diff --git a/.github/workflows/ci.cli.yml b/.github/workflows/ci.cli.yml
index e98d5523..a79f54db 100644
--- a/.github/workflows/ci.cli.yml
+++ b/.github/workflows/ci.cli.yml
@@ -53,6 +53,8 @@ jobs:
       - run: bin/bk test
       - run: test $(pkgx +stark.com/foo -- stark) = not_much_u
       - run: bin/bk audit
+      # check build can run twice, see https://github.com/pkgxdev/brewkit/issues/303
+      - run: bin/bk build
 
 
   unit-tests:
diff --git a/build/build.ts b/build/build.ts
index 8ff8d07c..175b6ec2 100755
--- a/build/build.ts
+++ b/build/build.ts
@@ -168,7 +168,8 @@ function make_toolchain() {
   }
 
   if (host().platform != "darwin") {
-    const d = config.path.home.join('toolchain').mkdir('p')
+    // rm ∵ // https://github.com/pkgxdev/brewkit/issues/303
+    const d = config.path.home.join('toolchain').rm({ recursive: true }).mkdir('p')
 
     const symlink = (names: string[], {to}: {to: string}) => {
       for (const name of names) {