diff --git a/specs/agents/metadata.md b/specs/agents/metadata.md
index 0959594e..b22df0d8 100644
--- a/specs/agents/metadata.md
+++ b/specs/agents/metadata.md
@@ -110,7 +110,7 @@ On Linux, the container ID and some of the Kubernetes metadata can be extracted
 
     - `^[[:xdigit:]]{64}$`
     - `^[[:xdigit:]]{8}-[[:xdigit:]]{4}-[[:xdigit:]]{4}-[[:xdigit:]]{4}-[[:xdigit:]]{4,}$`
-    - `^[[:xdigit:]]{32}-[[:digit:]]{10}$` (AWS ECS/Fargate environments)
+    - `^[[:xdigit:]]{32}-[[:digit:]]{9,10}$` (AWS ECS/Fargate environments)
 
  If we match, then the basename is assumed to be a container ID.