
+}
diff --git a/src/Projection/Projector/MetadataProjectorAccessorRepository.php b/src/Projection/Projector/MetadataProjectorAccessorRepository.php
new file mode 100644
index 00000000..81c4714a
--- /dev/null
+++ b/src/Projection/Projector/MetadataProjectorAccessorRepository.php
@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Projection\Projector;
+
+use Patchlevel\EventSourcing\Metadata\Projector\AttributeProjectorMetadataFactory;
+use Patchlevel\EventSourcing\Metadata\Projector\ProjectorMetadataFactory;
+
+use function array_values;
+
+final class MetadataProjectorAccessorRepository implements ProjectorAccessorRepository
+{
+    /** @var array<string, ProjectorAccessor> */
+    private array $projectorsMap = [];
+
+    /** @param iterable<object> $projectors */
+    public function __construct(
+        private readonly iterable $projectors,
+        private readonly ProjectorMetadataFactory $metadataFactory = new AttributeProjectorMetadataFactory(),
+    ) {
+    }
+
+    /** @return iterable<ProjectorAccessor> */
+    public function all(): iterable
+    {
+        return array_values($this->projectorAccessorMap());
+    }
+
+    public function get(string $id): ProjectorAccessor|null
+    {
+        $map = $this->projectorAccessorMap();
+
+        return $map[$id] ?? null;
+    }
+
+    /** @return array<string, ProjectorAccessor> */
+    private function projectorAccessorMap(): array
+    {
+        if ($this->projectorsMap !== []) {
+            return $this->projectorsMap;
+        }
+
+        foreach ($this->projectors as $projector) {
+            $metadata = $this->metadataFactory->metadata($projector::class);
+            $this->projectorsMap[$metadata->id] = new MetadataProjectorAccessor($projector, $metadata);
+        }
+
+        return $this->projectorsMap;
+    }
+}
diff --git a/src/Projection/Projector/ProjectorAccessor.php b/src/Projection/Projector/ProjectorAccessor.php
new file mode 100644
index 00000000..00e378da
--- /dev/null
+++ b/src/Projection/Projector/ProjectorAccessor.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Projection\Projector;
+
+use Closure;
+use Patchlevel\EventSourcing\EventBus\Message;
+use Patchlevel\EventSourcing\Projection\Projection\RunMode;
+
+interface ProjectorAccessor
+{
+    public function id(): string;
+
+    public function group(): string;
+
+    public function runMode(): RunMode;
+
+    public function setupMethod(): Closure|null;
+
+    public function teardownMethod(): Closure|null;
+
+    /**
+     * @param class-string $eventClass
+     *
+     * @return list<Closure(Message):void>
+     */
+    public function subscribeMethods(string $eventClass): array;
+}
diff --git a/src/Projection/Projector/ProjectorAccessorRepository.php b/src/Projection/Projector/ProjectorAccessorRepository.php
new file mode 100644
index 00000000..267a97e5
--- /dev/null
+++ b/src/Projection/Projector/ProjectorAccessorRepository.php
@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Projection\Projector;
+
+interface ProjectorAccessorRepository
+{
+    /** @return iterable<ProjectorAccessor> */
+    public function all(): iterable;
+
+    public function get(string $id): ProjectorAccessor|null;
+}
diff --git a/src/Projection/Projector/TraceableProjectorAccessor.php b/src/Projection/Projector/TraceableProjectorAccessor.php
new file mode 100644
index 00000000..1ba70b22
--- /dev/null
+++ b/src/Projection/Projector/TraceableProjectorAccessor.php
@@ -0,0 +1,79 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Projection\Projector;
+
+use Closure;
+use Patchlevel\EventSourcing\EventBus\Message;
+use Patchlevel\EventSourcing\Projection\Projection\RunMode;
+use Patchlevel\EventSourcing\Repository\MessageDecorator\Trace;
+use Patchlevel\EventSourcing\Repository\MessageDecorator\TraceStack;
+
+use function array_map;
+
+/** @experimental */
+final class TraceableProjectorAccessor implements ProjectorAccessor
+{
+    public function __construct(
+        private readonly ProjectorAccessor $parent,
+        private readonly TraceStack $traceStack,
+    ) {
+    }
+
+    public function id(): string
+    {
+        return $this->parent->id();
+    }
+
+    public function group(): string
+    {
+        return $this->parent->group();
+    }
+
+    public function runMode(): RunMode
+    {
+        return $this->parent->runMode();
+    }
+
+    public function setupMethod(): Closure|null
+    {
+        return $this->parent->setupMethod();
+    }
+
+    public function teardownMethod(): Closure|null
+    {
+        return $this->parent->teardownMethod();
+    }
+
+    /**
+     * @param class-string $eventClass
+     *
+     * @return list<Closure(Message):void>
+     */
+    public function subscribeMethods(string $eventClass): array
+    {
+        return array_map(
+            /**
+             * @param Closure(Message):void $closure
+             *
+             * @return Closure(Message):void
+             */
+            fn (Closure $closure) => function (Message $message) use ($closure): void {
+                $trace = new Trace(
+                    $this->id(),
+                    'event_sourcing/projector/' . $this->group(),
+                );
+
+                $this->traceStack->add($trace);
+
+                try {
+                    $closure($message);
+                } finally {
+                    $this->traceStack->remove($trace);
+                }
+            },
+            $this->parent->subscribeMethods($eventClass),
+        );
+    }
+}
diff --git a/src/Projection/Projector/TraceableProjectorAccessorRepository.php b/src/Projection/Projector/TraceableProjectorAccessorRepository.php
new file mode 100644
index 00000000..cb5beb78
--- /dev/null
+++ b/src/Projection/Projector/TraceableProjectorAccessorRepository.php
