diff --git a/crates/aldabra-mcp/src/tools.rs b/crates/aldabra-mcp/src/tools.rs
index 256bb6b..7928d07 100644
--- a/crates/aldabra-mcp/src/tools.rs
+++ b/crates/aldabra-mcp/src/tools.rs
@@ -417,6 +417,20 @@ impl WalletService {
         if lovelace == 0 {
             return Err("lovelace must be > 0".into());
         }
+        // AUDIT4-G2 fix: catch sub-min-utxo ada-only sends client-side
+        // before the chain rejects them (saves a koios round-trip + the
+        // user's mental model of "tx submitted" → "tx failed minutes later").
+        // Asset-bearing sends have a dynamic min driven by asset count +
+        // name lengths — let those reach chain so the real number is in
+        // the error.
+        let default_min = ProtocolParams::default().min_utxo_lovelace;
+        if assets.is_empty() && lovelace < default_min {
+            return Err(format!(
+                "lovelace {lovelace} below min-utxo {default_min}; \
+                 the chain would reject this output. Send ≥ {default_min} \
+                 (1 ADA), or pass assets to use the dynamic asset-aware min."
+            ));
+        }
         self.enforce_value_cap(lovelace, force)?;
 
         let utxos = self