diff --git a/Makefile b/Makefile
index 92ea74b..675ba50 100644
--- a/Makefile
+++ b/Makefile
@@ -3,12 +3,14 @@ rwildcard=$(foreach d,$(wildcard $1*),$(call rwildcard,$d/,$2) $(filter $(subst
 
 default: ${GOPATH}/bin/hwtd ${GOPATH}/bin/hwtc
 	
-${GOPATH}/bin/hwtd: $(call rwildcard,,*.go)
+${GOPATH}/bin/hwtd: $(call rwildcard,,*.go) hwt.go
 	go install -v mcquay.me/hwt/cmd/hwtd
 
-${GOPATH}/bin/hwtc: $(call rwildcard,,*.go)
+${GOPATH}/bin/hwtc: $(call rwildcard,,*.go) hwt.go
 	go install -v mcquay.me/hwt/cmd/hwtc
 
+hwt.go: service.twirp.go service.pb.go
+
 service.twirp.go: service.proto
 	protoc --proto_path=${GOPATH}/src:. --twirp_out=. --go_out=. ./service.proto