diff --git a/CHANGELOG.md b/CHANGELOG.md
index 58b0792e..9999835c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,4 +3,5 @@
 ## 1.0.0 under development
 
 - Initial release.
+- Bug #341: Pass the message a handler was registered for to that handler instead of the envelope an adapter wrapped it in, so a handler no longer reads properties off an `IdEnvelope`, `DelayEnvelope` or `FailureEnvelope` and works on empty values; what the envelope carried comes with the message as meta, and consume middleware still receive the envelope itself (@KalimeroMK)
 - Bug #347: `SignalLoop` installs signal handlers only while messages are consumed and restores the previous ones afterwards, instead of replacing them when it is created (@samdark)
diff --git a/docs/guide/en/messages-and-handlers.md b/docs/guide/en/messages-and-handlers.md
index 533e95dc..306ceb09 100644
--- a/docs/guide/en/messages-and-handlers.md
+++ b/docs/guide/en/messages-and-handlers.md
@@ -113,6 +113,12 @@ final class SendEmailHandler implements \Yiisoft\Queue\Message\Handler\HandlerIn
 
 The handler can have any dependencies injected through the DI container. The message payload remains plain data.
 
+The handler is always given the message its type was registered for, never an envelope wrapped
+around it on the way through the queue, so the `assert()` above holds on every adapter. What the
+envelopes carried comes with it as message meta, so the handler still reads those values —
+`IdEnvelope::fromMessage($message)->getId()`, or `$message->getMeta()` directly. Consume
+middleware run before that step and receive the envelope itself.
+
 ## Why the separation matters
 
 ### Versioning
diff --git a/src/Middleware/Consume/ConsumeFinalHandler.php b/src/Middleware/Consume/ConsumeFinalHandler.php
index 44c96e47..3da61943 100644
--- a/src/Middleware/Consume/ConsumeFinalHandler.php
+++ b/src/Middleware/Consume/ConsumeFinalHandler.php
@@ -5,6 +5,7 @@
 namespace Yiisoft\Queue\Middleware\Consume;
 
 use Closure;
+use Yiisoft\Queue\Message\Envelope;
 
 /**
  * @internal
@@ -17,8 +18,19 @@ public function __construct(
 
     public function handleConsume(ConsumeRequest $request): ConsumeRequest
     {
+        $message = $request->getMessage();
+
+        // The handler is registered for a message type and is given that message, not whatever
+        // the adapter wrapped it in on the way. The envelope's meta is carried over rather than
+        // dropped with the wrapper: the envelope holds the merged meta while the message it wraps
+        // keeps its own, so unwrapping alone would lose the id, the delay and the failure counts.
+        // Middleware run before this step and still see the envelope itself.
+        if ($message instanceof Envelope) {
+            $message = $message->getMessage()->withMeta($message->getMeta());
+        }
+
         $handler = $this->handler;
-        $handler($request->getMessage());
+        $handler($message);
 
         return $request;
     }
diff --git a/tests/Unit/WorkerTest.php b/tests/Unit/WorkerTest.php
index 0eea359b..f68a4480 100644
--- a/tests/Unit/WorkerTest.php
+++ b/tests/Unit/WorkerTest.php
@@ -12,11 +12,15 @@
 use Yiisoft\Queue\Exception\MessageFailureException;
 use Yiisoft\Queue\Message\Handler\HandlerNotFoundException;
 use Yiisoft\Queue\Message\Handler\HandlerResolver;
+use Yiisoft\Queue\Message\Envelope;
 use Yiisoft\Queue\Message\GenericMessage;
+use Yiisoft\Queue\Message\IdEnvelope;
 use Yiisoft\Queue\Message\MessageInterface;
+use Yiisoft\Queue\Middleware\Consume\ConsumeHandlerInterface;
 use Yiisoft\Queue\Middleware\Consume\ConsumeMiddlewareDispatcher;
 use Yiisoft\Queue\Middleware\Consume\ConsumeMiddlewareFactoryInterface;
 use Yiisoft\Queue\Middleware\Consume\ConsumeMiddlewareInterface;
+use Yiisoft\Queue\Middleware\Consume\ConsumeRequest;
 use Yiisoft\Queue\Middleware\FailureHandling\FailureHandlingRequest;
 use Yiisoft\Queue\Middleware\FailureHandling\FailureMiddlewareDispatcher;
 use Yiisoft\Queue\Middleware\FailureHandling\FailureMiddlewareFactoryInterface;
@@ -140,6 +144,75 @@ public function testUnresolvableHandlerIsHandledByFailurePipeline(): void
         $worker->process($message, $queueName);
     }
 
