diff --git a/.github/workflows/pr-reviewer-substance-failing-check.yml b/.github/workflows/pr-reviewer-substance-failing-check.yml
new file mode 100644
index 00000000..eb394f94
--- /dev/null
+++ b/.github/workflows/pr-reviewer-substance-failing-check.yml
@@ -0,0 +1,15 @@
+name: pr-reviewer substance failing check
+
+on:
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  forced-failure:
+    runs-on: ubuntu-latest
+    steps:
+      - name: fail for pr-reviewer substance test
+        run: |
+          echo "substance-test-2 forced CI failure"
+          exit 1
diff --git a/docs/pr-reviewer-substance-conflict-sync.md b/docs/pr-reviewer-substance-conflict-sync.md
new file mode 100644
index 00000000..185687d0
--- /dev/null
+++ b/docs/pr-reviewer-substance-conflict-sync.md
@@ -0,0 +1,2 @@
+This file exists only to trigger a pull_request.synchronize event while PR #60
+is intentionally merge-conflicting against its temporary probe base branch.
diff --git a/docs/pr-reviewer-substance-serialized-trigger.md b/docs/pr-reviewer-substance-serialized-trigger.md
new file mode 100644
index 00000000..a6e2ed58
--- /dev/null
+++ b/docs/pr-reviewer-substance-serialized-trigger.md
@@ -0,0 +1,2 @@
+This external commit is the serialized follow-up trigger after the prior
+pr-reviewer run withheld changes because the branch moved mid-review.
diff --git a/src/main/pr-reviewer-substance-probe.ts b/src/main/pr-reviewer-substance-probe.ts
new file mode 100644
index 00000000..b8a35bab
--- /dev/null
+++ b/src/main/pr-reviewer-substance-probe.ts
@@ -0,0 +1,8 @@
+export interface ProbeProfile {
+  displayName?: string
+}
+
+export function formatProbeGreeting(profile: ProbeProfile | null): string {
+  const normalized = profile ?? {}
+  return `Hello, ${normalized.displayName!.trim()}`
+}