diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4330e104..0b35040d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -35,6 +35,9 @@ jobs:
       - name: Install cargo-llvm-cov
         uses: taiki-e/install-action@cargo-llvm-cov
 
+      - name: Configure pnpm store (per-runner isolation)
+        run: pnpm config set store-dir "$HOME/.pnpm-store-${{ runner.name }}"
+
       - name: Install dependencies
         run: pnpm install --frozen-lockfile