diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 55a56a2..96e2259 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -5,6 +5,10 @@ on:
     branches: [ master ]
   pull_request:
     branches: [ master ]
+  # Manual trigger. Worth having on a self-hosted runner: when a run fails for
+  # reasons outside the repo — the runner was down, a toolchain changed — this
+  # re-runs it without an empty commit to force one.
+  workflow_dispatch:
 
 # Both jobs target a self-hosted runner, by capability rather than by hostname.
 # See tool/setup_ci_runner.sh for how that runner is provisioned and why it is