diff --git a/src/fxhnt/application/ucits_map.py b/src/fxhnt/application/ucits_map.py
index 04ee4a7..d72b11c 100644
--- a/src/fxhnt/application/ucits_map.py
+++ b/src/fxhnt/application/ucits_map.py
@@ -10,5 +10,13 @@ def apply_ucits_map(weights: dict[str, float], prices: dict[str, float],
     if missing:
         raise ValueError(f"unmapped sleeve(s) for UCITS routing: {missing} — refusing to route")
     w = {mapping[s]: v for s, v in weights.items()}
+    if len(w) < len(weights):
+        targets: dict[str, list[str]] = {}
+        for s in weights:
+            targets.setdefault(mapping[s], []).append(s)
+        colliding = {t: ss for t, ss in targets.items() if len(ss) > 1}
+        raise ValueError(
+            f"UCITS map collision(s): multiple sleeves route to the same ticker {colliding} "
+            "— refusing to silently drop a sleeve")
     p = {mapping[s]: prices[s] for s in weights}
     return w, p
diff --git a/src/fxhnt/cli.py b/src/fxhnt/cli.py
index 6c209ae..4fe5c7c 100644
--- a/src/fxhnt/cli.py
+++ b/src/fxhnt/cli.py
@@ -276,6 +276,11 @@ def execute_multistrat(
     from fxhnt.application.multistrat_exec_record import plan_and_record
     from fxhnt.domain.strategies import multistrat
 
+    if venue_kind not in ("us", "ucits"):
+        raise typer.BadParameter("--venue must be 'us' or 'ucits'")
+    if venue_kind == "ucits" and broker_name != "ibkr":
+        raise typer.BadParameter("--venue ucits requires --broker ibkr (UCITS ETFs are IBKR-only)")
+
     settings = get_settings()
     if live:
         settings.execution.allow_live = True
diff --git a/tests/unit/test_ucits_routing.py b/tests/unit/test_ucits_routing.py
index f7632c4..61f50bd 100644
--- a/tests/unit/test_ucits_routing.py
+++ b/tests/unit/test_ucits_routing.py
@@ -17,6 +17,21 @@ def test_unmapped_sleeve_refuses():
         apply_ucits_map({"SPY": 0.5, "QQQ": 0.5}, {"SPY": 1.0, "QQQ": 1.0}, MAP)
 
 
+def test_non_injective_map_raises():
+    with pytest.raises(ValueError, match="collision"):
+        apply_ucits_map({"SPY": 0.5, "VOO": 0.5}, {"SPY": 1.0, "VOO": 1.0}, {"SPY": "CSPX", "VOO": "CSPX"})
+
+
+def test_default_map_covers_all_fund_instruments():
+    """The shipped default UCITS map must cover every multistrat sleeve — a sleeve added later without a
+    UCITS mapping would fail this."""
+    from fxhnt.config import UcitsSettings
+    from fxhnt.domain.strategies.multistrat import FUND_INSTRUMENTS
+
+    default_map = UcitsSettings().map
+    apply_ucits_map({s: 1.0 for s in FUND_INSTRUMENTS}, {s: 100.0 for s in FUND_INSTRUMENTS}, default_map)
+
+
 def test_ucits_rebalancer_cronjob_yaml_suspended():
     """The UCITS CronJob ships SUSPENDED (paper-envelope routing wiring, no armed schedule yet)."""
     docs = list(yaml.safe_load_all(open("infra/k8s/jobs/fxhnt-ucits-rebalancer.yaml")))