diff --git a/.github/actions/install-deps/action.yml b/.github/actions/install-deps/action.yml
new file mode 100644
index 000000000..aaab13d8d
--- /dev/null
+++ b/.github/actions/install-deps/action.yml
@@ -0,0 +1,71 @@
+name: 'Install dependencies'
+description: 'Install dependencies to bootstrap MLton'
+defaults:
+  run:
+runs:
+  using: "composite"
+  steps:
+    - name: Check
+      shell: 'bash'
+      run: echo "${{ matrix.runner }}"
+
+    - name: Install dependencies (ubuntu)
+      if: ${{ startsWith(runner, 'ubuntu') }}
+      shell: 'bash'
+      run: |
+        sudo apt-get update
+        sudo apt-get install libgmp-dev
+        if [[ "${{ matrix.codegen }}" == "llvm" ]]; then sudo apt-get install llvm; fi
+        mkdir boot && cd boot
+        curl -O -L https://github.com/MLton/mlton/releases/download/on-20210117-release/mlton-20210117-1.amd64-linux-glibc2.31.tgz
+        tar xzf mlton-20210117-1.amd64-linux-glibc2.31.tgz --exclude='*/share'
+        mv mlton-20210117-1.amd64-linux-glibc2.31/* .
+        rmdir mlton-20210117-1.amd64-linux-glibc2.31
+
+    - name: Install dependencies (macos (amd64))
+      if: ${{ runner == 'macos-13' }}
+      shell: 'bash'
+      run: |
+        # brew update
+        brew install -q gmp
+        echo "WITH_GMP_DIR=/usr/local" >> $GITHUB_ENV
+        if [[ "${{ matrix.codegen }}" == "llvm" ]]; then brew install llvm; echo "$(brew --prefix llvm)/bin" >> $GITHUB_PATH; fi
+        mkdir boot && cd boot
+        curl -O -L https://github.com/MLton/mlton/releases/download/on-20210117-release/mlton-20210117-1.amd64-darwin-19.6.gmp-homebrew.tgz
+        tar xzf mlton-20210117-1.amd64-darwin-19.6.gmp-homebrew.tgz --exclude='*/share'
+        mv mlton-20210117-1.amd64-darwin-19.6.gmp-homebrew/* .
+        rmdir mlton-20210117-1.amd64-darwin-19.6.gmp-homebrew
+
+    - name: Install dependencies (macos (arm64))
+      if: ${{ runner == 'macos-14' }}
+      shell: 'bash'
+      run: |
+        # brew update
+        brew install -q gmp
+        echo "WITH_GMP_DIR=/opt/homebrew" >> $GITHUB_ENV
+        if [[ "${{ matrix.codegen }}" == "llvm" ]]; then brew install llvm; echo "$(brew --prefix llvm)/bin" >> $GITHUB_PATH; fi
+        mkdir boot && cd boot
+        curl -O -L https://projects.laas.fr/tina/software/mlton-20210117-1.arm64-darwin-21.6-gmp-static.tgz
+        tar xzf mlton-20210117-1.arm64-darwin-21.6-gmp-static.tgz --exclude='*/share'
+        mv mlton-20210117-1.arm64-darwin-21.6-gmp-static/* .
+        rmdir mlton-20210117-1.arm64-darwin-21.6-gmp-static
+
+    - name: Install msys2 (windows)
+      if: ${{ startsWith(runner, 'windows') }}
+      uses: msys2/setup-msys2@v2
+      with:
+        update: false
+        install: >-
+          base-devel
+          git
+          pactoys
+    - name: Install dependencies (windows)
+      if: ${{ startsWith(runner, 'windows') }}
+      shell: 'msys2 {0}'
+      run: |
+        pacboy --noconfirm -S --needed gcc:p gmp-devel:
+        mkdir boot && cd boot
+        curl -O -L https://github.com/MLton/mlton/releases/download/on-20200817-release/mlton-20200817-amd64-mingw.tgz
+        tar xzf mlton-20200817-amd64-mingw.tgz --exclude='*/share'
+        mv mlton-20200817-amd64-mingw/* .
