From root directory of repo: GOPATH=$PWD goapp serve app/app.yaml This repo was created with: GOPATH=$PWD goapp get golang.org/x/tools/cmd/present > # golang.org/x/tools/cmd/present > runtime.main_main: main.main: not defined > runtime.main_main: undefined: main.main cp -R src/golang.org/x/tools/cmd/present app/present