diff --git a/.github/workflows/schema-sync.yml b/.github/workflows/schema-sync.yml
index 5bf6069..7a011a8 100644
--- a/.github/workflows/schema-sync.yml
+++ b/.github/workflows/schema-sync.yml
@@ -82,6 +82,7 @@ jobs:
             git push -f origin schema-sync-auto
             if gh pr list --head schema-sync-auto --state open --json number -q '.[0].number' | grep -q .; then
               echo "::notice::Schema sync PR already open — branch refreshed."
+              echo "pr_refreshed=true" >> "$GITHUB_OUTPUT"
             else
               gh pr create --base main --head schema-sync-auto \
                 --title "chore: auto-sync schema from cvr-cortex registry" \
@@ -94,19 +95,41 @@ jobs:
         env:
           GH_TOKEN: ${{ github.token }}
 
-      # PRs opened above use the default GITHUB_TOKEN, which cannot trigger
-      # the slack-pr-notify.yml pull_request workflow (GitHub anti-recursion
-      # rule) — so announce the PR to Slack from here instead.
+      # Announce the PR from here: slack-pr-notify.yml skips bot-opened PRs
+      # (their pull_request runs park at action_required and would announce
+      # a second time on approval — observed on PR #37, 2026-08-31). A
+      # refresh (force-push to an open PR) re-parks the checks, so it
+      # notifies too (DS-1133).
       - name: Notify Slack of schema sync PR
-        if: steps.sync.outputs.pr_created == 'true'
+        if: steps.sync.outputs.pr_created == 'true' || steps.sync.outputs.pr_refreshed == 'true'
         env:
           SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
           GH_TOKEN: ${{ github.token }}
+          REFRESHED: ${{ steps.sync.outputs.pr_refreshed }}
         run: |
           pr_url=$(gh pr list --head schema-sync-auto --state open \
             --json url -q '.[0].url')
+          verb="opened"
+          if [ "$REFRESHED" = "true" ]; then verb="refreshed"; fi
           payload=$(jq -n \
-            --arg text "New PR in ${GITHUB_REPOSITORY}: <${pr_url}|chore: auto-sync schema from cvr-cortex registry> by schema-sync automation (schema-sync-auto → main)" \
+            --arg text ":arrows_counterclockwise: Schema sync PR ${verb} in ${GITHUB_REPOSITORY}: <${pr_url}|chore: auto-sync schema from cvr-cortex registry>. Its checks are parked at *action_required* — open the PR, hit *Approve and run workflows* under Checks, then merge. <@U0820C4GQ9E> <@U0574KJ4USH>" \
+            '{text: $text}')
+          curl -sf -X POST -H 'Content-type: application/json' \
+            --data "$payload" "$SLACK_WEBHOOK_URL"
+
+      # Cortex's dispatch leg only sees "queued" (204) — a failure here,
+      # e.g. an expired SLICER_READ_TOKEN, is invisible from cortex.
+      - name: Notify Slack of sync failure
+        if: failure()
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
+        run: |
+          if [ -z "$SLACK_WEBHOOK_URL" ]; then
+            echo "::warning::SLACK_WEBHOOK_URL not set — skipping Slack notification."
+            exit 0
+          fi
+          payload=$(jq -n \
+            --arg text ":x: Schema sync failed in ${GITHUB_REPOSITORY} — could not regenerate from the cortex registry. Usual cause: SLICER_READ_TOKEN expired. ${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}/actions/runs/${GITHUB_RUN_ID} <@U0820C4GQ9E> <@U0574KJ4USH>" \
             '{text: $text}')
           curl -sf -X POST -H 'Content-type: application/json' \
             --data "$payload" "$SLACK_WEBHOOK_URL"
diff --git a/.github/workflows/slack-pr-notify.yml b/.github/workflows/slack-pr-notify.yml
index 8c27196..4540f88 100644
--- a/.github/workflows/slack-pr-notify.yml
+++ b/.github/workflows/slack-pr-notify.yml
@@ -3,9 +3,13 @@ name: Slack PR notify
 # Posts to Slack when a PR opens against main. Complements the org-wide
 # GitHub Slack app subscription with an explicit, repo-specific message.
 #
-# Covers human PRs only: PRs opened by schema-sync.yml with the default
-# GITHUB_TOKEN cannot trigger pull_request workflows (GitHub anti-recursion
-# rule), so schema-sync.yml posts its own notification after `gh pr create`.
+# Covers human PRs only. PRs opened by schema-sync.yml (github-actions[bot])
+# are excluded explicitly: GitHub does NOT suppress pull_request runs for
+# bot-opened PRs — it creates them parked at action_required, and they
+# execute the moment a human hits "Approve and run workflows". Without the
+# author guard that meant a second Slack message for the same PR (observed
+# on PR #37, 2026-08-31); schema-sync.yml already announces its own PRs
+# after `gh pr create`.
 # Dependabot PRs are skipped — dependabot-triggered runs read from the
 # Dependabot secret store where SLACK_WEBHOOK_URL is not defined, and the
 # GitHub Slack app already announces them.
@@ -21,7 +25,7 @@ on:
 
 jobs:
   notify:
-    if: github.actor != 'dependabot[bot]' && !github.event.pull_request.draft
+    if: github.actor != 'dependabot[bot]' && github.event.pull_request.user.login != 'github-actions[bot]' && !github.event.pull_request.draft
     runs-on: ubuntu-latest
     steps:
       - name: Post to Slack
@@ -35,7 +39,7 @@ jobs:
           PR_BASE: ${{ github.event.pull_request.base.ref }}
         run: |
           payload=$(jq -n \
-            --arg text "New PR in ${GITHUB_REPOSITORY}: <${PR_URL}|#${PR_NUMBER} ${PR_TITLE}> by ${PR_AUTHOR} (${PR_HEAD} → ${PR_BASE})" \
+            --arg text "New PR in ${GITHUB_REPOSITORY}: <${PR_URL}|#${PR_NUMBER} ${PR_TITLE}> by ${PR_AUTHOR} (${PR_HEAD} → ${PR_BASE}) <@U0820C4GQ9E> <@U0574KJ4USH>" \
             '{text: $text}')
           curl -sf -X POST -H 'Content-type: application/json' \
             --data "$payload" "$SLACK_WEBHOOK_URL"
diff --git a/src/cognitive3dpy/_schema_generated.py b/src/cognitive3dpy/_schema_generated.py
index bedeb58..f2c2459 100644
--- a/src/cognitive3dpy/_schema_generated.py
+++ b/src/cognitive3dpy/_schema_generated.py
@@ -3,7 +3,7 @@
 DO NOT EDIT MANUALLY. Regenerate with:
     uv run python scripts/sync_schema.py
 
-Source: slicer_fields.yaml (sha256:ff76761d1595)
+Source: slicer_fields.yaml (sha256:4901ca640e47)
 """
 
 from __future__ import annotations