diff --git a/run.sh b/run.sh
index 0103b0cec4..6adb1f4771 100755
--- a/run.sh
+++ b/run.sh
@@ -72,12 +72,25 @@ then
   echo_success "Done"
 fi
 
+# Key values are synced to rules_java_gapic/java_gapic.bzl.
+SERVICE_CONFIG_OPT=""
+if [ -n "$FLAGS_service_config" ]
+then
+  SERVICE_CONFIG_OPT="grpc-service-config=$FLAGS_service_config"
+fi
+GAPIC_CONFIG_OPT=""
+if [ -n "$FLAGS_gapic_config" ]
+then
+  GAPIC_CONFIG_OPT="gapic-config=$FLAGS_gapic_config"
+fi
+
 # Run protoc.
 protoc -I="${PROTOC_INCLUDE_DIR}" -I="${FLAGS_googleapis}" -I="${FLAGS_protos}" \
     -I="${FLAGS_googleapis}/google/longrunning" \
+    --include_source_info \
     --plugin=bazel-bin/protoc-gen-java_gapic ${FLAGS_protos}/*.proto \
     --java_gapic_out="${FLAGS_out}" \
-    --java_gapic_opt="${FLAGS_service_config},${FLAGS_gapic_config}" \
+    --java_gapic_opt="${SERVICE_CONFIG_OPT},${GAPIC_CONFIG_OPT}" \
     --experimental_allow_proto3_optional
 
 echo_success "Output files written to ${FLAGS_out}"
diff --git a/src/main/java/com/google/api/generator/gapic/protoparser/PluginArgumentParser.java b/src/main/java/com/google/api/generator/gapic/protoparser/PluginArgumentParser.java
index d5e325e3bb..784a9ae496 100644
--- a/src/main/java/com/google/api/generator/gapic/protoparser/PluginArgumentParser.java
+++ b/src/main/java/com/google/api/generator/gapic/protoparser/PluginArgumentParser.java
@@ -22,36 +22,48 @@
 // Parses the arguments from the protoc plugin.
 public class PluginArgumentParser {
   private static final String COMMA = ",";
+  private static final String EQUALS = "=";
+
+  // Synced to rules_java_gapic/java_gapic.bzl.
+  @VisibleForTesting static final String KEY_GRPC_SERVICE_CONFIG = "grpc-service-config";
+  @VisibleForTesting static final String KEY_GAPIC_CONFIG = "gapic-config";
+
   private static final String JSON_FILE_ENDING = "grpc_service_config.json";
   private static final String GAPIC_YAML_FILE_ENDING = "gapic.yaml";
 
-  public static Optional<String> parseJsonConfigPath(CodeGeneratorRequest request) {
+  static Optional<String> parseJsonConfigPath(CodeGeneratorRequest request) {
     return parseJsonConfigPath(request.getParameter());
   }
 
-  public static Optional<String> parseGapicYamlConfigPath(CodeGeneratorRequest request) {
+  static Optional<String> parseGapicYamlConfigPath(CodeGeneratorRequest request) {
     return parseGapicYamlConfigPath(request.getParameter());
   }
 
   /** Expects a comma-separated list of file paths. */
   @VisibleForTesting
   static Optional<String> parseJsonConfigPath(String pluginProtocArgument) {
-    return parseArgument(pluginProtocArgument, JSON_FILE_ENDING);
+    return parseArgument(pluginProtocArgument, KEY_GRPC_SERVICE_CONFIG, JSON_FILE_ENDING);
   }
 
   @VisibleForTesting
   static Optional<String> parseGapicYamlConfigPath(String pluginProtocArgument) {
-    return parseArgument(pluginProtocArgument, GAPIC_YAML_FILE_ENDING);
+    return parseArgument(pluginProtocArgument, KEY_GAPIC_CONFIG, GAPIC_YAML_FILE_ENDING);
   }
 
