diff --git a/packages/core/src/validation.test.ts b/packages/core/src/validation.test.ts
index 85fefb47..1bd89c5d 100644
--- a/packages/core/src/validation.test.ts
+++ b/packages/core/src/validation.test.ts
@@ -152,6 +152,16 @@ describe("builtInValidationFunctions", () => {
       expect(builtInValidationFunctions.numeric(NaN)).toBe(false);
       expect(builtInValidationFunctions.numeric(null)).toBe(false);
     });
+
+    it("fails for strings with trailing non-numeric characters", () => {
+      expect(builtInValidationFunctions.numeric("123abc")).toBe(false);
+      expect(builtInValidationFunctions.numeric("99bottles")).toBe(false);
+    });
+
+    it("fails for empty and whitespace-only strings", () => {
+      expect(builtInValidationFunctions.numeric("")).toBe(false);
+      expect(builtInValidationFunctions.numeric("   ")).toBe(false);
+    });
   });
 
   describe("url", () => {
diff --git a/packages/core/src/validation.ts b/packages/core/src/validation.ts
index fd9c20e8..848870a1 100644
--- a/packages/core/src/validation.ts
+++ b/packages/core/src/validation.ts
@@ -153,7 +153,9 @@ export const builtInValidationFunctions: Record<string, ValidationFunction> = {
    */
   numeric: (value: unknown) => {
     if (typeof value === "number") return !isNaN(value);
-    if (typeof value === "string") return !isNaN(parseFloat(value));
+    if (typeof value === "string") {
+      return value.trim() !== "" && !isNaN(Number(value));
+    }
     return false;
   },