@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Projection\Projector;
+
+use Patchlevel\EventSourcing\Repository\MessageDecorator\TraceStack;
+
+use function array_values;
+
+/** @experimental */
+final class TraceableProjectorAccessorRepository implements ProjectorAccessorRepository
+{
+    /** @var array<string, TraceableProjectorAccessor> */
+    private array $projectorsMap = [];
+
+    public function __construct(
+        private readonly ProjectorAccessorRepository $parent,
+        private readonly TraceStack $traceStack,
+    ) {
+    }
+
+    /** @return iterable<TraceableProjectorAccessor> */
+    public function all(): iterable
+    {
+        return array_values($this->projectorAccessorMap());
+    }
+
+    public function get(string $id): TraceableProjectorAccessor|null
+    {
+        $map = $this->projectorAccessorMap();
+
+        return $map[$id] ?? null;
+    }
+
+    /** @return array<string, TraceableProjectorAccessor> */
+    private function projectorAccessorMap(): array
+    {
+        if ($this->projectorsMap !== []) {
+            return $this->projectorsMap;
+        }
+
+        foreach ($this->parent->all() as $projectorAccessor) {
+            $this->projectorsMap[$projectorAccessor->id()] = new TraceableProjectorAccessor(
+                $projectorAccessor,
+                $this->traceStack,
+            );
+        }
+
+        return $this->projectorsMap;
+    }
+}
diff --git a/src/Repository/MessageDecorator/Trace.php b/src/Repository/MessageDecorator/Trace.php
new file mode 100644
index 00000000..bcc2357b
--- /dev/null
+++ b/src/Repository/MessageDecorator/Trace.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Repository\MessageDecorator;
+
+/** @experimental */
+final class Trace
+{
+    public function __construct(
+        public readonly string $name,
+        public readonly string $category,
+    ) {
+    }
+}
diff --git a/src/Repository/MessageDecorator/TraceDecorator.php b/src/Repository/MessageDecorator/TraceDecorator.php
new file mode 100644
index 00000000..5ca913eb
--- /dev/null
+++ b/src/Repository/MessageDecorator/TraceDecorator.php
@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Repository\MessageDecorator;
+
+use Patchlevel\EventSourcing\EventBus\Message;
+
+use function array_map;
+
+/** @experimental */
+final class TraceDecorator implements MessageDecorator
+{
+    public function __construct(
+        private readonly TraceStack $traceStack,
+    ) {
+    }
+
+    public function __invoke(Message $message): Message
+    {
+        $traces = $this->traceStack->get();
+
+        if ($traces === []) {
+            return $message;
+        }
+
+        return $message->withHeader(new TraceHeader(
+            array_map(
+                static fn (Trace $trace) => [
+                    'name' => $trace->name,
+                    'category' => $trace->category,
+                ],
+                $traces,
+            ),
+        ));
+    }
+}
diff --git a/src/Repository/MessageDecorator/TraceHeader.php b/src/Repository/MessageDecorator/TraceHeader.php
new file mode 100644
index 00000000..c7c10d23
--- /dev/null
+++ b/src/Repository/MessageDecorator/TraceHeader.php
@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Repository\MessageDecorator;
+
+use Patchlevel\EventSourcing\Attribute\Header;
+
+/** @experimental */
+#[Header('trace')]
+final class TraceHeader
+{
+    /** @param list<array{name: string, category: string}> $traces */
+    public function __construct(
+        public readonly array $traces,
+    ) {
+    }
+}
diff --git a/src/Repository/MessageDecorator/TraceStack.php b/src/Repository/MessageDecorator/TraceStack.php
new file mode 100644
index 00000000..24b71b9e
--- /dev/null
+++ b/src/Repository/MessageDecorator/TraceStack.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Repository\MessageDecorator;
+
+use function array_values;
+
+/** @experimental */
+final class TraceStack
+{
+    /** @var array<string, Trace> */
+    private array $traces = [];
+
+    public function add(Trace $trace): void
+    {
+        $this->traces[self::key($trace)] = $trace;
+    }
+
+    /** @return list<Trace> */
+    public function get(): array
+    {
+        return array_values($this->traces);
+    }
+
+    public function remove(Trace $trace): void
+    {
+        unset($this->traces[self::key($trace)]);
+    }
+
+    private static function key(Trace $trace): string
+    {
+        return $trace->category . '#' . $trace->name;
+    }
+}
diff --git a/tests/Benchmark/ProjectionistBench.php b/tests/Benchmark/ProjectionistBench.php
index fd5050e4..fa8ff604 100644
--- a/tests/Benchmark/ProjectionistBench.php
+++ b/tests/Benchmark/ProjectionistBench.php
@@ -11,6 +11,7 @@
 use Patchlevel\EventSourcing\Projection\Projection\Store\DoctrineStore;
 use Patchlevel\EventSourcing\Projection\Projectionist\DefaultProjectionist;
 use Patchlevel\EventSourcing\Projection\Projectionist\Projectionist;
+use Patchlevel\EventSourcing\Projection\Projector\MetadataProjectorAccessorRepository;
 use Patchlevel\EventSourcing\Repository\DefaultRepository;
 use Patchlevel\EventSourcing\Repository\Repository;
 use Patchlevel\EventSourcing\Schema\ChainDoctrineSchemaConfigurator;
@@ -83,10 +84,12 @@ public function setUp(): void
         $this->projectionist = new DefaultProjectionist(
             $this->store,
             $projectionStore,
-            [
-                new ProfileProjector($connection),
-                new SendEmailProcessor(),
-            ],
+            new MetadataProjectorAccessorRepository(
+                [
+                    new ProfileProjector($connection),
+                    new SendEmailProcessor(),
+                ],
+            ),
         );
     }
 
