diff --git a/kotlin/builder/integrationtests/KotlinBuilderTestCase.java b/kotlin/builder/integrationtests/KotlinBuilderTestCase.java
index f21119d..5fe32c7 100644
--- a/kotlin/builder/integrationtests/KotlinBuilderTestCase.java
+++ b/kotlin/builder/integrationtests/KotlinBuilderTestCase.java
@@ -88,7 +88,8 @@
     builder.getInfoBuilder()
             .setLabel("//some/bogus:" + label)
             .setModuleName("some_bogus_module")
-            .setRuleKind("kt_jvm_library")
+            .setPlatform(KotlinModel.CompilationTask.Info.Platform.JVM)
+            .setRuleKind(KotlinModel.CompilationTask.Info.RuleKind.LIBRARY)
             .setToolchainInfo(
                 KotlinModel.KotlinToolchainInfo.newBuilder()
                     .setCommon(
diff --git a/kotlin/builder/proto/jars/libkotlin_model_proto-speed.jar b/kotlin/builder/proto/jars/libkotlin_model_proto-speed.jar
index 80467f0..57e15f8 100755
--- a/kotlin/builder/proto/jars/libkotlin_model_proto-speed.jar
+++ b/kotlin/builder/proto/jars/libkotlin_model_proto-speed.jar
Binary files differ
diff --git a/kotlin/builder/proto/kotlin_model.proto b/kotlin/builder/proto/kotlin_model.proto
index 7b5bb38..f54fd54 100644
--- a/kotlin/builder/proto/kotlin_model.proto
+++ b/kotlin/builder/proto/kotlin_model.proto
@@ -67,19 +67,33 @@
 // Mested messages not marked with stable could be refactored.
 message CompilationTask {
     message Info {
+        enum RuleKind {
+            LIBRARY = 0;
+            BINARY = 1;
+            TEST = 2;
+            IMPORT = 3;
+        }
+
+        enum Platform {
+            JVM = 0;
+            JS = 1;
+        }
+
         string label = 1;
-        // The rule kind requesting the build.
-        string rule_kind = 2;
+        // The Platform type.
+        Platform platform = 2;
+        // The kind of the rule.
+        RuleKind rule_kind = 3;
         // The name of the module being compiled.
-        string module_name = 3;
+        string module_name = 4;
         // Flags to be passed straight through to the compiler.
-        string passthrough_flags = 4;
+        string passthrough_flags = 5;
         // Toolchain info for this build.
-        KotlinToolchainInfo toolchain_info = 5;
+        KotlinToolchainInfo toolchain_info = 6;
         // Compiler plugin descriptors.
-        CompilerPlugins plugins = 6;
+        CompilerPlugins plugins = 7;
         // Paths to Jars that the kotlin compiler will allow package private access to.
-        repeated string friend_paths = 7;
+        repeated string friend_paths = 8;
     }
 
     // Directories used by the builder.
diff --git a/kotlin/builder/src/io/bazel/kotlin/builder/TaskBuilder.kt b/kotlin/builder/src/io/bazel/kotlin/builder/TaskBuilder.kt
index 84d24fc..204d623 100644
--- a/kotlin/builder/src/io/bazel/kotlin/builder/TaskBuilder.kt
+++ b/kotlin/builder/src/io/bazel/kotlin/builder/TaskBuilder.kt
@@ -103,7 +103,15 @@
 
             with(root.infoBuilder) {
                 label = argMap.mandatorySingle(JavaBuilderFlags.TARGET_LABEL.flag)
-                ruleKind = argMap.mandatorySingle(JavaBuilderFlags.RULE_KIND.flag)
+                argMap.mandatorySingle(JavaBuilderFlags.RULE_KIND.flag).split("_").also {
+                    check(it.size == 3 && it[0] == "kt")
+                    platform = checkNotNull(CompilationTask.Info.Platform.valueOf(it[1].toUpperCase())) {
+                        "unrecognized platform ${it[1]}"
+                    }
+                    ruleKind = checkNotNull(CompilationTask.Info.RuleKind.valueOf(it[2].toUpperCase())) {
+                        "unrecognized rule kind ${it[2]}"
+                    }
+                }
                 moduleName = argMap.mandatorySingle("--kotlin_module_name").also {
                     check(it.isNotBlank()) { "--kotlin_module_name should not be blank" }
                 }
diff --git a/kotlin/builder/src/io/bazel/kotlin/builder/tasks/jvm/OutputJarCreator.kt b/kotlin/builder/src/io/bazel/kotlin/builder/tasks/jvm/OutputJarCreator.kt
index 540f673..15c3be1 100644
--- a/kotlin/builder/src/io/bazel/kotlin/builder/tasks/jvm/OutputJarCreator.kt
+++ b/kotlin/builder/src/io/bazel/kotlin/builder/tasks/jvm/OutputJarCreator.kt
@@ -16,6 +16,7 @@
 package io.bazel.kotlin.builder.tasks.jvm
 
 import com.google.inject.ImplementedBy
+import io.bazel.kotlin.builder.utils.bazelRuleKind
 import io.bazel.kotlin.builder.utils.jars.JarCreator
 import io.bazel.kotlin.model.KotlinModel
 import java.nio.file.Paths
@@ -34,7 +35,7 @@
         ).also {
             it.addDirectory(Paths.get(command.directories.classes))
             it.addDirectory(Paths.get(command.directories.generatedClasses))
-            it.setJarOwner(command.info.label, command.info.ruleKind)
+            it.setJarOwner(command.info.label, command.info.bazelRuleKind)
             it.execute()
         }
     }
diff --git a/kotlin/builder/src/io/bazel/kotlin/builder/utils/TaskUtils.kt b/kotlin/builder/src/io/bazel/kotlin/builder/utils/TaskUtils.kt
index 55cfc0e..7003979 100644
--- a/kotlin/builder/src/io/bazel/kotlin/builder/utils/TaskUtils.kt
+++ b/kotlin/builder/src/io/bazel/kotlin/builder/utils/TaskUtils.kt
@@ -29,6 +29,8 @@
 
 val CompilationTask.Inputs.joinedClasspath: String get() = this.classpathList.joinToString(File.pathSeparator)
 
+val CompilationTask.Info.bazelRuleKind: String get() = "kt_${platform.name.toLowerCase()}_${ruleKind.name.toLowerCase()}"
+
 private fun CompilationTask.updateBuilder(
     init: (CompilationTask.Builder) -> Unit
 ): CompilationTask =