+    public function testHandlerReceivesTheMessageAndNotTheEnvelopeAroundIt(): void
+    {
+        $message = new GenericMessage('simple', ['test-data']);
+        $envelope = new IdEnvelope($message, 'id-42');
+
+        $received = null;
+        $handlerResolver = $this->createHandlerResolver(
+            $message,
+            static function (MessageInterface $message) use (&$received): void {
+                $received = $message;
+            },
+        );
+
+        $this->createWorkerByParams($handlerResolver)->process($envelope, 'test-queue');
+
+        // The handler is registered for the message type and gets that message, whatever the
+        // adapter wrapped it in on the way back.
+        $this->assertInstanceOf(GenericMessage::class, $received);
+        $this->assertNotInstanceOf(Envelope::class, $received);
+        $this->assertSame($message->getType(), $received->getType());
+        $this->assertSame($message->getPayload(), $received->getPayload());
+
+        // What the envelope carried comes with it, so a handler that logs or de-duplicates on
+        // the id still has one.
+        $this->assertSame($envelope->getMeta(), $received->getMeta());
+        $this->assertSame('id-42', IdEnvelope::fromMessage($received)->getId());
+    }
+
+    public function testConsumeMiddlewareStillSeesTheEnvelope(): void
+    {
+        $message = new GenericMessage('simple', null);
+        $envelope = new IdEnvelope($message, 'id-42');
+
+        $seenByMiddleware = null;
+        /** @var ConsumeMiddlewareInterface&MockObject $consumeMiddleware */
+        $consumeMiddleware = $this->createMock(ConsumeMiddlewareInterface::class);
+        $consumeMiddleware
+            ->method('processConsume')
+            ->willReturnCallback(
+                static function (ConsumeRequest $request, ConsumeHandlerInterface $handler) use (&$seenByMiddleware) {
+                    $seenByMiddleware = $request->getMessage();
+
+                    return $handler->handleConsume($request);
+                },
+            );
+
+        /** @var ConsumeMiddlewareFactoryInterface&MockObject $consumeMiddlewareFactory */
+        $consumeMiddlewareFactory = $this->createMock(ConsumeMiddlewareFactoryInterface::class);
+        $consumeMiddlewareFactory->method('createConsumeMiddleware')->willReturn($consumeMiddleware);
+        $consumeDispatcher = new ConsumeMiddlewareDispatcher($consumeMiddlewareFactory, 'simple');
+
+        $receivedByHandler = null;
+        $handlerResolver = $this->createHandlerResolver(
+            $message,
+            static function (MessageInterface $message) use (&$receivedByHandler): void {
+                $receivedByHandler = $message;
+            },
+        );
+
+        $worker = $this->createWorkerByParams($handlerResolver, new NullLogger(), $consumeDispatcher);
+        $worker->process($envelope, 'test-queue');
+
+        // Unwrapping happens at the last step, so middleware keep the envelope itself, and only
+        // the handler is given the message — with the meta the envelope carried.
+        $this->assertSame($envelope, $seenByMiddleware);
+        $this->assertNotInstanceOf(Envelope::class, $receivedByHandler);
+        $this->assertSame('id-42', IdEnvelope::fromMessage($receivedByHandler)->getId());
+    }
+
     private function createHandlerResolver(MessageInterface $message, callable $handler): HandlerResolver
     {
         $container = new SimpleContainer();