diff --git a/.github/workflows/flake-update.yml b/.github/workflows/flake-update.yml
index a4ff4c5..535bcac 100644
--- a/.github/workflows/flake-update.yml
+++ b/.github/workflows/flake-update.yml
@@ -7,7 +7,6 @@ on:
 jobs:
   createPullRequest:
     runs-on: ubuntu-latest
-    # if: github.ref == 'refs/heads/main' # ensure workflow_dispatch only runs on main
     steps:
       - uses: actions/checkout@v4
       # - name: Login to Docker Hub
@@ -21,13 +20,6 @@ jobs:
           extra_nix_config: |
             experimental-features = nix-command flakes
           install_url: https://releases.nixos.org/nix/nix-2.19.0/install
-      - name: Setup Attic cache
-        uses: ryanccn/attic-action@v0
-        with:
-          endpoint: ${{ secrets.ATTIC_ENDPOINT }}
-          cache: ${{ secrets.ATTIC_CACHE }}
-          token: ${{ secrets.ATTIC_TOKEN }}
-          skip-push: "true"
       - name: Calculate pre-drv
         run: nix run git+https://nayeonie.com/ahuston-0/flake-update-diff -- --build .
       # - name: Pull latest docker images
@@ -70,12 +62,21 @@ jobs:
       #       automated
   update_lockfile:
     runs-on: ubuntu-latest
+    if: github.ref == 'refs/heads/main' # ensure workflow_dispatch only runs on main
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
       - name: Install nix
         uses: https://github.com/DeterminateSystems/nix-installer-action@main
-
+      - name: Setup Attic cache
+        uses: ryanccn/attic-action@v0
+        with:
+          endpoint: ${{ secrets.ATTIC_ENDPOINT }}
+          cache: ${{ secrets.ATTIC_CACHE }}
+          token: ${{ secrets.ATTIC_TOKEN }}
+          skip-push: "true"
+      - name: Get pre-snapshot of evaluations
+        run: nix ./utils/eval-to-drv.sh pre
       - name: Update flake.lock
         id: update
         run: |
@@ -90,7 +91,18 @@ jobs:
           echo "EOF" >> $GITHUB_ENV
 
           rm update.log
-
+      - name: Get post-snapshot of evaluations
+        run: nix ./utils/eval-to-drv.sh post
+      - name: Calculate diff
+        run: nix ./utils/diff-evals.sh
+      - name: Read diff into environment
+        run: |
+          delimiter="$(openssl rand -hex 8)"
+          {
+          echo "POSTDIFF<<${delimiter}"
+          cat post-diff
+          echo "${delimiter}"
+          } >> $GITHUB_ENV
       - name: Write PR body template
         uses: https://github.com/DamianReeves/write-file-action@v1.3
         with:
@@ -102,10 +114,14 @@ jobs:
             ${{ env.UPDATE_LOG }}
             ```
 
+            ```
+            {{ env.POSTDIFF }}
+            ```
+
             Auto-generated by [update.yml][1] with the help of
             [create-pull-request][2].
 
-            [1]: https://forgejo.stefka.eu/jiriks74/nix.nvim/src/branch/main/.github/workflows/update.yml
+            [1]: https://nayeonie.com/ahuston-0/nix-dotfiles/src/branch/main/.github/workflows/flake-update.yml
             [2]: https://forgejo.stefka.eu/jiriks74/create-pull-request
 
       - name: Generate PR body
@@ -123,6 +139,9 @@ jobs:
         run: |
           rm pr_body.template
           rm pr_body.md
+          rm pre.json
+          rm post.json
+          rm post-diff
 
       - name: Create Pull Request
         id: create-pull-request
@@ -140,6 +159,9 @@ jobs:
 
           branch: update-flake-lock
           delete-branch: true
+          pr-labels: |                  # Labels to be set on the PR
+            dependencies
+            automated
       - name: Push to Attic
         run: nix ./utils/attic-push.bash
         continue-on-error: true
diff --git a/utils/diff-evals.sh b/utils/diff-evals.sh
index 1ee6cd1..950699d 100755
--- a/utils/diff-evals.sh
+++ b/utils/diff-evals.sh
@@ -10,15 +10,4 @@ set -e
 script_path=$(dirname "$(readlink -f $0)")
 parent_path=$(dirname "$script_path")
 
-readarray -t pre_drv < "$parent_path/pre-drv"
-readarray -t post_drv < "$parent_path/post-drv"
-
-post_drv_path="$parent_path/post-diff"
-# cleanup any files with the same name
-rm "$post_drv_path" || true
-touch "$post_drv_path"
-
-for i in $(seq 0 $(( "${#pre_drv[@]}" -1 ))); do
-    echo "Diffing updates to $(echo "${pre_drv[$i]}" | cut -f 2- -d '-')" >> "$post_drv_path"
-    nvd diff "${pre_drv[$i]}" "${post_drv[$i]}" >> "$post_drv_path"
-done
+nix run git+https://nayeonie.com/ahuston-0/flake-update-diff -- --compare-drvs "$parent_path"
diff --git a/utils/eval-to-drv.sh b/utils/eval-to-drv.sh
index 8841f96..81a06cc 100755
--- a/utils/eval-to-drv.sh
+++ b/utils/eval-to-drv.sh
@@ -14,9 +14,6 @@ fi
 
 script_path=$(dirname "$(readlink -f $0)")
 parent_path=$(dirname "$script_path")
-out_path="$parent_path/$1-drv"
+out_path="$parent_path/$1.json"
 
-
-drv=$(nix flake check --verbose 2> >(grep -P -o "derivation evaluated to (/nix/store/.*\.drv)" | grep -P -o "/nix/store/.*\.drv"))
-
-echo "$drv" > "$out_path"
+nix run git+https://nayeonie.com/ahuston-0/flake-update-diff -- --evaluate --json "$out_path" "$parent_path"