diff --git a/Makefile b/Makefile
index a0c22bc..87e87c4 100644
--- a/Makefile
+++ b/Makefile
@@ -43,7 +43,7 @@ export DOCKER_HOST := unix://$(PODMAN_SOCK)
 endif
 endif
 
-.PHONY: ci lint build unit mutation frontend integration verify verify-up verify-acl verify-nrc verify-projection verify-bff verify-domain verify-notifications smoke up down local verify-local local-down changelog openzaak-up openzaak-smoke openzaak-seed openzaak-down stack-up stack-smoke stack-down keycloak-up keycloak-smoke keycloak-down flowable-up flowable-smoke flowable-down help
+.PHONY: ci lint build unit mutation frontend integration verify verify-up verify-acl verify-nrc verify-projection verify-bff verify-domain verify-observability verify-notifications smoke up down local verify-local local-down changelog openzaak-up openzaak-smoke openzaak-seed openzaak-down stack-up stack-smoke stack-down keycloak-up keycloak-smoke keycloak-down flowable-up flowable-smoke flowable-down help
 
 ## ci: run the full pipeline — lint, build, unit, mutation, frontend, verify (mirrors Gitea Actions)
 ## `verify` is the live-stack stage (full stack up once → ACL + notification checks).
@@ -170,6 +170,11 @@ verify-bff:
 verify-e2e:
 	bash infra/run-e2e-check.sh
 
+## verify-observability: assert the observability backplane (Grafana + provisioned Tempo &
+## Prometheus datasources) is live, against the already-running stack (S-16a).
+verify-observability:
+	bash infra/run-observability-check.sh
+
 ## verify: local mirror of the CI verify-stack job — full stack up once, all checks,
 ## tear down (always). For fast single-concern local iteration use `integration`
 ## (oz-only) or `verify-notifications` (oz+nrc) instead.
diff --git a/infra/run-observability-check.sh b/infra/run-observability-check.sh
new file mode 100755
index 0000000..69b7be5
--- /dev/null
+++ b/infra/run-observability-check.sh
@@ -0,0 +1,35 @@
+#!/usr/bin/env bash
+#
+# S-16a (#122): assert the observability backplane is live against the running stack.
+# Not just "the containers started" — it asks Grafana to health-check its provisioned
+# Tempo and Prometheus datasources, which proves Grafana can actually reach both over
+# the `cg` network and that provisioning landed. Polls, so it tolerates a cold Grafana.
+#
+# Usage: run-observability-check.sh   (override GRAFANA_URL / GRAFANA_AUTH / OBS_TIMEOUT)
+set -euo pipefail
+
+GRAFANA="${GRAFANA_URL:-http://localhost:3000}"
+AUTH="${GRAFANA_AUTH:-admin:admin}"
+TIMEOUT="${OBS_TIMEOUT:-60}"
+
+# poll <description> <url> <json-path-expr> <expected>
+poll() {
+  local desc="$1" url="$2" path="$3" want="$4" got deadline
+  deadline=$(( $(date +%s) + TIMEOUT ))
+  while :; do
+    got="$(curl -fsS -u "$AUTH" "$url" 2>/dev/null \
+      | python3 -c "import sys,json;print(json.load(sys.stdin)$path)" 2>/dev/null || true)"
+    [ "$got" = "$want" ] && { echo "  ✓ $desc"; return 0; }
+    if [ "$(date +%s)" -ge "$deadline" ]; then
+      echo "  ✗ $desc — got '$got', want '$want' ($url)" >&2
+      return 1
+    fi
+    sleep 2
+  done
+}
+
+echo "Checking observability backplane at $GRAFANA ..."
+poll "Grafana is healthy"               "$GRAFANA/api/health"                             "['database']" "ok"
+poll "Prometheus datasource reachable"  "$GRAFANA/api/datasources/uid/prometheus/health"  "['status']"   "OK"
+poll "Tempo datasource reachable"       "$GRAFANA/api/datasources/uid/tempo/health"       "['status']"   "OK"
+echo "Observability backplane OK."