diff --git a/codegen-server-test/build.gradle.kts b/codegen-server-test/build.gradle.kts
index 808d476058..5d9464b3a4 100644
--- a/codegen-server-test/build.gradle.kts
+++ b/codegen-server-test/build.gradle.kts
@@ -21,6 +21,8 @@ val properties = PropertyRetriever(rootProject, project)
 val pluginName = "rust-server-codegen"
 val workingDirUnderBuildDir = "smithyprojections/codegen-server-test/"
 
+val checkedInSmithyRuntimeLockfile = rootProject.projectDir.resolve("rust-runtime/Cargo.lock")
+
 dependencies {
     implementation(project(":codegen-server"))
     implementation("software.amazon.smithy:smithy-aws-protocol-tests:$smithyVersion")
@@ -104,9 +106,10 @@ val allCodegenTests = "../codegen-core/common-test-models".let { commonModels ->
 project.registerGenerateSmithyBuildTask(rootProject, pluginName, allCodegenTests)
 project.registerGenerateCargoWorkspaceTask(rootProject, pluginName, allCodegenTests, workingDirUnderBuildDir)
 project.registerGenerateCargoConfigTomlTask(layout.buildDirectory.dir(workingDirUnderBuildDir).get().asFile)
+project.registerCopyCheckedInCargoLockfileTask(checkedInSmithyRuntimeLockfile, layout.buildDirectory.dir(workingDirUnderBuildDir).get().asFile)
 
 tasks["smithyBuild"].dependsOn("generateSmithyBuild")
-tasks["assemble"].finalizedBy("generateCargoWorkspace", "generateCargoConfigToml")
+tasks["assemble"].finalizedBy("generateCargoWorkspace", "copyCheckedInCargoLockfile", "generateCargoConfigToml")
 
 project.registerModifyMtimeTask()
 project.registerCargoCommandsTasks(layout.buildDirectory.dir(workingDirUnderBuildDir).get().asFile)