+        rmdir mlton-20200817-amd64-mingw
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 9c5cb0525..6e7a89c81 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,22 +13,26 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        runner: [ubuntu-24.04, macos-13, macos-14, windows-2022]
-        cc: ["gcc", "clang"]
-        codegen: ["amd64", "c", "llvm"]
-        exclude:
-          - runner: macos-13
-            cc: "gcc"
-          - runner: macos-14
-            cc: "gcc"
-          - runner: macos-14
-            codegen: "amd64"
-          - runner: windows-2022
-            cc: "clang"
-          - runner: windows-2022
-            codegen: "llvm"
-          - cc: "gcc"
-            codegen: "llvm"
+        runner: [ubuntu-24.04]
+        cc: ["gcc"]
+        codegen: ["amd64"]
+      # matrix:
+      #   runner: [ubuntu-24.04, macos-13, macos-14, windows-2022]
+      #   cc: ["gcc", "clang"]
+      #   codegen: ["amd64", "c", "llvm"]
+      #   exclude:
+      #     - runner: macos-13
+      #       cc: "gcc"
+      #     - runner: macos-14
+      #       cc: "gcc"
+      #     - runner: macos-14
+      #       codegen: "amd64"
+      #     - runner: windows-2022
+      #       cc: "clang"
+      #     - runner: windows-2022
+      #       codegen: "llvm"
+      #     - cc: "gcc"
+      #       codegen: "llvm"
 
     # The type of runner that the job will run on
     runs-on: ${{ matrix.runner }}
@@ -48,62 +52,8 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
-      - name: Install dependencies (ubuntu)
-        if: ${{ startsWith(matrix.runner, 'ubuntu') }}
-        run: |
-          sudo apt-get update
-          sudo apt-get install libgmp-dev
-          if [[ "${{ matrix.codegen }}" == "llvm" ]]; then sudo apt-get install llvm; fi
-          mkdir boot && cd boot
-          curl -O -L https://github.com/MLton/mlton/releases/download/on-20210117-release/mlton-20210117-1.amd64-linux-glibc2.31.tgz
-          tar xzf mlton-20210117-1.amd64-linux-glibc2.31.tgz --exclude='*/share'
-          mv mlton-20210117-1.amd64-linux-glibc2.31/* .
-          rmdir mlton-20210117-1.amd64-linux-glibc2.31
-
-      - name: Install dependencies (macos (amd64))
-        if: ${{ matrix.runner == 'macos-13' }}
-        run: |
-          # brew update
-          brew install -q gmp
-          echo "WITH_GMP_DIR=/usr/local" >> $GITHUB_ENV
-          if [[ "${{ matrix.codegen }}" == "llvm" ]]; then brew install llvm; echo "$(brew --prefix llvm)/bin" >> $GITHUB_PATH; fi
-          mkdir boot && cd boot
-          curl -O -L https://github.com/MLton/mlton/releases/download/on-20210117-release/mlton-20210117-1.amd64-darwin-19.6.gmp-homebrew.tgz
-          tar xzf mlton-20210117-1.amd64-darwin-19.6.gmp-homebrew.tgz --exclude='*/share'
-          mv mlton-20210117-1.amd64-darwin-19.6.gmp-homebrew/* .
-          rmdir mlton-20210117-1.amd64-darwin-19.6.gmp-homebrew
-
-      - name: Install dependencies (macos (arm64))
-        if: ${{ matrix.runner == 'macos-14' }}
-        run: |
-          # brew update
-          brew install -q gmp
-          echo "WITH_GMP_DIR=/opt/homebrew" >> $GITHUB_ENV
-          if [[ "${{ matrix.codegen }}" == "llvm" ]]; then brew install llvm; echo "$(brew --prefix llvm)/bin" >> $GITHUB_PATH; fi
-          mkdir boot && cd boot
-          curl -O -L https://projects.laas.fr/tina/software/mlton-20210117-1.arm64-darwin-21.6-gmp-static.tgz
-          tar xzf mlton-20210117-1.arm64-darwin-21.6-gmp-static.tgz --exclude='*/share'
-          mv mlton-20210117-1.arm64-darwin-21.6-gmp-static/* .
-          rmdir mlton-20210117-1.arm64-darwin-21.6-gmp-static
-
-      - name: Install msys2 (windows)
-        if: ${{ startsWith(matrix.runner, 'windows') }}
-        uses: msys2/setup-msys2@v2
-        with:
-          update: false
-          install: >-
-            base-devel
-            git
-            pactoys
-      - name: Install dependencies (windows)
-        if: ${{ startsWith(matrix.runner, 'windows') }}
-        run: |
-          pacboy --noconfirm -S --needed gcc:p gmp-devel:
-          mkdir boot && cd boot
-          curl -O -L https://github.com/MLton/mlton/releases/download/on-20200817-release/mlton-20200817-amd64-mingw.tgz
-          tar xzf mlton-20200817-amd64-mingw.tgz --exclude='*/share'
-          mv mlton-20200817-amd64-mingw/* .
-          rmdir mlton-20200817-amd64-mingw
+      - name: Install dependencies
+        uses: ./.github/actions/install-deps
 
       - name: Check versions
         run: |