diff --git a/tests/Integration/BankAccountSplitStream/IntegrationTest.php b/tests/Integration/BankAccountSplitStream/IntegrationTest.php
index 7fff903b..9df66124 100644
--- a/tests/Integration/BankAccountSplitStream/IntegrationTest.php
+++ b/tests/Integration/BankAccountSplitStream/IntegrationTest.php
@@ -12,6 +12,7 @@
 use Patchlevel\EventSourcing\Projection\Projection\Store\InMemoryStore;
 use Patchlevel\EventSourcing\Projection\Projectionist\DefaultProjectionist;
 use Patchlevel\EventSourcing\Projection\Projectionist\ProjectionistCriteria;
+use Patchlevel\EventSourcing\Projection\Projector\MetadataProjectorAccessorRepository;
 use Patchlevel\EventSourcing\Repository\DefaultRepositoryManager;
 use Patchlevel\EventSourcing\Repository\MessageDecorator\ChainMessageDecorator;
 use Patchlevel\EventSourcing\Repository\MessageDecorator\SplitStreamDecorator;
@@ -60,7 +61,7 @@ public function testSuccessful(): void
         $projectionist = new DefaultProjectionist(
             $store,
             new InMemoryStore(),
-            [$bankAccountProjector],
+            new MetadataProjectorAccessorRepository([$bankAccountProjector]),
         );
 
