diff --git a/.github/workflows/prototyping.yml b/.github/workflows/prototyping.yml
index e2758d54..4c0329ba 100644
--- a/.github/workflows/prototyping.yml
+++ b/.github/workflows/prototyping.yml
@@ -11,6 +11,8 @@ jobs:
     strategy:
       matrix:
         agda: [2.6.2.1]
+        hackageDate: ["2022-01-31"]
+        hackageTime: ["23:42:28"]
     name: prototyping
     runs-on: ubuntu-latest
     steps:
@@ -18,7 +20,7 @@ jobs:
     - uses: actions/cache@v2
       with:
         path: ~/.cabal/store
-        key: "prototyping-${{ runner.os }}-${{ matrix.agda }}"
+        key: "prototyping-${{ runner.os }}-${{ matrix.agda }}-${{ matrix.hackageDate }}-${{ matrix.hackageTime }}"
     - uses: actions/cache@v2
       id: luau-ast-cache
       with: