diff --git a/driver-multiplatform-wire/src/commonTest/kotlin/OpMsgUtils.kt b/driver-multiplatform-wire/src/commonTest/kotlin/OpMsgUtils.kt
new file mode 100644
index 00000000..6c6d7936
--- /dev/null
+++ b/driver-multiplatform-wire/src/commonTest/kotlin/OpMsgUtils.kt
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2026, OpenSavvy and contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package opensavvy.ktmongo.multiplatform.wire
+
+import opensavvy.ktmongo.bson.BsonFieldWriter
+import opensavvy.ktmongo.bson.multiplatform.BsonFactory
+import opensavvy.ktmongo.dsl.LowLevelApi
+import opensavvy.ktmongo.multiplatform.wire.Message.OpMsg
+
+/**
+ * Creates an [OpMsg] message with the given [body] and no [OpMsg.sequences].
+ */
+@OptIn(LowLevelApi::class)
+fun OpMsg(body: BsonFieldWriter.() -> Unit): OpMsg =
+	OpMsg(
+		MessageSection.Body(
+			eager(
+				BsonFactory().buildDocument(body)
+			)
+		),
+		sequences = emptySequence()
+	)
+
+/**
+ * Creates a copy of this [OpMsg], concatenating a new sequence named [id] and composed of the given [documents].
+ */
+@OptIn(LowLevelApi::class)
+fun OpMsg.withSequence(
+	id: String,
+	vararg documents: BsonFieldWriter.() -> Unit,
+): OpMsg = OpMsg(
+	body,
+	sequences + MessageSection.DocumentSequence(
+		id,
+		documents.map { eager(BsonFactory().buildDocument(it)) }
+	)
+)
diff --git a/driver-multiplatform-wire/src/commonTest/kotlin/fake/FakeServerTest.kt b/driver-multiplatform-wire/src/commonTest/kotlin/fake/FakeServerTest.kt
index b53820e9..4fb05486 100644
--- a/driver-multiplatform-wire/src/commonTest/kotlin/fake/FakeServerTest.kt
+++ b/driver-multiplatform-wire/src/commonTest/kotlin/fake/FakeServerTest.kt
@@ -18,11 +18,9 @@
 
 package opensavvy.ktmongo.multiplatform.wire.fake
 
-import opensavvy.ktmongo.bson.multiplatform.BsonFactory
 import opensavvy.ktmongo.dsl.LowLevelApi
 import opensavvy.ktmongo.multiplatform.wire.Message
-import opensavvy.ktmongo.multiplatform.wire.MessageSection
-import opensavvy.ktmongo.multiplatform.wire.eager
+import opensavvy.ktmongo.multiplatform.wire.OpMsg
 import opensavvy.ktmongo.multiplatform.wire.fake.FakeServer.Companion.fakeServer
 import opensavvy.prepared.runner.testballoon.preparedSuite
 
@@ -40,25 +38,13 @@ val FakeServerTest by preparedSuite {
 	}
 
 	test("Round-trip hello") {
-		val helloMessage = Message.OpMsg(
-			MessageSection.Body(
-				eager(
-					BsonFactory().buildDocument {
-						writeInt32("hello", 1)
-					}
-				)
-			)
-		)
+		val helloMessage = OpMsg {
+			writeInt32("hello", 1)
+		}
 
-		val okMessage = Message.OpMsg(
-			MessageSection.Body(
-				eager(
-					BsonFactory().buildDocument {
-						writeDouble("ok", 1.0)
-					}
-				)
-			)
-		)
+		val okMessage = OpMsg {
+			writeDouble("ok", 1.0)
+		}
 
 		val server = fakeServer {
 			expect(helloMessage)