         $eventBus = DefaultEventBus::create([$bankAccountProjector]);
diff --git a/tests/Integration/BasicImplementation/BasicIntegrationTest.php b/tests/Integration/BasicImplementation/BasicIntegrationTest.php
index 0b095150..f8f3fe47 100644
--- a/tests/Integration/BasicImplementation/BasicIntegrationTest.php
+++ b/tests/Integration/BasicImplementation/BasicIntegrationTest.php
@@ -11,6 +11,7 @@
 use Patchlevel\EventSourcing\Projection\Projection\Store\InMemoryStore;
 use Patchlevel\EventSourcing\Projection\Projectionist\DefaultProjectionist;
 use Patchlevel\EventSourcing\Projection\Projectionist\ProjectionistCriteria;
+use Patchlevel\EventSourcing\Projection\Projector\MetadataProjectorAccessorRepository;
 use Patchlevel\EventSourcing\Repository\DefaultRepositoryManager;
 use Patchlevel\EventSourcing\Schema\DoctrineSchemaDirector;
 use Patchlevel\EventSourcing\Serializer\DefaultEventSerializer;
@@ -57,7 +58,7 @@ public function testSuccessful(): void
         $projectionist = new DefaultProjectionist(
             $store,
             new InMemoryStore(),
-            [$profileProjector],
+            new MetadataProjectorAccessorRepository([$profileProjector]),
         );
 
         $eventBus = DefaultEventBus::create([
@@ -125,7 +126,7 @@ public function testSnapshot(): void
         $projectionist = new DefaultProjectionist(
             $store,
             new InMemoryStore(),
-            [$profileProjection],
+            new MetadataProjectorAccessorRepository([$profileProjection]),
         );
 
         $eventBus = DefaultEventBus::create([
diff --git a/tests/Integration/Projectionist/Aggregate/Profile.php b/tests/Integration/Projectionist/Aggregate/Profile.php
index 0d827bad..64a4378a 100644
--- a/tests/Integration/Projectionist/Aggregate/Profile.php
+++ b/tests/Integration/Projectionist/Aggregate/Profile.php
@@ -9,6 +9,7 @@
 use Patchlevel\EventSourcing\Attribute\Apply;
 use Patchlevel\EventSourcing\Attribute\Id;
 use Patchlevel\EventSourcing\Serializer\Normalizer\IdNormalizer;
+use Patchlevel\EventSourcing\Tests\Integration\Projectionist\Events\NameChanged;
 use Patchlevel\EventSourcing\Tests\Integration\Projectionist\Events\ProfileCreated;
 use Patchlevel\EventSourcing\Tests\Integration\Projectionist\ProfileId;
 
@@ -28,13 +29,24 @@ public static function create(ProfileId $id, string $name): self
         return $self;
     }
 
