diff --git a/.github/workflows/deploy-github-page.yml b/.github/workflows/deploy-github-page.yml
index 16ace823..5c07d97e 100644
--- a/.github/workflows/deploy-github-page.yml
+++ b/.github/workflows/deploy-github-page.yml
@@ -45,6 +45,7 @@ jobs:
       - name: Build and test xeus-cpp in node, then install
         shell: bash -l {0}
         run: |
+          set -e
           micromamba create -f environment-wasm-host.yml \
           --platform=emscripten-wasm32 \
           -c https://prefix.dev/emscripten-forge-4x \
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 0ed0adec..a35b8752 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -227,6 +227,7 @@ jobs:
       - name: Build and test xeus-cpp in node, then install
         shell: bash -l {0}
         run: |
+          set -e
           micromamba create -f environment-wasm-host.yml \
           --platform=emscripten-wasm32 \
           -c https://prefix.dev/emscripten-forge-4x \