diff --git a/.github/workflows/cache-probe.yml b/.github/workflows/cache-probe.yml
index 40196616f..49b45bc60 100644
--- a/.github/workflows/cache-probe.yml
+++ b/.github/workflows/cache-probe.yml
@@ -43,6 +43,17 @@ jobs:
       - name: Install dotslash
         uses: facebook/install-dotslash@v2
 
+      # The buck2 binary itself, not build artifacts: this job deliberately
+      # clears buck-out and rebuilds cold, but re-downloading buck2 from the
+      # releases CDN is a network dependency the probe does not exist to test.
+      - name: Cache dotslash artifacts
+        uses: actions/cache@v5
+        with:
+          path: ~/.cache/dotslash
+          key: dotslash-linux-x64-${{ hashFiles('buck2') }}
+          restore-keys: |
+            dotslash-linux-x64-
+
       - name: Guard — secret present
         env:
           KEY: ${{ secrets.BUILDBUDDY_API_KEY }}
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 2134d63ac..7dc2e6bfd 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -33,6 +33,18 @@ jobs:
       - name: Install dotslash
         uses: facebook/install-dotslash@v2  # pinned: the moving `latest` branch broke macOS runners (sha256sum flags) on 2026-06-18
 
+      # Cache the dotslash-downloaded buck2 binary (see the `test` job for the
+      # rationale on which paths are worth caching).
+      - name: Cache dotslash artifacts
+        uses: actions/cache@v5
+        with:
+          path: |
+            ~/.cache/dotslash
+            ~/Library/Caches/dotslash
+          key: dotslash-linux-x64-${{ hashFiles('buck2') }}
+          restore-keys: |
+            dotslash-linux-x64-
+
       - name: Check formatting
         # Every crate emits its own `<name>-fmt-check` test from the
         # rue_crate/rue_binary macros (RUE-1153), so coverage follows the
@@ -148,6 +160,18 @@ jobs:
       - name: Install dotslash
         uses: facebook/install-dotslash@v2
 
+      # Cache the dotslash-downloaded buck2 binary (see the `test` job for the
+      # rationale on which paths are worth caching).
+      - name: Cache dotslash artifacts
+        uses: actions/cache@v5
+        with:
+          path: |
+            ~/.cache/dotslash
+            ~/Library/Caches/dotslash
+          key: dotslash-linux-x64-${{ hashFiles('buck2') }}
+          restore-keys: |
+            dotslash-linux-x64-
+
       - name: Require and provision remote execution
         env:
           BUILDBUDDY_API_KEY: ${{ secrets.BUILDBUDDY_API_KEY }}