diff --git a/go.mod b/go.mod
index a5a140f..bab097a 100644
--- a/go.mod
+++ b/go.mod
@@ -2,7 +2,4 @@ module github.com/acomagu/bufpipe
 
 go 1.12
 
-require (
-	github.com/matryer/is v1.2.0
-	golang.org/x/tools v0.0.0-20190617190820-da514acc4774 // indirect
-)
+require github.com/matryer/is v1.2.0
diff --git a/go.sum b/go.sum
index 6145721..6378c9b 100644
--- a/go.sum
+++ b/go.sum
@@ -1,10 +1,2 @@
 github.com/matryer/is v1.2.0 h1:92UTHpy8CDwaJ08GqLDzhhuixiBUUD1p3AU6PHddz4A=
 github.com/matryer/is v1.2.0/go.mod h1:2fLPjFQM9rhQ15aVEtbuwhJinnOqrmgXPNdZsdwlWXA=
-golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
-golang.org/x/net v0.0.0-20190311183353-d8887717615a h1:oWX7TPOiFAMXLq8o0ikBYfCJVlRHBcsciT5bXOrH628=
-golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
-golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
-golang.org/x/tools v0.0.0-20190617190820-da514acc4774 h1:CQVOmarCBFzTx0kbOU0ru54Cvot8SdSrNYjZPhQl+gk=
-golang.org/x/tools v0.0.0-20190617190820-da514acc4774/go.mod h1:/rFqwRUd4F7ZHNgwSSTFct+R/Kf4OFW1sUzUTQQTgfc=