diff --git a/go.mod b/go.mod
index 525ea5c..a477b9e 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,9 @@
 module github.com/google/fmtserver
 
 require (
-	github.com/bazelbuild/buildtools v0.0.0-20190404153937-93253d6efaa9 // indirect
+	github.com/bazelbuild/buildtools v0.0.0-20190405103555-895625218c56 // indirect
+	github.com/fsnotify/fsnotify v1.4.7 // indirect
 	github.com/golang/protobuf v1.3.1 // indirect
+	github.com/google/slothfs v0.0.0-20190417171004-6b42407d9230
+	golang.org/x/sys v0.0.0-20190405154228-4b34438f7a67 // indirect
 )
diff --git a/go.sum b/go.sum
index 8324bbe..abc0ccf 100644
--- a/go.sum
+++ b/go.sum
@@ -1,4 +1,16 @@
 github.com/bazelbuild/buildtools v0.0.0-20190404153937-93253d6efaa9 h1:WHyHxJd9ZTyyXqlEuheY93v4cPJLBy0SIEshPCcK0xQ=
 github.com/bazelbuild/buildtools v0.0.0-20190404153937-93253d6efaa9/go.mod h1:5JP0TXzWDHXv8qvxRC4InIazwdyDseBDbzESUMKk1yU=
+github.com/bazelbuild/buildtools v0.0.0-20190405103555-895625218c56 h1:PD9jdAihEJPtB7Slxf9MXAsVVTJBR9DQznTE65Q/bZc=
+github.com/bazelbuild/buildtools v0.0.0-20190405103555-895625218c56/go.mod h1:5JP0TXzWDHXv8qvxRC4InIazwdyDseBDbzESUMKk1yU=
+github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV9I=
+github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
 github.com/golang/protobuf v1.3.1 h1:YF8+flBXS5eO826T4nzqPrxfhQThhXl0YzfuUPu4SBg=
 github.com/golang/protobuf v1.3.1/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/google/slothfs v0.0.0-20170112234537-ecdd255f653d h1:ADHffp2KLaMypb4pG5pBJ8AezYRvGxQQ8vnH0E1K04c=
+github.com/google/slothfs v0.0.0-20170112234537-ecdd255f653d/go.mod h1:kzvK/MFjZSNdFgc1tCZML3E1nVvnB4/npSKEuvMoECU=
+github.com/google/slothfs v0.0.0-20171212170352-85e1ea13e2e1 h1:ZMkp7Df6FFzf7lXn3Yv/5/K9pLoQJXm0AxaQ2i2N0Hc=
+github.com/google/slothfs v0.0.0-20171212170352-85e1ea13e2e1/go.mod h1:kzvK/MFjZSNdFgc1tCZML3E1nVvnB4/npSKEuvMoECU=
+github.com/google/slothfs v0.0.0-20190417171004-6b42407d9230 h1:iBLrJ79cF90CZmpskySqhPvzrWr9njBYEsOZubXLZlc=
+github.com/google/slothfs v0.0.0-20190417171004-6b42407d9230/go.mod h1:kzvK/MFjZSNdFgc1tCZML3E1nVvnB4/npSKEuvMoECU=
+golang.org/x/sys v0.0.0-20190405154228-4b34438f7a67 h1:1Fzlr8kkDLQwqMP8GxrhptBLqZG/EDpiATneiZHY998=
+golang.org/x/sys v0.0.0-20190405154228-4b34438f7a67/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=