diff --git a/knowledge/runbooks/hermes-triage-demo.md b/knowledge/runbooks/hermes-triage-demo.md
index 2dc292a9c..4374d0d8e 100644
--- a/knowledge/runbooks/hermes-triage-demo.md
+++ b/knowledge/runbooks/hermes-triage-demo.md
@@ -36,6 +36,15 @@ curl -u <user>:<token> -X POST \
 
 That is the only manual step. Everything after the red build is automatic.
 
+Run `scripts/ops/hermes_triage_demo.sh preflight` first. The check that most
+often decides whether a rehearsal holds its timings is the agent pool: the
+Kubernetes cloud caps concurrent agent pods at `containerCapStr: "5"`, and when
+real CI has taken all five the demo build sits in the queue reporting *"All
+nodes of label ... are offline"* with no other symptom. Observed 2026-08-06: a
+run armed at 02:13:42 did not start seeding until 02:19:37, close to six
+minutes of dead air, purely because five other builds held the pool. Wait for a
+free slot before starting, or quiesce CI.
+
 ## Expected timings (measured live, first full loop 2026-08-05)
 
 - Armed → seeded build red: **1m49s** (mostly agent-pod scheduling; longer