diff --git a/script/theme-watcher b/script/theme-watcher
index 55ba802ddb1..d8aa9d9c44f 100755
--- a/script/theme-watcher
+++ b/script/theme-watcher
@@ -11,6 +11,7 @@ require 'net/http'
 require 'net/http/post/multipart'
 require 'uri'
 require 'listen'
+require 'json'
 
 # Work in progress theme watcher for Discourse
 #
@@ -21,13 +22,31 @@ def usage
   exit 1
 end
 
+WATCHER_SETTINGS_FILE = File.expand_path("~/.discourse-theme-watcher")
+
 $api_key = ENV['DISCOURSE_API_KEY']
 $dir = ARGV[0]
 $site = ARGV[1]
 
+if $site !~ /https?:\/\//i
+  $site = "http://#{$site}"
+end
+
+puts "Watching #{$dir} and uploading changes to #{$site}"
+
+if !$api_key && File.exist?(WATCHER_SETTINGS_FILE)
+  $api_key = File.read(WATCHER_SETTINGS_FILE).strip
+  puts "Using previously stored api key in #{WATCHER_SETTINGS_FILE}"
+end
+
 if !$api_key
   puts "No API key found in DISCOURSE_API_KEY env var enter your API key: "
-  $api_key = gets
+  $api_key = STDIN.gets.strip
+  puts "Would you like me to store this API key in #{WATCHER_SETTINGS_FILE}? (Yes|No)"
+  answer = STDIN.gets.strip
+  if answer =~ /y(es)?/i
+    File.write WATCHER_SETTINGS_FILE, $api_key
+  end
 end
 
 if !File.exist?("#{$dir}/about.json")
@@ -53,6 +72,23 @@ ensure
   sgz.close
 end
 
+def diagnose_errors(text)
+  count = 0
+  json = JSON.parse(text)
+  json["theme"]["theme_fields"].each do |row|
+    if (error = row["error"]) && error.length > 0
+      if count == 0
+        puts
+      end
+      count += 1
+      puts
+      puts "Error in #{row["target"]} #{row["name"]}} : #{row["error"]}"
+      puts
+    end
+  end
+  count
+end
+
 def upload_full_theme(dir, site)
   filename = "#{Pathname.new(Dir.tmpdir).realpath}/bundle_#{SecureRandom.hex}.tar.gz"
   compress_dir(filename, dir)
@@ -67,7 +103,11 @@ def upload_full_theme(dir, site)
       "bundle" => UploadIO.new(tgz, "application/tar+gzip", "bundle.tar.gz"),
     )
     response = http.request(request)
-    p response.code
+    if response.code.to_i == 201
+      if diagnose_errors(response.body) == 0
+        puts "(done)"
+      end
+    end
   end
 
 ensure
@@ -76,9 +116,19 @@ end
 
 upload_full_theme($dir, $site)
 
+def resolve_file(path)
+end
+
 listener = Listen.to($dir) do |modified, added, removed|
-  puts "Change detected"
-  upload_full_theme($dir, $site)
+  if modified.length == 1 &&
+      added.length == 0 &&
+      removed.length == 0 &&
+      (target, name = resolve_file(modified[0]))
+    print "Updating #{target} #{name}"
+  else
+    print "Full re-sync is required, re-uploading theme"
+    upload_full_theme($dir, $site)
+  end
 end
 
 listener.start