-  private static Optional<String> parseArgument(String pluginProtocArgument, String fileEnding) {
+  private static Optional<String> parseArgument(
+      String pluginProtocArgument, String key, String fileEnding) {
     if (Strings.isNullOrEmpty(pluginProtocArgument)) {
       return Optional.<String>empty();
     }
-    for (String rawPath : pluginProtocArgument.split(COMMA)) {
-      String path = rawPath.trim();
-      if (path.endsWith(fileEnding)) {
-        return Optional.of(path);
+    for (String argComponent : pluginProtocArgument.split(COMMA)) {
+      String[] args = argComponent.trim().split(EQUALS);
+      if (args.length < 2) {
+        continue;
+      }
+      String keyVal = args[0];
+      String valueVal = args[1];
+      if (keyVal.equals(key) && valueVal.endsWith(fileEnding)) {
+        return Optional.of(valueVal);
       }
     }
     return Optional.<String>empty();
diff --git a/src/test/java/com/google/api/generator/gapic/protoparser/PluginArgumentParserTest.java b/src/test/java/com/google/api/generator/gapic/protoparser/PluginArgumentParserTest.java
index c17c3c101d..e8bbd21de9 100644
--- a/src/test/java/com/google/api/generator/gapic/protoparser/PluginArgumentParserTest.java
+++ b/src/test/java/com/google/api/generator/gapic/protoparser/PluginArgumentParserTest.java
@@ -21,10 +21,28 @@
 import org.junit.Test;
 
 public class PluginArgumentParserTest {
+
   @Test
   public void parseJsonPath_onlyOnePresent() {
     String jsonPath = "/tmp/grpc_service_config.json";
-    assertEquals(jsonPath, PluginArgumentParser.parseJsonConfigPath(jsonPath).get());
+    assertEquals(
+        jsonPath,
+        PluginArgumentParser.parseJsonConfigPath(createGrpcServiceConfig(jsonPath)).get());
+  }
+
+  @Test
+  public void parseJsonPath_returnsFirstOneFound() {
+    String jsonPathOne = "/tmp/foobar_grpc_service_config.json";
+    String jsonPathTwo = "/tmp/some_other_grpc_service_config.json";
+    assertEquals(
+        jsonPathOne,
+        PluginArgumentParser.parseJsonConfigPath(
+                String.join(
+                    ",",
+                    Arrays.asList(
+                        createGrpcServiceConfig(jsonPathOne),
+                        createGrpcServiceConfig(jsonPathTwo))))
+            .get());
   }
 
   @Test
@@ -35,11 +53,11 @@ public void parseJsonPath_similarFileAppearsFirst() {
         String.join(
             ",",
             Arrays.asList(
-                gapicPath,
-                "/tmp/something.json",
-                "/tmp/some_grpc_service_configjson",
-                jsonPath,
-                gapicPath));
+                createGapicConfig(gapicPath),
+                createGrpcServiceConfig("/tmp/something.json"),
+                createGrpcServiceConfig("/tmp/some_grpc_service_configjson"),
+                createGrpcServiceConfig(jsonPath),
+                createGapicConfig(gapicPath)));
     assertEquals(jsonPath, PluginArgumentParser.parseJsonConfigPath(rawArgument).get());
   }
 
@@ -51,11 +69,11 @@ public void parseJsonPath_argumentHasSpaces() {
         String.join(
             " , ",
             Arrays.asList(
-                gapicPath,
-                "/tmp/something.json",
-                "/tmp/some_grpc_service_configjson",
-                jsonPath,
-                gapicPath));
+                createGapicConfig(gapicPath),
+                createGrpcServiceConfig("/tmp/something.json"),
+                createGrpcServiceConfig("/tmp/some_grpc_service_configjson"),
+                createGrpcServiceConfig(jsonPath),
+                createGapicConfig(gapicPath)));
     assertEquals(jsonPath, PluginArgumentParser.parseJsonConfigPath(rawArgument).get());
   }
 
