diff --git a/deploy/run-production-canary.sh b/deploy/run-production-canary.sh
index 9f7756a..fca8e4b 100644
--- a/deploy/run-production-canary.sh
+++ b/deploy/run-production-canary.sh
@@ -68,10 +68,7 @@ JSON
 fi
 
 curl -fsS --max-time 10 -X POST "$SUPERVISOR_CONTROL_URL/v1/releases/start-set" -H 'Content-Type: application/json' --data "$release_json" >/dev/null || fail_rollback
-observation=$(cat <<JSON
-{"release_id":"candidate-$REVISION","ready":true,"reason":"all ReleaseSet healthchecks and image revisions passed","observed_at_unix_millis":$(date +%s%3N),"components":{"creator-web":{"revision":"$REVISION","health":true,"ready":true},"core-runtime":{"revision":"$REVISION","health":true,"ready":true},"cognitive-worker":{"revision":"$REVISION","health":true,"ready":true},"research-runtime":{"revision":"$REVISION","health":true,"ready":true}}}
-JSON
-)
+observation=$(printf '{"release_id":"candidate-%s","ready":true,"reason":"all ReleaseSet healthchecks and image revisions passed","observed_at_unix_millis":%s,"components":{"creator-web":{"revision":"%s","health":true,"ready":true},"core-runtime":{"revision":"%s","health":true,"ready":true},"cognitive-worker":{"revision":"%s","health":true,"ready":true},"research-runtime":{"revision":"%s","health":true,"ready":true}}}\n' "$REVISION" "$(date +%s%3N)" "$REVISION" "$REVISION" "$REVISION" "$REVISION")
 curl -fsS --max-time 10 -X POST "$SUPERVISOR_CONTROL_URL/v1/releases/observe-set" -H 'Content-Type: application/json' --data "$observation" >/dev/null || fail_rollback
 control /v1/traffic/canary || fail_rollback