diff --git a/src/config/schema.rs b/src/config/schema.rs
index be6f768..3ef7c42 100644
--- a/src/config/schema.rs
+++ b/src/config/schema.rs
@@ -1613,26 +1613,23 @@ default_temperature = 0.7
 
     #[test]
     fn env_override_temperature() {
+        // Both temperature cases tested in one function to avoid env-var
+        // races when tests run in parallel.
         std::env::remove_var("ZEROCLAW_TEMPERATURE");
-        let mut config = Config::default();
 
+        // Valid temperature is applied
+        let mut config = Config::default();
         std::env::set_var("ZEROCLAW_TEMPERATURE", "0.5");
         config.apply_env_overrides();
         assert!((config.default_temperature - 0.5).abs() < f64::EPSILON);
 
-        std::env::remove_var("ZEROCLAW_TEMPERATURE");
-    }
-
-    #[test]
-    fn env_override_temperature_out_of_range_ignored() {
-        std::env::remove_var("ZEROCLAW_TEMPERATURE");
-        let mut config = Config::default();
-        let original_temp = config.default_temperature;
-
+        // Out-of-range temperature is ignored
+        let mut config2 = Config::default();
+        let original_temp = config2.default_temperature;
         std::env::set_var("ZEROCLAW_TEMPERATURE", "3.0");
-        config.apply_env_overrides();
+        config2.apply_env_overrides();
         assert!(
-            (config.default_temperature - original_temp).abs() < f64::EPSILON,
+            (config2.default_temperature - original_temp).abs() < f64::EPSILON,
             "Temperature 3.0 should be ignored (out of range)"
         );
 
diff --git a/src/security/secrets.rs b/src/security/secrets.rs
index 38a8d6a..8dea343 100644
--- a/src/security/secrets.rs
+++ b/src/security/secrets.rs
@@ -242,7 +242,7 @@ fn hex_encode(data: &[u8]) -> String {
 /// Hex-decode a hex string to bytes.
 #[allow(clippy::manual_is_multiple_of)]
 fn hex_decode(hex: &str) -> Result<Vec<u8>> {
-    if !hex.len().is_multiple_of(2) {
+    if hex.len() % 2 != 0 {
         anyhow::bail!("Hex string has odd length");
     }
     (0..hex.len())