diff --git a/crates/fidc-core/src/platform_expr_strategy.rs b/crates/fidc-core/src/platform_expr_strategy.rs
index 4a0920f..c2c6517 100644
--- a/crates/fidc-core/src/platform_expr_strategy.rs
+++ b/crates/fidc-core/src/platform_expr_strategy.rs
@@ -202,6 +202,13 @@ impl PlatformExprStrategy {
         engine.register_fn("iff", |condition: bool, when_true: Dynamic, when_false: Dynamic| {
             if condition { when_true } else { when_false }
         });
+        engine.register_fn("contains", |value: &str, needle: &str| value.contains(needle));
+        engine.register_fn("starts_with", |value: &str, prefix: &str| value.starts_with(prefix));
+        engine.register_fn("ends_with", |value: &str, suffix: &str| value.ends_with(suffix));
+        engine.register_fn("lower", |value: &str| value.to_lowercase());
+        engine.register_fn("upper", |value: &str| value.to_uppercase());
+        engine.register_fn("trim", |value: &str| value.trim().to_string());
+        engine.register_fn("strlen", |value: &str| value.chars().count() as i64);
         Self { config, engine }
     }