diff --git a/.kiro/specs/ha-config-bootstrap/manual-tests.md b/.kiro/specs/ha-config-bootstrap/manual-tests.md
index 1831100..c0a3398 100644
--- a/.kiro/specs/ha-config-bootstrap/manual-tests.md
+++ b/.kiro/specs/ha-config-bootstrap/manual-tests.md
@@ -97,13 +97,13 @@ The controller looks for config at:
 {workdir}/{myname}/conf/cluster.bin.<hex_tag>      ← capnp config blob
 ```
 
-The `<hex_tag>` is the first 16 hex chars of the SHA-256 of the config blob
-(= first 8 bytes).
+The `<hex_tag>` is the first **12 hex chars** of the SHA-256 of the config blob
+(= first 6 bytes). The controller validates exactly 12 lowercase hex characters.
 
 **Install config on Node A only:**
 
 ```bash
-TAG=$(sha256sum /path/to/your_config.bin | awk '{print $1}' | cut -c1-16)
+TAG=$(sha256sum /path/to/your_config.bin | awk '{print $1}' | cut -c1-12)
 echo "Config tag: $TAG"
 
 CONF_DIR="/tmp/xce-a/ctrl-a/conf"