diff --git a/tools/bundler.js b/tools/bundler.js
index db87c937ae..53aee9a947 100644
--- a/tools/bundler.js
+++ b/tools/bundler.js
@@ -438,6 +438,8 @@ var Target = function (options) {
   // Map from package name to package directory of all packages used.
   self.pluginProviderPackageDirs = {};
 
+  self.usedPackages = {};
+
   // node_modules directories that we need to copy into the target (or
   // otherwise make available at runtime). A map from an absolute path
   // on disk (NodeModulesDirectory.sourcePath) to a
@@ -569,12 +571,15 @@ _.extend(Target.prototype, {
       // What unibuilds will be used in the target? Built in Phase 1, read in
       // Phase 2.
       var usedUnibuilds = {};  // Map from unibuild.id to Unibuild.
-      var usedPackages = {};  // Map from package name to true;
+      self.usedPackages = {};  // Map from package name to true;
       var addToGetsUsed = function (unibuild) {
         if (_.has(usedUnibuilds, unibuild.id))
           return;
         usedUnibuilds[unibuild.id] = unibuild;
-        usedPackages[unibuild.pkg.name] = true;
+        if (unibuild.name === 'main') {
+          // Only track real packages, not plugin pseudo-packages.
+          self.usedPackages[unibuild.pkg.name] = true;
+        }
         // XXX #3006 combine
         if (isopackCache) {
           isopackCompiler.eachUsedUnibuild({
@@ -647,14 +652,14 @@ _.extend(Target.prototype, {
             arch: self.arch,
             isopackCache: isopackCache,
             skipUnordered: true,
-            acceptableWeakPackages: usedPackages,
+            acceptableWeakPackages: self.usedPackages,
             skipDebugOnly: !project.project.includeDebug
           }, processUnibuild);
         } else {
           compiler.eachUsedUnibuild(
             unibuild.uses, self.arch, packageLoader,
             { skipUnordered: true,
-              acceptableWeakPackages: usedPackages,
+              acceptableWeakPackages: self.usedPackages,
               skipDebugOnly: !project.project.includeDebug
             },
             processUnibuild);
@@ -2367,7 +2372,8 @@ exports.buildJsImage = function (options) {
   return {
     image: target.toJsImage(),
     watchSet: target.getWatchSet(),
-    pluginProviderPackageDirs: target.getPluginProviderPackageDirs()
+    pluginProviderPackageDirs: target.getPluginProviderPackageDirs(),
+    usedPackageNames: _.keys(target.usedPackages)
   };
 };
 
diff --git a/tools/isopack-compiler.js b/tools/isopack-compiler.js
index eab2921bca..ad6621dfc3 100644
--- a/tools/isopack-compiler.js
+++ b/tools/isopack-compiler.js
@@ -54,6 +54,8 @@ exports.compile = function (packageSource, options) {
   var pluginWatchSet = packageSource.pluginWatchSet.clone();
   var plugins = {};
 
+  var pluginProviderPackageNames = {};
+
   // Build plugins
   _.each(packageSource.pluginInfo, function (info) {
     buildmessage.enterJob({
@@ -76,11 +78,16 @@ exports.compile = function (packageSource, options) {
                                        'plugin', info.name)),
         catalog: packageSource.catalog
       });
+      if (buildmessage.jobHasMessages())
+        return;
 
       // Add the plugin's sources to our list.
       _.each(info.sources, function (source) {
         sources.push(source);
       });
+      _.each(buildResult.usedPackageNames, function (packageName) {
+        pluginProviderPackageNames[packageName] = true;
+      });
 
       // Add this plugin's dependencies to our "plugin dependency"
       // WatchSet. buildResult.watchSet will end up being the merged
@@ -135,8 +142,6 @@ exports.compile = function (packageSource, options) {
     debugOnly: packageSource.debugOnly
   });
 
-  var pluginProviderPackageNames = {};
-
   _.each(packageSource.architectures, function (unibuild) {
     var unibuildResult = compileUnibuild({
       isopack: isopk,
diff --git a/tools/isopack.js b/tools/isopack.js
index 1e14808f3a..b5374351ab 100644
--- a/tools/isopack.js
+++ b/tools/isopack.js
@@ -41,6 +41,7 @@ var Unibuild = function (isopack, options) {
   options = options || {};
   self.pkg = isopack;
 
+  self.name = options.name;
   self.arch = options.arch;
 
   self.uses = options.uses;
@@ -58,7 +59,7 @@ var Unibuild = function (isopack, options) {
   // to keep track of Unibuilds in a map; it's used by bundler
   // and compiler. We put some human readable info in here too to make
   // debugging easier.
-  self.id = isopack.name + "." + self.pkg.name + "@" + self.arch + "#" +
+  self.id = self.pkg.name + "." + self.name + "@" + self.arch + "#" +
     (nextBuildId ++);
 
   // Prelink output.