-    #[Apply(ProfileCreated::class)]
+    public function changeName(string $name): void
+    {
+        $this->recordThat(new NameChanged($name));
+    }
+
+    #[Apply]
     protected function applyProfileCreated(ProfileCreated $event): void
     {
         $this->id = $event->profileId;
         $this->name = $event->name;
     }
 
+    #[Apply]
+    protected function applyNameChanged(NameChanged $event): void
+    {
+        $this->name = $event->name;
+    }
+
     public function name(): string
     {
         return $this->name;
diff --git a/tests/Integration/Projectionist/Events/NameChanged.php b/tests/Integration/Projectionist/Events/NameChanged.php
new file mode 100644
index 00000000..3ffd6e5d
--- /dev/null
+++ b/tests/Integration/Projectionist/Events/NameChanged.php
@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Tests\Integration\Projectionist\Events;
+
+use Patchlevel\EventSourcing\Attribute\Event;
+
+#[Event('profile.name_changed')]
+final class NameChanged
+{
+    public function __construct(
+        public string $name,
+    ) {
+    }
+}
diff --git a/tests/Integration/Projectionist/Projection/ProfileProcessor.php b/tests/Integration/Projectionist/Projection/ProfileProcessor.php
new file mode 100644
index 00000000..7982cdcf
--- /dev/null
+++ b/tests/Integration/Projectionist/Projection/ProfileProcessor.php
@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Tests\Integration\Projectionist\Projection;
+
+use Patchlevel\EventSourcing\Attribute\Projector;
+use Patchlevel\EventSourcing\Attribute\Subscribe;
+use Patchlevel\EventSourcing\EventBus\Message;
+use Patchlevel\EventSourcing\Repository\RepositoryManager;
+use Patchlevel\EventSourcing\Tests\Integration\Projectionist\Aggregate\Profile;
+use Patchlevel\EventSourcing\Tests\Integration\Projectionist\Events\ProfileCreated;
+
+use function assert;
+
+#[Projector('profile')]
+final class ProfileProcessor
+{
+    public function __construct(
+        private RepositoryManager $repositoryManager,
+    ) {
+    }
+
+    #[Subscribe(ProfileCreated::class)]
+    public function handleProfileCreated(Message $message): void
+    {
+        $profileCreated = $message->event();
+
+        assert($profileCreated instanceof ProfileCreated);
+
+        $repository = $this->repositoryManager->get(Profile::class);
+
+        $profile = $repository->load($profileCreated->profileId);
+
+        $profile->changeName('new name');
+
+        $repository->save($profile);
+    }
+}
diff --git a/tests/Integration/Projectionist/ProjectionistTest.php b/tests/Integration/Projectionist/ProjectionistTest.php
index a80ac1e1..0b5ca0c5 100644
--- a/tests/Integration/Projectionist/ProjectionistTest.php
+++ b/tests/Integration/Projectionist/ProjectionistTest.php
@@ -8,6 +8,7 @@
 use Doctrine\DBAL\Connection;
 use Patchlevel\EventSourcing\Clock\FrozenClock;
 use Patchlevel\EventSourcing\EventBus\DefaultEventBus;
+use Patchlevel\EventSourcing\EventBus\Message;
 use Patchlevel\EventSourcing\EventBus\Serializer\DefaultHeadersSerializer;
 use Patchlevel\EventSourcing\Metadata\AggregateRoot\AggregateRootRegistry;
 use Patchlevel\EventSourcing\Projection\Projection\Projection;
@@ -16,8 +17,13 @@
 use Patchlevel\EventSourcing\Projection\Projection\Store\DoctrineStore;
 use Patchlevel\EventSourcing\Projection\Projectionist\DefaultProjectionist;
 use Patchlevel\EventSourcing\Projection\Projectionist\ProjectionistCriteria;
+use Patchlevel\EventSourcing\Projection\Projector\MetadataProjectorAccessorRepository;
+use Patchlevel\EventSourcing\Projection\Projector\TraceableProjectorAccessorRepository;
 use Patchlevel\EventSourcing\Projection\RetryStrategy\ClockBasedRetryStrategy;
 use Patchlevel\EventSourcing\Repository\DefaultRepositoryManager;
+use Patchlevel\EventSourcing\Repository\MessageDecorator\TraceDecorator;
+use Patchlevel\EventSourcing\Repository\MessageDecorator\TraceHeader;
+use Patchlevel\EventSourcing\Repository\MessageDecorator\TraceStack;
 use Patchlevel\EventSourcing\Schema\ChainDoctrineSchemaConfigurator;
 use Patchlevel\EventSourcing\Schema\DoctrineSchemaDirector;
 use Patchlevel\EventSourcing\Serializer\DefaultEventSerializer;
@@ -25,9 +31,12 @@
 use Patchlevel\EventSourcing\Tests\DbalManager;
 use Patchlevel\EventSourcing\Tests\Integration\Projectionist\Aggregate\Profile;
 use Patchlevel\EventSourcing\Tests\Integration\Projectionist\Projection\ErrorProducerProjector;
+use Patchlevel\EventSourcing\Tests\Integration\Projectionist\Projection\ProfileProcessor;
 use Patchlevel\EventSourcing\Tests\Integration\Projectionist\Projection\ProfileProjector;
 use PHPUnit\Framework\TestCase;
 
