diff --git a/scripts/README.md b/scripts/README.md
index c476b32..6e3b118 100644
--- a/scripts/README.md
+++ b/scripts/README.md
@@ -10,7 +10,7 @@ whose identifiers will be used here.
 
 - [infinisil-test-org](https://github.com/infinisil-test-org): A GitHub organisation you're part of
 - Repositories:
-  - [infinisil-test-org/empty](https://github.com/infinisil-test-org/empty): An empty one with no activity on it
+  - [infinisil-test-org/empty](https://github.com/infinisil-test-org/empty): A repository with only one commit, not attributed to your GitHub user
   - [infinisil-test-org/active](https://github.com/infinisil-test-org/active): One where you have some activity
   - [infinisil-test-org/nixpkgs-committers](https://github.com/infinisil-test-org/nixpkgs-committers): A fork of the upstream repo
 
@@ -22,7 +22,7 @@ whose identifiers will be used here.
 Once you have the above setup (or got @infinisil to add yourself to his), you have to prepare the following:
 
 - Add some activity of yours to the `active` repo.
-  To cover all code branches it's recommended to create, push to and delete a branch.
+  To match Nixpkgs, it’s recommended to do this by setting the “Default commit message” for merge commits to “Pull request title”, then creating and merging a PR.
   You can do this from the web interface.
 - Get the GitHub CLI available (`pkgs.github-cli`) and authenticate it using `gh auth login`
 - A local Git clone of this repository with the `origin` remote set to the test repository:
diff --git a/scripts/common.sh b/scripts/common.sh
index 1cd2c42..0d91611 100755
--- a/scripts/common.sh
+++ b/scripts/common.sh
@@ -1,5 +1,7 @@
 set -euo pipefail
 
+export TZ=UTC
+
 log() {
   echo "$@" >&2
 }
diff --git a/scripts/retire.sh b/scripts/retire.sh
index 88b3f01..cf144b5 100755
--- a/scripts/retire.sh
+++ b/scripts/retire.sh
@@ -59,9 +59,16 @@ cd "$DIR"
 for login in *; do
 
   # Figure out when this person received the commit bit
-  # Get the unix epoch of the first commit that touched this file
+  # Get the unix epoch of the last commit that added this file
   # --first-parent is important to get the time of when the main branch was changed
-  fileCommitEpoch=$(git log --reverse --first-parent --format=%cd --date=unix -- "$login" | head -1)
+  fileCommitEpoch=$(git log \
+    --first-parent \
+    --no-follow \
+    --diff-filter=A \
+    --max-count=1 \
+    --format=%cd \
+    --date=unix \
+    -- "$login")
   if (( fileCommitEpoch < createdOnReceptionEpoch )); then
     # If it was created before creation actually matched the reception date
     # This branch can be removed after 2026-04-23
@@ -101,22 +108,20 @@ for login in *; do
     continue
   fi
 
-  trace gh api -X GET /repos/"$ORG"/"$ACTIVITY_REPO"/activity \
-    -f time_period=year \
-    -f actor="$login" \
+  PR_PREFIX="$ORG/$ACTIVITY_REPO" \
+  trace gh api -X GET /repos/"$ORG"/"$ACTIVITY_REPO"/commits \
+    -f since="$(date --date='1 year ago' --iso-8601=seconds)" \
+    -f author="$login" \
+    -f committer=web-flow \
     -f per_page=100 \
     --jq '.[] |
-      "- \(.timestamp) [\(.activity_type) on \(.ref | ltrimstr("refs/heads/"))](https://github.com/'"$ORG/$ACTIVITY_REPO"'/\(
-        if .activity_type == "branch_creation" then
-          "commit/\(.after)"
-        elif .activity_type == "branch_deletion" then
-          "commit/\(.before)"
-        else
-          "compare/\(.before)...\(.after)"
-        end
-      ))"' \
+      # PR merge commits have two parents. We also check it’s an
+      # authentic GitHub commit, because… why not?
+      select((.parents | length) == 2 and .commit.verification.verified) |
+      (.commit.message | capture(" \\((?<pr>#[0-9]+)\\)$").pr) as $pr |
+      "- `\(.commit.committer.date)` – \(env.PR_PREFIX)\($pr)"' \
     > "$tmp/$login"
-  activityCount=$(wc -l <"$tmp/$login")
+  mergeCount=$(wc -l <"$tmp/$login")
 
   if [[ "$prState" == open ]]; then
     # If there is an open PR already
@@ -126,7 +131,7 @@ for login in *; do
       log "$login has a retirement PR due, unmarking PR as draft and commenting with next steps"
       effect gh pr ready --repo "$ORG/$MEMBER_REPO" "$prNumber"
       {
-        if (( activityCount > 0 )); then
+        if (( mergeCount > 0 )); then
           echo "One month has passed, and @$login has been active again:"
           cat "$tmp/$login"
           echo ""
@@ -151,7 +156,7 @@ for login in *; do
     else
       log "$login has a retirement PR pending"
     fi
-  elif (( activityCount <= 0 )); then
+  elif (( mergeCount <= 0 )); then
     log "$login has become inactive, opening a PR"
     # If there is no PR yet, but they have become inactive
     (
@@ -185,7 +190,7 @@ for login in *; do
         -f "labels[]=retirement" >/dev/null
     )
   else
-    log "$login is active with $activityCount activities"
+    log "$login is active with $mergeCount merges"
   fi
   log ""
 done