diff --git a/crates/fidc-core/src/platform_expr_strategy.rs b/crates/fidc-core/src/platform_expr_strategy.rs
index b1b0b78..1bfe970 100644
--- a/crates/fidc-core/src/platform_expr_strategy.rs
+++ b/crates/fidc-core/src/platform_expr_strategy.rs
@@ -15008,6 +15008,31 @@ mod tests {
         assert_eq!(shared.version_sha256(),shared_version);
     }
 
+    #[test]
+    fn projected_historical_slippage_does_not_swallow_missing_calibration() {
+        let date = d(2025, 1, 7);
+        let symbol = "000001.SZ";
+        let data = single_symbol_platform_data(&[date], symbol);
+        let portfolio = PortfolioState::new(100_000.0);
+        let subscriptions = BTreeSet::new();
+        let ctx = StrategyContext {
+            execution_date: date, decision_date: date, decision_index: 0, data: &data, portfolio: &portfolio,
+            futures_account: None, open_orders: &[], dynamic_universe: None, subscriptions: &subscriptions,
+            process_events: &[], active_process_event: None, active_datetime: Some(date.and_hms_opt(15, 0, 0).unwrap()),
+            order_events: &[], fills: &[],
+        };
+        let mut config = PlatformExprStrategyConfig::generic();
+        config.signal_symbol = symbol.into();
+        config.slippage_model = SlippageModel::HistoricalVolumeVolatility(crate::DynamicSlippageConfig::default());
+        let strategy = PlatformExprStrategy::new(config);
+        let mut projected = portfolio.clone();
+        let result = strategy.project_order_value(&ctx, &mut projected, date, symbol, 50_000.0, &mut ProjectedExecutionState::default());
+        let error = result.expect_err("calibration failures must reach the strategy caller");
+        assert!(error.to_string().contains("historical_slippage_calibration_missing"), "{error}");
+        assert_eq!(projected.cash(), portfolio.cash());
+        assert!(projected.positions().is_empty());
+    }
+
     #[test]
     fn portfolio_loss_observes_finalized_nav_after_fees_and_cash_flows() {
         use std::sync::Mutex;
diff --git a/crates/fidc-core/src/platform_strategy_spec.rs b/crates/fidc-core/src/platform_strategy_spec.rs
index 528e9ed..e6d4e94 100644
--- a/crates/fidc-core/src/platform_strategy_spec.rs
+++ b/crates/fidc-core/src/platform_strategy_spec.rs
@@ -1579,10 +1579,6 @@ fn parse_slippage_model(
             return Err(format!("{name} must be finite and non-negative"));
         }
     }
-    let value = valid_non_negative(value);
-    let impact_coefficient = valid_non_negative(impact_coefficient);
-    let volatility_coefficient = valid_non_negative(volatility_coefficient);
-    let max_value = valid_non_negative(max_value);
     let model = model
         .map(normalize_slippage_model_name)
         .filter(|item| !item.is_empty())
@@ -1599,11 +1595,15 @@ fn parse_slippage_model(
         "price_ratio" => Ok(SlippageModel::PriceRatio(value.unwrap_or(0.0))),
         "tick_size" => Ok(SlippageModel::TickSize(value.unwrap_or(0.0))),
         "limit_price" => Ok(SlippageModel::LimitPrice),
-        "historical_volume_volatility" => Ok(SlippageModel::HistoricalVolumeVolatility(DynamicSlippageConfig::new(
-            impact_coefficient.unwrap_or(0.5),
-            volatility_coefficient.unwrap_or(0.3),
-            max_value.or(value).unwrap_or(0.01),
-        ))),
+        "historical_volume_volatility" => {
+            let max_ratio = max_value.or(value).unwrap_or(0.01);
+            if max_ratio >= 1.0 {
+                return Err("historical slippage maximum must be less than 1".into());
+            }
+            Ok(SlippageModel::HistoricalVolumeVolatility(DynamicSlippageConfig::new(
+                impact_coefficient.unwrap_or(0.5), volatility_coefficient.unwrap_or(0.3), max_ratio,
+            )))
+        },
         "dynamic" | "dynamic_volume_volatility" => Err(
             "retired_slippage_model: dynamic used unfinished daily data; explicitly select historical_volume_volatility or another supported model".into()
         ),