+use function iterator_to_array;
+
 /** @coversNothing */
 final class ProjectionistTest extends TestCase
 {
@@ -86,7 +95,7 @@ public function testHappyPath(): void
         $projectionist = new DefaultProjectionist(
             $store,
             $projectionStore,
-            [new ProfileProjector($this->projectionConnection)],
+            new MetadataProjectorAccessorRepository([new ProfileProjector($this->projectionConnection)]),
         );
 
         self::assertEquals(
@@ -128,7 +137,10 @@ public function testHappyPath(): void
             $projectionist->projections(),
         );
 
-        $result = $this->projectionConnection->fetchAssociative('SELECT * FROM projection_profile_1 WHERE id = ?', ['1']);
+        $result = $this->projectionConnection->fetchAssociative(
+            'SELECT * FROM projection_profile_1 WHERE id = ?',
+            ['1'],
+        );
 
         self::assertIsArray($result);
         self::assertArrayHasKey('id', $result);
@@ -195,7 +207,7 @@ public function testErrorHandling(): void
         $projectionist = new DefaultProjectionist(
             $store,
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
             new ClockBasedRetryStrategy(
                 $clock,
                 ClockBasedRetryStrategy::DEFAULT_BASE_DELAY,
@@ -289,6 +301,111 @@ public function testErrorHandling(): void
         self::assertEquals(0, $projection->retryAttempt());
     }
 
+    public function testProcessor(): void
+    {
+        $store = new DoctrineDbalStore(
+            $this->connection,
+            DefaultEventSerializer::createFromPaths([__DIR__ . '/Events']),
+            DefaultHeadersSerializer::createFromPaths([
+                __DIR__ . '/../../../src',
+                __DIR__,
+            ]),
+            'eventstore',
+        );
+
+        $clock = new FrozenClock(new DateTimeImmutable('2021-01-01T00:00:00'));
+
+        $projectionStore = new DoctrineStore(
+            $this->connection,
+            $clock,
+        );
+
+        $traceStack = new TraceStack();
+
+        $manager = new DefaultRepositoryManager(
+            new AggregateRootRegistry(['profile' => Profile::class]),
+            $store,
+            DefaultEventBus::create(),
+            null,
+            new TraceDecorator($traceStack),
+        );
+
+        $projectorAccessorRepository = new TraceableProjectorAccessorRepository(
+            new MetadataProjectorAccessorRepository([new ProfileProcessor($manager)]),
+            $traceStack,
+        );
+
+        $repository = $manager->get(Profile::class);
+
+        $schemaDirector = new DoctrineSchemaDirector(
+            $this->connection,
+            new ChainDoctrineSchemaConfigurator([
+                $store,
+                $projectionStore,
+            ]),
+        );
+
+        $schemaDirector->create();
+
+        $projectionist = new DefaultProjectionist(
+            $store,
+            $projectionStore,
+            $projectorAccessorRepository,
+        );
+
+        self::assertEquals(
+            [new Projection('profile', lastSavedAt: new DateTimeImmutable('2021-01-01T00:00:00'))],
+            $projectionist->projections(),
+        );
+
+        $projectionist->boot();
+
+        self::assertEquals(
+            [
+                new Projection(
+                    'profile',
+                    Projection::DEFAULT_GROUP,
+                    RunMode::FromBeginning,
+                    ProjectionStatus::Active,
+                    lastSavedAt: new DateTimeImmutable('2021-01-01T00:00:00'),
+                ),
+            ],
+            $projectionist->projections(),
+        );
+
+        $profile = Profile::create(ProfileId::fromString('1'), 'John');
+        $repository->save($profile);
+
+        $projectionist->run();
+
+        $projections = $projectionist->projections();
+
+        self::assertCount(1, $projections);
+        self::assertArrayHasKey(0, $projections);
+
+        $projection = $projections[0];
+
+        self::assertEquals('profile', $projection->id());
+
+        self::assertEquals(ProjectionStatus::Active, $projection->status());
+
+        /** @var list<Message> $messages */
+        $messages = iterator_to_array($store->load());
+
+        self::assertCount(2, $messages);
+        self::assertArrayHasKey(1, $messages);
+
+        self::assertEquals(
+            new TraceHeader([
+                [
+                    'name' => 'profile',
+                    'category' => 'event_sourcing/projector/default',
+                ],
+            ]),
+            $messages[1]->header(TraceHeader::class),
+        );
+    }
+
     /** @param list<Projection> $projections */
     private static function findProjection(array $projections, string $id): Projection
     {
diff --git a/tests/Unit/Projection/Projectionist/DefaultProjectionistTest.php b/tests/Unit/Projection/Projectionist/DefaultProjectionistTest.php
index 33506502..b87f83e0 100644
--- a/tests/Unit/Projection/Projectionist/DefaultProjectionistTest.php
+++ b/tests/Unit/Projection/Projectionist/DefaultProjectionistTest.php
@@ -21,6 +21,7 @@
 use Patchlevel\EventSourcing\Projection\Projection\ThrowableToErrorContextTransformer;
 use Patchlevel\EventSourcing\Projection\Projectionist\DefaultProjectionist;
 use Patchlevel\EventSourcing\Projection\Projectionist\ProjectionistCriteria;
+use Patchlevel\EventSourcing\Projection\Projector\MetadataProjectorAccessorRepository;
 use Patchlevel\EventSourcing\Projection\RetryStrategy\RetryStrategy;
 use Patchlevel\EventSourcing\Store\ArrayStream;
 use Patchlevel\EventSourcing\Store\Criteria;
@@ -49,7 +50,7 @@ public function testNothingToBoot(): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $store,
-            [],
+            new MetadataProjectorAccessorRepository([]),
         );
 
