diff --git a/.gitea/workflows/gates.yml b/.gitea/workflows/gates.yml
index 95731f0..3c14be2 100644
--- a/.gitea/workflows/gates.yml
+++ b/.gitea/workflows/gates.yml
@@ -16,7 +16,16 @@
 # A failing run must reach a person — a detector nobody hears is the defect R-29 filed, rebuilt one
 # layer up. That is the last step, and it runs ONLY on failure.
 name: gates
-on: [push]
+# R-1129: `workflow_dispatch` is the manual PROOF that the failure mail can be sent. A push run is
+# unchanged by it: the proof step below is skipped on a push, and `force_alarm` is then empty.
+on:
+  push:
+  workflow_dispatch:
+    inputs:
+      force_alarm:
+        description: "Fail this run on purpose so the alarm step sends its real mail (a proof, not a gate result)"
+        type: boolean
+        default: false
 
 jobs:
   gates:
@@ -45,6 +54,22 @@ jobs:
         # exit code IS the result: no `|| true`, no pipe that could swallow it.
         run: cd ws/felhom-controller/controller && python3 scripts/controller_gates.py --fast
 
+      - name: Manual proof - alarm key present, optional forced failure (dispatch only, R-1129)
+        # Runs ONLY on a manual dispatch, never on a push. It prints the key's LENGTH, never the key,
+        # so "CI can see the secret" is an observable rather than an assumption. With
+        # force_alarm=true it then fails on purpose so the alarm step below sends its real mail;
+        # the commit itself stays green, because its push run skips this step.
+        if: github.event_name == 'workflow_dispatch'
+        env:
+          RESEND_API_KEY: ${{ secrets.RESEND_API_KEY }}
+          FORCE_ALARM: ${{ github.event.inputs.force_alarm }}
+        run: |
+          python3 -c 'import os;print("RESEND_API_KEY length: %d" % len(os.environ.get("RESEND_API_KEY","")))'
+          if [ "$FORCE_ALARM" = "true" ]; then
+            echo "force_alarm=true - failing on purpose so the alarm step runs (R-1129 proof)"
+            exit 1
+          fi
+
       - name: Alarm on failure
         # THE POINT OF THE WHOLE THING. Probe P5 measured that a failed run produces NO mail, NO
         # notification row and NO log line from Gitea itself — a red tick in a web UI nobody watches
@@ -58,6 +83,8 @@ jobs:
         if: failure()
         env:
           RESEND_API_KEY: ${{ secrets.RESEND_API_KEY }}
+          # Empty on a push, so a push run's mail is exactly what it was before R-1129.
+          FORCE_ALARM: ${{ github.event.inputs.force_alarm }}
         run: |
           python3 - <<'PY'
           import json, os, sys, urllib.request, urllib.error
@@ -75,7 +102,9 @@ jobs:
           body = json.dumps({
               "from": "Felhom CI <monitoring@felhom.eu>",
               "to": ["admin@felhom.eu"],
-              "subject": "[felhom CI] gates FAILED in %s" % repo,
+              "subject": ("[felhom CI] FORCED TEST, not a real failure - gates FAILED in %s"
+                          if os.environ.get("FORCE_ALARM") == "true"
+                          else "[felhom CI] gates FAILED in %s") % repo,
               "text": (
                   "The gate entry point exited non-zero.\n\n"
                   "Repository : %s\n"
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 87a789c..dfbfce8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,12 @@
+## Unreleased (2026-10-17) — CI workflow: a manual proof that the failure mail can be sent (R-1129); no code change
+
+`.gitea/workflows/gates.yml` gains a manual `workflow_dispatch` trigger with one input, `force_alarm` (default false), and
+one step that runs ONLY on a dispatch: it prints the length of `RESEND_API_KEY` (never the key) and, with
+`force_alarm=true`, fails on purpose so the existing alarm step sends its real mail; the mail's subject then starts
+„FORCED TEST, not a real failure". A push run is unchanged: the new step is skipped and the subject is the old one. Same
+change in all four repos' workflows. Purpose: prove the failure mail now goes out after the operator set the key
+(every failed run until today ended „ALARM FAILED: RESEND_API_KEY is empty").
+
 ## v0.326.0 — FileBrowser's default password is checked at every FileBrowser start; the decoy suite is a gate (2026-10-17)
 
 **MinAgent: 0.158.1** — the floor's, carried. Nothing here calls the agent. No golden (`09` §3 decision 250). Task: