diff --git a/scripts/claude-smoke-5endturn.sh b/scripts/claude-smoke-5endturn.sh
new file mode 100755
index 00000000..6ff76dce
--- /dev/null
+++ b/scripts/claude-smoke-5endturn.sh
@@ -0,0 +1,108 @@
+#!/usr/bin/env bash
+# p2-71 — 5-EndTurn smoke driver for the Claude Player API harness.
+#
+# Spawns claude-player-server.sh, sends 5 act:end_turn requests over stdin,
+# parses JSON-Lines responses, and prints a one-line verdict:
+#
+#   {"turns": 5, "ai_turn_completed_events": N,
+#    "actions_applied_per_turn": [...], "passed": true|false}
+#
+# Passing requires `actions_applied > 0` on every turn 1..5 for every AI slot.
+# Exits 0 on pass, 1 on fail.
+#
+# Env: CP_SEED, CP_PLAYERS (default 3), CP_CLAUDE_SLOT (default 0), CP_MAP_SIZE.
+
+set -uo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_DIR="$(dirname "$SCRIPT_DIR")"
+
+: "${CP_PLAYERS:=3}"
+: "${CP_CLAUDE_SLOT:=0}"
+: "${CP_SEED:=42}"
+: "${CP_MAP_SIZE:=duel}"
+: "${SMOKE_TURNS:=5}"
+
+export CP_PLAYERS CP_CLAUDE_SLOT CP_SEED CP_MAP_SIZE
+
+TMP=$(mktemp -d -t mc-smoke-XXXXXX)
+trap "rm -rf '$TMP'" EXIT
+
+# Build the request stream — N end_turn acts followed by shutdown.
+{
+    for i in $(seq 1 "$SMOKE_TURNS"); do
+        printf '{"type":"act","id":%d,"action":{"action":"end_turn"}}\n' "$i"
+    done
+    printf '{"type":"shutdown","id":999}\n'
+} > "$TMP/in.jsonl"
+
+# Run harness with timeout safety. 60s should be plenty for 5 turns on duel.
+timeout 90 "$SCRIPT_DIR/claude-player-server.sh" < "$TMP/in.jsonl" > "$TMP/out.jsonl" 2>"$TMP/err.log" || true
+
+# Parse — for each turn-response, count `ai_turn_completed` events and
+# sum actions_applied across slots. Output one verdict line.
+python3 - "$TMP/out.jsonl" "$SMOKE_TURNS" <<'PY'
+import json, sys
+out_path = sys.argv[1]
+n_turns = int(sys.argv[2])
+
+per_turn = []
+total_ai_events = 0
+with open(out_path) as f:
+    for line in f:
+        line = line.strip()
+        if not line:
+            continue
+        try:
+            obj = json.loads(line)
+        except Exception:
+            continue
+        if obj.get("ok") is not True:
+            continue
+        events = obj.get("events") or []
+        if not events:
+            continue
+        # Only process act-response envelopes (they have events).
+        slot_actions = {}
+        for ev in events:
+            ev_type = ev.get("event") or ev.get("type")
+            if ev_type == "ai_turn_completed":
+                total_ai_events += 1
+                slot = ev.get("player")
+                applied = ev.get("actions_applied", 0)
+                slot_actions[slot] = slot_actions.get(slot, 0) + int(applied)
+        if slot_actions:
+            per_turn.append(slot_actions)
+
+# Verdict: every turn must have ai_turn_completed events with actions_applied>0
+# on at least one slot (any non-Claude slot). Stronger requirement: every AI
+# slot on every turn > 0.
+passed = True
+reasons = []
+if len(per_turn) < n_turns:
+    passed = False
+    reasons.append(f"only {len(per_turn)} turn responses out of {n_turns}")
+for i, slot_actions in enumerate(per_turn, 1):
+    if not slot_actions:
+        passed = False
+        reasons.append(f"turn {i}: no ai_turn_completed events")
+    for slot, applied in slot_actions.items():
+        if applied <= 0:
+            passed = False
+            reasons.append(f"turn {i} slot {slot}: actions_applied={applied}")
+
+print(json.dumps({
+    "turns_observed": len(per_turn),
+    "ai_turn_completed_events": total_ai_events,
+    "actions_applied_per_turn": per_turn,
+    "passed": passed,
+    "reasons": reasons,
+}))
+sys.exit(0 if passed else 1)
+PY
+RC=$?
+if [[ $RC -ne 0 ]]; then
+    echo "--- stderr ---" >&2
+    tail -40 "$TMP/err.log" >&2 || true
+fi
+exit $RC