         $projectionist->boot();
@@ -73,7 +74,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->boot();
@@ -122,7 +123,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->boot();
@@ -182,7 +183,7 @@ public function handle(Message $message): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->boot();
@@ -254,7 +255,7 @@ public function handle(Message $message): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->boot(new ProjectionistCriteria(), 1);
@@ -338,7 +339,7 @@ public function handle(Message $message): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector1, $projector2],
+            new MetadataProjectorAccessorRepository([$projector1, $projector2]),
         );
 
         $projectionist->boot();
@@ -405,7 +406,7 @@ public function create(): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->boot();
@@ -462,7 +463,7 @@ public function handle(Message $message): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->boot();
@@ -518,7 +519,7 @@ public function handle(Message $message): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->boot();
@@ -567,7 +568,7 @@ public function handle(Message $message): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->boot();
@@ -616,7 +617,7 @@ public function handle(Message $message): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->boot();
@@ -654,7 +655,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->run();
@@ -700,7 +701,7 @@ public function handle(Message $message): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->run();
@@ -753,7 +754,7 @@ public function handle(Message $message): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->run(new ProjectionistCriteria(), 1);
@@ -821,7 +822,7 @@ public function handle(Message $message): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector1, $projector2],
+            new MetadataProjectorAccessorRepository([$projector1, $projector2]),
         );
 
         $projectionist->run();
@@ -881,7 +882,7 @@ public function handle(Message $message): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->run();
@@ -924,7 +925,7 @@ public function testRunningMarkOutdated(): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [],
+            new MetadataProjectorAccessorRepository([]),
         );
 
         $projectionist->run();
@@ -959,7 +960,7 @@ public function testRunningWithoutActiveProjectors(): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [],
+            new MetadataProjectorAccessorRepository([]),
         );
 
         $projectionist->run();
@@ -1000,7 +1001,7 @@ public function handle(Message $message): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->run();
@@ -1031,7 +1032,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->teardown();
@@ -1067,7 +1068,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->teardown();
@@ -1105,7 +1106,7 @@ public function drop(): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->teardown();
@@ -1144,7 +1145,7 @@ public function drop(): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->teardown();
@@ -1171,7 +1172,7 @@ public function testTeardownWithoutProjector(): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [],
+            new MetadataProjectorAccessorRepository([]),
         );
 
         $projectionist->teardown();
@@ -1193,7 +1194,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->remove();
@@ -1235,7 +1236,7 @@ public function drop(): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->remove();
@@ -1265,7 +1266,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->remove();
@@ -1301,7 +1302,7 @@ public function drop(): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->remove();
@@ -1327,7 +1328,7 @@ public function testRemoveWithoutProjector(): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [],
+            new MetadataProjectorAccessorRepository([]),
         );
 
         $projectionist->remove();
@@ -1349,7 +1350,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->reactivate();
@@ -1387,7 +1388,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->reactivate();
@@ -1424,7 +1425,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->reactivate();
@@ -1460,7 +1461,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->reactivate();
@@ -1496,7 +1497,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->reactivate();
@@ -1524,7 +1525,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->pause();
@@ -1560,7 +1561,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->pause();
@@ -1596,7 +1597,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->pause();
@@ -1634,7 +1635,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->pause();
@@ -1664,7 +1665,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projections = $projectionist->projections();
@@ -1722,7 +1723,7 @@ public function subscribe(): void
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
             $retryStrategy->reveal(),
         );
 
@@ -1774,7 +1775,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore,
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
             $retryStrategy->reveal(),
         );
 
@@ -1809,7 +1810,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore->reveal(),
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionistCriteria = new ProjectionistCriteria(
@@ -1849,7 +1850,7 @@ class {
         $projectionist = new DefaultProjectionist(
             $streamableStore->reveal(),
             $projectionStore->reveal(),
-            [$projector],
+            new MetadataProjectorAccessorRepository([$projector]),
         );
 