@@ -63,7 +81,8 @@ public void parseJsonPath_argumentHasSpaces() {
   public void parseJsonPath_restAreEmpty() {
     String jsonPath = "/tmp/foobar_grpc_service_config.json";
     String gapicPath = "";
-    String rawArgument = String.join(",", Arrays.asList(gapicPath, jsonPath, gapicPath));
+    String rawArgument =
+        String.join(",", Arrays.asList(gapicPath, createGrpcServiceConfig(jsonPath), gapicPath));
     assertEquals(jsonPath, PluginArgumentParser.parseJsonConfigPath(rawArgument).get());
   }
 
@@ -77,7 +96,23 @@ public void parseJsonPath_noneFound() {
   @Test
   public void parseGapicYamlPath_onlyOnePresent() {
     String gapicPath = "/tmp/something_gapic.yaml";
-    assertEquals(gapicPath, PluginArgumentParser.parseGapicYamlConfigPath(gapicPath).get());
+    assertEquals(
+        gapicPath,
+        PluginArgumentParser.parseGapicYamlConfigPath(createGapicConfig(gapicPath)).get());
+  }
+
+  @Test
+  public void parseGapicYamlPath_returnsFirstOneFound() {
+    String gapicPathOne = "/tmp/something_gapic.yaml";
+    String gapicPathTwo = "/tmp/other_gapic.yaml";
+    assertEquals(
+        gapicPathOne,
+        PluginArgumentParser.parseGapicYamlConfigPath(
+                String.join(
+                    ",",
+                    Arrays.asList(
+                        createGapicConfig(gapicPathOne), createGapicConfig(gapicPathTwo))))
+            .get());
   }
 
   @Test
@@ -86,7 +121,12 @@ public void parseGapicYamlPath_similarFileAppearsFirst() {
     String gapicPath = "/tmp/something_gapic.yaml";
     String rawArgument =
         String.join(
-            ",", Arrays.asList(jsonPath, "/tmp/something.yaml", "/tmp/some_gapicyaml", gapicPath));
+            ",",
+            Arrays.asList(
+                createGrpcServiceConfig(jsonPath),
+                createGapicConfig("/tmp/something.yaml"),
+                createGapicConfig("/tmp/some_gapicyaml"),
+                createGapicConfig(gapicPath)));
     assertEquals(gapicPath, PluginArgumentParser.parseGapicYamlConfigPath(rawArgument).get());
   }
 
@@ -94,7 +134,8 @@ public void parseGapicYamlPath_similarFileAppearsFirst() {
   public void parseGapicYamlPath_restAreEmpty() {
     String jsonPath = "";
     String gapicPath = "/tmp/something_gapic.yaml";
-    String rawArgument = String.join(",", Arrays.asList(jsonPath, gapicPath, jsonPath));
+    String rawArgument =
+        String.join(",", Arrays.asList(jsonPath, createGapicConfig(gapicPath), jsonPath));
     assertEquals(gapicPath, PluginArgumentParser.parseGapicYamlConfigPath(rawArgument).get());
   }
 
@@ -102,7 +143,16 @@ public void parseGapicYamlPath_restAreEmpty() {
   public void parseGapicYamlPath_noneFound() {
     String jsonPath = "/tmp/foo_grpc_service_config.json";
     String gapicPath = "";
-    String rawArgument = String.join(",", Arrays.asList(jsonPath, gapicPath));
+    String rawArgument =
+        String.join(",", Arrays.asList(createGrpcServiceConfig(jsonPath), gapicPath));
     assertFalse(PluginArgumentParser.parseGapicYamlConfigPath(rawArgument).isPresent());
   }
+
+  private static String createGrpcServiceConfig(String path) {
+    return String.format("%s=%s", PluginArgumentParser.KEY_GRPC_SERVICE_CONFIG, path);
+  }
+
+  private static String createGapicConfig(String path) {
+    return String.format("%s=%s", PluginArgumentParser.KEY_GAPIC_CONFIG, path);
+  }
 }