diff --git a/crates/fidc-core/src/platform_strategy_spec.rs b/crates/fidc-core/src/platform_strategy_spec.rs
index df947d4..5d49047 100644
--- a/crates/fidc-core/src/platform_strategy_spec.rs
+++ b/crates/fidc-core/src/platform_strategy_spec.rs
@@ -364,6 +364,55 @@ fn parse_policy_bool(canonical: &str, value: Value) -> Result<bool, String> {
     }
 }
 
+fn policy_value_semantically_equals(canonical: &str, left: &Value, right: &Value) -> bool {
+    if left == right {
+        return true;
+    }
+    if let (Some(left_number), Some(right_number)) =
+        (policy_value_as_number(left), policy_value_as_number(right))
+    {
+        if canonical == "volumePercent" {
+            return (normalize_percent_ratio_for_alias_compare(left_number)
+                - normalize_percent_ratio_for_alias_compare(right_number))
+            .abs()
+                < 1e-12;
+        }
+        return (left_number - right_number).abs() < 1e-12;
+    }
+    if let (Some(left_text), Some(right_text)) = (left.as_str(), right.as_str()) {
+        return left_text.trim() == right_text.trim();
+    }
+    false
+}
+
+fn normalize_percent_ratio_for_alias_compare(value: f64) -> f64 {
+    if value > 1.0 { value / 100.0 } else { value }
+}
+
+fn policy_value_as_number(value: &Value) -> Option<f64> {
+    match value {
+        Value::Number(number) => number.as_f64(),
+        Value::String(text) => text.trim().parse::<f64>().ok(),
+        _ => None,
+    }
+}
+
+fn reject_conflicting_policy_values(canonical: &str, values: &[Value]) -> Result<(), String> {
+    let Some(first) = values.first() else {
+        return Ok(());
+    };
+    if values
+        .iter()
+        .skip(1)
+        .any(|value| !policy_value_semantically_equals(canonical, first, value))
+    {
+        return Err(format!(
+            "riskPolicy.{canonical} has conflicting alias values"
+        ));
+    }
+    Ok(())
+}
+
 fn push_blacklist_symbols_from_str(
     raw: &str,
     symbols: &mut Vec<Value>,
@@ -384,17 +433,25 @@ fn normalize_risk_policy_object_aliases(
     for (canonical, aliases) in RISK_POLICY_BOOL_ALIAS_GROUPS {
         let values = remove_policy_alias_values(object, canonical, aliases);
         if !values.is_empty() {
-            let mut merged = false;
+            let mut parsed_values = Vec::with_capacity(values.len());
             for value in values {
-                merged |= parse_policy_bool(canonical, value)?;
+                parsed_values.push(parse_policy_bool(canonical, value)?);
             }
-            object.insert((*canonical).to_string(), Value::Bool(merged));
+            let first = parsed_values[0];
+            if parsed_values.iter().any(|value| *value != first) {
+                return Err(format!(
+                    "riskPolicy.{canonical} has conflicting alias values"
+                ));
+            }
+            object.insert((*canonical).to_string(), Value::Bool(first));
         }
     }
 
     for (canonical, aliases) in RISK_POLICY_VALUE_ALIAS_GROUPS {
         let values = remove_policy_alias_values(object, canonical, aliases);
-        if let Some(value) = values.into_iter().next() {
+        if !values.is_empty() {
+            reject_conflicting_policy_values(canonical, &values)?;
+            let value = values.into_iter().next().expect("non-empty values");
             object.insert((*canonical).to_string(), value);
         }
     }
@@ -2423,6 +2480,63 @@ mod tests {
         );
     }
 
+    #[test]
+    fn accepts_equivalent_risk_policy_alias_values() {
+        let spec = serde_json::json!({
+            "engineConfig": {
+                "riskPolicy": {
+                    "rejectStBuy": false,
+                    "reject_st_buy": 0,
+                    "volumePercent": 0.25,
+                    "volume_percent": 25,
+                    "minimumCommission": 5,
+                    "minimum_commission": "5"
+                }
+            }
+        });
+
+        let cfg = platform_expr_config_from_value("", "", &spec).expect("config");
+
+        assert!(!cfg.risk_config.static_rules.reject_st_buy);
+        assert!((cfg.risk_config.trading_constraints.volume_percent - 0.25).abs() < 1e-12);
+        assert_eq!(cfg.risk_config.trading_constraints.minimum_commission, 5.0);
+    }
+
+    #[test]
+    fn rejects_conflicting_risk_policy_alias_values() {
+        let bool_conflict = serde_json::json!({
+            "engineConfig": {
+                "riskPolicy": {
+                    "rejectStBuy": false,
+                    "reject_st_buy": true
+                }
+            }
+        });
+        let bool_error = platform_expr_config_from_value("", "", &bool_conflict)
+            .expect_err("conflicting bool aliases must fail");
+        assert!(
+            bool_error
+                .to_string()
+                .contains("riskPolicy.rejectStBuy has conflicting alias values")
+        );
+
+        let value_conflict = serde_json::json!({
+            "engineConfig": {
+                "riskPolicy": {
+                    "minimumCommission": 5,
+                    "minimum_commission": 6
+                }
+            }
+        });
+        let value_error = platform_expr_config_from_value("", "", &value_conflict)
+            .expect_err("conflicting value aliases must fail");
+        assert!(
+            value_error
+                .to_string()
+                .contains("riskPolicy.minimumCommission has conflicting alias values")
+        );
+    }
+
     #[test]
     fn parses_execution_slippage_overrides_into_platform_config() {
         let spec = serde_json::json!({