diff --git a/gradle-conjure/src/main/java/com/palantir/gradle/conjure/ConjureJavaServiceDependenciesTask.java b/gradle-conjure/src/main/java/com/palantir/gradle/conjure/ConjureJavaServiceDependenciesTask.java
index b9de4653f..259606bde 100644
--- a/gradle-conjure/src/main/java/com/palantir/gradle/conjure/ConjureJavaServiceDependenciesTask.java
+++ b/gradle-conjure/src/main/java/com/palantir/gradle/conjure/ConjureJavaServiceDependenciesTask.java
@@ -50,7 +50,7 @@ public final void populateServiceDependencies() throws IOException {
         for (Jar jarTask : subproject.getTasks().withType(Jar.class)) {
             jarTask.getManifest()
                     .getAttributes()
-                    .put(SLS_RECOMMENDED_PRODUCT_DEPENDENCIES,
+                    .putIfAbsent(SLS_RECOMMENDED_PRODUCT_DEPENDENCIES,
                             GenerateConjureServiceDependenciesTask.jsonMapper.writeValueAsString(
                                     new RecommendedProductDependencies(getServiceDependencies())));
         }