diff --git a/build.sbt b/build.sbt
index bfc6acf..5cc119f 100644
--- a/build.sbt
+++ b/build.sbt
@@ -4,13 +4,17 @@ version := "0.1"
 
 scalaVersion := "2.12.8"
 
-libraryDependencies += "org.scalatest" %% "scalatest" % "3.0.7" % "test"
-libraryDependencies += "org.typelevel" %% "cats-effect" % "1.2.0" withSources() withJavadoc()
+// command line arguments parser
 libraryDependencies += "com.github.scopt" %% "scopt" % "4.0.0-RC2"
 
+// i/o stream processor
 libraryDependencies += "co.fs2" %% "fs2-core" % "1.0.4"
 libraryDependencies += "co.fs2" %% "fs2-io" % "1.0.4"
 
+// testing
+libraryDependencies += "org.scalatest" %% "scalatest" % "3.0.7" % "test"
+
+// recommended for cats-effects
 scalacOptions ++= Seq(
   "-feature",
   "-deprecation",