         $projectionist->{$method}();
diff --git a/tests/Unit/Projection/Projector/MetadataProjectorAccessorRepositoryTest.php b/tests/Unit/Projection/Projector/MetadataProjectorAccessorRepositoryTest.php
new file mode 100644
index 00000000..48615474
--- /dev/null
+++ b/tests/Unit/Projection/Projector/MetadataProjectorAccessorRepositoryTest.php
@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Tests\Unit\Projection\Projector;
+
+use Patchlevel\EventSourcing\Attribute\Projector;
+use Patchlevel\EventSourcing\Metadata\Projector\AttributeProjectorMetadataFactory;
+use Patchlevel\EventSourcing\Projection\Projector\MetadataProjectorAccessor;
+use Patchlevel\EventSourcing\Projection\Projector\MetadataProjectorAccessorRepository;
+use PHPUnit\Framework\TestCase;
+
+final class MetadataProjectorAccessorRepositoryTest extends TestCase
+{
+    public function testEmpty(): void
+    {
+        $repository = new MetadataProjectorAccessorRepository(
+            [],
+        );
+
+        self::assertEquals([], $repository->all());
+        self::assertNull($repository->get('foo'));
+    }
+
+    public function testWithProjector(): void
+    {
+        $projector = new #[Projector('foo')]
+        class {
+        };
+        $metadataFactory = new AttributeProjectorMetadataFactory();
+
+        $repository = new MetadataProjectorAccessorRepository(
+            [$projector],
+            $metadataFactory,
+        );
+
+        $accessor = new MetadataProjectorAccessor(
+            $projector,
+            $metadataFactory->metadata($projector::class),
+        );
+
+        self::assertEquals([$accessor], $repository->all());
+        self::assertEquals($accessor, $repository->get('foo'));
+    }
+}
diff --git a/tests/Unit/Projection/Projector/MetadataProjectorAccessorTest.php b/tests/Unit/Projection/Projector/MetadataProjectorAccessorTest.php
new file mode 100644
index 00000000..9b5d801e
--- /dev/null
+++ b/tests/Unit/Projection/Projector/MetadataProjectorAccessorTest.php
@@ -0,0 +1,206 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Tests\Unit\Projection\Projector;
+
+use Patchlevel\EventSourcing\Attribute\Projector;
+use Patchlevel\EventSourcing\Attribute\Setup;
+use Patchlevel\EventSourcing\Attribute\Subscribe;
+use Patchlevel\EventSourcing\Attribute\Teardown;
+use Patchlevel\EventSourcing\EventBus\Message;
+use Patchlevel\EventSourcing\Metadata\Projector\AttributeProjectorMetadataFactory;
+use Patchlevel\EventSourcing\Projection\Projection\RunMode;
+use Patchlevel\EventSourcing\Projection\Projector\MetadataProjectorAccessor;
+use Patchlevel\EventSourcing\Tests\Unit\Fixture\ProfileCreated;
+use PHPUnit\Framework\TestCase;
+
+/** @covers \Patchlevel\EventSourcing\Projection\Projector\MetadataProjectorAccessor */
+final class MetadataProjectorAccessorTest extends TestCase
+{
+    public function testId(): void
+    {
+        $projector = new #[Projector('profile')]
+        class {
+        };
+
+        $accessor = new MetadataProjectorAccessor(
+            $projector,
+            (new AttributeProjectorMetadataFactory())->metadata($projector::class),
+        );
+
+        self::assertEquals('profile', $accessor->id());
+    }
+
+    public function testGroup(): void
+    {
+        $projector = new #[Projector('profile')]
+        class {
+        };
+
+        $accessor = new MetadataProjectorAccessor(
+            $projector,
+            (new AttributeProjectorMetadataFactory())->metadata($projector::class),
+        );
+
+        self::assertEquals('default', $accessor->group());
+    }
+
+    public function testRunMode(): void
+    {
+        $projector = new #[Projector('profile')]
+        class {
+        };
+
+        $accessor = new MetadataProjectorAccessor(
+            $projector,
+            (new AttributeProjectorMetadataFactory())->metadata($projector::class),
+        );
+
+        self::assertEquals(RunMode::FromBeginning, $accessor->runMode());
+    }
+
+    public function testSubscribeMethod(): void
+    {
+        $projector = new #[Projector('profile')]
+        class {
+            #[Subscribe(ProfileCreated::class)]
+            public function onProfileCreated(Message $message): void
+            {
+            }
+        };
+
+        $accessor = new MetadataProjectorAccessor(
+            $projector,
+            (new AttributeProjectorMetadataFactory())->metadata($projector::class),
+        );
+
+        $result = $accessor->subscribeMethods(ProfileCreated::class);
+
+        self::assertEquals([
+            $projector->onProfileCreated(...),
+        ], $result);
+    }
+
+    public function testMultipleSubscribeMethod(): void
+    {
+        $projector = new #[Projector('profile')]
+        class {
+            #[Subscribe(ProfileCreated::class)]
+            public function onProfileCreated(Message $message): void
+            {
+            }
+
+            #[Subscribe(ProfileCreated::class)]
+            public function onFoo(Message $message): void
+            {
+            }
+        };
+
+        $accessor = new MetadataProjectorAccessor(
+            $projector,
+            (new AttributeProjectorMetadataFactory())->metadata($projector::class),
+        );
+
+        $result = $accessor->subscribeMethods(ProfileCreated::class);
+
+        self::assertEquals([
+            $projector->onProfileCreated(...),
+            $projector->onFoo(...),
+        ], $result);
+    }
+
+    public function testSubscribeAllMethod(): void
+    {
+        $projector = new #[Projector('profile')]
+        class {
+            #[Subscribe('*')]
+            public function onProfileCreated(Message $message): void
+            {
+            }
+        };
+
+        $accessor = new MetadataProjectorAccessor(
+            $projector,
+            (new AttributeProjectorMetadataFactory())->metadata($projector::class),
+        );
+
+        $result = $accessor->subscribeMethods(ProfileCreated::class);
+
+        self::assertEquals([
+            $projector->onProfileCreated(...),
+        ], $result);
+    }
+
+    public function testSetupMethod(): void
+    {
+        $projector = new #[Projector('profile')]
+        class {
+            #[Setup]
+            public function method(): void
+            {
+            }
+        };
+
+        $accessor = new MetadataProjectorAccessor(
+            $projector,
+            (new AttributeProjectorMetadataFactory())->metadata($projector::class),
+        );
+
+        $result = $accessor->setupMethod();
+
+        self::assertEquals($projector->method(...), $result);
+    }
+
+    public function testNotSetupMethod(): void
+    {
+        $projector = new #[Projector('profile')]
+        class {
+        };
+
+        $accessor = new MetadataProjectorAccessor(
+            $projector,
+            (new AttributeProjectorMetadataFactory())->metadata($projector::class),
+        );
+
+        $result = $accessor->setupMethod();
+
+        self::assertNull($result);
+    }
+
+    public function testTeardownMethod(): void
+    {
+        $projector = new #[Projector('profile')]
+        class {
+            #[Teardown]
+            public function method(): void
+            {
+            }
+        };
+
+        $accessor = new MetadataProjectorAccessor(
+            $projector,
+            (new AttributeProjectorMetadataFactory())->metadata($projector::class),
+        );
+
+        $result = $accessor->teardownMethod();
+
+        self::assertEquals($projector->method(...), $result);
+    }
+
+    public function testNotTeardownMethod(): void
+    {
+        $projector = new #[Projector('profile')]
+        class {
+        };
+
+        $accessor = new MetadataProjectorAccessor(
+            $projector,
+            (new AttributeProjectorMetadataFactory())->metadata($projector::class),
+        );
+
+        $result = $accessor->teardownMethod();
+
+        self::assertNull($result);
+    }
+}
diff --git a/tests/Unit/Repository/MessageDecorator/TraceDecoratorTest.php b/tests/Unit/Repository/MessageDecorator/TraceDecoratorTest.php
new file mode 100644
index 00000000..4434d586
--- /dev/null
+++ b/tests/Unit/Repository/MessageDecorator/TraceDecoratorTest.php
@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Tests\Unit\Repository\MessageDecorator;
+
+use Patchlevel\EventSourcing\EventBus\HeaderNotFound;
+use Patchlevel\EventSourcing\EventBus\Message;
+use Patchlevel\EventSourcing\Repository\MessageDecorator\Trace;
+use Patchlevel\EventSourcing\Repository\MessageDecorator\TraceDecorator;
+use Patchlevel\EventSourcing\Repository\MessageDecorator\TraceHeader;
+use Patchlevel\EventSourcing\Repository\MessageDecorator\TraceStack;
+use PHPUnit\Framework\TestCase;
+use Prophecy\PhpUnit\ProphecyTrait;
+use stdClass;
+
+/** @covers \Patchlevel\EventSourcing\Repository\MessageDecorator\TraceDecorator */
+final class TraceDecoratorTest extends TestCase
+{
+    use ProphecyTrait;
+
+    public function testWithoutTrace(): void
+    {
+        $this->expectException(HeaderNotFound::class);
+
+        $stack = new TraceStack();
+        $decorator = new TraceDecorator($stack);
+
+        $message = new Message(new stdClass());
+
+        $decoratedMessage = $decorator($message);
+
+        self::assertEquals($message, $decoratedMessage);
+
+        $decoratedMessage->header(TraceHeader::class);
+    }
+
+    public function testWithTrace(): void
+    {
+        $stack = new TraceStack();
+        $stack->add(new Trace('name', 'category'));
+
+        $decorator = new TraceDecorator($stack);
+
+        $message = new Message(new stdClass());
+
+        $decoratedMessage = $decorator($message);
+
+        self::assertEquals(
+            new TraceHeader([
+                [
+                    'name' => 'name',
+                    'category' => 'category',
+                ],
+            ]),
+            $decoratedMessage->header(TraceHeader::class),
+        );
+    }
+}
diff --git a/tests/Unit/Repository/MessageDecorator/TraceStackTest.php b/tests/Unit/Repository/MessageDecorator/TraceStackTest.php
new file mode 100644
index 00000000..f348e353
--- /dev/null
+++ b/tests/Unit/Repository/MessageDecorator/TraceStackTest.php
@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Tests\Unit\Repository\MessageDecorator;
+
+use Patchlevel\EventSourcing\Repository\MessageDecorator\Trace;
+use Patchlevel\EventSourcing\Repository\MessageDecorator\TraceStack;
+use PHPUnit\Framework\TestCase;
+use Prophecy\PhpUnit\ProphecyTrait;
+
+/** @covers \Patchlevel\EventSourcing\Repository\MessageDecorator\TraceStack */
+final class TraceStackTest extends TestCase
+{
+    use ProphecyTrait;
+
+    public function testStack(): void
+    {
+        $stack = new TraceStack();
+
+        self::assertEquals([], $stack->get());
+
+        $trace = new Trace('name', 'category');
+
+        $stack->add($trace);
+
+        self::assertEquals([$trace], $stack->get());
+
+        $stack->remove($trace);
+
+        self::assertEquals([], $stack->get());
+    }
+}