diff --git a/services/mam-api/src/db/migrations/031-cluster-nodes-last-seen.sql b/services/mam-api/src/db/migrations/031-cluster-nodes-last-seen.sql
new file mode 100644
index 0000000..1dd0ab0
--- /dev/null
+++ b/services/mam-api/src/db/migrations/031-cluster-nodes-last-seen.sql
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+-- Migration 031 — Add last_seen_at to cluster_nodes
+--
+-- Playout failover (routes/playout.js restartChannel) queries cluster_nodes.last_seen_at
+-- to find healthy nodes for channel re-placement. Column was missing from original
+-- cluster schema; heartbeat endpoint updates it via /cluster/heartbeat.
+
+ALTER TABLE cluster_nodes ADD COLUMN IF NOT EXISTS last_seen_at TIMESTAMPTZ;
+
+-- Backfill existing nodes to NOW() so they're immediately eligible for failover
+UPDATE cluster_nodes SET last_seen_at = NOW() WHERE last_seen_at IS NULL;